Academic literature on the topic 'Large-scale climate patterns'
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Journal articles on the topic "Large-scale climate patterns"
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Krinner, Gerhard, and Mark G. Flanner. "Striking stationarity of large-scale climate model bias patterns under strong climate change." Proceedings of the National Academy of Sciences 115, no. 38 (September 4, 2018): 9462–66. http://dx.doi.org/10.1073/pnas.1807912115.
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Because all climate models exhibit biases, their use for assessing future climate change requires implicitly assuming or explicitly postulating that the biases are stationary or vary predictably. This hypothesis, however, has not been, and cannot be, tested directly. This work shows that under very large climate change the bias patterns of key climate variables exhibit a striking degree of stationarity. Using only correlation with a model’s preindustrial bias pattern, a model’s 4xCO2bias pattern is objectively and correctly identified among a large model ensemble in almost all cases. This outcome would be exceedingly improbable if bias patterns were independent of climate state. A similar result is also found for bias patterns in two historical periods. This provides compelling and heretofore missing justification for using such models to quantify climate perturbation patterns and for selecting well-performing models for regional downscaling. Furthermore, it opens the way to extending bias corrections to perturbed states, substantially broadening the range of justified applications of climate models.
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Wiens, John J. "Explaining large-scale patterns of vertebrate diversity." Biology Letters 11, no. 7 (July 2015): 20150506. http://dx.doi.org/10.1098/rsbl.2015.0506.
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The major clades of vertebrates differ dramatically in their current species richness, from 2 to more than 32 000 species each, but the causes of this variation remain poorly understood. For example, a previous study noted that vertebrate clades differ in their diversification rates, but did not explain why they differ. Using a time-calibrated phylogeny and phylogenetic comparative methods, I show that most variation in diversification rates among 12 major vertebrate clades has a simple ecological explanation: predominantly terrestrial clades (i.e. birds, mammals, and lizards and snakes) have higher net diversification rates than predominantly aquatic clades (i.e. amphibians, crocodilians, turtles and all fish clades). These differences in diversification rates are then strongly related to patterns of species richness. Habitat may be more important than other potential explanations for richness patterns in vertebrates (such as climate and metabolic rates) and may also help explain patterns of species richness in many other groups of organisms.
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Ning, Liang, and Raymond S. Bradley. "Winter Climate Extremes over the Northeastern United States and Southeastern Canada and Teleconnections with Large-Scale Modes of Climate Variability*." Journal of Climate 28, no. 6 (March 13, 2015): 2475–93. http://dx.doi.org/10.1175/jcli-d-13-00750.1.
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Abstract The relationship between winter climate extremes across the northeastern United States and adjacent parts of Canada and some important modes of climate variability are examined to determine how these circulation patterns are related to extreme events. Linear correlations between 15 extreme climate indices related to winter daily precipitation, maximum and minimum temperature, and three dominant large-scale patterns of climate variability [the North Atlantic Oscillation (NAO), Pacific–North American (PNA) pattern, and El Niño–Southern Oscillation (ENSO)] were analyzed for the period 1950–99. The mechanisms behind these teleconnections are analyzed by applying composite analysis to the geopotential height, sea level pressure (SLP), moisture flux, and wind fields. Pressure anomalies and associated airflow patterns related with the different modes of climate variability explain the patterns of temperature and precipitation extremes across the region. The responses of the daily scale climate extremes to the seasonally averaged large-scale circulation patterns are achieved through shifts in the probability distributions.
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Bartolini, E., P. Claps, and P. D'Odorico. "Connecting European snow cover variability with large scale atmospheric patterns." Advances in Geosciences 26 (September 1, 2010): 93–97. http://dx.doi.org/10.5194/adgeo-26-93-2010.
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Abstract. Winter snowfall and its temporal variability are important factors in the development of water management strategies for snow-dominated regions. For example, mountain regions of Europe rely on snow for recreation, and on snowmelt for water supply and hydropower. It is still unclear whether in these regions the snow regime is undergoing any major significant change. Moreover, snow interannual variability depends on different climatic variables, such as precipitation and temperature, and their interplay with atmospheric and pressure conditions. This paper uses the EASE Grid weekly snow cover and Ice Extent database from the National Snow and Ice Data Center to assess the possible existence of trends in snow cover across Europe. This database provides a representation of snow cover fields in Europe for the period 1972–2006 and is used here to construct snow cover indices, both in time and space. These indices allow us to investigate the historical spatial and temporal variability of European snow cover fields, and to relate them to the modes of climate variability that are known to affect the European climate. We find that both the spatial and temporal variability of snow cover are strongly related to the Arctic Oscillation during wintertime. In the other seasons, weaker correlation appears between snow cover and the other patterns of climate variability, such as the East Atlantic, the East Atlantic West Russia, the North Atlantic Oscillation, the Polar Pattern and the Scandinavian Pattern.
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Huo, Xueli, Zhongfang Liu, Qingyun Duan, Pengmei Hao, Yanyan Zhang, Yonghong Hao, and Hongbin Zhan. "Linkages between Large-Scale Climate Patterns and Karst Spring Discharge in Northern China." Journal of Hydrometeorology 17, no. 2 (February 1, 2016): 713–24. http://dx.doi.org/10.1175/jhm-d-15-0085.1.
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Abstract The Niangziguan Springs (NS) discharge is used as a proxy indicator of the variability of the karst groundwater system in relation to major climate indices such as El Niño–Southern Oscillation (ENSO), Pacific decadal oscillation (PDO), Indian summer monsoon (ISM), and west North Pacific monsoon (WNPM). The relationships between spring discharge and these climate indices are determined using the multitaper method (MTM), continuous wavelet transform (CWT), and wavelet transform coherence (WTC). Significant periodic components of spring discharge in the 1-, 3.4-, and 26.8-yr periodicities are identified and reconstructed for further investigation of the correlation between spring discharge and large-scale climate patterns on these time scales. Correlation coefficients and WTC between spring discharge and the climate indices indicate that variability in spring discharge is significantly and positively correlated with monsoon indices in the 1-yr periodicity and negatively correlated with ENSO in the 3.4-yr periodicity and PDO in the 26.8-yr periodicity. This suggests that the oscillations of the spring discharge on annual, interannual, and interdecadal time scales are dominated by monsoon, ENSO, and PDO in the NS basin, respectively. Results show that monsoons modulate the spring discharge by affecting local meteorological parameters. ENSO and PDO impact the variability of the NS discharge by affecting the climate conditions in northern China.
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Zhang, Shuyu, Thian Yew Gan, and Andrew B. G. Bush. "Variability of Arctic Sea Ice Based on Quantile Regression and the Teleconnection with Large-Scale Climate Patterns." Journal of Climate 33, no. 10 (May 15, 2020): 4009–25. http://dx.doi.org/10.1175/jcli-d-19-0375.1.
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AbstractUnder global warming, Arctic sea ice has declined significantly in recent decades, with years of extremely low sea ice occurring more frequently. Recent studies suggest that teleconnections with large-scale climate patterns could induce the observed extreme sea ice loss. In this study, a probabilistic analysis of Arctic sea ice was conducted using quantile regression analysis with covariates, including time and climate indices. From temporal trends at quantile levels from 0.01 to 0.99, Arctic sea ice shows statistically significant decreases over all quantile levels, although of different magnitudes at different quantiles. At the representative extreme quantile levels of the 5th and 95th percentiles, the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), and the Pacific–North American pattern (PNA) have more significant influence on Arctic sea ice than El Niño–Southern Oscillation (ENSO), the Pacific decadal oscillation (PDO), and the Atlantic multidecadal oscillation (AMO). Positive AO as well as positive NAO contribute to low winter sea ice, and a positive PNA contributes to low summer Arctic sea ice. If, in addition to these conditions, there is concurrently positive AMO and PDO, the sea ice decrease is amplified. Teleconnections between Arctic sea ice and the climate patterns were demonstrated through a composite analysis of the climate variables. The anomalously strong anticyclonic circulation during the years of positive AO, NAO, and PNA promotes more sea ice export through Fram Strait, resulting in excessive sea ice loss. The probabilistic analyses of the teleconnections between the Arctic sea ice and climate patterns confirm the crucial role that the climate patterns and their combinations play in overall sea ice reduction, but particularly for the low and high quantiles of sea ice concentration.
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Wang, Chun-Jing, and Ji-Zhong Wan. "Historical and contemporary climate legacy of the large-scale distributional patterns of plant richness across different taxonomic levels: An assessment of protected areas in China." Botanical Sciences 97, no. 3 (September 1, 2019): 323. http://dx.doi.org/10.17129/botsci.2211.
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<p align="left"><strong>Background: </strong>Historical and contemporary climates may shape the distributional patterns of plant species richness across different scales. However, few studies have focused on the effects of historical and contemporary climate changes on the distributional patterns of plant richness in Chinese protected areas across different taxonomic levels.</p><p align="left"><strong>Hypotheses: </strong>Historical and contemporary climates can have an important legacy effect on the large-scale distributional patterns of plant richness across different taxonomic levels.</p><p align="left"><strong>Studied species: </strong>Vascular plants.</p><p align="left"><strong>Study site: </strong>China.</p><p align="left"><strong>Method:</strong> We used data on plant richness at the family, genus, and species levels from Chinese protected areas and applied regression modelling to explore the relationships between climate change and plant richness among vascular, fern, seed, gymnosperm, and angiosperm plants based on paleoclimate (Last Glacial Maximum; LGM, ca. 22,000 years ago) and contemporary climate data.</p><p align="left"><strong>Results: </strong>The large-scale distributional patterns of plant richness could be predicted across different taxonomic levels on the basis of paleoclimate and contemporary climate data. Specifically, historical and contemporary climate variables were found to better correlate with fern plant richness than seed plant richness. For seed plants, the explanatory power of historical and contemporary climate variables was found to be stronger for the richness of gymnosperms than for the richness of angiosperms.</p><strong>Conclusions: </strong>The distributional pattern of plant richness could be predicted across different taxonomic levels after including paleoclimate (LGM, ca. 22,000 years ago) and contemporary climate data from China. Our study could support the effectiveness of the management of protected areas in China.
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Balting, Daniel F., Monica Ionita, Martin Wegmann, Gerhard Helle, Gerhard H. Schleser, Norel Rimbu, Mandy B. Freund, Ingo Heinrich, Diana Caldarescu, and Gerrit Lohmann. "Large-scale climate signals of a European oxygen isotope network from tree rings." Climate of the Past 17, no. 3 (May 7, 2021): 1005–23. http://dx.doi.org/10.5194/cp-17-1005-2021.
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Abstract. We investigate the climate signature of δ18O tree-ring records from sites distributed all over Europe covering the last 400 years. An empirical orthogonal function (EOF) analysis reveals two distinct modes of variability on the basis of the existing δ18O tree-ring records. The first mode is associated with anomaly patterns projecting onto the El Niño–Southern Oscillation (ENSO) and reflects a multi-seasonal climatic signal. The ENSO link is pronounced for the last 130 years, but it is found to be weak over the period from 1600 to 1850, suggesting that the relationship between ENSO and the European climate may not be stable over time. The second mode of δ18O variability, which captures a north–south dipole in the European δ18O tree-ring records, is related to a regional summer atmospheric circulation pattern, revealing a pronounced centre over the North Sea. Locally, the δ18O anomalies associated with this mode show the same (opposite) sign with temperature (precipitation). Based on the oxygen isotopic signature derived from tree rings, we argue that the prevailing large-scale atmospheric circulation patterns and the related teleconnections can be analysed beyond instrumental records.
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Khadgarai, Sunilkumar, Vinay Kumar, and Prabodha Kumar Pradhan. "The Connection between Extreme Precipitation Variability over Monsoon Asia and Large-Scale Circulation Patterns." Atmosphere 12, no. 11 (November 11, 2021): 1492. http://dx.doi.org/10.3390/atmos12111492.
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Spatial and temporal variability in precipitation has been dramatically changed due to climate variability and climate change over the global domain. Increasing in extreme precipitation events are pronounced in various regions, including monsoon Asia (MA) in recent decades. The present study evaluated precipitation variability in light of intensity, duration, and frequency with several extreme precipitation climate change indices developed by the Expert Team on Climate Change Detection Indices (ETCCDI) over the MA region. This study uses an improved version (APHRO_V1901) of the Asian Precipitation Highly Resolved Observation Data Integration Towards Evaluation of extreme events (APHRODITE-2) gridded rainfall product. Results showed that the spatial variability of the extreme precipitation climate change indices is reflected in the annual mean rainfall distribution in MA. Maximum one-day precipitation (R × 1) and precipitation contributed from extremes (R95) depict a peak in decadal mean rainfall values over topography regions. A significant positive trend in R × 1 (with a slope of 0.3 mm/yr) and precipitation greater than the 95th percentile (R95: with a slope of 0.5 mm/yr) are predominantly observed in decadal trends in regional average extreme precipitation climate change indices over MA. Maritime continental countries exhibit an inclined trend in R10, whereas central Asian arid regions show a decreasing tendency in continuous dry days (CDD). The positive trend in R95 is observed over central India, the monsoon region in China, countries that reside over the equator and some parts of Japan, and the Philippines. When comparing the influence of surface temperature (T) and total column water vapor (TCW) on precipitation climate change indices, TCW seems to be a crucial attributor to climate change indices meridional variability. The mutual correlation analysis depicts that precipitation contributed from extremes (R95) strongly correlates in terms of temporal variability with all extreme precipitation indices. Among various global circulation patterns, the prevalent conditions of sea surface temperature (SST) over the equatorial Pacific Ocean have a significant influence on decadal variability in extreme precipitation climate change indices. R10 and R95 possess a relatively significant correlation (0.86 and 0.91) with the Southern Oscillation Index. The maximum number of consecutive dry days (CDD) shows an increasing trend with a positive phase of the North Atlantic Oscillation Index.
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Juliano, Timothy W., and Zachary J. Lebo. "Linking large-scale circulation patterns to low-cloud properties." Atmospheric Chemistry and Physics 20, no. 12 (June 17, 2020): 7125–38. http://dx.doi.org/10.5194/acp-20-7125-2020.
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Abstract. The North Pacific High (NPH) is a fundamental meteorological feature present during the boreal warm season. Marine boundary layer (MBL) clouds, which are persistent in this oceanic region, are influenced directly by the NPH. In this study, we combine 11 years of reanalysis and an unsupervised machine learning technique to examine the gamut of 850 hPa synoptic-scale circulation patterns. This approach reveals two distinguishable regimes – a dominant NPH setup and a land-falling cyclone – and in between a spectrum of large-scale patterns. We then use satellite retrievals to elucidate for the first time the explicit dependence of MBL cloud properties (namely cloud droplet number concentration, liquid water path, and shortwave cloud radiative effect – CRESW) on 850 hPa circulation patterns over the northeast Pacific Ocean. We find that CRESW spans from −146.8 to −115.5 W m−2, indicating that the range of observed MBL cloud properties must be accounted for in global and regional climate models. Our results demonstrate the value of combining reanalysis and satellite retrievals to help clarify the relationship between synoptic-scale dynamics and cloud physics.
Dissertations / Theses on the topic "Large-scale climate patterns"
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Aragon, Christina Marie. "Connecting Local-scale Heavy Precipitation to Large-scale Meteorological Patterns over Portland, Oregon using Observations and Climate Models." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5174.
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Precipitation timing and magnitude is essential to human, ecological, and economic systems. Climate change may be altering the character of precipitation locally to globally, thus it is vital that resource managers, practitioners, and decision makers understand the nature of this change. This thesis was conducted in partnership with the City of Portland Bureau of Environmental Services (BES), and the Portland Water Bureau (PWB) in order to support resiliency planning around precipitation and precipitation extremes.
This work has two primary phases, which are discussed in chapter 2 and 3 of this thesis. The first phase of this research entails characterization of the large-scale meteorological patterns (LSMPs) associated with high hourly intensity and heavy daily accumulation of precipitation over Portland, OR. Heavy precipitation is associated with a multitude of impacts on urban environments, thus it is important to understand the meteorological drivers behind these events. This phase of work describes the range of meteorological patterns associated with heavy precipitation totals and high intensity precipitation days over the city of Portland, Oregon. The range of large-scale meteorological patterns (LSMPs) associated with high intensity precipitation days are clustered using the self-organizing map (SOM) approach and are defined using sea level pressure, 500 hPa geopotential height, and 250 hPa wind. Results show that an array of LSMPs are associated with heavy precipitation days, the majority of which occur in fall and winter, usually driven by extratropical cyclones and associated atmospheric rivers. Spring and summer heavy and high intensity precipitation days, while less common than in fall and winter, are typically related to upper level disturbances. Examination of two case studies, one occurring in summer and one in winter, supports the ability of the SOMs approach to realistically capture key observed storm types. Methods developed here may be extensible to other locations and results build an observational foundation for validating the ability of climate models to simulate the LSMPs associated with local extremes.
The second phase of this thesis involves evaluation of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) to simulate wet season LSMPs and associated precipitation in the Pacific Northwest of North America. As in the first phase, LSMPs are identified using the self-organizing maps (SOMs) approach, except in this phase all wet season days are included, and defined with sea level pressure, 500 hPa geopotential height, and 250 hPa wind speed. Using SOMs, the range of LSMPs over the region is constructed with reanalysis, providing the target for the multi-model evaluation. Overall, the CMIP5 models are able to reproduce reference LSMPs with reasonable fidelity, though the low pressure LSMPs are generally captured better than the ridging patterns. Furthermore, there is a hierarchy in model ability to capture key LSMPs, with some models exhibiting overall higher fidelity than others. To further evaluate model fidelity, precipitation associated with the LSMPs is evaluated. In general, the observations, reanalysis, and CMIP5 models agree on the LSMPs associated with wet and dry days, but wet patterns are captured somewhat better than dry patterns. The LSMPs associated with the driest and wettest conditions in the PNW are generally overrepresented, while the LSMPs associated with light average daily precipitation across the pacific northwest are underrepresented in the models. Results provide a mechanistic perspective on model fidelity in capturing synoptic climatology and associated precipitation characteristics across the PNW.
This research focuses on Portland and the Pacific Northwest, but has helped to develop methodology that is extensible to any location. The first phase gives us target LSMPs to understand future extreme precipitation over Portland, and the second phase of work lays the groundwork for developing projections of future changes to precipitation and precipitation extremes.
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Lee, Cameron C. "The Relationship of Large-Scale Atmospheric Circulation Patterns to Tornadoes and the Impacts of Climate Change." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1274371690.
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Helaouet, Pierre. "Large-scale study of Calanus in the North Atlantic Ocean : macroecological patterns and potential impacts of climate change." Thesis, University of Plymouth, 2009. http://hdl.handle.net/10026.1/2656.
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Marine ecosystems show natural fluctuation throughout a large range of spatial and temporal scales. Despite the large amount of study devoted to the North Atlantic Ocean, drivers of those fluctuations remain unclear. By changing global climate, polluting, introducing exotic species, expanding and intensifying land uses and overharvesting biological resources, human activities have degraded the global ecosystem and drastically accelerated species extinction rates. Consequences of this human forcing become apparent in the progressive degradation of ecosystem that are used by humans (Schroter et al. , 2005), climate change- induced shifts in species distributions toward the poles (Parmesan et al. , 1999) and higher elevations (Wilson et al. , 2005), and in rapidly changing phenology (Edwards & Richardson, 2004). Data collected by the Continuous Plankton Recorder (CPR) constitutes, by both their temporal and biogeographical extends, one of the most useful datasets to investigate further major marine management issues as the distinction between anthropogenic, climatically forced and natural ecosystems fluctuations. The present work is a contribution to environmental change biology focused on copepods Calanus species as key structural species characteristic of the North Atlantic Ocean and adjacent seas. The purpose is to (1) identify environmental factors leading to the large-scale distribution patterns of Calanus that occurred in the North Atlantic Ocean, and (2) to propose and investigate new methods to assess both fundamental and realised niches of a dominant species in these basins. Most current approaches using Hutchinson concept of ecological niches to model species distribution belong to correlative or mechanistic models. A correlative approach has been developed to assess statistical relationships between the observed spatial distributions of two congeneric species and a set of environmental variables characteristic of the studied area. The method is designed to show the seasonal dynamics of environmental restriction driving observed distributions. Both Calanus finmarchicus and C. helgolandicus environmental preferences and optimum have been defined for 11 environmental parameters. A principal component analysis (PCA) has been used (1) to quantify the importance on the spatial distribution of each environmental parameter and (2) to identify the ecological niche. A numerical analysis based on Multiple Response Permutation Procedures (MRPP) was utilised to assess the breath of each niche and to compare them. The egg production rate of Calanus finmarchicus has been defined to investigate the link between physiology, macroecological patterns and ecological niches. It typically assesses the fundamental niche as in opposition to the correlative approach, the model based on a fundamental biological process is more focused on the potential response of C. finmarchicus to environmental conditions. The simplicity of the method which used only Sea Surface Temperature (SST) allows us to use IPCC scenarios and predict a shift in distribution over the 21st century.
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Wetterhall, Fredrik. "Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937.
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A global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis evaluates different approaches of statistical downscaling of precipitation from large-scale circulation variables, both concerning the method performance and the optimum choice of predictor variables.
The analogue downscaling method (AM) was found to work well as “benchmark” method in comparison to more complicated methods. AM was implemented using principal component analysis (PCA) and Teweles-Wobus Scores (TWS). Statistical properties of daily and monthly precipitation on a catchment in south-central Sweden, as well as daily precipitation in three catchments in China were acceptably downscaled.
A regression method conditioning a weather generator (SDSM) as well as a fuzzy-rule based circulation-pattern classification method conditioning a stochastical precipitation model (MOFRBC) gave good results when applied on Swedish and Chinese catchments. Statistical downscaling with MOFRBC from GMC (HADAM3P) output improved the statistical properties as well as the intra-annual variation of precipitation.
The studies show that temporal and areal settings of the predictor are important factors concerning the success of precipitation modelling. The MOFRCB and SDSM are generally performing better than the AM, and the best choice of method is depending on the purpose of the study. MOFRBC applied on output from a GCM future scenario indicates that the large-scale circulation will not be significantly affected. Adding humidity flux as predictor indicated an increased intensity both in extreme events and daily amounts in central and northern Sweden.
Books on the topic "Large-scale climate patterns"
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Reconstructing large-scale climatic patterns from tree-ring data: A diagnostic analysis. Tucson: University of Arizona Press, 1991.
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Schmidt-Thomé, Philipp. Climate Change Adaptation. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.635.
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Climate change adaptation is the ability of a society or a natural system to adjust to the (changing) conditions that support life in a certain climate region, including weather extremes in that region. The current discussion on climate change adaptation began in the 1990s, with the publication of the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Since the beginning of the 21st century, most countries, and many regions and municipalities have started to develop and implement climate change adaptation strategies and plans. But since the implementation of adaptation measures must be planned and conducted at the local level, a major challenge is to actually implement adaptation to climate change in practice. One challenge is that scientific results are mainly published on international or national levels, and political guidelines are written at transnational (e.g., European Union), national, or regional levels—these scientific results must be downscaled, interpreted, and adapted to local municipal or community levels. Needless to say, the challenges for implementation are also rooted in a large number of uncertainties, from long time spans to matters of scale, as well as in economic, political, and social interests. From a human perspective, climate change impacts occur rather slowly, while local decision makers are engaged with daily business over much shorter time spans.Among the obstacles to implementing adaptation measures to climate change are three major groups of uncertainties: (a) the uncertainties surrounding the development of our future climate, which include the exact climate sensitivity of anthropogenic greenhouse gas emissions, the reliability of emission scenarios and underlying storylines, and inherent uncertainties in climate models; (b) uncertainties about anthropogenically induced climate change impacts (e.g., long-term sea level changes, changing weather patterns, and extreme events); and (c) uncertainties about the future development of socioeconomic and political structures as well as legislative frameworks.Besides slow changes, such as changing sea levels and vegetation zones, extreme events (natural hazards) are a factor of major importance. Many societies and their socioeconomic systems are not properly adapted to their current climate zones (e.g., intensive agriculture in dry zones) or to extreme events (e.g., housing built in flood-prone areas). Adaptation measures can be successful only by gaining common societal agreement on their necessity and overall benefit. Ideally, climate change adaptation measures are combined with disaster risk reduction measures to enhance resilience on short, medium, and long time scales.The role of uncertainties and time horizons is addressed by developing climate change adaptation measures on community level and in close cooperation with local actors and stakeholders, focusing on strengthening resilience by addressing current and emerging vulnerability patterns. Successful adaptation measures are usually achieved by developing “no-regret” measures, in other words—measures that have at least one function of immediate social and/or economic benefit as well as long-term, future benefits. To identify socially acceptable and financially viable adaptation measures successfully, it is useful to employ participatory tools that give all involved parties and decision makers the possibility to engage in the process of identifying adaptation measures that best fit collective needs.
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Busuioc, Aristita, and Alexandru Dumitrescu. Empirical-Statistical Downscaling: Nonlinear Statistical Downscaling. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.770.
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This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Climate Science. Please check back later for the full article.The concept of statistical downscaling or empirical-statistical downscaling became a distinct and important scientific approach in climate science in recent decades, when the climate change issue and assessment of climate change impact on various social and natural systems have become international challenges. Global climate models are the best tools for estimating future climate conditions. Even if improvements can be made in state-of-the art global climate models, in terms of spatial resolution and their performance in simulation of climate characteristics, they are still skillful only in reproducing large-scale feature of climate variability, such as global mean temperature or various circulation patterns (e.g., the North Atlantic Oscillation). However, these models are not able to provide reliable information on local climate characteristics (mean temperature, total precipitation), especially on extreme weather and climate events. The main reason for this failure is the influence of local geographical features on the local climate, as well as other factors related to surrounding large-scale conditions, the influence of which cannot be correctly taken into consideration by the current dynamical global models.Impact models, such as hydrological and crop models, need high resolution information on various climate parameters on the scale of a river basin or a farm, scales that are not available from the usual global climate models. Downscaling techniques produce regional climate information on finer scale, from global climate change scenarios, based on the assumption that there is a systematic link between the large-scale and local climate. Two types of downscaling approaches are known: a) dynamical downscaling is based on regional climate models nested in a global climate model; and b) statistical downscaling is based on developing statistical relationships between large-scale atmospheric variables (predictors), available from global climate models, and observed local-scale variables of interest (predictands).Various types of empirical-statistical downscaling approaches can be placed approximately in linear and nonlinear groupings. The empirical-statistical downscaling techniques focus more on details related to the nonlinear models—their validation, strengths, and weaknesses—in comparison to linear models or the mixed models combining the linear and nonlinear approaches. Stochastic models can be applied to daily and sub-daily precipitation in Romania, with a comparison to dynamical downscaling. Conditional stochastic models are generally specific for daily or sub-daily precipitation as predictand.A complex validation of the nonlinear statistical downscaling models, selection of the large-scale predictors, model ability to reproduce historical trends, extreme events, and the uncertainty related to future downscaled changes are important issues. A better estimation of the uncertainty related to downscaled climate change projections can be achieved by using ensembles of more global climate models as drivers, including their ability to simulate the input in downscaling models. Comparison between future statistical downscaled climate signals and those derived from dynamical downscaling driven by the same global model, including a complex validation of the regional climate models, gives a measure of the reliability of downscaled regional climate changes.
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Bartkowicz, Leszek. Tekstura drzewostanów naturalnych w polskich parkach narodowych na tle teorii dynamiki lasu. Publishing House of the University of Agriculture in Krakow, 2021. http://dx.doi.org/10.15576/978-83-66602-20-5.
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The aim of the study was to compare a patch-mosaic pattern in the old-growth forest stands developed in various climate and soil conditions occurring in different regions of Poland. Based on the assumption, that the patch-mosaic pattern in the forest reflect the dynamic processes taking place in it, and that each type of forest ecosystem is characterized by a specific regime of natural disturbances, the following hypotheses were formulated: (i) the patches with a complex structure in stands composed of latesuccessional, shade-tolerant tree species are more common than those composed of early-successional, light-demanding ones, (ii) the patch-mosaic pattern is more heterogeneous in optimal forest site conditions than in extreme ones, (iii) in similar site conditions differentiation of the stand structure in distinguished patches is determined by the successional status of the tree species forming a given patch, (iv) the successional trends leading to changes of species composition foster diversification of the patch structure, (v) differentiation of the stand structure is negatively related to their local basal area, especially in patches with a high level of its accumulation. Among the best-preserved old-growth forest remaining under strict protection in the Polish national parks, nineteen research plots of around 10 ha each were selected. In each plot, a grid (50 × 50 m) of circular sample subplots (with radius 12,62 m) was established. In the sample subplots, species and diameter at breast height of living trees (dbh ≥ 7 cm) were determined. Subsequently, for each sample subplot, several numerical indices were calculated: local basal area (G), dbh structure differentiation index (STR), climax index (CL) and successional index (MS). Statistical tests of Kruskal- Wallis, Levene and Generalized Additive Models (GAM) were used to verify the hypotheses. All examined forests were characterized by a large diversity of stand structure. A particularly high frequency of highly differentiated patches (STR > 0,6) was recorded in the alder swamp forest. The patch mosaic in the examined plots was different – apart from the stands with a strongly pronounced mosaic character (especially subalpine spruce forests), there were also stands with high spatial homogeneity (mainly fir forests). The stand structure in the distinguished patches was generally poorly related to the other studied features. Consequently, all hypotheses were rejected. These results indicate a very complex, mixed pattern of forest natural dynamics regardless of site conditions. In beech forests and lowland multi-species deciduous forests, small-scale disturbances of the gap dynamics type dominate, which are overlapped with less frequent medium-scale disturbances. In more difficult site conditions, large-scale catastrophic disturbances, which occasionally appear in communities formed under the influence of gap dynamics (mainly spruce forests) or cohort dynamics (mainly pine forests), gain importance.
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Kucharski, Fred, and Muhammad Adnan Abid. Interannual Variability of the Indian Monsoon and Its Link to ENSO. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.615.
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The interannual variability of Indian summer monsoon is probably one of the most intensively studied phenomena in the research area of climate variability. This is because even relatively small variations of about 10% to 20% from the mean rainfall may have dramatic consequences for regional agricultural production. Forecasting such variations months in advance could help agricultural planning substantially. Unfortunately, a perfect forecast of Indian monsoon variations, like any other regional climate variations, is impossible in a long-term prediction (that is, more than 2 weeks or so in advance). The reason is that part of the atmospheric variations influencing the monsoon have an inherent predictability limit of about 2 weeks. Therefore, such predictions will always be probabilistic, and only likelihoods of droughts, excessive rains, or normal conditions may be provided. However, even such probabilistic information may still be useful for agricultural planning. In research regarding interannual Indian monsoon rainfall variations, the main focus is therefore to identify the remaining predictable component and to estimate what fraction of the total variation this component accounts for. It turns out that slowly varying (with respect to atmospheric intrinsic variability) sea-surface temperatures (SSTs) provide the dominant part of the predictable component of Indian monsoon variability. Of the predictable part arising from SSTs, it is the El Niño Southern Oscillation (ENSO) that provides the main part. This is not to say that other forcings may be neglected. Other forcings that have been identified are, for example, SST patterns in the Indian Ocean, Atlantic Ocean, and parts of the Pacific Ocean different from the traditional ENSO region, and springtime snow depth in the Himalayas, as well as aerosols. These other forcings may interact constructively or destructively with the ENSO impact and thus enhance or reduce the ENSO-induced predictable signal. This may result in decade-long changes in the connection between ENSO and the Indian monsoon. The physical mechanism for the connection between ENSO and the Indian monsoon may be understood as large-scale adjustment of atmospheric heatings and circulations to the ENSO-induced SST variations. These adjustments modify the Walker circulation and connect the rising/sinking motion in the central-eastern Pacific during a warm/cold ENSO event with sinking/rising motion in the Indian region, leading to reduced/increased rainfall.
Book chapters on the topic "Large-scale climate patterns"
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Jaiser, Ralf, and Dörthe Handorf. "Arctic Sea Ice Change, Large-Scale Atmospheric Circulation Patterns and Extreme Climate and Weather in Europe." In Building Bridges at the Science-Stakeholder Interface, 95–100. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-75919-7_14.
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Pretzsch, H., T. Hilmers, E. Uhl, M. del Río, A. Avdagić, K. Bielak, A. Bončina, et al. "Efficacy of Trans-geographic Observational Network Design for Revelation of Growth Pattern in Mountain Forests Across Europe." In Climate-Smart Forestry in Mountain Regions, 141–87. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-80767-2_5.
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AbstractUnderstanding tree and stand growth dynamics in the frame of climate change calls for large-scale analyses. For analysing growth patterns in mountain forests across Europe, the CLIMO consortium compiled a network of observational plots across European mountain regions. Here, we describe the design and efficacy of this network of plots in monospecific European beech and mixed-species stands of Norway spruce, European beech, and silver fir.First, we sketch the state of the art of existing monitoring and observational approaches for assessing the growth of mountain forests. Second, we introduce the design, measurement protocols, as well as site and stand characteristics, and we stress the innovation of the newly compiled network. Third, we give an overview of the growth and yield data at stand and tree level, sketch the growth characteristics along elevation gradients, and introduce the methods of statistical evaluation. Fourth, we report additional measurements of soil, genetic resources, and climate smartness indicators and criteria, which were available for statistical evaluation and testing hypotheses. Fifth, we present the ESFONET (European Smart Forest Network) approach of data and knowledge dissemination. The discussion is focussed on the novelty and relevance of the database, its potential for monitoring, understanding and management of mountain forests toward climate smartness, and the requirements for future assessments and inventories.In this chapter, we describe the design and efficacy of this network of plots in monospecific European beech and mixed-species stands of Norway spruce, European beech, and silver fir. We present how to acquire and evaluate data from individual trees and the whole stand to quantify and understand the growth of mountain forests in Europe under climate change. It will provide concepts, models, and practical hints for analogous trans-geographic projects that may be based on the existing and newly recorded data on forests.
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Chervenkov, Hristo, and Valery Spiridonov. "Precipitation Pattern Estimation with the Standardized Precipitation Index in Projected Future Climate over Bulgaria." In Large-Scale Scientific Computing, 443–49. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73441-5_48.
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Dajuma, Alima, Siélé Silué, Kehinde O. Ogunjobi, Heike Vogel, Evelyne Touré N’Datchoh, Véronique Yoboué, Arona Diedhiou, and Bernhard Vogel. "Biomass Burning Effects on the Climate over Southern West Africa During the Summer Monsoon." In African Handbook of Climate Change Adaptation, 1515–32. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_86.
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AbstractBiomass Burning (BB) aerosol has attracted considerable attention due to its detrimental effects on climate through its radiative properties. In Africa, fire patterns are anticorrelated with the southward-northward movement of the intertropical convergence zone (ITCZ). Each year between June and September, BB occurs in the southern hemisphere of Africa, and aerosols are carried westward by the African Easterly Jet (AEJ) and advected at an altitude of between 2 and 4 km. Observations made during a field campaign of Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) (Knippertz et al., Bull Am Meteorol Soc 96:1451–1460, 2015) during the West African Monsoon (WAM) of June–July 2016 have revealed large quantities of BB aerosols in the Planetary Boundary Layer (PBL) over southern West Africa (SWA).This chapter examines the effects of the long-range transport of BB aerosols on the climate over SWA by means of a modeling study, and proposes several adaptation and mitigation strategies for policy makers regarding this phenomenon. A high-resolution regional climate model, known as the Consortium for Small-scale Modelling – Aerosols and Reactive Traces (COSMO-ART) gases, was used to conduct two set of experiments, with and without BB emissions, to quantify their impacts on the SWA atmosphere. Results revealed a reduction in surface shortwave (SW) radiation of up to about 6.5 W m−2 and an 11% increase of Cloud Droplets Number Concentration (CDNC) over the SWA domain. Also, an increase of 12.45% in Particulate Matter (PM25) surface concentration was observed in Abidjan (9.75 μg m−3), Accra (10.7 μg m−3), Cotonou (10.7 μg m−3), and Lagos (8 μg m−3), while the carbon monoxide (CO) mixing ratio increased by 90 ppb in Abidjan and Accra due to BB. Moreover, BB aerosols were found to contribute to a 70% increase of organic carbon (OC) below 1 km in the PBL, followed by black carbon (BC) with 24.5%. This work highlights the contribution of the long-range transport of BB pollutants to pollution levels in SWA and their effects on the climate. It focuses on a case study of 3 days (5–7 July 2016). However, more research on a longer time period is necessary to inform decision making properly.This study emphasizes the need to implement a long-term air quality monitoring system in SWA as a method of climate change mitigation and adaptation.
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Herrero, Mario, Marta Hugas, Uma Lele, Aman Wirakartakusumah, and Maximo Torero. "A Shift to Healthy and Sustainable Consumption Patterns." In Science and Innovations for Food Systems Transformation, 59–85. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-15703-5_5.
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AbstractThis chapter recognises that current food consumption patterns, often characterised by higher levels of food waste and a transition in diets towards higher energy, more resource-intensive foods, need to be transformed. Food systems in both developed and developing countries are changing rapidly. Increasingly characterised by a high degree of vertical integration, evolutions in food systems are being driven by new technologies that are changing production processes, distribution systems, marketing strategies, and the food products that people eat. These changes offer the opportunity for system-wide change in the way in which production interacts with the environment, giving greater attention to the ecosystem services offered by the food sector. However, developments in food systems also pose new challenges and controversies. Food system changes have responded to shifts in consumer preferences towards larger shares of more animal-sourced and processed foods in diets, raising concerns regarding the calorific and nutritional content of many food items. By increasing food availability, lowering prices and increasing quality standards, they have also induced greater food waste at the consumer end. In addition, the potential fast transmission of food-borne disease, antimicrobial resistance and food-related health risks throughout the food chain has increased, and the ecological footprint of the global food system continues to grow in terms of energy, resource use, and impact on climate change. The negative consequences of food systems from a nutritional, environmental and livelihood perspective are increasingly being recognised by consumers in some regions. With growing consumer awareness, driven by concerns about the environmental and health impacts of investments and current supply chain technologies and practices, as well as by a desire among new generations of city dwellers to reconnect with their rural heritage and use their own behaviour to drive positive change, opportunities exist to define and establish added-value products that are capable of internalising social or environmental delivery within their price. These forces can be used to fundamentally reshape food systems by stimulating coordinated government action in changing the regulatory environment that, in turn, incentivises improved private sector investment decisions. Achieving healthy diets from sustainable food systems is complex and requires a multi-pronged approach. Actions necessary include awareness-raising, behaviour change interventions in food environments, food education, strengthened urban-rural linkages, improved product design, investments in food system innovations, public-private partnerships, public procurement, and separate collection that enables alternative uses of food waste, all of which can contribute to this transition. Local and national policy-makers and small- and large-scale private sector actors have a key role in both responding to and shaping the market opportunities created by changing consumer demands.
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Lehmann, Marco M., Philipp Schuler, Marc-André Cormier, Scott T. Allen, Markus Leuenberger, and Steve Voelker. "The Stable Hydrogen Isotopic Signature: From Source Water to Tree Rings." In Stable Isotopes in Tree Rings, 331–59. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_11.
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AbstractThe hydrogen isotopic signature (δ2H) of water in trees contains information on plant functional responses to climatic changes and on the origin of the water. This is also true for the non-exchangeable hydrogen isotopic signature (δ2HNE) of plant organic matter, which contains additional physiological and biochemical information that can be dated to specific years if extracted from annual rings of trees. Despite this potential for gaining unique insights from δ2HNEof tree-ring cellulose (δ2HTRC), it has not been widely used compared to other isotope signals, likely due to challenging methodological constraints and interpretations of these isotopic signals. In this chapter, we first summarize hydrogen isotope (2H-) fractionation that occurs between source water and tree rings and review methods (e.g. nitration, equilibration, position-specific applications) and calculations to determine δ2HNE in tree material. Building upon a summary of the current state of knowledge, this chapter also provides an exhaustive synthesis of δ2HTRC papers, applications, and associated data from approximately 180 sites across the globe (paired with modelled precipitation δ2H values and climate data). The data allow us to investigate the hydrological-climatic effects driving δ2HTRC pattern on a global scale, the relationship of hydrogen with oxygen isotopes in the same tree-ring material, as well as the influence of physiological-biochemical effects (e.g., species differences, tree growth) that appear to be more important on local or temporal scales than on a large spatial scales. Thus, when local hydro-climatic influences on source water δ2H can be isolated, δ2HTRC gives novel insights on tree physiological responses to abiotic and biotic stresses. We conclude that the growing constellation of tree-ring metrics, including advancements in 2H-processing (i.e., equilibration techniques allowing rapid determinations of δ2HNE) and further refinements to the understanding of post-photosynthetic 2H-fractionations will together provide many new opportunities to understand past climates and ecophysiology by using δ2H in tree rings.
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Gage, Stuart H. "Climate Variability in the North Central Region: Characterizing Drought Severity Patterns." In Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0010.
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This chapter examines the spatial and temporal variability and patterns of climate for the period 1972–1991 in the North Central Region of North America (NCR). Since the mid-1970s, climate has become more variable in the region, compared to the more benign period 1950–1970. The regional perspective presented in this chapter characterizes the general climatology of the NCR from 1972 to 1991 and compares the climate to a severe drought that occurred in 1988. This one-year drought was one of the most substantial in the region’s recent history, and it had a significant impact on the region’s agricultural economy and ecosystems. Petersen et al. (1995) characterize the 1988 drought with respect to solar radiation, and Zangvil et al. (2001) consider this drought from the perspective of a large-scale atmosphere moisture budget. A major reason for the seriousness of the drought in 1988 was the fact that May and June were unusually dry and hot (Kunkel and Angel 1989). Drought is defined as a condition of moisture deficit sufficient to adversely affect vegetation, animals, and humans over a sizeable area (Warwick 1975). The condition of drought may be considered from a meteorological, agricultural, and hydrologic perspective. Meteorological drought is a period of abnormally dry weather sufficiently prolonged to a point where the lack of water causes a serious hydrologic imbalance in the affected area (Huschke 1959). Agricultural drought is a climatic digression involving a shortage of precipitation sufficient to adversely affect crop production or the range of production (Rosenberg 1980). Hydrologic drought is a period of below-average water content in streams, reservoirs, groundwater aquifers, lakes, and soils (Yevjevich et al. 1977). All of these drought conditions are mutually linked. The objectives of this chapter are to (1) address the issues of climatic spatial scale to quantify variability of climate in the NCR, (2) examine the characteristics of the 1988 drought as it relates to characteristics of an ecoregion, (3) illustrate a means to quantify drought through a potential plant stress index, and (4) examine the link of regional drought to ecosystem processes. This analysis will provide background and methodology for ecologists, agriculturalists, and others interested in spatial and temporal characterization of climate patterns within large geographic regions.
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Naidu, Diwakar, Babita Majhi, and Surendra Kumar Chandniha. "Development of Rainfall Prediction Models Using Machine Learning Approaches for Different Agro-Climatic Zones." In Advances in Data Mining and Database Management, 72–94. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-6659-6.ch005.
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This study focuses on modelling the changes in rainfall patterns in different agro-climatic zones due to climate change through statistical downscaling of large-scale climate variables using machine learning approaches. Potential of three machine learning algorithms, multilayer artificial neural network (MLANN), radial basis function neural network (RBFNN), and least square support vector machine (LS-SVM) have been investigated. The large-scale climate variable are obtained from National Centre for Environmental Prediction (NCEP) reanalysis product and used as predictors for model development. Proposed machine learning models are applied to generate projected time series of rainfall for the period 2021-2050 using the Hadley Centre coupled model (HadCM3) B2 emission scenario data as predictors. An increasing trend in anticipated rainfall is observed during 2021-2050 in all the ACZs of Chhattisgarh State. Among the machine learning models, RBFNN found as more feasible technique for modeling of monthly rainfall in this region.
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Wainright, John. "Climate and Climatological Variations in the Jornada Basin." In Structure and Function of a Chihuahuan Desert Ecosystem. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195117769.003.0007.
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The purpose of this chapter is to review the climatic data for the Jornada Basin over the period for which instrumental records exist. Over this time period, up to 83 years in the case of the Jornada Experimental Range (JER), we can deduce both the long-term mean characteristics and variability on a range of different spatial and temporal scales. Short-term variability is seen in individual rainstorms. Longer-term patterns are controlled spatially by factors such as large-scale circulation patterns and basin and regional orography and temporally by the large-scale fluctuations in atmospheric and oceanic circulation patterns. Variability can have significant impacts on the biogeography of a region (Neilson 1986) or its geomorphic processes (Cooke and Reeves 1976), which may set in motion a series of feedbacks, most important those referring to desertification (Schlesinger et al. 1990; Conley et al. 1992). Understanding the frequency and magnitude of such variability is therefore fundamental in explaining the observed landscape changes in areas such as the Jornada Basin. The patterns observed for different climatic variables within the available instrumental records for the Jornada Basin are defined in a hierarchical series of temporal scales, starting with the patterns that emerge from long-term average conditions and moving to seasonal and monthly, daily, and subdaily time scales. Two further analyses are made because of their potential importance to the hydrological and ecological characteristics of the basin, namely, the occurrence of extreme rainfall events and of longer-term changes. The effects of El Niño events in controlling the rainfall over decadal time scales will be addressed in particular. Spatial variability is an additional important concern, especially when characterizing dryland areas such as the Jornada Basin, where spatial variability tends to be high. The overall climate of the basin can be defined according to the Köppen classification as being cool and arid, belonging to the midlatitude desert zone (BWk). However, interannual variability is important, and occasionally, the annual conditions are more characteristic of the semiarid steppe (BSk) zone. The higher rainfall rates in the higher altitudes of the basin are also more characteristic of semiarid conditions.
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Cohen, Andrew S. "Facies Models at the Lake Basin Scale." In Paleolimnology. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195133530.003.0012.
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Understanding the historical evolution of sedimentation in a lake requires not only a grounding in facies interpretation but also an understanding of the larger-scale, lakewide linkages between deposition and those factors influencing sedimentation. The facies models we examined in chapter 7 can be linked to understand the differences in deposits between lake basins. Basin-scale facies models focus on the major interactions between climate or tectonic/ volcanic activity and sedimentation, attempting to explain why particular facies types develop in particular areas or at particular times in a lake’s history. Here I will focus on a few examples from the most intensively studied depositional settings, including lake types defined by mode of origin and evolution (rifts, glacial lakes, etc.) as well as saline lakes and playas, which share chemical and climatic attributes. Large-scale facies modeling in rift lakes has been driven by a need to understand the occurrence of hydrocarbons in ancient rifts (Lambiase, 1990; Katz, 2001). This in turn spurred a rapid accumulation of seismic reflection and facies data in the East African rift lakes and Lake Baikal (Russia) during the 1980s and 1990s, as well as attempts to synthesize these data and integrate them into general models. As we saw in chapter 2, the evolution of rift basins involves the development of asymmetric half-grabens and, in larger lake systems, the linkage of these half-grabens in a linear chain. As rift basins age, progressive deformation will eventually cause extensive deformation on both sides of the basin, transforming them into asymmetric full grabens, as seen in Lake Baikal today. This pattern of tectonic development has consequences for geomorphology, sediment delivery rates and locations, and sediment composition, that also vary depending on whether the lake basin is relatively full (high-stand conditions) or empty (low-stand) (Rosendahl et al., 1986; Cohen, 1990; Scholz and Rosendahl, 1990; Tiercelin et al., 1992; Soreghan and Cohen, 1996). Large-scale depositional patterns in a rift lake therefore represent an interplay between tectonic and climatic forces, factors that operate on somewhat different time scales.
Conference papers on the topic "Large-scale climate patterns"
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Wang, Hongbin. "Prediction of the large scale outbreak patterns of pine caterpillars under climate scenarios." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.112309.
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C., Andrade, Santos J. A., Theodore E. Simos, George Psihoyios, Ch Tsitouras, and Zacharias Anastassi. "CCA Diagnosis of the Large-scale Patterns Associated to a Climate Temperature Index in Europe." In NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2011: International Conference on Numerical Analysis and Applied Mathematics. AIP, 2011. http://dx.doi.org/10.1063/1.3636991.
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Babanin, Alexander V. "Wave-Induced Turbulence, Linking Metocean and Large Scales." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18373.
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Abstract Until recently, large-scale models did not explicitly take account of ocean surface waves which are a process of much smaller scales. However, it is rapidly becoming clear that many large-scale geophysical processes are essentially coupled with the surface waves, and those include ocean circulation, weather, Tropical Cyclones and polar sea ice in both Hemispheres, climate and other phenomena in the atmosphere, at air/sea, sea/ice and sea/land interface, and many issues of the upper-ocean mixing below the surface. Besides, the wind-wave climate itself experiences large-scale trends and fluctuations, and can serve as an indicator for changes in the weather climate. In the presentation, we will discuss wave influences at scales from turbulence to climate, on the atmospheric and oceanic sides. At the atmospheric side of the interface, the air-sea coupling is usually described by means of the drag coefficient Cd, which is parameterised in terms of the wind speed, but the scatter of experimental data with respect to such dependences is very significant and has not improved noticeably over some 40 years. It is argued that the scatter is due to multiple mechanisms which contribute into the sea drag, many of them are due to surface waves and cannot be accounted for unless the waves are explicitly known. The Cd concept invokes the assumption of constant-flux layer, which is also employed for vertical profiling of the wind measured at some elevation near the ocean surface. The surface waves, however, modify the balance of turbulent stresses very near the surface, and therefore such extrapolations can introduce significant biases. This is particularly essential for buoy measurements in extreme conditions, when the anemometer mast is within the Wave Boundary Layer (WBL) or even below the wave crests. In this presentation, field data and a WBL model are used to investigate such biases. It is shown that near the surface the turbulent fluxes are less than those obtained by extrapolation using the logarithmic-layer assumption, and the mean wind speeds very near the surface, based on Lake George field observations, are up to 5% larger. The dynamics is then simulated by means of a WBL model coupled with nonlinear waves, which revealed further details of complex behaviours at wind-wave boundary layer. Furthermore, we analyse the structure of WBL for strong winds (U10 > 20 m/s) based on field observations. We used vertical distribution of wind speed and momentum flux measured in Topical Cyclone Olwyn (April 2015) in the North-West shelf of Australia. A well-established layer of constant stress is observed. The values obtained for u⁎ from the logarithmic profile law against u⁎ from turbulence measurements (eddy correlation method) differ significantly as wind speed increases. Among wave-induced influences at the ocean side, the ocean mixing is most important. Until recently, turbulence produced by the orbital motion of surface waves was not accounted for, and this fact limits performance of the models for the upper-ocean circulation and ultimately large-scale air-sea interactions. While the role of breaking waves in producing turbulence is well appreciated, such turbulence is only injected under the interface at the vertical scale of wave height. The wave-orbital turbulence is depth-distributed at the scale of wavelength (∼10 times the wave height) and thus can mix through the ocean thermocline in the spring-summer seasons. Such mixing then produces feedback to the large-scale processes, from weather to climate. In order to account for the wave-turbulence effects, large-scale air-sea interaction models need to be coupled with wave models. Theory and practical applications for the wave-induced turbulence will be reviewed in the presentation. These include viscous and instability theories of wave turbulence, direct numerical simulations and laboratory experiments, field and remote sensing observations and validations, and finally implementations in ocean, Tropical Cyclone, ocean and ice models. As a specific example of a wave-coupled environment, the wave climate in the Arctic as observed by altimeters will be presented. This is an important topic for the Arctic Seas, which are opening from ice in summer time. Challenges, however, are many as their Metocean environment is more complicated and, in addition to winds and waves, requires knowledge and understanding of ice material properties and its trends. On one hand, no traditional statistical approach is possible since in the past for most of the Arctic Ocean there was limited wave activity. Extrapolations of the current trends into the future are not feasible, because ice cover and wind patterns in the Arctic are changing. On the other hand, information on the mean and extreme wave properties is of great importance for oceanographic, meteorological, climate, naval and maritime applications in the Arctic Seas.
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Arellano Ramos, Blanca, and Josep Roca Cladera. "Identifying urban heat island: the Barcelona case." In Virtual City and Territory. Barcelona: Centre de Política de Sòl i Valoracions, 2016. http://dx.doi.org/10.5821/ctv.8130.
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There is a large consensus that cities have a special role in the process of climate change. Cities are responsible for 75% of global energy consumption and 80% of GHG emissions, both due to "lifestyle" generated in the last 150 years and changes associated with urbanization process in the era of globalization and urban sprawl. The specialized literature has devoted many efforts to analyze the contribution of urban systems to climate change, occupying the Urban Heat Island (UHI) an important place in studies on urban climate. In this sense, the use of remote sensing technology has allowed detailed mapping of (daytime) land surface temperature (LST) for urban and metropolitan systems. These studies have demonstrated the key role played by vegetation, impervious soil and land uses to explain differences in the spatial distribution of LST. However, the information provided by satellites has important limitations: especially the low resolution of the thermal band of night images. MODIS, for example, provides valuable information on the night LST; however, the spatial resolution of the thermal band is about one km², scale clearly insufficient to identify accurately the spatial structure of the UHI. In the opposite site, Landsat offers a more accepTabla spatial resolution (30 m² / pixel for the visible bands of the electromagnetic spectrum as well as 60 to 100 m² / pixel in the thermal bands), but does not provide information about night soil temperature. In addition, it is at night when the urban heat island becomes more evident. Therefore, to determine the night LST in an appropriate scale (as offered by Landsat) remains a significant challenge in studies aimed at identifying the spatial structure of the UHI.
In Metropolitan Area of Barcelona (AMB, 3,200 km² and 4.8 million inhabitants), the (day) highest temperatures are not in the CBD but in areas that are more peripheral specialized in economic activity such as industrial parks, producing a "donut" in the spatial distribution of the LST. Bare soil also shows a (day) high surface temperature. In contrast, sprawled areas have a less pronounced LST. The spatial structure of the LST, however, changed significantly during the night: compact and sprawl areas maintain high levels of heat, facing the agricultural soil, which cools more sharply as also happens in the industrial land. UHI appears therefore overnight.
This paper aims to show the spatial patterns of Urban Heat Island in the Metropolitan Area of Barcelona at medium scale (30 m² / pixel). It develops a new methodology aimed at modeling the night temperature at one km² resolution (MODIS) and then extrapolating this methodology to a most accurate scale of 30 m² / pixel (Landsat). The study allows identifying differences in (night) LST according to the distribution of land use, quantity and quality of the vegetation, intensity of urban sprawl, spatial distribution of economic activity and type of urban morphology (continuous vs. scattered urbanization).
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Chiu, Wing Tung Ruby, Moriaki Yasuhara, Thomas M. Cronin, Gene Hunt, Laura Gemery, and Chih-Lin Wei. "EVALUATING RESPONSE OF LARGE-SCALE SHALLOW MARINE BIODIVERSITY PATTERN TO CLIMATE CHANGE USING MICROPALEONTOLOGICAL RECORDS." In GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-281814.
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Janjić, Jelena, Sarah Gallagher, Emily Gleeson, and Frédéric Dias. "Wave Energy Extraction by the End of the Century: Impact of the North Atlantic Oscillation." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78107.
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Using wind speeds and sea ice fields from the EC-Earth global climate model to run the WAVEWATCH III model, we investigate the changes in the wave climate of the northeast Atlantic by the end of the 21st century. Changes in wave climate parameters are related to changes in wind forcing both locally and remotely. In particular, we are interested in the behavior of large-scale atmospheric oscillations and their influence on the wave climate of the North Atlantic Ocean. Knowing that the North Atlantic Oscillation (NAO) is related to large-scale atmospheric circulation, we carried out a correlation analysis of the NAO pattern using an ensemble of EC-Earth global climate simulations. These simulations include historical periods (1980–2009) and projected changes (2070–2099) by the end of the century under the RCP4.5 and RCP8.5 Representative Concentration Pathway (RCP) forcing scenarios with three members in each RCP wave model ensemble. In addition, we analysed the correlations between the NAO and a range of wave parameters that describe the wave climate from EC-Earth driven WAVEWATCH III model simulation over the North Atlantic basin, focusing on a high resolution two-way nested grid over the northeast Atlantic. The results show a distinct decrease by the end of the century and a strong positive correlation with the NAO for all wave parameters observed.
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Wong, Kaufui V., and John Plackemeier. "Policies for Effective Trading Scheme to Reduce Carbon Dioxide Emissions." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39723.
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The World Bank and the Intergovernmental panel on climate change have concluded that human activities such as fossil fuel combustion have caused higher average temperatures, more violent weather patterns and higher sea levels. Governments, politicians and corporations have started to take steps to curb emissions of carbon dioxide and other greenhouse gases to reduce its imbalance in the atmosphere, and in so doing, diminish the impacts it will have in the near future. While these parties have recognized the importance of significantly reducing emissions in the coming decades, there are currently no policies in the USA to accomplish these goals. At the same time that the need to reduce emissions become more and more apparent, the realization that the world’s current economy is highly carbon-dependent and that shifting to renewable energy sources would be extremely expensive as well, thus compelling governments to approach the problem cautiously. Maybe because of this reality, governments have preferred emissions trading schemes over emissions caps and taxes with no trading. Unlike a cap affecting carbon emitters uniformly, the trading schemes that have been introduced recently allow for a collective cap on emissions under which emitters are held to standards which can be achieved by reducing emissions or by buying carbon credits, which are emissions reductions that have been achieved by a different third party. At this time, the Kyoto Protocol is the most comprehensive of the commitments governments have made toward the ultimate aim of curbing greenhouse gases. Under its umbrella, many of the world’s industrialized nations (excluding the US, which signed but did not ratify owing to economic concerns) agreed to an emissions reduction of 6 to 8 percent from 1990 levels by 2012. Governments are responsible for reducing overall emissions and do this by passing on reduction goals to specific emitters who can reduce their emissions through a slew of methods. The methods include directly reducing carbon emitted as gas or purchasing carbon credits that provide a reduction in place of emissions that cannot be directly reduced. While fossil fuels have played an important role in the development of the world in the past century, financial markets have had an equally important role in creating economic growth. Emissions trading schemes have emerged in the past five years as a method to reduce carbon dioxide emissions through market forces. They are an attractive solution because they grant economic leeway to subject parties. While they carry this benefit, they are not universally ideal. This paper aims to identify the most effective ways in which emissions trading schemes can be used. An analysis of the limitations of emissions trading schemes is conducted with respect to technological and regulatory concerns in addition to different economic sectors. Further analysis of the benefits of large scale emissions trading schemes over other large scale emissions reduction methods is conducted. From this analysis, a full recommendation of strategies which would maximize the effectiveness of an emissions trading scheme is provided.
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Camporeale, Sergio Mario, Patrizia Domenica Ciliberti, Bernardo Fortunato, Marco Torresi, and Antonio Marco Pantaleo. "Externally Fired Micro Gas Turbine and ORC Bottoming Cycle: Optimal Biomass/Natural Gas CHP Configuration for Residential Energy Demand." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43571.
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Small scale Combined Heat and Power (CHP) plants present lower electric efficiency in comparison to large scale ones, and this is particularly true when biomass fuels are used. In most cases, the use of both heat and electricity to serve on site energy demand is a key issue to achieve acceptable global energy efficiency and investment profitability. However, the heat demand follows a typical daily and seasonal pattern and is influenced by climatic conditions, in particular in the case of residential and tertiary end users. During low heat demand periods, a lot of heat produced by the CHP plant is discharged. In order to increase the electric conversion efficiency of small scale micro turbine for heat and power cogeneration, a bottoming ORC system can be coupled to the cycle, however this option reduces the temperature and quantity of cogenerated heat available to the load. In this perspective, the paper presents the results of a thermo-economic analysis of small scale CHP plants composed by a micro gas turbine (MGT) and a bottoming Organic Rankine Cycle (ORC), serving a typical residential energy demand. For the topping cycle three different configurations are examined: 1) a simple recuperative micro gas turbine fuelled by natural gas (NG), 2) a dual fuel EFGT cycle, fuelled by biomass and natural gas (50% energy input) (DF) and 3) an externally fired gas turbine (EFGT) with direct combustion of biomass (B). The bottoming cycle is a simple saturated Rankine cycle with regeneration and no superheating. The ORC cycle and the fluid selection are optimized on the basis of the available exhaust gas temperature at the turbine exit. The research assesses the influence of the thermal energy demand typology (residential demand with cold, mild and hot climate conditions) and CHP plant operational strategies (baseload vs heat driven vs electricity driven operation mode) on the global energy efficiency and profitability of the following three configurations: A) MGT with cogeneration; B) MGT+ ORC without cogeneration; C) MGT+ORC with cogeneration. In all cases, a back-up boiler is assumed to match the heat demand of the load (fed by natural gas or biomass). The research explores the profitability of bottoming ORC in view of the following tradeoffs: (i) lower energy conversion efficiency and higher investment cost of high biomass input rate with respect to natural gas; (ii) higher efficiency but higher costs and reduced heat available for cogeneration in the bottoming ORC; (ii) higher primary energy savings and revenues from feed-in tariff available for biomass electricity fed into the grid.
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Xu, Siqing, Ahmed A. BinAmro, Aaesha K. Al Keebali, Mohamed Baslaib, and Shehadeh Masalmeh. "Miscible Gas Injection EOR Complex Challenges – A CCUS Hub Approach to Unlock Value for a Multi Reservoir Onshore Field." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/208175-ms.
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Abstract Miscible CO2 flood is a well-established proven EOR recovery mechanism. There have been a large number of CO2 EOR developments worldwide, in both carbonate and clastic reservoirs. Potential control or influence factors on incremental production and incremental recovery over water flood are well documented in the published literature. Some of the published CO2 EOR developments have reported relatively high incremental recoveries. ADNOC is a leader in miscible gas injection EOR in carbonate reservoirs. There are a number of ongoing miscible gas injection EOR developments within its portfolio contributing a significant amount of production. Miscible CO2 flood is a key EOR development for ADNOC. Following intensive screening studies and laboratory experiments, the first CO2 EOR pilot in the MENA region was conducted as early as 2009 in one of ADNOC Onshore fields. This paved the way for further large-scale deployment and CO2 WAG pilots starting in 2016, both onshore. Appreciable progresses have been made since 2009. This bodes well with the significant initiatives undertaken by the UAE towards carbon emissions and greenhouse gas reduction, climate control and sustainable development. There are broad consensus that climate changes are now and will continue to affect all countries on all continents. Potential global warming can disrupt national economies and adversely impact on lives, costing people, communities and countries already today and perhaps more in the future. Carbon Capture, Utilization, and Storage (CCUS) technologies have been making headlines and attracting increasing amount of renewed attention, because they are in line with meeting global greenhouse gas reduction goals, and contributing towards climate control and sustainable development. The giant Abu Dhabi onshore field consists of 6 carbonate reservoirs. Several pilots, immiscible hydrocarbon gas injection and CO2 WAG, and a pattern immiscible gas injection WAG flood have been executed. Miscible gas injection EOR is therefore field proven. However, due to large field size, surface congestion constraints, geological and fluid variations, miscible gas injection EOR development by reservoir individually becomes complex and economically challenging. This paper presents a comprehensive study and recommends an integrated CCUS Hub development approach - enabling field-wide EOR development with several hundred million-barrels of incremental recovery. The study follows a step-by-step systematic method. Existing water flood performances were assessed first. History matched full field simulation then leads to identification of CO2 EOR targets by area/flank for each reservoir. These are referred to as sweet development areas. Available advanced PVT data were analysed and a multi-reservoir single equation of state developed. It has been found that only CO2 is miscible across all six reservoirs, while hydrocarbon gas is also miscible for the deepest two reservoirs. Dedicated fine scale sector models (EOR history matched where applicable) were developed to generate multiple CO2 EOR development scenarios, for example, depending on water flood maturity at the time of CO2 EOR start-up, and potential impact on incremental oil production, incremental oil recovery due to reservoir heterogeneity. First results from sector modelling show that quite a few areas/flanks would be sub-economical if CO2 EOR development on a stand-alone basis. Hence the concept of a CCUS Hub is proposed, which would allow sweet development areas in any or all of the six reservoirs to be developed from a single common surface Cluster. There is potential space for development phasing, allowing additional CO2 EOR developments within the same cluster area once ullage and CO2 supply becomes available. The CCUS Hub development approach facilitates optimization and sharing of injection/production flow-lines; surface space, gathering and processing facilities, CO2 supply, CO2 recovery unit deployment coupled with produced gas re-injection into the 2 deepest reservoirs. Compared to a more conventional development approach of reservoir by reservoir, considerable scope for CAPEX and OPEX savings was found. Assuming a constant future oil price, a reduction in development costs would allow more sweet development areas to pass the threshold of economical development, leading to an increase in overall incremental production and recovery from CO2 EOR.
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Takahashi, Koji, Yasuo Kasugai, and Isao Fukuda. "Port Placement Theory in Consideration of Geographical Characteristics and Disaster Risks in Case of Ocean Space Utilization." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24345.
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In case of ocean space utilization, the factors which have to be taken into consideration in order to form an international basic container route are geographical factors which are the position on a global scale, the economic scale of port hinterland, the ocean climatic condition for setting the route etc. as well as factors from the viewpoint of transport such as the volume of container cargo and both size of container ships and container terminals. It is important to consider these geographical factors not only in order to study the port placement from the global point of view but also to devise the port policy. Although there are many studies on factors from the viewpoint of transport, there is almost no study on these geographical factors. Then, the authors made a new simulation model and analyzed these geographical factors of the international container ports in all parts of the world. As a result of analysis, the authors got the conclusion that there were three port placement patterns. The first type is ‘the Continent Base Port Type’, which it is located in the continent and has the large economic hinterland. Typical ports of this type are Antwerp, LA, LB and Shanghai. The second type is ‘the Ocean Base Port Type’, which is located in the ocean space where geographical predominance is high. This type forms route hubs. Typical ports of this type are Singapore, Malta and Kaohsiung. The third type is ‘the Tight Hinterland Port Type’, which is located in an island and has the tight economic hinterland where the economic activities density is very high. This type has characteristics that the distance between the ports is short and there are a lot of numbers of ports, which is unique and special in the world. Japan’s ports are classified in the third type. Furthermore, Japan has a characteristic that there are many large-scale earthquakes and has to consider earthquake measures to reduce disaster risks. The authors will suggest the most suitable port placement theory in consideration of these characteristics in case of ocean space utilization.
Reports on the topic "Large-scale climate patterns"
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Aragon, Christina. Connecting Local-scale Heavy Precipitation to Large-scale Meteorological Patterns over Portland, Oregon using Observations and Climate Models. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.7050.
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Harms, Nathan, Judy Shearer, James Cronin, and John Gaskin. Geographic and genetic variation in susceptibility of Butomus umbellatus to foliar fungal pathogens. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41662.
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Large-scale patterns of plant invasions may reflect regional heterogeneity in biotic and abiotic factors and genetic variation within and between invading populations. Having information on how effects of biotic resistance vary spatially can be especially important when implementing biological control because introduced agents may have different Impacts through interactions with host-plant genotype, local environment, or other novel enemies. We conducted a series of field surveys and laboratory studies to determine whether there was evidence of biotic resistance, as foliar fungal pathogens, in two introduced genotypes (triploid G1, diploid G4) of the Eurasian wetland weed, Butomus umbellatus L. in the USA. We tested whether genotypes differed in disease attack and whether spatial patterns in disease incidence were related to geographic location or climate for either genotype. After accounting for location (latitude, climate), G1 plants had lower disease incidence than G4 plants in the field (38% vs. 70%) but similar pathogen richness. In contrast, bioassays revealed G1 plants consistently received a higher damage score and had larger leaf lesions regardless of pathogen. These results demonstrate that two widespread B. umbellatus genotypes exhibit different susceptibility to pathogens and effectiveness of pathogen biological controls may depend on local conditions.
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Douglas, Thomas A., Christopher A. Hiemstra, Stephanie P. Saari, Kevin L. Bjella, Seth W. Campbell, M. Torre Jorgenson, Dana R. N. Brown, and Anna K. Liljedahl. Degrading Permafrost Mapped with Electrical Resistivity Tomography, Airborne Imagery and LiDAR, and Seasonal Thaw Measurements. U.S. Army Engineer Research and Development Center, July 2021. http://dx.doi.org/10.21079/11681/41185.
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Accurate identification of the relationships between permafrost extent and landscape patterns helps develop airborne geophysical or remote sensing tools to map permafrost in remote locations or across large areas. These tools are particularly applicable in discontinuous permafrost where climate warming or disturbances such as human development or fire can lead to rapid permafrost degradation. We linked field-based geophysical, point-scale, and imagery surveying measurements to map permafrost at five fire scars on the Tanana Flats in central Alaska. Ground-based elevation surveys, seasonal thaw-depth profiles, and electrical resistivity tomography (ERT) measurements were combined with airborne imagery and light detection and ranging (LiDAR) to identify relationships between permafrost geomorphology and elapsed time since fire disturbance. ERT was a robust technique for mapping the presence or absence of permafrost because of the marked difference in resistivity values for frozen versus unfrozen material. There was no clear relationship between elapsed time since fire and permafrost extent at our sites. The transition zone boundaries between permafrost soils and unfrozen soils in the collapse-scar bogs at our sites had complex and unpredictable morphologies, suggesting attempts to quantify the presence or absence of permafrost using aerial measurements alone could lead to incomplete results. The results from our study indicated limitations in being able to apply airborne surveying measurements at the landscape scale toward accurately estimating permafrost extent.
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Lynch, Clifford, and Diane Goldenberg-Hart. Beyond the Pandemic: The Future of the Research Enterprise in Academic Year 2021-22 and Beyond. Coalition for Networked Information, August 2021. http://dx.doi.org/10.56561/mwrp9673.
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In early June 2021, representatives from a number of CNI member institutions gathered for the third in a series of Executive Roundtable discussions that began in spring 2020, during the early days of the COVID-19 emergency. The conversations were intended to inform our understanding of how the pandemic had impacted the research enterprise and to share information about how institutions were planning to shape investments and strategies surrounding the research enterprise going forward. Previous Roundtables were held in April and September 2020 and reports from those conversations are available from http://www.cni.org/tag/executive-roundtable-report. As with the earlier Roundtables on this topic, June participants primarily included senior library administrators, directors of research computing and information technology, and chief research officers from a variety of higher education institutions across the US and Canada; most participating member institutions were public universities with high research activity, though some mid-sized and private institutions participated as well. The June Roundtable took place in a single convening, supplemented by an additional conversation with a key institution unable to join the group meeting due to last-minute scheduling conflicts. As before, we urged participants to think about research broadly, encompassing the humanities, social sciences, and fieldwork activities, as well as the work that takes place in campus laboratories or facilities shared by broader research communities; indeed, the discussions occasionally considered adjacent areas such as the performing arts. The discussion was wide-ranging, including, but not limited to: the challenges involving undergraduate, graduate and international students; labs and core instrumentation; access to physical collections (libraries, museums, herbaria, etc.) and digital materials; patterns of impact on various disciplines and mitigation strategies; and institutional approaches to improving research resilience. We sensed a growing understanding and sensitivity to the human toll the pandemic has taken on the research community. There were several consistent themes throughout the Roundtable series, but shifts in assumptions, planning, and preparation have been evident as vaccination rates have increased and as organizations have grown somewhat more confident in their ability to sustain largely in-person operations by fall 2021. Still, uncertainties abound and considerable notes of tentativeness remain, and indeed, events subsequent to the Roundtable, such as the large-scale spread of the Delta variant of COVID-19 in the US, have eroded much of the confidence we heard in June 2021, though probably more around instructional strategies than the continuity of the research enterprise. The events of the past 18 months, combined with a growing series of climate change-driven disruptions, have infused a certain level of humility into institutional planning, and they continue to underscore the importance of approaches that emphasize resilience and flexibility.
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Tanny, Josef, Gabriel Katul, Shabtai Cohen, and Meir Teitel. Application of Turbulent Transport Techniques for Quantifying Whole Canopy Evapotranspiration in Large Agricultural Structures: Measurement and Theory. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7592121.bard.
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Original objectives and revisions The original objectives of this research, as stated in the approved proposal were: 1. To establish guidelines for the use of turbulent transport techniques as accurate and reliable tool for continuous measurements of whole canopy ET and other scalar fluxes (e.g. heat and CO2) in large agricultural structures. 2. To conduct a detailed experimental study of flow patterns and turbulence characteristics in agricultural structures. 3. To derive theoretical models of air flow and scalar fluxes in agricultural structures that can guide the interpretation of TT measurements for a wide range of conditions. All the objectives have been successfully addressed within the project. The only modification was that the study focused on screenhouses only, while it was originally planned to study large greenhouses as well. This was decided due to the large amount of field and theoretical work required to meet the objectives within screenhouses. Background In agricultural structures such as screenhouses and greenhouses, evapotranspiration (ET) is currently measured using lysimeters or sap flow gauges. These measurements provide ET estimates at the single-plant scale that must then be extrapolated, often statistically or empirically, to the whole canopy for irrigation scheduling purposes. On the other hand, turbulent transport techniques, like the eddy covariance, have become the standard for measuring whole canopy evapotranspiration in the open, but their applicability to agricultural structures has not yet been established. The subject of this project is the application of turbulent transport techniques to estimate ET for irrigation scheduling within large agricultural structures. Major conclusions and achievements The major conclusions of this project are: (i) the eddy covariance technique is suitable for reliable measurements of scalar fluxes (e.g., evapotranspiration, sensible heat, CO2) in most types of large screenhouses under all climatic conditions tested. All studies resulted with fair energy balance closures; (ii) comparison between measurements and theory show that the model is capable in reliably predicting the turbulent flow characteristics and surface fluxes within screenhouses; (iii) flow characteristics within the screenhouse, like flux-variance similarity and turbulence intensity were valid for the application of the eddy covariance technique in screenhouses of relatively dilute screens used for moderate shading and wind breaking. In more dense screens, usually used for insect exclusions, development of turbulent conditions was marginal; (iv) installation of the sensors requires that the system’s footprint will be within the limits of the screenhouse under study, as is the case in the open. A footprint model available in the literature was found to be reliable in assessing the footprint under screenhouse conditions. Implications, both scientific and agricultural The study established for the first time, both experimentally and theoretically, the use of the eddy covariance technique for flux measurements within agricultural screenhouses. Such measurements, along with reliable theoretical models, will enable more accurate assessments of crop water use which may lead to improved crop water management and increased water use efficiency of screenhouse crops.
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Hunter, Fraser, and Martin Carruthers. Iron Age Scotland. Society for Antiquaries of Scotland, September 2012. http://dx.doi.org/10.9750/scarf.09.2012.193.
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The main recommendations of the panel report can be summarised under five key headings: Building blocks: The ultimate aim should be to build rich, detailed and testable narratives situated within a European context, and addressing phenomena from the longue durée to the short-term over international to local scales. Chronological control is essential to this and effective dating strategies are required to enable generation-level analysis. The ‘serendipity factor’ of archaeological work must be enhanced by recognising and getting the most out of information-rich sites as they appear. o There is a pressing need to revisit the archives of excavated sites to extract more information from existing resources, notably through dating programmes targeted at regional sequences – the Western Isles Atlantic roundhouse sequence is an obvious target. o Many areas still lack anything beyond the baldest of settlement sequences, with little understanding of the relations between key site types. There is a need to get at least basic sequences from many more areas, either from sustained regional programmes or targeted sampling exercises. o Much of the methodologically innovative work and new insights have come from long-running research excavations. Such large-scale research projects are an important element in developing new approaches to the Iron Age. Daily life and practice: There remains great potential to improve the understanding of people’s lives in the Iron Age through fresh approaches to, and integration of, existing and newly-excavated data. o House use. Rigorous analysis and innovative approaches, including experimental archaeology, should be employed to get the most out of the understanding of daily life through the strengths of the Scottish record, such as deposits within buildings, organic preservation and waterlogging. o Material culture. Artefact studies have the potential to be far more integral to understandings of Iron Age societies, both from the rich assemblages of the Atlantic area and less-rich lowland finds. Key areas of concern are basic studies of material groups (including the function of everyday items such as stone and bone tools, and the nature of craft processes – iron, copper alloy, bone/antler and shale offer particularly good evidence). Other key topics are: the role of ‘art’ and other forms of decoration and comparative approaches to assemblages to obtain synthetic views of the uses of material culture. o Field to feast. Subsistence practices are a core area of research essential to understanding past society, but different strands of evidence need to be more fully integrated, with a ‘field to feast’ approach, from production to consumption. The working of agricultural systems is poorly understood, from agricultural processes to cooking practices and cuisine: integrated work between different specialisms would assist greatly. There is a need for conceptual as well as practical perspectives – e.g. how were wild resources conceived? o Ritual practice. There has been valuable work in identifying depositional practices, such as deposition of animals or querns, which are thought to relate to house-based ritual practices, but there is great potential for further pattern-spotting, synthesis and interpretation. Iron Age Scotland: ScARF Panel Report v Landscapes and regions: Concepts of ‘region’ or ‘province’, and how they changed over time, need to be critically explored, because they are contentious, poorly defined and highly variable. What did Iron Age people see as their geographical horizons, and how did this change? Attempts to understand the Iron Age landscape require improved, integrated survey methodologies, as existing approaches are inevitably partial. Aspects of the landscape’s physical form and cover should be investigated more fully, in terms of vegetation (known only in outline over most of the country) and sea level change in key areas such as the firths of Moray and Forth. Landscapes beyond settlement merit further work, e.g. the use of the landscape for deposition of objects or people, and what this tells us of contemporary perceptions and beliefs. Concepts of inherited landscapes (how Iron Age communities saw and used this longlived land) and socal resilience to issues such as climate change should be explored more fully. Reconstructing Iron Age societies. The changing structure of society over space and time in this period remains poorly understood. Researchers should interrogate the data for better and more explicitly-expressed understandings of social structures and relations between people. The wider context: Researchers need to engage with the big questions of change on a European level (and beyond). Relationships with neighbouring areas (e.g. England, Ireland) and analogies from other areas (e.g. Scandinavia and the Low Countries) can help inform Scottish studies. Key big topics are: o The nature and effect of the introduction of iron. o The social processes lying behind evidence for movement and contact. o Parallels and differences in social processes and developments. o The changing nature of houses and households over this period, including the role of ‘substantial houses’, from crannogs to brochs, the development and role of complex architecture, and the shift away from roundhouses. o The chronology, nature and meaning of hillforts and other enclosed settlements. o Relationships with the Roman world
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Introduction Success of Less Common Species from the Genus Berberis L. Ukrainian Journal of Ecology, 2019. http://dx.doi.org/10.31812/123456789/3641.
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The study dealt with the patterns of adaptation of the genus Berberis L. low-abundant alien plants to the climatic conditions of the steppe zone of Ukraine. The success of the introduction, which was conducted on the territory of the Botanical Garden of Oles Honchar Dnipro National University (city of Dnipro) near 60 years ago, was evaluated by a set of indicators. According to the study of phenological rhythms, introduced plants can be characterized as plants with a relatively short growing season, a relatively long shoot growth, a short flowering period and a long maturing period. This indicates the lability of the phenological rhythms of the introduced plants, which respond to changes in environmental conditions in terms of the beginning and end of the phenological phases. The aquatic regime of introduced plants reflects the level of their adaptation to the environment due to the ability of plant organism to withstand water consumption. The study of water exchange features of Berberis L. plants revealed a moderate decrease in the intensity of transpiration and a moderate water deficit in the plant leaves, which indicates the adaptation of the species to the difficult climatic conditions of the steppe zone. The response of introduced plants to the level of moisture in the steppe region confirmed the universal mechanism of plant adaptation to arid conditions. Comparative analysis of the reproductive ability of introduced plants of the genus Berberis L. in the conditions of the Botanical Garden revealed a significant variability of quantitative indicators. The weight of 100 fruits ranged from 12.5 g (B. vulgaris) to 16.3 g (B. declinata). Seed length varied from 4.5 mm (B. canadensis) to 5.2 mm (B. declinata, B. amurensis), seed width varied from 1.8 mm (B. amurensis, B. vulgaris) to 2.1 mm (B. koreana). The highest mass of 1000 seeds was observed in the species B. koreana. To compare sample averages, the criterion for the significant difference of Tukey's group averages was used. The investigated plants of the genus Berberis L. can be recommended for the introduction into large-scale and individual gardening in order to expand the range of fruit products and obtain biologically valuable raw materials for the industrial production of functional products.