Journal articles on the topic 'Weather Effect of mountains on Mathematical models'
To see the other types of publications on this topic, follow the link: Weather Effect of mountains on Mathematical models.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Weather Effect of mountains on Mathematical models.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Lindner, André, Francois Jost, Mariana Vidal Merino, Natalia Reategui, and Jürgen Pretzsch. "Aligning Socio-economic Field Laboratories and Agent Based Models assessing local climate change adaptation measures of Andean farmers." Journal of Forest and Landscape Research 2, no. 1 (March 31, 2017): 7–17. http://dx.doi.org/10.13141/jflr.v2i1.77.
Full textAbstract:
The increase in extreme weather events is a major consequence of climate change in tropical mountain rangeslike the Andes of Peru. The impact on farming households is of growing interest since adaptation and mitigation strategies are required to keep race with environmental conditions and to prevent people from increasing poverty. In this regard it becomes more and more obvious that a bottom-up approach incorporating the local socioeconomic processes and their interplay is needed. Socio-economic field laboratories are used to understand such processes on site. This integrates multi-disciplinary and participatory analyses of production and its relationship with biophysical and socio-economic determinants. Farmers react individually based on their experiences, financial situation, labor conditions, or attitude among others. In this regard socio-economic field laboratories also serve to develop and test scenarios about development paths, which involve the combination of both, local and scientific knowledge. For a comprehensive understanding of the multitude of interactions the agent-based modeling framework MPMAS (Mathematical Programming-based Multi-Agent System) is applied. In combination with continued ground-truthing, the model is used to gain insights into the functioning of the complex social system and to forecast its development in the near future. The assessment of the effect of humans’ behavior in changing environmental conditions including the comparison of different sites, transforms the model to a communication tool bridging the gap between adaptation policies and local realities.
2
Gentilucci, Matteo, and Gilberto Pambianchi. "Prediction of Snowmelt Days Using Binary Logistic Regression in the Umbria-Marche Apennines (Central Italy)." Water 14, no. 9 (May 6, 2022): 1495. http://dx.doi.org/10.3390/w14091495.
Full textAbstract:
Snow cover in a mountain area is a physical parameter that induces quite rapid changes in the landscape, from a geomorphological point of view. In particular, snowmelt plays a crucial role in the assessment of avalanche risk, so it is essential to know the days when snowmelt is expected, in order to prepare operational alert levels. Moreover, melting of the snow cover has a direct effect on the recharge of the water table, as well as on the regulation of the vegetative cycle of mountain plants. Therefore, a study on snowmelt, its persistence on the ground, and the height of the snow cover in the Umbria-Marche Apennines in central Italy is of great interest, since this is an area that is extremely poorly sampled and analysed. This study was conducted on the basis of four mountain weather stations equipped with a recently installed sonar-based snow depth gauge, so that a relatively short period, 2010–2020, was evaluated. A trend analysis revealed non-significant decreases in snow cover height and snow persistence time, in contrast to the significant increasing trend of mean temperature, while parameters such as relative humidity and wind speed did not appear to have a dominant trend. Further analysis showed relationships between snowmelt and the climatic parameters considered, leading to the definition of a mathematical model developed using the binary logistic regression technique, and having a predictive power of 82.6% in the case of days with snowmelt on the ground. The aim of this study was to be a first step towards models aimed at preventing avalanche risk, hydrological risk, and plant species adaptation, as well as providing a more complete definition of the climate of the study area.
3
Huggel, C., N. Salzmann, S. Allen, J. Caplan-Auerbach, L. Fischer, W. Haeberli, C. Larsen, D. Schneider, and R. Wessels. "Recent and future warm extreme events and high-mountain slope stability." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 368, no. 1919 (May 28, 2010): 2435–59. http://dx.doi.org/10.1098/rsta.2010.0078.
Full textAbstract:
The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored. We describe several large slope failures in rock and ice in recent years in Alaska, New Zealand and the European Alps, and analyse weather patterns in the days and weeks before the failures. Although we did not find one general temperature pattern, all the failures were preceded by unusually warm periods; some happened immediately after temperatures suddenly dropped to freezing. We assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed European Union programme ENSEMBLES for the central Swiss Alps. The models show an increase in the higher frequency of high-temperature events for the period 2001–2050 compared with a 1951–2000 reference period. Warm events lasting 5, 10 and 30 days are projected to increase by about 1.5–4 times by 2050 and in some models by up to 10 times. Warm extremes can trigger large landslides in temperature-sensitive high mountains by enhancing the production of water by melt of snow and ice, and by rapid thaw. Although these processes reduce slope strength, they must be considered within the local geological, glaciological and topographic context of a slope.
4
BISWAS, B. C. "Forecasting for agricultural application." MAUSAM 41, no. 2 (February 22, 2022): 188–93. http://dx.doi.org/10.54302/mausam.v41i2.2630.
Full textAbstract:
Methods for agro-meteorological forecasts are mainly based on crop-weather relationship and statistical/mathematical models. Models developed from historic data make it possible to obtain the expected values fairly in advance so that appropriate action may be taken to avail of beneficial aspect of weather and minimise or avoid detrimental effect. Validity of these models under different conditions is imperative as the climatic conditions of general field may be quite different from those of experimental one. This paper discusses the work done on the above aspects.
5
Bradstock, R. A., J. S. Cohn, A. M. Gill, M. Bedward, and C. Lucas. "Prediction of the probability of large fires in the Sydney region of south-eastern Australia using fire weather." International Journal of Wildland Fire 18, no. 8 (2009): 932. http://dx.doi.org/10.1071/wf08133.
Full textAbstract:
The probability of large-fire (≥1000 ha) ignition days, in the Sydney region, was examined using historical records. Relative influences of the ambient and drought components of the Forest Fire Danger Index (FFDI) on large fire ignition probability were explored using Bayesian logistic regression. The preferred models for two areas (Blue Mountains and Central Coast) were composed of the sum of FFDI (Drought Factor, DF = 1) (ambient component) and DF as predictors. Both drought and ambient weather positively affected the chance of large fire ignitions, with large fires more probable on the Central Coast than in the Blue Mountains. The preferred, additive combination of drought and ambient weather had a marked threshold effect on large-fire ignition and total area burned in both localities. This may be due to a landscape-scale increase in the connectivity of available fuel at high values of the index. Higher probability of large fires on the Central Coast may be due to more subdued terrain or higher population density and ignitions. Climate scenarios for 2050 yielded predictions of a 20–84% increase in potential large-fire ignitions days, using the preferred model.
6
Förster, K., G. Meon, T. Marke, and U. Strasser. "Effect of meteorological forcing and snow model complexity on hydrological simulations in the Sieber catchment (Harz Mountains, Germany)." Hydrology and Earth System Sciences 18, no. 11 (November 28, 2014): 4703–20. http://dx.doi.org/10.5194/hess-18-4703-2014.
Full textAbstract:
Abstract. Detailed physically based snow models using energy balance approaches are spatially and temporally transferable and hence regarded as particularly suited for scenario applications including changing climate or land use. However, these snow models place high demands on meteorological input data at the model scale. Besides precipitation and temperature, time series of humidity, wind speed, and radiation have to be provided. In many catchments these time series are rarely available or provided by a few meteorological stations only. This study analyzes the effect of improved meteorological input on the results of four snow models with different complexity for the Sieber catchment (44.4 km2) in the Harz Mountains, Germany. The Weather Research and Forecast model (WRF) is applied to derive spatial and temporal fields of meteorological surface variables at hourly temporal resolution for a regular grid of 1.1 km × 1.1 km. All snow models are evaluated at the point and the catchment scale. For catchment-scale simulations, all snow models were integrated into the hydrological modeling system PANTA RHEI. The model results achieved with a simple temperature-index model using observed precipitation and temperature time series as input are compared to those achieved with WRF input. Due to a mismatch between modeled and observed precipitation, the observed melt runoff as provided by a snow lysimeter and the observed streamflow are better reproduced by application of observed meteorological input data. In total, precipitation is simulated statistically reasonably at the seasonal scale but some single precipitation events are not captured by the WRF data set. Regarding the model efficiencies achieved for all simulations using WRF data, energy balance approaches generally perform similarly compared to the temperature-index approach and partially outperform the latter.
7
Briz-Redón, Álvaro, and Ángel Serrano-Aroca. "The effect of climate on the spread of the COVID-19 pandemic: A review of findings, and statistical and modelling techniques." Progress in Physical Geography: Earth and Environment 44, no. 5 (August 4, 2020): 591–604. http://dx.doi.org/10.1177/0309133320946302.
Full textAbstract:
The new SARS-CoV-2 coronavirus has spread rapidly around the world since it was first reported in humans in Wuhan, China, in December 2019 after being contracted from a zoonotic source. This new virus produces the so-called coronavirus 2019 or COVID-19. Although several studies have supported the epidemiological hypothesis that weather patterns may affect the survival and spread of droplet-mediated viral diseases, the most recent have concluded that summer weather may offer partial or no relief of the COVID-19 pandemic to some regions of the world. Some of these studies have considered only meteorological variables, while others have included non-meteorological factors. The statistical and modelling techniques considered in this research line have included correlation analyses, generalized linear models, generalized additive models, differential equations, or spatio-temporal models, among others. In this paper we provide a systematic review of the recent literature on the effects of climate on COVID-19’s global expansion. The review focuses on both the findings and the statistical and modelling techniques used. The disparate findings reported seem to indicate that the estimated impact of hot weather on the transmission risk is not large enough to control the pandemic, although the wide range of statistical and modelling approaches considered may have partly contributed to the inconsistency of the findings. In this regard, we highlight the importance of being aware of the limitations of the different mathematical approaches, the influence of choosing geographical units and the need to analyse COVID-19 data with great caution. The review seems to indicate that governments should remain vigilant and maintain the restrictions in force against the pandemic rather than assume that warm weather and ultraviolet exposure will naturally reduce COVID-19 transmission.
8
SHAPOVALOV, Vitaly A., Aida A. ADZHIEVA, Lyudmila M. FEDCHENKO, and Egor A. KOVALEV. "Mathematical Modeling of Formation of Transparency Regions in Supercooled Stratiform Clouds and Fogs." Journal of Environmental Management and Tourism 9, no. 1 (June 19, 2018): 17. http://dx.doi.org/10.14505//jemt.v9.1(25).03.
Full textAbstract:
We developed models of active influence on clouds using crystallization reagents to ensure transparency of the atmosphere. Numerical modeling of various versions of influence on stratiform clouds at aviation seeding was performed. Variation of characteristics of supercooled fogs when bringing man-made crystals was studied. The determination of reagents application rates, estimating impact effect and some other issues were solved using the results of modelling of clouds evolution (both natural and under active influence). Based on generalization of the results of numerical simulation of cloud evolution, the proposals for improvement of cloud seeding technology under different weather conditions are developed.
9
Abbas, Ehsan F., and Jawdat A. Yaqub. "The Effect of using Insulation on the Energy Saving in Building." Tikrit Journal of Engineering Sciences 17, no. 3 (September 30, 2010): 25–38. http://dx.doi.org/10.25130/tjes.17.3.10.
Full textAbstract:
The aim of the present study is to analyze the thermal performance of a building which is of 600 m3 size. The building is built in three different models. In the first model, walls are built with brick. In the second model, a layer of foam (Polystyrene) of 4 cm thickness has been used as an insulation layer inside walls and on the roof. In the third model, walls are constructed from two parts separated by air gap of 8 cm wide; moreover a secondary roof is added to this model. A Qbasic program is prepared to simulate the required mathematical equations in finite difference method and the weather conditions data of Baghdad city at January, 1994. The results of the simulation showed that the ratio of the saved energy by the second and third models with respect to the first model are 29.96%, and 35.40% respectively.
10
Plăiaşu, Rodica, Arpat Ozgul, Benedikt R. Schmidt, and Raluca I. Băncilă. "Estimation of apparent survival probability of the harvestman Paranemastoma sillii sillii (Herman, 1871) from two caves." Animal Biology 67, no. 2 (2017): 165–76. http://dx.doi.org/10.1163/15707563-00002529.
Full textAbstract:
Reliable estimates of population parameters are lacking for most cave-dwelling species. This lack of knowledge may hinder the appropriate management of caves and populations of cave-dwelling species. Using monthly capture-recapture data and Cormack-Jolly-Seber models, we (i) estimated the apparent survival of individuals in two cave populations of the harvestman Paranemastoma sillii sillii (Herman, 1871) from the Mehedinti Mountains in south-western Romania; (ii) investigated temporal variation in apparent survival; (iii) tested if surface weather conditions affect apparent survival of cave-dwelling harvestmen through their influence upon cave environmental conditions and (iv) tested for sex differences in apparent survival. Our results show that the apparent monthly survival estimates were high for both studied cave populations and there was a significant sex effect on survival. Males had lower survival than females, and the survival difference between caves was larger in males than in females. Temporal (i.e., monthly) variation in apparent survival was low and the weather conditions at the surface had little influence on apparent survival as the environment inside the caves is well buffered against weather fluctuations outside the caves. Our results indicate that caves stabilize survival of facultative cave-dwelling species and may serve as microrefugia for epigean species. We suggest that caves should be considered for conservation because they may serve as a refuge for some epigean species during harsh weather conditions.
11
Marshall, Shawn J., and Kristina Miller. "Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains." Cryosphere 14, no. 10 (October 2, 2020): 3249–67. http://dx.doi.org/10.5194/tc-14-3249-2020.
Full textAbstract:
Abstract. In situ observations of summer (June through August, or JJA) albedo are presented for the period 2002–2017 from Haig Glacier in the Canadian Rocky Mountains. The observations provide insight into the seasonal evolution and interannual variability of snow and ice albedo, including the effects of summer snowfall, the decay of snow albedo through the melt season, and the potential short-term impacts of regional wildfire activity on glacier-albedo reductions. Mean JJA albedo (± 1σ) recorded at an automatic weather station in the upper ablation zone of the glacier was αS=0.55 ± 0.07 over this period, with no evidence of long-term trends in surface albedo. Each summer the surface conditions at the weather station undergo a transition from a dry, reflective spring snowpack (αS∼0.8) to a wet, homogeneous midsummer snowpack (αS∼0.5) to exposed, impurity-rich glacier ice, with a measured albedo of 0.21 ± 0.06 over the study period. The ice albedo drops to ∼ 0.12 during years of intense regional wildfire activity such as 2003 and 2017, but it recovers from this in subsequent years. This seasonal albedo decline is well simulated through a parameterization of snow-albedo decay based on cumulative positive degree days (PDDs), but the parameterization does not capture the impact of summer snowfall events, which cause transient increases in albedo and significantly reduce glacier melt. We introduce this effect through a stochastic parameterization of summer precipitation events within a surface energy balance model. The amount of precipitation and the date of snowfall are randomly selected for each model realization based on a predefined number of summer snow events. This stochastic parameterization provides an improved representation of the mean summer albedo and mass balance at Haig Glacier. We also suggest modifications to conventional degree-day melt factors to better capture the effects of seasonal albedo evolution in temperature-index or positive-degree-day melt models on mountain glaciers. Climate, hydrology, or glacier mass balance models that use these methods typically use a binary rather than continuum approach to prescribing melt factors, with one melt factor for snow and one for ice. As alternatives, monthly melt factors effectively capture the seasonal albedo evolution, or melt factors can be estimated as a function of the albedo where these data are available.
12
Samuel, Mbelle Bisong, Paune Felix, Youmene Nongosso Miguel, Tambere Samam Cyrille, and Pierre Kisito Talla. "STUDY AND SIMULATION OF THE FUEL CONSUMPTION OF A VEHICLE WITH RESPECT TO AMBIENT TEMPERATURE AND WEATHER CONDITIONS." International Journal of Engineering Technologies and Management Research 7, no. 1 (January 31, 2020): 24–35. http://dx.doi.org/10.29121/ijetmr.v7.i1.2020.480.
Full textAbstract:
The consumption of fuel in vehicles depends on many factors such as the state of the roads, the state of the engine and the driver’s behavior. A mathematical model for evaluating vehicle fuel consumption on a 100 km interval at standard operating weather conditions was developed. This mathematical model developed took into consideration many factors, but the main factors were those related to weather conditions and temperature. Here a new simulation program for determining the influence of temperature and weather conditions on fuel consumption is built using the software Matlab. For efficient simulations the model uses a set of data for an SUV and then makes varying only the parameters that are related to weather and temperature for the simulation. During the simulation process, a set of 10 vehicle models and 8 roads conditions were chosen to run down the simulations and only the parameters of temperature, the drag coefficient and coefficient of rolling resistances respectively were subjected to variations during each of the simulations. Upon simulation, different results were obtained for the different parameters considered. For every 15% drop in temperature, 0.1litre, 0.12litre and 0.04litre increase in fuel consumption for the set of parameters chosen was noticed. These results were analyzed and interpreted with the help of Microsoft Excel and were found to be satisfactory given that it permits manufacturers and car users to have a notion of the impact of ambient temperature and weather conditions on fuel consumption, thereby promoting optimum usage of fuel, hence reducing the effect of greenhouse emissions in the atmosphere.
13
Vasilevich and Nikanorova. "ANALYTICAL MATHEMATICAL MODELS OF THE POPULATION OF ARTHROPODS IN THE NON-BLACK EARTH ZONE." THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL, no. 22 (May 19, 2021): 128–32. http://dx.doi.org/10.31016/978-5-6046256-1-3.2021.22.128-132.
Full textAbstract:
The article provides an example of mathematical analytical modeling of the population size of blood-sucking arthropods on the example of mosquitoes and ixodid ticks that inhabit the Kaluga Region. The presented analytical mathematical models make it possible to clearly assess the influence of environmental factors on parasite populations. The following factors were taken into account: average temperature (monthly and yearly, t, oС); average precipitation (monthly and yearly, S, mm); mean atmospheric pressure (P, mm Hg) for mosquitoes, and monthly average temperature (t, o С), monthly mean relative humidity (Q, %), and mean atmospheric pressure (P, mm Hg) for ixodid ticks. The analysis of the obtained models shows that under weather conditions when monthly mean values of the considered factors are at a zero level, the estimated number of ixodid ticks and mosquitoes will be 1150 and 1529 individuals in the control area per year. The population of ixodid ticks is most significantly influenced by the mean atmospheric pressure; its influence is twice as strong as monthly mean humidity and 6.4 times stronger than the influence of monthly average temperature. The "+" sign indicates that the higher the atmospheric pressure is, the more active ticks are observed. Monthly average precipitation has the greatest effect on the mosquito population.
14
Rayburn, Edward B. "Validating a Simple Mechanistic Model That Describes Weather Impact on Pasture Growth." Plants 10, no. 9 (August 24, 2021): 1754. http://dx.doi.org/10.3390/plants10091754.
Full textAbstract:
Mathematical models have many uses. When input data is limited, simple models are required. This occurs in pasture agriculture when managers typically only have access to temperature and rainfall values. A simple pasture growth model was developed that requires only latitude and daily maximum and minimum temperature and rainfall. The accuracy of the model was validated using ten site-years of measured pasture growth at a site under continuous stocking where management controlled the height of grazing (HOG) and a site under rotational stocking at a West Virginia University farm (WVU). Relative forage growth, expressed as a fraction of maximum growth observed at the sites, was reasonably accurate. At the HOG site constant bias in relative growth was not different from zero. There was a year effect due to the weather station used for predicting growth at HOG being 1.8 km from the pasture. However, the error was only about 10-percent. At the WVU site constant bias for relative growth was not different from zero and year effect was eliminated when adjusted for nitrogen status of the treatments. This simple model described relative pasture growth within 10-percent of average for a given site, environment, and management using only daily weather inputs that are readily available. Using predictions of climate change impact on temperature and rainfall frequency and intensity this model can be used to predict the impact on pasture growth.
15
Moore, Simon C., Thomas E. Woolley, and James White. "An Exploration of the Multiplicative Effect of “Other People” and Other Environmental Effects on Violence in the Night-Time Environment." International Journal of Environmental Research and Public Health 19, no. 24 (December 16, 2022): 16963. http://dx.doi.org/10.3390/ijerph192416963.
Full textAbstract:
Background: The characteristics of night-time environments (NTEs) in which alcohol is consumed and that contribute to violence are poorly described. We explore competing explanations for violence in the NTE, with a particular focus on the number of patrons and its association with assault-related visits to a hospital emergency department. Other environmental features including the weather and notable events were also considered. The primary aim was to stimulate debate around the causal mechanisms responsible for violence. Methods: Assault-related ED visits occurring between 8 pm and 4 am were recorded at the University Hospital of Wales, the single Emergency Department (ED) serving Cardiff, Wales, United Kingdom. Footfall was derived from the total number of unique MAC addresses recorded per hour collected from ten wireless fidelity monitoring tools located in the city centre. A narrative review of the literature concerning alcohol and violence informed exploratory analyses into the association between night-time footfall, sporting events, the weather, and other potential predictors of assault-related visits to the ED. We developed analytic methods from formal accounts of queueing. Results: International rugby matches at home, the weather (temperature), national holidays, the day of the week, and number of patrons in the NTE predicted assault-related injury (R2 = 0.70), with footfall yielding a positive non-linear exponential association consistent with predictions derived from mathematical models of queueing. Discussion: Assault-related visits to the ED have a non-linear association with the number of people socialising in the night-time environment and are further influenced by the weather and notable events. Opportunities for further research that might inform policy and interventions aimed at better managing NTEs are discussed.
16
Rodriguez, MS, Jose M., Julius Codjoe, Osama Osman, Sherif Ishak, PhD, and Brian Wolshon, PhD. "Experimental modeling of the effect of hurricane wind forces on driving behavior and vehicle performance." Journal of Emergency Management 13, no. 2 (March 1, 2015): 159. http://dx.doi.org/10.5055/jem.2015.0228.
Full textAbstract:
While traffic planning is important for developing a hurricane evacuation plan, vehicle performance on the roads during extreme weather conditions is critical to the success of the planning process. This novel study investigates the effect of gusty hurricane wind forces on the driving behavior and vehicle performance. The study explores how the parameters of a driving simulator could be modified to reproduce wind loadings experienced by three vehicle types (passenger car, ambulance, and bus) during gusty hurricane winds, through manipulation of appropriate software. Thirty participants were then tested on the modified driving simulator under five wind conditions (ranging from normal to hurricane category 4). The driving performance measures used were heading error and lateral displacement. The results showed that higher wind forces resulted in more varied and greater heading error and lateral displacement. The ambulance had the greatest heading errors and lateral displacements, which were attributed to its large lateral surface area and light weight. Two mathematical models were developed to estimate the heading error and lateral displacements for each of the vehicle types for a given change in lateral wind force. Through a questionnaire, participants felt the different characteristics while driving each vehicle type. The findings of this study demonstrate the valuable use of a driving simulator to model the behavior of different vehicle types and to develop mathematical models to estimate and quantify driving behavior and vehicle performance under hurricane wind conditions.
17
Oerlemans, J., and W. H. Knap. "A 1 year record of global radiation and albedo in the ablation zone of Morteratschgletscher, Switzerland." Journal of Glaciology 44, no. 147 (1998): 231–38. http://dx.doi.org/10.3189/s0022143000002574.
Full textAbstract:
AbstractWe analyse data on solar radiation measured with an automatic weather station on Morteratschgletscher, Switzerland, for the period 1 October 1995–30 September 1996. The station is in the lower ablation zone. Due to shading by surrounding mountains and atmospheric attenuation, only 49% of the annual extraterrestrial irradiance (mean: 292 W m−2) reaches the glacier surface. About 48% of this is absorbed at the surface (mean: 79 W m−2; annual albedo of 0.53).We present a simple albedo scheme for use in glacier mass-balance models. We fit the model to the 1 year dataset by optimizing five control parameters (optimal values in brackets): albedo of snow (0.75), albedo of firn (0.53), albedo of ice (0.34), e-folding constant for effect of ageing on snow albedo (21.9 days) and e-folding constant for effect of snow depth on albedo (3.2 cm). The input consists of daily albedo, snow depth and dates of snowfall events. The correlation coefficient between observed and simulated albedo is 0.931, the corresponding rms difference being 0.067.
18
Oerlemans, J., and W. H. Knap. "A 1 year record of global radiation and albedo in the ablation zone of Morteratschgletscher, Switzerland." Journal of Glaciology 44, no. 147 (1998): 231–38. http://dx.doi.org/10.1017/s0022143000002574.
Full textAbstract:
AbstractWe analyse data on solar radiation measured with an automatic weather station on Morteratschgletscher, Switzerland, for the period 1 October 1995–30 September 1996. The station is in the lower ablation zone. Due to shading by surrounding mountains and atmospheric attenuation, only 49% of the annual extraterrestrial irradiance (mean: 292 W m−2) reaches the glacier surface. About 48% of this is absorbed at the surface (mean: 79 W m−2; annual albedo of 0.53).We present a simple albedo scheme for use in glacier mass-balance models. We fit the model to the 1 year dataset by optimizing five control parameters (optimal values in brackets): albedo of snow (0.75), albedo of firn (0.53), albedo of ice (0.34),e-folding constant for effect of ageing on snow albedo (21.9 days) ande-folding constant for effect of snow depth on albedo (3.2 cm). The input consists of daily albedo, snow depth and dates of snowfall events. The correlation coefficient between observed and simulated albedo is 0.931, the corresponding rms difference being 0.067.
19
Haegeli, Pascal, Bret Shandro, and Patrick Mair. "Using avalanche problems to examine the effect of large-scale atmosphere–ocean oscillations on avalanche hazard in western Canada." Cryosphere 15, no. 3 (March 29, 2021): 1567–86. http://dx.doi.org/10.5194/tc-15-1567-2021.
Full textAbstract:
Abstract. Numerous large-scale atmosphere–ocean oscillations including the El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Pacific North American Teleconnection Pattern (PNA), and the Arctic Oscillation (AO) are known to substantially affect winter weather patterns in western Canada. Several studies have examined the effect of these oscillations on avalanche hazard using long-term avalanche activity records from highway avalanche safety programmes. We present a new approach for gaining additional insight into these relationships that uses avalanche problem information published in public avalanche bulletins during the winters of 2010 to 2019. For each avalanche problem type, we calculate seasonal prevalence values for each forecast area, elevation band, and season, which are then included in a series of beta mixed-effects regression models to explore both the overall and regional effects of the Pacific-centered oscillations (POs; including ENSO, PDO, and PNA) and AO on the nature of avalanche hazard in the study area. We find significant negative effects of PO on the prevalence of storm slab avalanche problems, wind slab avalanche problems, and dry loose avalanche problems, which agree reasonably well with the known impacts of PO on winter weather in western Canada. The analysis also reveals a positive relationship between AO and the prevalence of deep persistent slab avalanche problems, particularly in the Rocky Mountains. In addition, we find several smaller-scale patterns that highlight that the avalanche hazard response to these oscillations varies regionally. Even though our study period is short, our study shows that the forecaster judgement included in avalanche problem assessments can add considerable value for these types of analyses. Since the predictability of the most important atmosphere–ocean oscillations is continuously improving, a better understanding of their effect on avalanche hazard can contribute to the development of informative seasonal avalanche forecasts in a relatively simple way.
20
Ponce-Farfán, Cristian, David Santillán, and Miguel Á. Toledo. "Thermal Simulation of Rolled Concrete Dams: Influence of the Hydration Model and the Environmental Actions on the Thermal Field." Water 12, no. 3 (March 19, 2020): 858. http://dx.doi.org/10.3390/w12030858.
Full textAbstract:
Mathematical models for the simulation of the thermal evolution of roller-compacted concrete (RCC) dams during construction constitute an important tool for preventing excessive temperature rise, which may lead to cracking and losses of functionality. Here, we present a framework for the simulation of the thermal process. We define the boundary conditions of the problem using a careful description that incorporates the main heat exchange mechanisms. We adopt both a non-adiabatic and an adiabatic heat generation model for the simulation of the cement hydration. Our numerical framework lets us study the effect of the adopted heat generation model on the thermal field. Moreover, we study the influence of the weather conditions on the evolution of the hydration, and on the starting date of construction. Our simulations have shown that the hydration model has an important influence over the temperature field during the construction and the heat generation rate. Moreover, the hydration process and the temperature evolution are driven by the weather conditions. Once the next lift is cast, its thermal insulation effect makes the hydration take place under quasi-adiabatic conditions. As expected, dams built in cold months are prone to dissipate more heat than those built in warm seasons.
21
Gu, Y., K. N. Liou, W. L. Lee, and L. R. Leung. "Simulating 3-D radiative transfer effects over the Sierra Nevada mountains using WRF." Atmospheric Chemistry and Physics Discussions 12, no. 8 (August 9, 2012): 19897–920. http://dx.doi.org/10.5194/acpd-12-19897-2012.
Full textAbstract:
Abstract. A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF) model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra Nevada in the Western United States as a testbed, we show that mountain effect could produce up to −50 to +50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shade side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the domain-averaged diurnal variation over the Sierras show that the mountain area receives more solar insolation during early morning and late afternoon, resulting in enhanced upward sensible heat and latent heat fluxes from the surface and a corresponding increase in surface skin temperature. During the middle of the day, however, the surface insolation and heat fluxes show negative changes, indicating a cooling effect. Hence overall, the diurnal variations of surface temperature and surface fluxes in the Sierra Nevada are reduced through the interactions of radiative transfer and mountains. The hourly differences of the surface solar insolation in higher elevated regions, however, show smaller magnitude in negative changes during the middle of the day and possibly more solar fluxes received during the whole day.
22
Gu, Y., K. N. Liou, W. L. Lee, and L. R. Leung. "Simulating 3-D radiative transfer effects over the Sierra Nevada Mountains using WRF." Atmospheric Chemistry and Physics 12, no. 20 (October 30, 2012): 9965–76. http://dx.doi.org/10.5194/acp-12-9965-2012.
Full textAbstract:
Abstract. A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF) model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra-Nevada in the western United States as a testbed, we show that mountain effect could produce up to −50 to + 50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shaded side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the domain-averaged diurnal variation over the Sierras show that the mountain area receives more solar insolation during early morning and late afternoon, resulting in enhanced upward sensible heat and latent heat fluxes from the surface and a corresponding increase in surface skin temperature. During the middle of the day, however, the surface insolation and heat fluxes show negative changes, indicating a cooling effect. Hence overall, the diurnal variations of surface temperature and surface fluxes in the Sierra-Nevada are reduced through the interactions of radiative transfer and mountains. The hourly differences of the surface solar insolation in higher elevated regions, however, show smaller magnitude in negative changes during the middle of the day and possibly more solar fluxes received during the whole day.
23
Pfafferott, Jens, Sascha Rißmann, Guido Halbig, Franz Schröder, and Sascha Saad. "Towards a Generic Residential Building Model for Heat–Health Warning Systems." International Journal of Environmental Research and Public Health 18, no. 24 (December 10, 2021): 13050. http://dx.doi.org/10.3390/ijerph182413050.
Full textAbstract:
A strong heat load in buildings and cities during the summer is not a new phenomenon. However, prolonged heat waves and increasing urbanization are intensifying the heat island effect in our cities; hence, the heat exposure in residential buildings. The thermophysiological load in the interior and exterior environments can be reduced in the medium and long term, through urban planning and building physics measures. In the short term, an increasingly vulnerable population must be effectively informed of an impending heat wave. Building simulation models can be favorably used to evaluate indoor heat stress. This study presents a generic simulation model, developed from monitoring data in urban multi-unit residential buildings during a summer period and using statistical methods. The model determines both the average room temperature and its deviations and, thus, consists of three sub-models: cool, average, and warm building types. The simulation model is based on the same mathematical algorithm, whereas each building type is described by a specific data set, concerning its building physical parameters and user behavior, respectively. The generic building model may be used in urban climate analyses with many individual buildings distributed across the city or in heat–health warning systems, with different building and user types distributed across a region. An urban climate analysis (with weather data from a database) may evaluate local differences in urban and indoor climate, whereas heat–health warning systems (driven by a weather forecast) obtain additional information on indoor heat stress and its expected deviations.
24
Galambos, Máté, and László Bacsárdi. "Comparing Calculated and Measured Losses in a Satellite-Earth Quantum Channel." Infocommunications journal, no. 3 (2018): 14–19. http://dx.doi.org/10.36244/icj.2018.3.3.
Full textAbstract:
Long distance distribution of quantum states is necessary for quantum communication and large scale quantum experiments. Currently this distance is limited by channel loss. Previous theoretical analisys and proof of concept experiments showed that satellite quantum communication may have lower losses than optical cable based counterparts. Recently the QuESS experiment [3] realized the first satellite-Earth quantum channel. In this paper we compare heoretical predictions of different mathematical models with experimental results regarding channel loss. We examine the HV-5/7 model, HV-Night model and Greenwood model of optical turbulences, the geometric [4] and diffraction [5][6] models of beam wander and beam widening. Furthermore we take into account the effect of atmospheric gases and aerosols as well as the effect of pointing error. We find that theoretical predictions are largely in the same order of magnitude as experimental results. The exception is the diffraction model of beam spreading where our calculations yielded only one tenth of the measured value. Given the ever changing nature of weather conditions and the changing composition of atmospheric aerosoles we conclude that calculated and measured losses are in good agreement.
25
Idzkowski, Adam, Karolina Karasowska, and Wojciech Walendziuk. "Analysis of Three Small-Scale Photovoltaic Systems Based on Simulation and Measurement Data." Proceedings 51, no. 1 (July 30, 2020): 19. http://dx.doi.org/10.3390/proceedings2020051019.
Full textAbstract:
Sunlight is converted into electrical energy due to the photovoltaic effect in photovoltaic arrays. The energy yield of photovoltaic systems depends on the solar array location, orientation, tilt, tracking and local weather conditions. Currently, simulation software is most often used to analyze the operation of photovoltaic (PV) systems and to estimate the energy yield. In this article, the differences in energy yield calculations given by the simulation software and the measured data are determined. The analysis was carried out based on mathematical models and real measurement data, regarding the dependence of the average temperature of PV arrays on variable and difficult to predict ambient conditions. For the purpose of this analysis, thermal models for flat-plate photovoltaic arrays were used. The photovoltaic installations PV1, PV2a and PV2b, belonging to the hybrid power plant of the Bialystok University of Technology in Poland, were indicated as the data source. There is no universal mathematical model to determine the average temperature of the PV modules for every type of the installation with a small normalized root-mean-squared error. The Skoplaki model proved to be the best method in the case of a free-standing solar system. On the other hand, the data values obtained from building integrated installations were better modeled by a method which used parameters under NOCT (Normal Operating Cell Temperature) conditions.
26
Li, Sihan, Philip W. Mote, David E. Rupp, Dean Vickers, Roberto Mera, and Myles Allen. "Evaluation of a Regional Climate Modeling Effort for the Western United States Using a Superensemble from Weather@home*." Journal of Climate 28, no. 19 (September 29, 2015): 7470–88. http://dx.doi.org/10.1175/jcli-d-14-00808.1.
Full textAbstract:
Abstract Simulations from a regional climate model (RCM) as part of a superensemble experiment were compared with observations of surface meteorological variables over the western United States. The RCM is the Hadley Centre Regional Climate Model, version 3, with improved physics parameterizations (HadRM3P) run at 25-km resolution and nested within the Hadley Centre Atmosphere Model, version 3 (HadAM3P). Overall, the means of seasonal temperature were well represented in the simulations; 95% of grid points were within 2.7°, 2.4°, and 3.6°C of observations in winter, spring, and summer, respectively. The model was too warm over most of the domain in summer except central California and southern Nevada. HadRM3P produced more extreme temperatures than observed. The overall magnitude and spatial pattern of precipitation were well characterized, though HadRM3P exaggerated the orographic enhancement along the coastal mountains, Cascade Range, and Sierra Nevada. HadRM3P produced warm/dry northwest, cool/wet southwest U.S. patterns associated with El Niño. However, there were notable differences, including the locations of the transition from warm (dry) to cool (wet) in the anomaly fields when compared with observations, though there was disagreement among observations. HadRM3P simulated the observed spatial pattern of mean annual temperature more faithfully than any of the RCM–GCM pairings in the North American Regional Climate Change Assessment Program (NARCCAP). Errors in mean annual precipitation from HadRM3P fell within the range of errors of the NARCCAP models. Last, this paper provided examples of the size of an ensemble required to detect changes at the local level and demonstrated the effect of parameter perturbation on regional precipitation.
27
Palamarchuk, Vitalii, and Oleksii Alieksieiev. "MATHEMATICAL MODELS OF HIGH-STARCH MAIZE HYBRIDS OF DIFFERENT GROUND GROUPS." Agriculture and Forestry, no. 1 (April 28, 2020): 28–47. http://dx.doi.org/10.37128/2707-5826-2020-1-3.
Full textAbstract:
The article presents the results of mathematical modeling based on the construction and usage of different images of an object, process or system. The research expected to study the dependence of the productivity level and the economically valuable features of corn hybrids in the form of mathematical models. Field studies were carried out during 2011-2017 at the field of research of the Department of Plant, Selection and Bioenergy Crops of SE EF “Kordelivske” of IP NAASU of Vinnytsia National Agrarian University under the conditions of the Forest-Steppe of the Right-Bank, in accordance with the recommendations presented in the Methodology Of The Maize Field Study. The soils in the study variants are represented by black earth soil of deep medium loamy on the loessial soil. The humus content (according to Tiurin) in the tilth soil was 4.60%. Soil reaction - pH (salt) 5.7. The soils contain lightly hydrolyzed nitrogen (according to Kornfield) 106 mg per 1 kg of soil, mobile phosphorus and exchangeable potassium (according to Chirikov) 186 and 160 mg per 1 kg of soil, respectively. The experiments established the economic and biological evaluation of corn hybrids depending on the sowing period, the size of the fraction and the depth of seed wrapping, foliar fertilizers by micro fertilizers. The plot area for hybrids was 10.5 m2. Repeatability in experiments for hybrids is 3 times. Placement of plots is by the method of randomized blocks. An ecological-genetic model of quantitative features was used to study the phenotypic productivity of maize hybrids and to establish the influence on the formation of their traits. The model construction is based on the hierarchy of production traits demonstration in ontogeny and the correspondence of their manifestation in organogenesis. The model consists of three modules of features, i.e. the resultant and two components which reflecting the phenotypic implementation of the genetic formula. Resulting features are those that have an environmentally stable relationships and the highest total contribution to the intended property, yield. As a result of the conducted research, the mathematical models of the duration of the growing season of early-maturing maize hybrids allowed us to determine that the biggest influence does sums of effective temperatures (≥ + 10° C) for May, June, August and September over correlation rate at r = -0.62 and r = -0.51, r = 0.59 and r = 0.39, respectively. Also precipitation amount significantly influenced on the duration of the growing season and the correlation coefficient was r = -0.44, and the influence of the HTI was at the level of r = -0.34. For middle-early hybrids the sum of effective temperatures (≥ + 10° C) in May and June r = -0.46 and r = -0.28, respectively, and also the sum of effective temperatures (≥ + 10° C) in August – r = 0.18 had a strong effect. However, for medium-maturing maize hybrids, the duration of the growing season was determined by the sum of effective temperatures (≥ + 10° C) for May, June and July – r = -0.37, r = -0.34 and r = -0.28, and the sum of effective temperatures (≥ + 10° C) in August – r = 0,18. It is also possible to note the influence and the total sum of effective temperatures (≥ + 10° C) during vegetation at the level of correlation coefficient r = -0.51. According to the research results of mathematical models of the influence of weather conditions on the formation of phenotypic productivity of maize hybrids of different maturity groups both general biological regularities and group differences of features formation were established. Thus, if we analyze the differences between groups of early-ripening and middle-early corn hybrids, their growth and development in general are influenced by the sum of the effective temperatures, rainfall and HTI. In fact, the studied groups of ripeness differ slightly and the main differences are observed only in the variability of the studied features or their close relationship with each other. However, middle-aged hybrids respond somewhat differently to environmental factors, which allow developing the elements of adaptive growing technology for each of the maturity groups. Key words: corn, hybrid, phenotype, mathematical model, productivity, economic and valuable features.
28
Parizi, Ana R. C., Adroaldo D. Robaina, Ana C. dos S. Gomes, Marcia X. Peiter, and Fátima C. Soares. "Corn yield under various simulated irrigation depths." Engenharia Agrícola 36, no. 3 (June 2016): 503–14. http://dx.doi.org/10.1590/1809-4430-eng.agric.v36n3p503-514/2016.
Full textAbstract:
ABSTRACT Mathematical models are tools to estimate and understand system behaviors against diverse situations; they may help in decision-making through simplified representations of the reality, allowing simulating various scenarios and estimating impacts of different courses of action on production systems, assisting thus in activity planning. Thus, this paper proposed a simulation of corn crop yields according to different field experiment characteristics and weather conditions in which it was conducted, with the purpose of setting a simulation model already calibrated and tested for corn crop cycle in the region of Santiago – RS, Brazil. The increasing water levels had a positive effect on grain yield and corn dry matter. On the other hand, a level of 800 mm reduced corn yield, as well as water application efficiency decreased from 550 mm. The proposed model can be used as a tool for regional planning in corn crop implementation under irrigation and enables identifying irrigation strategies for high grain yields, being considered a tool for yield prediction in irrigated crops.
29
Crossland, Paul, Mark J. Evans, David Grist, Mark Lowten, Helen Jones, and Robert S. Bridger. "Motion-induced interruptions aboard ship: Model development and application to ship design." Occupational Ergonomics 7, no. 3 (January 11, 2008): 183–99. http://dx.doi.org/10.3233/oer-2007-7304.
Full textAbstract:
The most severe direct motion induced effect on the ability of an individual to work in a moving environment probably occurs in gross body tasks requiring balance and co-ordination, be it the crew trying to undertake their task effectively or the passenger trying to walk around the vessel. During rough weather working in the ship becomes more difficult and even the most experienced sailor will experience events where they must stop their activity, be it a specific task or merely standing, and hold on to some suitable point to minimise the risk of injury; these events are called Motion-induced interruptions (MIIs). MIIs were recorded during the performance of a series of tasks on board a ship at sea in rough weather. The tasks were: standing facing aft, walking athwartships, a simulated weapon loading task, standing facing athwartships and a simulated fire-fighting task. Complex mathematical models of postural stability exist but currently lack the fidelity to accurately predict MIIs. This paper presents data from an empirical study in which MIIs experienced by subjects on a ship at sea were logged by an observer. Measurements of lateral and vertical acceleration of the deck immediately prior to the MII were made and thresholds of acceleration for undertaking task were determined. These so called tipping coefficients are presented for use with predictive tools in ship design.
30
Soldatenko, Sergei. "On the Effects of Mixed and Deep Ocean Layers on Climate Change and Variability." Journal of Marine Science and Engineering 10, no. 9 (August 31, 2022): 1216. http://dx.doi.org/10.3390/jmse10091216.
Full textAbstract:
The ocean, one of the five major components of the Earth’s climate system, plays a key role in climate-forming processes, affecting its change and variability. The ocean influences climate over a wide range of time–space scales. To explore the climate, its components, interactions between them and, in particular, the effect of the ocean on weather and climate, researchers commonly use extremely complex mathematical models of the climate system that describe the atmospheric and ocean general circulations. However, this class of climate models requires enormous human and computing resources to simulate the climate system itself and to analyze the output results. For simple climate models, such as energy balance and similar models, the computational cost is insignificant, which is why these models represent a test tool to mimic a complex climate system and obtaining preliminary estimates of the influence of various internal and external factors on climate, its change and variability. The global mean surface temperature (GMST) and its fluctuations in time serve as critical indicators of changes in the climate system state. We apply a simple two-box ocean model to explore the effect of mixed and deep ocean layers on climate-forming processes and especially on climate change and variability. The effect of mixed and deep ocean layers on GMST is parameterized via the layers’ effective heat capacities and heat exchange between layers. For the listed parameters, the sensitivity functions were derived numerically and analytically, allowing one to obtain an idea of how the mixed and deep ocean layers affect climate change and variability. To study climate change, a deterministic version of the model was used with radiative forcing parameterized by both stepwise and linear functions. In climate variability experiments, a stochastic version of the model was applied in which the radiative forcing is considered as a delta-correlated random process.
31
Liou, K. N., Y. Gu, L. R. Leung, W. L. Lee, and R. G. Fovell. "A WRF simulation of the impact of 3-D radiative transfer on surface hydrology over the Rocky–Sierra Mountains." Atmospheric Chemistry and Physics Discussions 13, no. 7 (July 23, 2013): 19389–419. http://dx.doi.org/10.5194/acpd-13-19389-2013.
Full textAbstract:
Abstract. Essentially all modern climate models utilize a plane-parallel (PP) radiative transfer approach in physics parameterizations; however, the potential errors that arise from neglecting three-dimensional (3-D) interactions between radiation and mountains/snow on climate simulations have not been studied and quantified. This paper is a continuation of our efforts to investigate 3-D mountains/snow effects on solar flux distributions and their impact on surface hydrology over the Western United States, specifically the Rocky and Sierra-Nevada Mountains. We use the Weather Research and Forecasting (WRF) model applied at a 30 km grid resolution with incorporation of a 3-D radiative transfer parameterization covering a time period from 1 November 2007 to 31 May 2008 during which abundant snowfall occurred. Comparison of the 3-D WRF simulation with the observed snow water equivalent (SWE) and precipitation from Snowpack Telemetry (SNOTEL) sites shows reasonable agreement in terms of spatial patterns and daily and seasonal variability, although the simulation generally has a positive precipitation bias. We show that 3-D mountain features have a profound impact on the diurnal and monthly variation of surface radiative and heat fluxes and on the consequent elevation-dependence of snowmelt and precipitation distributions. In particular, during the winter months, large deviations (3-D–PP) of the monthly mean surface solar flux are found in the morning and afternoon hours due to shading effects for elevations below 2.5 km. During spring, positive deviations shift to earlier morning. Over the mountain tops above 3 km, positive deviations are found throughout the day, with the largest values of 40–60 W m−2 occurring at noon during the snowmelt season of April to May. The monthly SWE deviations averaged over the entire domain show an increase in lower elevations due to reduced snowmelt, leading to a reduction in cumulative runoff. Over higher elevation areas, positive SWE deviations are found because of increased solar radiation available at the surface. Overall, this study shows that deviations of SWE due to 3-D radiation effects range from an increase of 18% at the lowest elevation range (1.5–2 km) to a decrease of 8% at the highest elevation range (above 3 km). Since lower elevation areas occupy larger fractions of the land surface, the net effect of 3-D radiative transfer is to extend snowmelt and snowmelt-driven runoff into the warm season. Additionally, because about 60–90% of water resources originate from mountains worldwide, the aforementioned differences in simulated hydrology due solely to 3-D interactions between solar radiation and mountains/snow merit further investigation in order to understand the implications to modeling mountain water resources and their vulnerability to climate change and air pollution.
32
Shen, Bo-Wen, Roger A. Pielke, and Xubin Zeng. "One Saddle Point and Two Types of Sensitivities within the Lorenz 1963 and 1969 Models." Atmosphere 13, no. 5 (May 7, 2022): 753. http://dx.doi.org/10.3390/atmos13050753.
Full textAbstract:
The fact that both the Lorenz 1963 and 1969 models suggest finite predictability is well known. However, less well known is the fact that the mechanisms (i.e., sensitivities) within both models, which lead to finite predictability, are different. Additionally, the mathematical and physical relationship between these two models has not been fully documented. New analyses, along with a literature review, are performed here to provide insights regarding similarities and differences for these two models. The models represent different physical systems, one for convection and the other for barotropic vorticity. From the perspective of mathematical complexities, the Lorenz 1963 (L63) model is limited-scale and nonlinear; and the Lorenz 1969 (L69) model is closure-based, physically multiscale, mathematically linear, and numerically ill-conditioned. The former possesses a sensitive dependence of solutions on initial conditions, known as the butterfly effect, and the latter contains numerical sensitivities due to an ill-conditioned matrix with a large condition number (i.e., a large variance of growth rates). Here, we illustrate that the existence of a saddle point at the origin is a common feature that produces instability in both systems. Within the chaotic regime of the L63 nonlinear model, unstable growth is constrained by nonlinearity, as well as dissipation, yielding time varying growth rates along an orbit, and, thus, a dependence of (finite) predictability on initial conditions. Within the L69 linear model, multiple unstable modes at various growth rates appear, and the growth of a specific unstable mode (i.e., the most unstable mode during a finite time interval) is constrained by imposing a saturation assumption, thereby yielding a time varying system growth rate. Both models were interchangeably applied for qualitatively revealing the nature of finite predictability in weather and climate. However, only single type solutions were examined (i.e., chaotic and linearly unstable solutions for the L63 and L69 models, respectively), and the L69 system is ill-conditioned and easily captures numerical instability. Thus, an estimate of the predictability limit using either of the above models, with or without additional assumptions (e.g., saturation), should be interpreted with caution and should not be generalized as an upper limit for atmospheric predictability.
33
Gripeos, Panagiotis J., Hector E. Nistazakis, Andreas D. Tsigopoulos, Vasilis Christofilakis, and Evgenia Roditi. "Time and Spatial Jitter Influence on the Performance of FSO Links with DF Relays and OC Diversity Over Turbulence Channels." Photonics 8, no. 8 (August 7, 2021): 318. http://dx.doi.org/10.3390/photonics8080318.
Full textAbstract:
FSO communication is a viral technology among optical wireless communications, gathering the interest of both researchers and manufacturers. This is because of the many advantages associated with FSO communication, including high data rates, reliability, safety, and economy. However, there are several unavoidable drawbacks that shadow the performance of FSO systems. For example, atmospheric turbulence is a well-known problem related to the weather conditions of the channel, which causes the scintillation effect. Also, spatial jitter due to pointing errors is a critical factor of the link’s performance, caused by occasional misalignments between the transmitter and the receiver. Moreover, time jitter is another limiting agent that deteriorates the total throughput, inducing bit stream misdetections, caused by the arrival of out-of-sync pulses. All three effects have been exhaustively studied and many statistical models and interesting solutions have been proposed in the literature to estimate their magnitude and compensate for their impact. In this work, the turbulence effect was treated by Málaga distribution, the spatial jitter effect was regulated by the non-zero boresight model, and the time jitter effect was modeled by the generalized Gaussian distribution. Various modulation schemes were studied, along with DF multi-hop and optimal combining diversity techniques at the receiver’s end. New, accurate mathematical expressions of average BER performance have been obtained, and valuable conclusions were drawn thanks to the presented numerical results.
34
Nikolaev, S. V., U. S. Zubairova, E. S. Skolotneva, E. A. Orlova, and D. A. Afonnikov. "A system approach to the modeling of fungal infections of the wheat leaf." Vavilov Journal of Genetics and Breeding 23, no. 1 (February 26, 2019): 100–109. http://dx.doi.org/10.18699/vj19.468.
Full textAbstract:
Currently, studies on the mechanisms of the pathogenesis of plant diseases and their distribution in crops are intensively conducted in Russia and the world. First of all, this interest is associated with a significant effect of pathogens on the harvest. In Western Siberia, brown rust and powdery mildew are almost annually recorded in the crops of spring and winter wheat, reaching in some years up to the epiphytotic level. In this regard, methods for monitoring the condition of crops in order to predict their dynamics and plan agrotechnological events to control the state of plants in crops, including the development of fungal infection are developing. Models of fungal infections development on the wheat leaf (for example, brown rust) are used to monitor, predict and control the state of crops in order to optimize the growing process. Mathematical models allow computational experiments to make predictions about the risk dynamics of infections in different scenarios of global weather changes. Such designation of models assumes their hierarchical structure characteristic of multilevel modeling systems. This review presents models for the development of foliar fungal infections in crops, and formulates the methodological aspects of system modeling that can be used for adapting existing models and their units, and developing new models based on them. The article presents the structure of the hierarchical system for modeling the development of leafy infection, provides an overview of the units constituting the system, and discusses the issues of parametric adaptation of submodels. We demonstrated that, to date, plant growth and development models have been developed with varying degrees of detail. Currently, to develop a system for modeling the development of an infection in a crop, it is necessary to determine a large body of available experimental data and, by taking into account this data, we can put together a model as a system consisting of model modules, for which the models of basic processes have already been developed and described.
35
Kuznetsov, I. E., A. V. Melnikov, E. A. Rogozin, and O. V. Strashko. "METHODOLOGY FOR ACCOUNTING THE INFLUENCE OF METEOROLOGICAL FACTORS ON THE EFFICIENCY OF APPLICATION OF UNMANNED AERIAL VEHICLES ON THE BASIS OF SYSTEM ANALYSIS." Herald of Dagestan State Technical University. Technical Sciences 45, no. 2 (December 17, 2018): 125–39. http://dx.doi.org/10.21822/2073-6185-2018-45-2-125-139.
Full textAbstract:
ObjectivesThe aim of the study is to increase the effectiveness of unmanned aerial vehicles (UAVs) in the context of destabilising meteorological factors on the basis of an identification of links and patterns of unmanned aerial vehicles operating in difficult weather conditions.MethodsIn this work, in order to account for the effect of meteorological factors on the effectiveness of unmanned aerial vehicles, the methods of system analysis, mathematical modelling of atmospheric phenomena and processes, as well as probability theory and statistical assessment, were applied.ResultAn analysis of open literature sources devoted to the issues of operation and practical application of unmanned aerial vehicles (UAVs) under the influence of environmental factors was carried out. A classification of destabilising influences (DI) affecting the performance of a UAV flight mission is developed and presented. The dynamic probabilistic indicator, which, in characterising the dynamics of UAV functions as a complex technical system is referred to as “time efficiency of the UAV flight mission”, is substantiated. A methodology for estimating the dynamic efficiency indicator of the UAV’s functionality during the performance of a flight mission (FM) underDI conditions is developed on the basisof a probabilistic model of the conflicting interaction between UAV and DI. Strategies for selecting the trajectories of flights around local zones in which UAVs can be influenced by DI are given. To estimate the DI intensity and determine the size of the local disturbance zone, a mathematical model is proposed, whose application makes it possible to improve the UAV functioning under complex meteorological conditions (CMC) by taking into account the information on the space-time variability of dangerous for UAV weather-related phenomena (DWP). In the process of constructing the UAV functioning model, the use of conflict theory methods permitted adequate models for the analysis and evaluation of the dynamic efficiency indicator of the UAV functioning during the performance of FM in DI conditions to be developed, as well as the patterns of meteorological factors influencing the effectiveness of the UAV application to be revealed.ConclusionThe methodology proposed in the article makes it possible to increase the effectiveness of unmanned aerial vehicles (UAVs) under complex meteorological conditions by a time index of 20-30% as compared with traditional approaches.
36
Minder, Justin R., Theodore W. Letcher, and Changhai Liu. "The Character and Causes of Elevation-Dependent Warming in High-Resolution Simulations of Rocky Mountain Climate Change." Journal of Climate 31, no. 6 (March 2018): 2093–113. http://dx.doi.org/10.1175/jcli-d-17-0321.1.
Full textAbstract:
The character and causes of elevation-dependent warming (EDW) of surface temperatures are examined in a suite of high-resolution ([Formula: see text] km) regional climate model (RCM) simulations of climate change over the Rocky Mountains using the Weather Research and Forecasting Model. A clear EDW signal is found over the region, with warming enhanced in certain elevation bands by as much as 2°C. During some months warming maximizes at middle elevations, whereas during others it increases monotonically with elevation or is nearly independent of elevation. Simulated EDW is primarily caused by the snow albedo feedback (SAF). Warming maximizes in regions of maximum snow loss and albedo reduction. The role of the SAF is confirmed by sensitivity experiments wherein the SAF is artificially suppressed. The elevation dependence of free-tropospheric warming appears to play a secondary role in shaping EDW. No evidence is found for a contribution from elevation-dependent water vapor feedbacks. Sensitivity experiments show that EDW depends strongly on certain aspects of RCM configuration. Simulations using 4- and 12-km horizontal grid spacings show similar EDW signals, but substantial differences are found when using a grid spacing of 36 km due to the influence of terrain resolution on snow cover and the SAF. Simulations using the Noah and Noah-MP land surface models (LSMs) exhibit large differences in EDW. These are caused by differences between LSMs in their representations of midelevation snow extent and in their parameterization of subpixel fractional snow cover. These lead to albedo differences that act to modulate the simulated SAF and its effect on EDW.
37
Idzkowski, Adam, Karolina Karasowska, and Wojciech Walendziuk. "Temperature Analysis of the Stand-Alone and Building Integrated Photovoltaic Systems Based on Simulation and Measurement Data." Energies 13, no. 16 (August 18, 2020): 4274. http://dx.doi.org/10.3390/en13164274.
Full textAbstract:
Sunlight is converted into electrical energy due to the photovoltaic effect in photovoltaic cells. Energy yield of photovoltaic systems depends on the solar array location, orientation, tilt, tracking and local weather conditions. In order to determine the amount of energy produced in a photovoltaic system, it is important to analyze the operation of the photovoltaic (PV) arrays in real operating conditions and take into account the impact of external factors such as irradiance, ambient temperature or the speed of blowing wind, which is the natural coolant of PV panels. The analysis was carried out based on mathematical models and actual measurement data, regarding the dependence of the average temperature of PV arrays on variable and difficult to predict ambient conditions. The analysis used standard (nominal operating cell temperature (NOCT)), King, Skoplaki, Faiman and Mattei thermal models and the standard model for flat-plate photovoltaic arrays. Photovoltaic installations PV1, PV2a and PV2b, being part of the hybrid power plant of the Bialystok University of Technology, Poland, were the objects of the research. In the case of a free-standing solar system, the Skoplaki model proved to be the best method for determining the average temperatures of the PV arrays. For building-integrated PV systems, a corrected value of the mounting coefficient in the Skoplaki model was proposed, and the original results were compared. The comparison of the accuracy measures of the average operating temperatures for three micro-power plants, differently mounted and located, is presented.
38
Muhlbauer, A., T. Hashino, L. Xue, A. Teller, U. Lohmann, R. M. Rasmussen, I. Geresdi, and Z. Pan. "Intercomparison of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds." Atmospheric Chemistry and Physics 10, no. 17 (September 2, 2010): 8173–96. http://dx.doi.org/10.5194/acp-10-8173-2010.
Full textAbstract:
Abstract. Anthropogenic aerosols serve as a source of both cloud condensation nuclei (CCN) and ice nuclei (IN) and affect microphysical properties of clouds. Increasing aerosol number concentrations is hypothesized to retard the cloud droplet coalescence and the riming in mixed-phase clouds, thereby decreasing orographic precipitation. This study presents results from a model intercomparison of 2-D simulations of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds. The sensitivity of orographic precipitation to changes in the aerosol number concentrations is analysed and compared for various dynamical and thermodynamical situations. Furthermore, the sensitivities of microphysical processes such as coalescence, aggregation, riming and diffusional growth to changes in the aerosol number concentrations are evaluated and compared. The participating numerical models are the model from the Consortium for Small-Scale Modeling (COSMO) with bulk microphysics, the Weather Research and Forecasting (WRF) model with bin microphysics and the University of Wisconsin modeling system (UWNMS) with a spectral ice habit prediction microphysics scheme. All models are operated on a cloud-resolving scale with 2 km horizontal grid spacing. The results of the model intercomparison suggest that the sensitivity of orographic precipitation to aerosol modifications varies greatly from case to case and from model to model. Neither a precipitation decrease nor a precipitation increase is found robustly in all simulations. Qualitative robust results can only be found for a subset of the simulations but even then quantitative agreement is scarce. Estimates of the aerosol effect on orographic precipitation are found to range from −19% to 0% depending on the simulated case and the model. Similarly, riming is shown to decrease in some cases and models whereas it increases in others, which implies that a decrease in riming with increasing aerosol load is not a robust result. Furthermore, it is found that neither a decrease in cloud droplet coalescence nor a decrease in riming necessarily implies a decrease in precipitation due to compensation effects by other microphysical pathways. The simulations suggest that mixed-phase conditions play an important role in buffering the effect of aerosol perturbations on cloud microphysics and reducing the overall susceptibility of clouds and precipitation to changes in the aerosol number concentrations. As a consequence the aerosol effect on precipitation is suggested to be less pronounced or even inverted in regions with high terrain (e.g., the Alps or Rocky Mountains) or in regions where mixed-phase microphysics is important for the climatology of orographic precipitation.
39
Yuan, Xinzhe, Mohammad Ali Karbasforoushha, Rahmad B. Y. Syah, Mohammad Khajehzadeh, Suraparb Keawsawasvong, and Moncef L. Nehdi. "An Effective Metaheuristic Approach for Building Energy Optimization Problems." Buildings 13, no. 1 (December 29, 2022): 80. http://dx.doi.org/10.3390/buildings13010080.
Full textAbstract:
Mathematical optimization can be a useful strategy for minimizing energy usage while designing low-energy buildings. To handle building energy optimization challenges, this study provides an effective hybrid technique based on the pelican optimization algorithm (POA) and the single candidate optimizer (SCO). The suggested hybrid algorithm (POSCO) benefits from both the robust local search power of the single candidate method and the efficient global search capabilities of the pelican optimization. To conduct the building optimization task, the optimization method was developed and integrated with the EnergyPlus codes. The effectiveness of the proposed POSCO method was verified using mathematical test functions, and the outcomes were contrasted with those of conventional POA and other effective optimization techniques. Application of POSCO for global function optimization reveals that, among the thirteen considered functions, the proposed method was best at finding the global solution for seven functions, while providing superior results for the other functions when compared with competitive techniques. The suggested POSCO is applied for reducing an office buildings’ annual energy use. Comparing POSCO to POA procedures, the building energy usage is reduced. Furthermore, POSCO is compared to simple POA and other algorithms, with the results showing that, at specific temperatures and lighting conditions, the POSCO approach outperforms selected state-of-the-art methods and reduces building energy usage. As a result, all data suggests that POSCO is a very promising, dependable, and feasible optimization strategy for dealing with building energy optimization models. Finally, the building energy optimization findings for various climatic conditions demonstrate that the changes to the weather dataset had limited effect on the efficiency of the optimization procedure.
40
Muhlbauer, A., T. Hashino, L. Xue, A. Teller, U. Lohmann, R. M. Rasmussen, I. Geresdi, and Z. Pan. "Intercomparison of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds." Atmospheric Chemistry and Physics Discussions 10, no. 4 (April 21, 2010): 10487–550. http://dx.doi.org/10.5194/acpd-10-10487-2010.
Full textAbstract:
Abstract. Anthropogenic aerosols serve as a source of both cloud condensation nuclei (CCN) and ice nuclei (IN) and affect microphysical properties of clouds. Increasing aerosol number concentrations is hypothesized to retard the cloud droplet collision/coalescence and the riming in mixed-phase clouds, thereby decreasing orographic precipitation. This study presents results from a model intercomparison of 2-D simulations of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds. The sensitivity of orographic precipitation to changes in the aerosol number concentrations is analyzed and compared for various dynamical and thermodynamical situations. Furthermore, the sensitivities of microphysical processes such as collision/coalescence, aggregation and riming to changes in the aerosol number concentrations are evaluated and compared. The participating models are the Consortium for Small-Scale Modeling's (COSMO) model with bulk-microphysics, the Weather Research and Forecasting (WRF) model with bin-microphysics and the University of Wisconsin modeling system (UWNMS) with a spectral ice-habit prediction microphysics scheme. All models are operated on a cloud-resolving scale with 2 km horizontal grid spacing. The results of the model intercomparison suggest that the sensitivity of orographic precipitation to aerosol modifications varies greatly from case to case and from model to model. Neither a precipitation decrease nor a precipitation increase is found robustly in all simulations. Qualitative robust results can only be found for a subset of the simulations but even then quantitative agreement is scarce. Estimates of the second indirect aerosol effect on orographic precipitation are found to range from –19% to 0% depending on the simulated case and the model. Similarly, riming is shown to decrease in some cases and models whereas it increases in others which implies that a decrease in riming with increasing aerosol load is not a robust result. Furthermore, it is found that neither a decrease in cloud droplet coalescence nor a decrease in riming necessarily implies a decrease in precipitation due to compensation effects by other microphysical pathways. The simulations suggest that mixed-phase conditions play an important role in reducing the overall susceptibility of clouds and precipitation with respect to changes in the aerosols number concentrations. As a consequence the indirect aerosol effect on precipitation is suggested to be less pronounced or even inverted in regions with high terrain (e.g., the Alps or Rocky Mountains) or in regions where mixed-phase microphysics climatologically plays an important role for orographic precipitation.
41
Sekigawa, Hiroshi. "Research on the effect of perturbation on algebraic problems and the methodology to cope with it." Impact 2019, no. 10 (December 30, 2019): 58–60. http://dx.doi.org/10.21820/23987073.2019.10.58.
Full textAbstract:
The reliance modern society has on computing is easily forgotten on a day-to-day basis. However, most people begin the day by looking at a mobile phone. A device that is connected to the Internet and gets the day started with weather updates, messages you've received via email or social media and the morning news. Then as they head out of the houses into the streets for the morning commute, they receive up to the minute directions, public transport schedules, delays or road traffic interruptions. During their commute people may even listen to their favourite songs, compressed to fit on the device in near perfect quality. All this, and more, is powered on some level by computing and it is hard to now imagine a world without it. However, it is equally hard to imagine what actually goes into making all of this happen. Perhaps, one has heard of the limits of computation, usually dependent on hardware like silicon chips. Less well known though is the mathematical nature of computation, the algorithms and calculations that go into designing the software which powers our economies and modern lifestyle. 'Computation underpins all computer science, a discipline that studies the processes that interact with data which we often refer to as programs,' outlines computation expert Professor Hiroshi Sekigawa, who is based at the Tokyo University of Science. Computation itself is a calculation that is carried out based on an explicitly designed model, like an algorithm. These algorithms make up the programs in our computers and are designed to solve problems. While there are different modes of developing algorithms and computing models, numeric computation is the one that is easily applicable to scientific computing. Fields like engineering, the physical sciences, life sciences, medicine and business all use elements of scientific computing to, among other things make detailed models of the world. 'To allow these computations to run more efficiently, using less memory, the technique of floating-point arithmetic is used,' explains Sekigawa. 'In short, this method uses formulas to represent real numbers resulting in approximations. This is useful for systems containing miniscule or immense numbers and require speedy processing times.' He says the drawback is that error analysis is needed to validate these outputs based on approximations. His team are working to improve on the current situation by exploring different modes of computation and the effects of combing them.
42
Евстегнеева, V. Evstegneeva, Честнова, Tatyana Chestnova, Смольянинова, and O. Smolyaninova. "Regression analysis forecasting pririrodno focal infections." Journal of New Medical Technologies. eJournal 9, no. 4 (December 8, 2015): 0. http://dx.doi.org/10.12737/17086.
Full textAbstract:
Regression analysis - a set of statistical methods for processing of experimental data to a condition
of stochastic dependence study of the value of non-random or random variables to define this relationship.
Statement of the problem of regression analysis is formulated as follows. There is a set of observational results.
Requires a quantitative relationship between the index and factors.
In this paper, we try to establish a quantitative relationship between the incidence of natural - focal infections
and biotic and abiotic factors of the environment. By biotic factors include: the number of infection and the
major carriers and vectors to abiotic factors - weather (average monthly air temperature, the monthly average
rainfall, snow depth in December, January, February, March).
When studying the effect of 22 factors on the incidence of leptospirosis using multiple regression the mathematical
model, which has a low level of trust, and when using the stepwise regression established the influence
of one factor - infection of the common vole of the 22 factors. Level of trust models and model coefficients
are significant. This method allows to determine only the linear relationship between the incidence and natural
factors, as in the case of the nonlinear coupling tightness does not install.
Natural foci of infection is a complex ecological system. Based on the terms of modeling complex systems,
which may include: the possible impact of non-linear elements in the output parameter, synergy and reciprocity
under the joint influence of individual factors, the need to address in some cases categorical factors and
multiple output parameters of a complex system, it is necessary to choose an artificial neural network (ANN),
allowing to realize these conditions in the preparation of a mathematical model of the system.
43
Kolawole, Olabamidele O., Thomas J. O. Afullo, and Modisa Mosalaosi. "Analysis of Scintillation Effects on Free Space Optical Communication Links in South Africa." Photonics 9, no. 7 (June 25, 2022): 446. http://dx.doi.org/10.3390/photonics9070446.
Full textAbstract:
The performance of free space optical communication (FSOC) systems is severely degraded by certain atmospheric conditions prevalent in places where they are deployed, in spite of their numerous advantages. In clear weather conditions, the random fluctuation in the atmosphere’s refractive index causes substantial scintillation losses to transmitted optical signals. It is therefore imperative to estimate the potential losses due to atmospheric turbulence in locations where FSOC links are to be deployed. This will provide the necessary fade margin for FSOC systems so that designed links withstand such atmospheric disturbances. In this paper, statistical analysis of wind speed data collected for various cities of South Africa is used for calculating the corresponding refractive index structure parameter (Cn2). These Cn2 values, as well as the zero inner scale and infinite outer scale model and finite inner and finite outer scale model, are used in computing the scintillation indices not exceeding 50%, 99%, 99.9%, and 99.99% of the time for the investigated locations. The Lognormal and Gamma–gamma distribution models are then employed for the computational analysis of the irradiance fluctuations and channel characteristics while considering the effect of pointing errors for weak and moderate to strong turbulence regimes. Finally, derived mathematical expressions for outage probabilities and bit error rate (BER) performances for FSOC links, employing various intensity modulation and direct detection (IM/DD) schemes, are presented.
44
Rokochinskiy, A. M., and P. P. Volk. "Models of system optimization for constructing and functioning drainage systems in current conditions." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 1 (May 7, 2021): 75–86. http://dx.doi.org/10.31073/mivg202101-277.
Full textAbstract:
Relevance of research. Land reclamation is important for stabilizing the resource and food security of our state and the world in a whole. Food production security is extremely important in extreme years of weather conditions.
Land reclamation has a high social significance, especially given the global climate change and land policy formation, taking into account European and world experience. Water, hydraulic, agro-technical, and other types of land reclamation require modern innovative solutions. These solutions must be created to achieve sustainable food, energy, the environmental and economic security of the state. Therefore, it is extremely important to change the approaches to constructing and functioning water reclamation facilities. It is also important to improve water management technologies that will be adapted to these changes.
Research goal is to develop a general theory of optimization and development of methods and models for optimal regime, technological and technical parameters of drainage systems on an ecological and economic basis.
Research methods are based on the application of systems theory with system analysis and modeling when developing the approaches to the optimization of regime, technological and technical solutions for constructing and functioning drainage systems on an ecological and economic basis. The system approach includes research of drainage systems as complex natural, technical, ecological and economic systems; research of their elements, laws of functioning and development; decomposition of complex problems of mainly hierarchical nature; application of the methodology of the hierarchy of analysis and synthesis when developing forecasting and optimization models and the methods of their implementation.
Research results and main conclusions. Finding the general (global) optimum for a drainage system on the basis of system optimization is a substantiation of intermediate local optimums for all its basic elements (effect, regime, technology, design). The general principles of construction and realization of complex models of system optimization which include the model of economic optimization have been developed. This model is built on the traditional economic and mathematical approach, and its environmental component determines the correctness of the optimal economic solution. The criteria of economic and ecological optimization of different levels of management decisions in time (1-project, 2-planned operation, 3-management) have been considered. We also present a complex of forecasting and simulation models for long-term forecasting on a multivariate basis, taking into account the variable natural agro-ameliorative conditions of a real object.
Prospects. The application of optimization methods requires a change in the design technology of water reclamation facilities based on the use of a multivariate approach, modern information and computer technologies. The use of system optimization will increase the overall technical, technological, environmental and economic efficiency of constructing and functioning drainage systems.
45
Orlowski, Andrzej. "Experimental verification of the acoustic characteristics of the clupeoid diel cycle in the Baltic." ICES Journal of Marine Science 62, no. 6 (January 1, 2005): 1180–90. http://dx.doi.org/10.1016/j.icesjms.2005.02.013.
Full textAbstract:
Abstract This paper describes the results of a short-term experiment using measurements of sv from the diel, spatial, clupeoid distribution in the southern Baltic. The aim of the experiment was to verify fish-behaviour characteristics measured over the period from 1995 to 2001. It was also intended to estimate the dynamics of fish behaviour over one separate diel cycle. The studies were based on a 24 h continuous integration of fish echoes using an EY500 echosounder at 38 kHz. Measurements were carried out by RV “Baltica” travelling along the sides of a square of 4 nautical miles at a constant speed of 8 knots. The South Gotland Deep was chosen for the experiment because of the greatest amplitude there of fish vertical, diel migrations within the Polish EEZ. The duration of the experiment was limited by weather conditions, but nearly 300 EDSU samples were collected. 3-D distributions of echoes were correlated to the values of coincident environmental factors of time, depth, water temperature, salinity, and oxygen level. Fish distribution compared with environmental factors is described by different macrosounding visualizations, statistical, and mathematical models. Measurements are compared with the average characteristics of fish behaviour based on data from the autumn acoustic studies between 1995 and 2001 in a wider environment of the Gotland Deep. The results strongly confirmed the instability of the diel acoustic response of fish echoes in both situations. More precise measurements during the experiment indicated the biggest column-scattering strength (Svc) increase during the sunrise period, appearing simultaneously in the whole area. A similar increase was detected by analysis of 1995–2001 data from the South Gotland Deep environment. Major emphasis is given to the explanation of the diel irregularities. Diel instability of fish acoustic response can significantly effect the results of target-strength measurements (up to 400% during the sunrise) and, as a consequence, the calibration of acoustic fish stock-assessment models.
46
Fong, Peter. "Influence Of Ice Sheets On Climate and Ice-Sheet Dynamics." Annals of Glaciology 14 (1990): 335. http://dx.doi.org/10.3189/s026030550000896x.
Full textAbstract:
The important role played by ice on climate is recognized in the ice–albedo feedback effect which is incorporated in most climate models. But the ice under consideration is two-dimensional and only its surface area enters into the interaction. Whereas this applies well to the seasonal ice and sea ice, it does not to the permanent ice sheets on earth because they are three-dimensional. A new feature is the ice flow down the ice-sheet slope. This increases the amount of ice on the ice-sheet periphery above that produced by local precipitation that is considered in most climate models. As a result the ice–albedo effect will be greater than that given in most climate models. The latter (a positive feedback) is generally smaller than the major negative feedback due to the infrared effect and therefore stable equilibrium is achieved in most climate models. When the positive feedback is thus increased to an amount equal to the infrared negative feedback, stable equilibrium is destroyed and the system changes to netural equilibrium – a mildly unstable form. This may be just what is necessary to explain the advance and retreat of the ice sheets, which cannot be explained by most climate models because in stable equilibrium an ice sheet cannot advance and retreat.The advance and retreat can be proven to be the manifestation of a neutral equilibrium. At any instant of time in an ice age, including the present time, the climate system is nearly in equilibrium. But as time goes on the equilibrium point shifts continuously, reflecting the advance of the ice sheet and the cooling of the ocean. Thus an ice age is represented by a continuous sequence of equilibrium points, which, by definition, constitutes a netural equilibrium. The argument is reinforced by the observation that the “cause” of ice ages is a very small perturbation – the variation of the eccentricity of the earth orbit. According to most climate models, this effect is one order of magnitude too small to generate the climate changes in an ice age. On the other hand in a neutral equilibrium a very weak perturbation can generate slow progressive changes, like the rolling of a cylinder on a plane. As a matter of fact, the small periodic changes of the eccentricity pace the advance and retreat of the ice sheets almost in phase; this is not possible in stable and unstable equilibrium and can be possible only in neutral equilibrium. The empirical conclusion of neutral equilibrium is solidly established. Any theory and any climate model must accommodate this fact.A deeper understanding requires the pinpointing of the physical origin of the meutral equilibrium. The origin can be shown, though not obviously, to be just the phase equilibrium of water and ice, which is quasi-static and may be considered as neutral equilibrium in a mechanical analogy. The argument is complicated by the fact that the temperature does not remain constant as expected in phase equilibrium but does decrease in an ice age. However, this can be accounted for by the complication of the albedo effect. Hypothetically if ice were brown and without albedo effect, then in an ice age the temperature would not decrease and the situation would be just like ice-water phase equilibrium. The physical origin of neutral equilibrium clarifies the fundamental principle but is not necessary for the mathematical formulation of a dynamic theory of the ice sheets that is given as follows. Instead neutral equilibrium emerges naturally from that theory and the advance and retreat can be explained readily.Most climate models are static models which cannot explain the advance and retreat – a manifestly dynamic process. A simple but adequate dynamic theory can be formulated considering the ice volume V(t) and the ocean surface temperature T(t) as the basic dynamic variables. The equations for their changes can be written down, making use of the latent heat of fusion of ice and the sensible heat capacity of the ocean mixed layer. Albedo positive feedback and infrared negative feedback will be included in the heat balance. The three-dimensional effect of the ice sheet will be introduced in the albedo effect. This involves the geometry of the ice sheet which will be specified in a constraint equation. Then a closed, deterministic set of intergral-differential equations may be formulated to describe the dynamics of the ice sheets. The equations may be solved without adjustable parameters. The solutions agree with the observed advance and retreat of ice sheets and the cooling and warming of the ocean. A close examination of the feedbacks involved reveals that the dynamics is indeed like a mechanical system in neutral equilibrium. However, the detailed mathematical theory shows that the netural equilibrium changes to stable when the ice sheets reach the middle latitudes. They thus stop there in maximum glaciation.There is no limit on the other end. The northern ice sheet did melt completely. So could the Antarctic ice sheet though it has not in the ice ages. But before the Pleistocene in 99% of the geological time the earth was free of ice sheets. Then, why did the “cause” of ice ages, the eccentricity variations, not generate ice ages in 99% of the earth history? Ice and water can co-exist (in equilibrium) only under unusual conditions, which are not fulfilled generally. But in recent geological times Antarctica drifted to the pole position and high mountains arose on the continents so that permanent ice can survive the summer season and accumulate year after year. Most important, the CO2 content in the atmosphere has been decreasing (Budyko, 1974), cooling down the earth. Eventually the earth was cool enough in Pleistocene to satisfy the neutral equilibrium condition. Then the ice ages began.But we are now burning fossil fuels to put CO2 back into the atmosphere, going back to pre-Pleistocene conditions. The Antarctic ice sheet will melt away; this will be the principal result of the greenhouse effect. However, current discussion of the greenhouse effect deals with only the warming of the earth and neglects the more serious effect of the melting of the Antarctic ice sheet because climatologists overlooked the effect of ice sheets on climate. This study will change the outlook.
47
Fong, Peter. "Influence Of Ice Sheets On Climate and Ice-Sheet Dynamics." Annals of Glaciology 14 (1990): 335. http://dx.doi.org/10.1017/s026030550000896x.
Full textAbstract:
The important role played by ice on climate is recognized in the ice–albedo feedback effect which is incorporated in most climate models. But the ice under consideration is two-dimensional and only its surface area enters into the interaction. Whereas this applies well to the seasonal ice and sea ice, it does not to the permanent ice sheets on earth because they are three-dimensional. A new feature is the ice flow down the ice-sheet slope. This increases the amount of ice on the ice-sheet periphery above that produced by local precipitation that is considered in most climate models. As a result the ice–albedo effect will be greater than that given in most climate models. The latter (a positive feedback) is generally smaller than the major negative feedback due to the infrared effect and therefore stable equilibrium is achieved in most climate models. When the positive feedback is thus increased to an amount equal to the infrared negative feedback, stable equilibrium is destroyed and the system changes to netural equilibrium – a mildly unstable form. This may be just what is necessary to explain the advance and retreat of the ice sheets, which cannot be explained by most climate models because in stable equilibrium an ice sheet cannot advance and retreat. The advance and retreat can be proven to be the manifestation of a neutral equilibrium. At any instant of time in an ice age, including the present time, the climate system is nearly in equilibrium. But as time goes on the equilibrium point shifts continuously, reflecting the advance of the ice sheet and the cooling of the ocean. Thus an ice age is represented by a continuous sequence of equilibrium points, which, by definition, constitutes a netural equilibrium. The argument is reinforced by the observation that the “cause” of ice ages is a very small perturbation – the variation of the eccentricity of the earth orbit. According to most climate models, this effect is one order of magnitude too small to generate the climate changes in an ice age. On the other hand in a neutral equilibrium a very weak perturbation can generate slow progressive changes, like the rolling of a cylinder on a plane. As a matter of fact, the small periodic changes of the eccentricity pace the advance and retreat of the ice sheets almost in phase; this is not possible in stable and unstable equilibrium and can be possible only in neutral equilibrium. The empirical conclusion of neutral equilibrium is solidly established. Any theory and any climate model must accommodate this fact. A deeper understanding requires the pinpointing of the physical origin of the meutral equilibrium. The origin can be shown, though not obviously, to be just the phase equilibrium of water and ice, which is quasi-static and may be considered as neutral equilibrium in a mechanical analogy. The argument is complicated by the fact that the temperature does not remain constant as expected in phase equilibrium but does decrease in an ice age. However, this can be accounted for by the complication of the albedo effect. Hypothetically if ice were brown and without albedo effect, then in an ice age the temperature would not decrease and the situation would be just like ice-water phase equilibrium. The physical origin of neutral equilibrium clarifies the fundamental principle but is not necessary for the mathematical formulation of a dynamic theory of the ice sheets that is given as follows. Instead neutral equilibrium emerges naturally from that theory and the advance and retreat can be explained readily. Most climate models are static models which cannot explain the advance and retreat – a manifestly dynamic process. A simple but adequate dynamic theory can be formulated considering the ice volume V(t) and the ocean surface temperature T(t) as the basic dynamic variables. The equations for their changes can be written down, making use of the latent heat of fusion of ice and the sensible heat capacity of the ocean mixed layer. Albedo positive feedback and infrared negative feedback will be included in the heat balance. The three-dimensional effect of the ice sheet will be introduced in the albedo effect. This involves the geometry of the ice sheet which will be specified in a constraint equation. Then a closed, deterministic set of intergral-differential equations may be formulated to describe the dynamics of the ice sheets. The equations may be solved without adjustable parameters. The solutions agree with the observed advance and retreat of ice sheets and the cooling and warming of the ocean. A close examination of the feedbacks involved reveals that the dynamics is indeed like a mechanical system in neutral equilibrium. However, the detailed mathematical theory shows that the netural equilibrium changes to stable when the ice sheets reach the middle latitudes. They thus stop there in maximum glaciation. There is no limit on the other end. The northern ice sheet did melt completely. So could the Antarctic ice sheet though it has not in the ice ages. But before the Pleistocene in 99% of the geological time the earth was free of ice sheets. Then, why did the “cause” of ice ages, the eccentricity variations, not generate ice ages in 99% of the earth history? Ice and water can co-exist (in equilibrium) only under unusual conditions, which are not fulfilled generally. But in recent geological times Antarctica drifted to the pole position and high mountains arose on the continents so that permanent ice can survive the summer season and accumulate year after year. Most important, the CO2 content in the atmosphere has been decreasing (Budyko, 1974), cooling down the earth. Eventually the earth was cool enough in Pleistocene to satisfy the neutral equilibrium condition. Then the ice ages began. But we are now burning fossil fuels to put CO2 back into the atmosphere, going back to pre-Pleistocene conditions. The Antarctic ice sheet will melt away; this will be the principal result of the greenhouse effect. However, current discussion of the greenhouse effect deals with only the warming of the earth and neglects the more serious effect of the melting of the Antarctic ice sheet because climatologists overlooked the effect of ice sheets on climate. This study will change the outlook.
48
Al-Maliki, Wisam Abed Kattea, Hayder Q. A. Khafaji, Hasanain A. Abdul Wahhab, Hussein M. H. Al-Khafaji, Falah Alobaid, and Bernd Epple. "Advances in Process Modelling and Simulation of Parabolic Trough Power Plants: A Review." Energies 15, no. 15 (July 29, 2022): 5512. http://dx.doi.org/10.3390/en15155512.
Full textAbstract:
The common design of thermal power plants is fundamentally oriented towards achieving a high-process performance, with market demands necessitating enhanced operational stability as a result of ongoing global support for renewable energy sources. Indeed, dynamic simulation represents one useful and cost-effective choice for optimizing the flexibility of parabolic trough power plants (PTPP) in a range of transient operating conditions, such as weather changes, resulting again in variations of the output load as well as varying start-up times. The purpose of this review is to provide an overview of steady-state and dynamic modelling for PTPP design, development, and optimization. This gives us a greater opportunity for a broad understanding of the PTPPs subjected to a variety of irradiance solar constraints. The most important features of the steady-state and their uses are reviewed, and the most important programs used in steady-state modelling are also highlighted. In addition, the start-up process of the plant, thermal storage system capacities and response dynamics (charging and discharging modes), and yearly electricity yield can be analyzed using dynamic modelling. Depending on the dynamic simulation, specific uses can be realized, including control loop optimization, load estimation for critical in-service equipment, and emergency safety assessment of power plants in the event of an outage. Based on this review, a detailed overview of the dynamic simulation of PTPP, and its development and application in various simulation programs, is presented. Here, a survey of computational dynamic modelling software commonly applied for commercial and academic applications is performed, accompanied by various sample models of simulation programs such as APROS, DYNAMICS, DYMOLA, and ASPEN PLUS. The simulation programs generally depend on the conservation equations of mass, momentum, species, and energy. However, for the equation of equilibrium, specific mathematical expressions rely on the basic flow model. The essential flow models involved, together with the basic assumptions, are presented, and are supplemented through a general survey covering popular simulation programs. Various previous research on the dynamic simulation of the PTPP are reviewed and analyzed in this paper. Here, several studies in the literature regarding the dynamic simulation of the PTPP are addressed and analyzed. Specific consideration is given to the studies including model verification, in order to explore the effect of modelling assumptions regarding the simulation outputs.
49
Lee and Oh. "Developing the Urban Thermal Environment Management and Planning (UTEMP) System to Support Urban Planning and Design." Sustainability 11, no. 8 (April 12, 2019): 2224. http://dx.doi.org/10.3390/su11082224.
Full textAbstract:
Mathematical Climate Simulation Modeling (MCSM) has the advantage of not only investigating the urban heat island phenomenon but also of identifying the effects of thermal environment improvement plans in detail. As a result, MCSM has been applied worldwide as a scientific tool to analyze urban thermal environment problems. However, the meteorological models developed thus far have been insufficient in terms of their direct application to the urban planning and design fields due to the preprocessing task for modeling operations and the excessive time required. By combining meteorological modeling and Geographic Information System (GIS) analysis methods, this study developed the Urban Thermal Environment Management and Planning (UTEMP) system that is user-friendly and can be applied to urban planning and design. Furthermore, the usefulness of UTEMP was investigated in this study by application to areas where the heat island phenomenon occurs frequently: Seoul, Korea. The accuracy of the UTEMP system was verified by comparing its results to the Automatic Weather Systems (AWSs) data. Urban spatial change scenarios were prepared and air temperature variations according to such changes were compared. Subsequently, the urban spatial change scenarios were distinguished by four cases, including the existing condition (before the development), applications of the thermal environment measures to the existing condition, allowable future urban development (the maximum development density under the urban planning regulations), and application of the thermal environment measures to allowable future development. The UTEMP system demonstrated an accuracy of adj. R2 0.952 and a ±0.91 Root Mean Square Error (RMSE). By applying the UTEMP system to urban spatial change scenarios, the average air temperature of 0.35 °C and maximum air temperature of 1.27 °C were found to rise when the maximum development density was achieved. Meanwhile, the air temperature reduction effect of rooftop greening was identified by an average of 0.12 °C with a maximum of 0.45 °C. Thus, the development of UTEMPS can be utilized as an effective tool to analyze the impacts of urban spatial changes and for planning and design. As a result, the UTEMP system will allow for more efficient and practical establishment of measures to improve the urban thermal environment.
50
Hoyos, Carlos D., and Peter J. Webster. "The Role of Intraseasonal Variability in the Nature of Asian Monsoon Precipitation." Journal of Climate 20, no. 17 (September 1, 2007): 4402–24. http://dx.doi.org/10.1175/jcli4252.1.
Full textAbstract:
Abstract The structure of the mean precipitation of the south Asian monsoon is spatially complex. Embedded in a broad precipitation maximum extending eastward from 70°E to the northwest tropical Pacific Ocean are strong local maxima to the west of the Western Ghats mountain range of India, in Cambodia extending into the eastern China Sea, and over the eastern tropical Indian Ocean and the Bay of Bengal (BoB), where the strongest large-scale global maximum in precipitation is located. In general, the maximum precipitation occurs over the oceans and not over the land regions. Distinct temporal variability also exists with time scales ranging from days to decades. Neither the spatial nor temporal variability of the monsoon can be explained simply as the response to the cross-equatorial pressure gradient force between the continental regions of Asia and the oceans of the Southern Hemisphere, as suggested in classical descriptions of the monsoon. Monthly (1979–2005) and daily (1997–present) rainfall estimates from the Global Precipitation Climatology Project (GPCP), 3-hourly (1998–present) rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM) microwave imager (TMI) estimates of sea surface temperature (SST), reanalysis products, and satellite-determined outgoing longwave radiation (OLR) data were used as the basis of a detailed diagnostic study to explore the physical basis of the spatial and temporal nature of monsoon precipitation. Propagation characteristics of the monsoon intraseasonal oscillations (MISOs) and biweekly signals from the South China Sea, coupled with local and regional effects of orography and land–atmosphere feedbacks are found to modulate and determine the locations of the mean precipitation patterns. Long-term variability is found to be associated with remote climate forcing from phenomena such as El Niño–Southern Oscillation (ENSO), but with an impact that changes interdecadally, producing incoherent responses of regional rainfall. A proportion of the interannual modulation of monsoon rainfall is found to be the direct result of the cumulative effect of rainfall variability on intraseasonal (25–80 day) time scales over the Indian Ocean. MISOs are shown to be the main modulator of weather events and encompass most synoptic activity. Composite analysis shows that the cyclonic system associated with the northward propagation of a MISO event from the equatorial Indian Ocean tends to drive moist air toward the Burma mountain range and, in so doing, enhances rainfall considerably in the northeast corner of the bay, explaining much of the observed summer maximum oriented parallel to the mountains. Similar interplay occurs to the west of the Ghats. While orography does not seem to play a defining role in MISO evolution in any part of the basin, it directly influences the cumulative MISO-associated rainfall, thus defining the observed mean seasonal pattern. This is an important conclusion since it suggests that in order for the climate models to reproduce the observed seasonal monsoon rainfall structure, MISO activity needs to be well simulated and sharp mountain ranges well represented.