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1
Schmidli, Juerg, Brian Billings, Fotini K. Chow, Stephan F. J. de Wekker, James Doyle, Vanda Grubišić, Teddy Holt, et al. "Intercomparison of Mesoscale Model Simulations of the Daytime Valley Wind System." Monthly Weather Review 139, no. 5 (May 2011): 1389–409. http://dx.doi.org/10.1175/2010mwr3523.1.
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Three-dimensional simulations of the daytime thermally induced valley wind system for an idealized valley–plain configuration, obtained from nine nonhydrostatic mesoscale models, are compared with special emphasis on the evolution of the along-valley wind. The models use the same initial and lateral boundary conditions, and standard parameterizations for turbulence, radiation, and land surface processes. The evolution of the mean along-valley wind (averaged over the valley cross section) is similar for all models, except for a time shift between individual models of up to 2 h and slight differences in the speed of the evolution. The analysis suggests that these differences are primarily due to differences in the simulated surface energy balance such as the dependence of the sensible heat flux on surface wind speed. Additional sensitivity experiments indicate that the evolution of the mean along-valley flow is largely independent of the choice of the dynamical core and of the turbulence parameterization scheme. The latter does, however, have a significant influence on the vertical structure of the boundary layer and of the along-valley wind. Thus, this ideal case may be useful for testing and evaluation of mesoscale numerical models with respect to land surface–atmosphere interactions and turbulence parameterizations.
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Miao, Miao, Suhua Lou, Yuanxin Zhang, and Xing Chen. "Research on the Optimized Operation of Hybrid Wind and Battery Energy Storage System Based on Peak-Valley Electricity Price." Energies 14, no. 12 (June 21, 2021): 3707. http://dx.doi.org/10.3390/en14123707.
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The combined operation of hybrid wind power and a battery energy storage system can be used to convert cheap valley energy to expensive peak energy, thus improving the economic benefits of wind farms. Considering the peak–valley electricity price, an optimization model of the economic benefits of a combined wind–storage system was developed. A charging/discharging strategy of the battery storage system was proposed to maximize the economic benefits of the combined wind–storage system based on the forecast wind power. The maximal economic benefits were obtained based on scenario analysis, taking into account the wind-power forecast error, and costs associated with the loss of battery life, battery operation, and maintenance. Case simulation results highlight the effectiveness of the proposed model. The results show that the hybrid wind–storage system is not only able to convert cheap electricity in the valley period into expensive electricity in the peak period, thus resulting in higher economic benefits, but can also balance the deviation between actual output and plans for the wind power generator to decrease the loss penalty. The analyzed examples show that, following an increase in the deviation of the forecast wind power, the profit of the combined wind–storage system can increase by up to 45% using the charging/discharging strategy, compared with a wind farm that does not utilize energy storage. In addition, the profit of the combined wind–storage system can increase by up to 16% compared with separate systems, following an increase in the deviation penalty deviation coefficient.
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Eigenmann, R., S. Metzger, and T. Foken. "Generation of free convection due to changes of the local circulation system." Atmospheric Chemistry and Physics Discussions 9, no. 3 (May 7, 2009): 11367–411. http://dx.doi.org/10.5194/acpd-9-11367-2009.
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Abstract. Eddy-covariance and Sodar/RASS experimental measurement data of the COPS (Convective and Orographically-induced Precipitation Study) field campaign 2007 are used to investigate the generation of near-ground free convection events in the Kinzig valley, Black Forest, Southwest Germany. The measured high-quality turbulent flux data revealed free convection to be induced in situations where high buoyancy fluxes and a simultaneously occurring wind speed collapse were present. The minimum in wind speed – observable by the Sodar measurements through the whole vertical extension of the valley atmosphere – is the consequence of a thermally-induced valley wind system, which changes its wind direction from down to up-valley winds in the morning hours. Buoyant forces then dominate over shear forces within turbulence production. These situations are detected by the stability parameter (ratio of the measurement height to the Obukhov length) calculated from directly measured turbulent fluxes. An analysis of the scales of turbulent motions during the free convection event using wavelet transform confirms the large-eddy scale character of the detected plume-like coherent structures. Regarding the entire COPS measurement period, free convection events (FCEs) in the morning hours occur on about 50% of all days.
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Shrestha, S., and R. P. Regmi. "Winter-time Hydraulic Jump over the Pokhara Valley, Nepal." Journal of Nepal Physical Society 9, no. 1 (August 25, 2023): 98–106. http://dx.doi.org/10.3126/jnphyssoc.v9i1.57739.
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The Pokhara Valley is set to be one of the aviation hubs of Nepal with the opening of an international airport. The complex mid-hill mountainous topography of the Gangi-Himalaya and the characteristic wind system of the valley make safe aviation rather challenging over the valley. This study using the Weather Research and Forecasting modeling system shows that hydraulic jump-like phenomena occur regularly during winter in the western and central part of the Pokhara Valley during late afternoon/early evening when the airport may remain relatively busy. The jump occurs over the western part of the valley when the regional southwesterly plain to mountain wind via the Putalibazar Valley intrudes into the Valley crossing the Deurali-Mattikhan hill. The jump-like flow is accompanied by the formation of a mild reverse roller above the jump region and the head-on convergence with the northeasterly katabatic/drainage wind from Parche-Namarjung along the southeast–northwest oriented valley axis generating an updraft of as much as 0.4 to 0.8 m s-1. The southwesterly overrides northeasterly generating clockwise vertical rotors and high turbulence over the northeastern region of the valley. An early prediction of possible wind hazards at high spatiotemporal resolutions are highly desired to make aviation activities in the region safer for civil aviation.
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Eigenmann, R., S. Metzger, and T. Foken. "Generation of free convection due to changes of the local circulation system." Atmospheric Chemistry and Physics 9, no. 21 (November 12, 2009): 8587–600. http://dx.doi.org/10.5194/acp-9-8587-2009.
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Abstract. Eddy-covariance and Sodar/RASS experimental measurement data of the COPS (Convective and Orographically-induced Precipitation Study) field campaign 2007 are used to investigate the generation of near-ground free convection conditions (FCCs) in the Kinzig valley, Black Forest, Southwest Germany. The measured high-quality turbulent flux data revealed that FCCs are initiated near the ground in situations where moderate to high buoyancy fluxes and a simultaneously occurring drop of the wind speed were present. The minimum in wind speed – observable by the Sodar measurements through the whole vertical extension of the valley atmosphere – is the consequence of a thermally-induced valley wind system, which changes its wind direction from down to up-valley winds in the morning hours. Buoyancy then dominates over shear within the production of turbulence kinetic energy near the ground. These situations are detected by the stability parameter (ratio of the measurement height to the Obukhov length) when the level of free convection, which starts above the Obukhov length, drops below that of the sonic anemometer. An analysis of the scales of turbulent motions during FCCs using wavelet transform shows the occurrence of large-scale turbulence structures. Regarding the entire COPS measurement period, FCCs in the morning hours occur on about 50% of all days. Enhanced surface fluxes of latent and sensible heat are found on these days.
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Katurji, Marwan, Bob Noonan, Peyman Zawar-Reza, Tobias Schulmann, and Andrew Sturman. "Characteristics of the Springtime Alpine Valley Atmospheric Boundary Layer Using Self-Organizing Maps." Journal of Applied Meteorology and Climatology 54, no. 10 (October 2015): 2077–85. http://dx.doi.org/10.1175/jamc-d-14-0317.1.
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AbstractVertical profiles of wind velocity and air temperature from a sound detection and ranging (sodar) radio acoustic sounding system (RASS)-derived dataset within an alpine valley of the New Zealand Southern Alps were analyzed. The data covered the month of September 2013, and self-organizing maps (SOM; a data-clustering approach that is based on an unsupervised machine-learning algorithm) are used to detect topological relationships between profiles. The results of the SOM were shown to reflect the physical processes within the valley boundary layer by preserving valley boundary layer dynamics and its response to wind shear. By examining the temporal evolution of ridgetop wind speed and direction and SOM node transitions, the sensitivity of the valley boundary layer to ridgetop weather conditions was highlighted. The approach of using a composite variable (wind speed and potential temperature) with SOM was successful in revealing the coupling of dynamics and atmospheric stability. The results reveal the capabilities of SOM in analyzing large datasets of atmospheric boundary layer measurements and elucidating the connectivity of ridgetop wind speeds and valley boundary layers.
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Liu, Yuanyuan, Pengcheng Guo, and Hao Zhang. "Optimal scheduling for wind-solar-hydro hybrid generation system with cascade hydropower considering regulation energy storage requirements." Journal of Physics: Conference Series 2707, no. 1 (February 1, 2024): 012100. http://dx.doi.org/10.1088/1742-6596/2707/1/012100.
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Abstract Large-scale integration of renewable energy into the grid can lead to significant changes in the net load, peak-to-valley difference, peak and valley occurrence time of the power system. As a result, the power of hydropower plants must take a rapid adjustment response. Aiming at the coordinated operation of multiple energy sources, such as wind power, solar power, cascade hydropower station and energy storage pumping station, a coordinated scheduling model is proposed which can fully improve the consumption capacity of wind and solar power by aiming at the maximum power generation, minimum net load fluctuation and minimum wind and solar abandonment. Through the configuration of three different pumping station capacities, the influence of energy storage pumping station capacity on the complementary power generation system is analyzed. When the pumping station capacity is large enough, the output of the wind and solar can be completely consumed. The studies show that the cascade power station and pump energy storage regulation have a strong net load filling valley effect, which can effectively reduce the impact of wind and solar access on system operation, maintain the efficient and stable operation of the unit, and ensure the absorption rate of renewable energy.
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Yunli, Yue, Sun Beibei, Yue Hao, Chen Dan, Zhou Yi, and Lu Jun. "An optimized demand-response operation method of regional integrated energy system considering 5G base station energy storage." Journal of Physics: Conference Series 2121, no. 1 (November 1, 2021): 012007. http://dx.doi.org/10.1088/1742-6596/2121/1/012007.
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Abstract The scheduling technology of regional integrated energy system is one of the key technologies to realize carbon neutralization by utilizing wind-power. Aiming at the optimal scheduling problem of regional electrothermal integrated energy system considering wind-power utilization and load side energy consumption, this paper proposes an optimized demand-response operation method of regional integrated energy system considering 5G base station energy storage. The regional integrated energy system of load side demand response is constructed based on the comprehensive consideration of technical and economic factors such as wind-power utilization and economic costs and load side peak valley difference. Finally, a two-layer particle swarm optimization method is proposed to solve the model. The experimental results show that the proposed method can effectively achieve wind-power utilization, economic dispatch and reduce the peak valley difference through load side demand response, which can improve the economic efficiency, environmental protection and low-carbon operation of regional integrated energy system.
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Wang, Hsueh-Ming Steve, Karl M. Spohn, LuAnn Piccard, and Lei Yao. "Feasibility Study of Wind Power Generation System at Arctic Valley." Engineering Management Journal 22, no. 3 (September 2010): 21–33. http://dx.doi.org/10.1080/10429247.2010.11431869.
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Whiteman, C. David, Sebastian W. Hoch, and Gregory S. Poulos. "Evening Temperature Rises on Valley Floors and Slopes: Their Causes and Their Relationship to the Thermally Driven Wind System." Journal of Applied Meteorology and Climatology 48, no. 4 (April 1, 2009): 776–88. http://dx.doi.org/10.1175/2008jamc2028.1.
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Abstract At slope and valley floor sites in the Owens Valley of California, the late afternoon near-surface air temperature decline is often followed by a temporary temperature rise before the expected nighttime cooling resumes. The spatial and temporal patterns of this evening warming phenomenon, as seen in the March/April 2006 Terrain-Induced Rotor Experiment, are investigated using a widely distributed network of 51 surface-based temperature dataloggers. Hypotheses on the causes of the temperature rises are tested using heavily instrumented 34-m meteorological towers that were located within the datalogger array. The evening temperature rise follows the development of a shallow temperature deficit layer over the slopes and floor of the valley in which winds blow downslope. Background winds within the valley, freed from frictional deceleration from the earth’s surface by this layer, accelerate. The increased vertical wind shear across the temperature deficit layer eventually creates shear instability and mixes out the layer, creating the observed warming near the ground. As momentum is exchanged during the mixing event, the wind direction near the surface gradually turns from downslope to the background wind direction. After the short period of warming associated with the mixing, ongoing net radiative loss causes a resumption of the cooling.
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Z�ngl, G. "A reexamination of the valley wind system in the Alpine Inn Valley with numerical simulations." Meteorology and Atmospheric Physics 87, no. 4 (January 28, 2004): 241–56. http://dx.doi.org/10.1007/s00703-003-0056-5.
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Raab, Thomas, and Georg Mayr. "Hydraulic Interpretation of the Footprints of Sierra Nevada Windstorms Tracked with an Automobile Measurement System." Journal of Applied Meteorology and Climatology 47, no. 10 (October 1, 2008): 2581–99. http://dx.doi.org/10.1175/2008jamc1675.1.
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Abstract This article reports results from the Sierra Rotors Project, which took place in the central part of Owens Valley, California, east of the Sierra Nevada in March and April 2004. The aim of the study is to describe the footprints of cross-mountain and downslope airflow by mobile surface measurements and radiosoundings. An instrumented car measured wind, temperature, pressure, and humidity. Four case studies cover the spectrum of forcings behind the foehn-like downslope windstorms. Hydraulic theory as a conceptual model was used to explain the data from the car in combination with radiosoundings. All four cases had a colder air mass on the upstream side, thus creating a hydrostatic pressure forcing. With weak flow parallel to the sierra, no downslope windstorm developed and a valley-slope circulation was documented, which for the first time related continuous pressure measurements to the thermal wind system. A second case with a stronger wind component perpendicular to the sierra caused the flow to plunge to the Owens Valley floor. Signatures indicating supercritical regions with accelerated flow reverting to a subcritical state in a hydraulic jump were found. In the third case, the flow separated from the lee slope and subsequently reattached. In the last case, a downslope windstorm developed ahead of a cold front. The downslope windstorm and cold front coexisted in the valley for several hours, with the latter being confined to its eastern side and the storm riding up over it.
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Regmi, Ram P., and Sangeeta Maharjan. "Wind Power Potential over the World’s Deepest River Valley." Journal of Nepal Physical Society 4, no. 1 (May 22, 2017): 54. http://dx.doi.org/10.3126/jnphyssoc.v4i1.17337.
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<p class="Default">Wind power potential prevailing over the world’s deepest river gorge, the Kali Gandaki River Valley, located in the western trans-Himalaya region of Nepal, has been assessed and mapped at 1 km × 1 km horizontal grid resolution with the application of Weather Research and Forecasting (WRF) modeling system. The wind power potential maps cover 70 km × 70 km area, which encloses the very first and failed wind power project in the country and the Jomsom Airport at the center. The simulated wind characteristics compare well with the available observed wind characteristic. The wind power potential appears to vary from good to outstanding over 200 km<sup>2</sup> area along the axis of Kali Gandaki River Valley. However, a detail long-term observation, numerical simulation as well as engineering examinations are desired to address abnormal valley wind characteristics for sustainable power production over the area.</p><p class="Default"><strong>Journal of Nepal Physical Society </strong></p><p><em>Volume 4, Issue 1, February 2017, Page : 54-59</em></p>
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Acharya, S., S. Neupane, R. Shrestha, C. Chapagain, P. Acharya, S. Maharjan, and R. Regmi. "Early Monsoon Time Local Flow Characteristics over the Hetauda Valley and its Implications." Journal of Institute of Science and Technology 19, no. 2 (November 9, 2015): 109–17. http://dx.doi.org/10.3126/jist.v19i2.13863.
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The early monsoon time atmospheric transport processes over the Hetauda valley, the closest low-land that accommodates the third largest industrial district of Nepal, has been studied with the application of Weather Research and Forecasting (WRF) Modeling System initialized with NCEP meteorological and USGS terrain elevation and land-use data. The study reveals that the mixing layer over the Hetauda valley may evolve as much as 3 km above the surface during the afternoon time. The near surface atmosphere of the valley appears very weakly stratified even in the early morning time indicating that prevailing meteorology over the valley favors efficient dispersion of air pollutants. The study also reveals that the daytime upslope winds over the Hetauda valley and associated northern mountains effectively intrude into the Kathmandu valley enhancing the southwesterly and northwesterly wind system of the valley. Intrusion of local flows appears to be accompanied with the excitation of mountain waves and plain-to-plateau wind. Formation of lowlevel rotors over the Hetauda valley, excitation of mountain waves and the strong downdrafts over the southwestern part of the Kathmandu valley may put aircrafts into high risk. The pattern of local flow fields strongly suggest that the increase emissions over the Hetauda valley can have significant help to further deteriorate the already unhealthy air of Kathmandu.Journal of Institute of Science and Technology, 2014, 19(2): 109-117
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Xu, Jian Fei, Jian Shao, Bu Han Zhang, Peng Yu, Kai Min Zhang, Bing Jie Jin, Teng Yu Ge, Xiao Kang Dai, and Wei Si Deng. "Research on Peak Load Regulation Demand of Power System with Large-Scale Wind Power Integration." Advanced Materials Research 953-954 (June 2014): 514–17. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.514.
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In china, increasing large-scale wind power integration has brought much more peak load regulation demand, which is the bottleneck of the integration of wind power to systems. This paper analyzed the influence mechanism of large-scale wind power on peak load regulation demand. And critical indicators are constructed based on the daily peak-valley difference to evaluate peak load regulation demand caused by wind power integration. Statistical analyses based on large number of actual dates reflect the influence of large-scale wind power integration on peak load regulation demand, which can help provide more decision-making information for planning and operation.
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Zhang, Yuqi, Chuan He, Anqi Xv, and Xiaoxiao Tang. "Two-Stage Chance-Constrained Coordinated Operation of an Integrated Gas–Electric System." Energies 15, no. 12 (June 18, 2022): 4458. http://dx.doi.org/10.3390/en15124458.
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Under the background that the high penetration of renewable energy generation, which mainly consists of wind power, will have a significant impact on electric power systems due to the volatility and uncertainty of renewable energy, energy systems with gas–electric coupling and interconnections have been widely studied to accommodate renewable energy generation. This paper proposes a two-stage chance-constrained coordinated operation model of an integrated gas–electric system and fully considers the uncertainty and high penetration of wind power. The Taylor series expansion method is used to linearize the Weymouth gas flow equation of a natural gas system and finally obtains a mixed integer linear programming model. Case studies show the effectiveness of the integrated energy system for peak shaving, valley filling, and promoting wind power accommodation. The proposed model ensures the consumption of wind power generation and also reduces the operation cost by about 0.7%.
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Zängl, Günther. "Dynamical Aspects of Wintertime Cold-Air Pools in an Alpine Valley System." Monthly Weather Review 133, no. 9 (September 1, 2005): 2721–40. http://dx.doi.org/10.1175/mwr2996.1.
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Abstract This study presents high-resolution numerical simulations in order to examine the dynamical mechanisms controlling the persistence of wintertime cold-air pools in an Alpine valley system. First, a case study of a cold-pool episode is conducted, the formation of which was related to the passage of a warm front north of the Alps. While the preexisting cold air was rapidly advected away in the Alpine foreland, a persistent cold pool was maintained in the inner-Alpine part of the valley system, associated with sustained horizontal temperature differences of up to 10 K over a distance of 30 km. The case study is complemented by a series of semi-idealized simulations, combining realistic topography with idealized large-scale flow conditions. These simulations consider a range of different ambient wind directions in order to investigate their impact on the cold-pool persistence. The results indicate that the most important dynamical mechanism controlling the persistence of cold-air pools in deep Alpine valleys is cold-air drainage toward the Alpine foreland. The preferred direction for such a drainage flow is down the pressure gradient imposed by the (geostrophically balanced) ambient flow. Thus, for a given valley geometry and a given strength of the ambient flow, the probability for persistent cold-air pools mainly depends on the ambient wind direction. If the direction of the imposed pressure gradient matches a sufficiently wide connection to the foreland (a valley or a low pass), then a drainage flow will lead to a rapid removal of the cold air. However, the presence of pronounced lateral constrictions in the connecting valley may strongly reduce the drainage efficiency. Cold-pool erosion by turbulent vertical mixing seems to play a comparatively minor role in deep valley systems as considered in this study.
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Schmidli, Juerg, Gregory S. Poulos, Megan H. Daniels, and Fotini K. Chow. "External Influences on Nocturnal Thermally Driven Flows in a Deep Valley." Journal of Applied Meteorology and Climatology 48, no. 1 (January 1, 2009): 3–23. http://dx.doi.org/10.1175/2008jamc1852.1.
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Abstract The dynamics that govern the evolution of nighttime flows in a deep valley, California’s Owens Valley, are analyzed. Measurements from the Terrain-Induced Rotor Experiment (T-REX) reveal a pronounced valley-wind system with often nonclassical flow evolution. Two cases with a weak high pressure ridge over the study area but very different valley flow evolution are presented. The first event is characterized by the appearance of a layer of southerly flow after midnight local time, sandwiched between a thermally driven low-level downvalley (northerly) flow and a synoptic northwesterly flow aloft. The second event is characterized by an unusually strong and deep downvalley jet, exceeding 15 m s−1. The analysis is based on the T-REX measurement data and the output of high-resolution large-eddy simulations using the Advanced Regional Prediction System (ARPS). Using horizontal grid spacings of 1 km and 350 m, ARPS reproduces the observed flow features for these two cases very well. It is found that the low-level along-valley forcing of the valley wind is the result of a superposition of the local thermal forcing and a midlevel (2–2.5 km MSL) along-valley pressure forcing. The analysis shows that the large difference in valley flow evolution derives primarily from differences in the midlevel pressure forcing, and that the Owens Valley is particularly susceptible to these midlevel external influences because of its specific geometry. The results demonstrate the delicate interplay of forces that can combine to determine the valley flow structure on any given night.
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Kefif, Nesrine, Bachir Melzi, Mehran Hashemian, Mamdouh El Haj Assad, and Siamak Hoseinzadeh. "Feasibility and optimal operation of micro energy hybrid system (hydro/wind) in the rural valley region." International Journal of Low-Carbon Technologies 17 (November 27, 2021): 58–68. http://dx.doi.org/10.1093/ijlct/ctab081.
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Abstract With the increase in the global and local demand for electrical energy, which is necessary for the functioning of several fields such as the economy and agriculture, this study introduces a micro-hydro–wind hybrid system in order to obtain an economic feasibility of the off-grid isolated and renewable energy system. The main objective of this research is to determine the optimum design size for a hydro–wind hybrid energy system that is supposed to meet the demand for the electric load in front of a valley in Algeria called Yesser with variable water flow and wind speeds in three positions. Batteries are supplied to increase the reliability of the system when the performance of the wind turbine energy and the flow rate of the hydro system are evaluated. This system is proposed to reduce financial costs in addition to the possibility of providing interchangeable energy and operating reserves with short start times. The Homer Pro software is used to model the hybrid renewable energy system and to perform the required analysis of the economic side of the system in terms of the valley's flow rate and the wind speed. The average speed of the water flow in Yesser valley is varied between 10 and 24.6 m3/s, and three cases of the valley's flow rate were studied with the maximum and minimum wind speeds: the passage (the transit) with 10 m3/s, the downstream (the estuary) with 19 m3/s and the valley's upstream (the source) with 24.6 m3/s. From the results, it appears that the hydro power was not enough to meet the load demand in the first area (the transit); however, the hydro/wind hybrid system was capable to feed the required load. For the second area (the estuary) the wind power was needed just in summer season, and for the third area (the source) the hydro generator was sufficient to feed the load all the year as the hydro power generated exceeds the load demand. The Homer Pro software calculations prove that the financial cost of the system is inversely proportional with the wind speed, such that the higher the wind speed the lower the cost of the system, the same relationship is for the flow rate speed as we consider the third case the most cost-effective with 61 330.46 USD.
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Piringer, M., and K. Baumann. "Modifications of a Valley Wind System by an Urban Area - Experimental Results." Meteorology and Atmospheric Physics 71, no. 1-2 (December 7, 1999): 117–25. http://dx.doi.org/10.1007/s007030050049.
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Zhang, De, Luyuan Chen, Feimin Zhang, Juan Tan, and Chenghai Wang. "Numerical Simulation of Near-Surface Wind during a Severe Wind Event in a Complex Terrain by Multisource Data Assimilation and Dynamic Downscaling." Advances in Meteorology 2020 (December 30, 2020): 1–14. http://dx.doi.org/10.1155/2020/7910532.
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Accurate forecast and simulation of near-surface wind is a great challenge for numerical weather prediction models due to the significant transient and intermittent nature of near-surface wind. Based on the analyses of the impact of assimilating in situ and Advanced Tiros Operational Vertical Sounder (ATOVS) satellite radiance data on the simulation of near-surface wind during a severe wind event, using the new generation mesoscale Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system, the dynamic downscaling of near-surface wind is further investigated by coupling the microscale California Meteorological (CALMET) model with the WRF and its 3DVAR system. Results indicate that assimilating in situ and ATOVS radiance observations strengthens the airflow across the Alataw valley and triggers the downward transport of momentum from the upper atmosphere in the downstream area of the valley in the initial conditions, thus improving near-surface wind simulations. Further investigations indicate that the CALMET model provides more refined microtopographic structures than the WRF model in the vicinity of the wind towers. Although using the CALMET model achieves the best simulation of near-surface wind through dynamic downscaling of the output from the WRF and its 3DVAR assimilation, the simulation improvements of near-surface wind speed are mainly within 1 m s−1. Specifically, the mean improvement proportions of near-surface wind speed are 64.8% for the whole simulation period, 58.7% for the severe wind period, 68.3% for the severe wind decay period, and 75.4% for the weak wind period. The observed near-surface wind directions in the weak wind conditions are better simulated in the coupled model with CALMET downscaling than in the WRF and its 3DVAR system. It is concluded that the simulation improvements of CALMET downscaling are distinct when near-surface winds are weak, and the downscaling effects are mainly manifested in the simulation of near-surface wind directions.
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Lyza, Anthony W., Todd A. Murphy, Barrett T. Goudeau, Preston T. Pangle, Kevin R. Knupp, and Ryan A. Wade. "Observed Near-Storm Environment Variations across the Southern Cumberland Plateau System in Northeastern Alabama." Monthly Weather Review 148, no. 4 (March 17, 2020): 1465–82. http://dx.doi.org/10.1175/mwr-d-19-0190.1.
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Abstract The Sand Mountain and Lookout Mountain Plateaus in northeastern Alabama have been established as a regional relative maximum in tornadogenesis reports within the southeastern United States. Investigation of long-term surface datasets has revealed (i) stronger and more backed winds atop Sand Mountain than over the Tennessee Valley, and (ii) measured cloud-base heights are lower to the surface atop Sand Mountain than over the Tennessee Valley. These observations suggest that low-level wind shear and lifting condensation level (LCL) height changes may lead to conditions more favorable for tornadogenesis atop the plateaus than over the Tennessee Valley. However, prior to fall 2016, no intensive observations had been made to further investigate low-level flow or thermodynamic changes in the topography of northeastern Alabama. This paper provides detailed analysis of observations gathered during VORTEX-SE field campaign cases from fall 2016 through spring 2019. These observations indicate that downslope winds form along the northwest edge of Sand Mountain in at least some severe storm environments in northeastern Alabama. Wind profiles gathered across northeastern Alabama indicate that low-level helicity changes can be substantial over small distances across different areas of the topographic system. LCL height changes often scale to changes in land elevation, which can be on the order of 200–300 m across northeastern Alabama.
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Han, Liang, and Yong Gang Li. "Analysis on Capacity of Wind Power Integration into Grid Based on Power Balance." Advanced Materials Research 986-987 (July 2014): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.243.
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Among all the factors influencing the capacity of wind power, peak regulation capability is commonly regarded as one of the most important constraint factors. From the perspective of peak regulation, the maximum peak-load regulating adequacy revised by the wind power characteristic coefficient is the limitation of the capacity of wind power. This paper proposes an assessment system on capacity of wind power integration into grid based on power balance. First of all, this assessment system takes the impact of wind power integration on the reserve capacity of the power system into consideration. Then calculate the reserve capacity based on power generation reliability index. Finally, evaluate the capacity of wind power based on the peak regulation capability of the units during the low load period. This paper analyses the capacity of wind power integration into Liaoning power grid based on power supply characteristics, load characteristics and peak-valley difference, and points out that the phenomenon of the “wind curtailment” is unavoidable. According to the specific situation of wind power limitation, this paper proposes measures to maximize the capacity of wind power.
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Arias, Santiago, Jose I. Rojas, Rathan B. Athota, and Adeline Montlaur. "Simulations of Wind Formation in Idealised Mountain–Valley Systems Using OpenFOAM." Sustainability 15, no. 2 (January 11, 2023): 1387. http://dx.doi.org/10.3390/su15021387.
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An OpenFOAM computational fluid dynamics model setup is proposed for simulating thermally driven winds in mountain–valley systems. As a first step, the choice of Reynolds Averaged Navier–Stokes k−ε turbulence model is validated on a 3D geometry by comparing its results vs. large-eddy simulations reported in the literature. Then, a numerical model of an idealised 2D mountain–valley system with mountain slope angle of 20° is developed to simulate thermally driven winds. A couple of top surface boundary conditions (BC) and various combinations of temperature initial conditions (IC) are tested. A transient solver for buoyant, turbulent flow of incompressible fluids is used. Contrary to classical approaches where buoyancy is set as a variable of the problem, here temperature linearly dependent with altitude is imposed as BC on the slope and successfully leads to thermally driven wind generation. The minimum fluid domain height needed to properly simulate the thermally driven winds and the effects of the different setups on the results are discussed. Slip wall BC on the top surface of the fluid domain and uniform temperature IC are found to be the most adequate choices. Finally, valleys with different widths are simulated to see how the mountain–valley geometry affects the flow behaviour, both for anabatic (daytime, up-slope) and katabatic (nighttime, down-slope) winds. The simulations correctly reproduce the acceleration and deceleration of the flow along the slope. Increasing the valley width does not significantly affect the magnitude of the thermally driven wind but does produce a displacement of the generated convective cell.
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Regmi, Ram P. "Aviation Hazards Over the Jomsom Airport of Nepal as Revealed by Numerical Simulation of Local Flows." Journal of Institute of Science and Technology 19, no. 1 (November 8, 2015): 111–20. http://dx.doi.org/10.3126/jist.v19i1.13836.
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Jomsom Airport of Nepal is considered to be one of the world’s most extreme airports. The frequency of aircraft crashing along the Kali Gandaki River Valley and over the Jomsom Airport is very high. Pre-monsoon time local flow characteristics over the Kali Gandaki Valley has been studied to understand the meteorological hazards for aviation activities along the valley and over the Jomsom Airport with the application of the WRF Modeling System initialized with NCEP meteorological, USGS 24 categories land use, and 30 second terrain data. Four days long simulation was carried out for the period of 15 May 0000 UTC to 19 May 0000 UTC, 2012 to capture the 16 May 2012 incidence of light aircraft crashing in the late morning time of the day. The study revealed that there are enough grounds to believe that the crashing of the plane resulted due to the adverse local flow system prevailing over the Jomsom Airport area during the period. The significant subsidence from the relatively strong boundary layer wind aloft, the ground level opposite wind and the low-level turbulence might have leaded the airplane to crash just after its takeoff from the runway. The local flow system over the Kali Gandaki Valley makes afternoon time flights over the Jomsom Airport almost impossible and the narrow slot of time during morning time is also not free from difficult situation. Journal of Institute of Science and Technology, 2014, 19(1): 111-120
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Schauberger, G., and M. Piringer. "Predicting odour impact using the Austrian odour dispersion model (AODM)." Water Science and Technology 44, no. 9 (November 1, 2001): 197–204. http://dx.doi.org/10.2166/wst.2001.0539.
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Using a dispersion model to calculate ambient odour concentrations, the separation distance between livestock buildings and residential areas is defined by the odour impact criteria using a combination of a pre-selected odour threshold and an exceeding probability. The dynamic Austrian Odour Dispersion Model (AODM), a Gaussian model, is used to calculate the direction-dependent separation distances for several combinations of these two values, which represent the protection level of various land use categories. The calculated direction-dependent separation distances are a function of the prevailing wind velocity and atmospheric stability conditions. At a site in the Austrian North-alpine foreland, the direction-dependent separation distance (calculated on the basis of a two year time series of meteorological data) for pure residential areas (3% exceeding probability over the year for an odour threshold of 1 OU/m3) lies between 99 m (for northerly winds with a probability of less than 3%) and 362 m (for westerly winds with a probability of 34%). For west and east the main wind directions, odour sensation can be expected more often for higher wind velocities and a neutral or stable atmosphere around sunset. Northerly and southerly winds show the typical diurnal variation of a local valley wind system with predominantly northerly daytime up-valley and southerly night-time down-valley winds.
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Arduini, Gabriele, Chantal Staquet, and Charles Chemel. "Interactions Between the Nighttime Valley-Wind System and a Developing Cold-Air Pool." Boundary-Layer Meteorology 161, no. 1 (June 2, 2016): 49–72. http://dx.doi.org/10.1007/s10546-016-0155-8.
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Laiti, L., D. Zardi, M. de Franceschi, and G. Rampanelli. "Analysis of the diurnal development of the <i>Ora del Garda</i> wind in the Alps from airborne and surface measurements." Atmospheric Chemistry and Physics Discussions 13, no. 7 (July 18, 2013): 19121–71. http://dx.doi.org/10.5194/acpd-13-19121-2013.
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Abstract. A lake-breeze and valley-wind coupled circulation system, known as Ora del Garda, typically arises in the late morning from the northern shorelines of Lake Garda (southeastern Italian Alps), and then channels into the Sarca and Lakes valleys to the north. After flowing over an elevated saddle, in the early afternoon this wind breaks out from the west into the nearby Adige Valley, hindering the regular development of the local up-valley wind by producing a strong and gusty anomalous flow in the area. Two targeted flights of an equipped motorglider were performed in the morning and afternoon of 23 August 2001 in the above valleys, exploring selected vertical slices of the atmosphere, from the lake's shore to the area where the two local airflows interact. At the same time, surface observations were collected during an intensive field measurement campaign held in the interaction area, as well as from routinely-operated weather stations disseminated along the whole study area, allowing the analysis of the different stages of the Ora del Garda development. From airborne measurements, an atmospheric boundary-layer (ABL) vertical structure, typical of deep Alpine valleys, was detected in connection with the wind flow, with rather shallow (∼500 m) convective mixed layers surmounted by deeper, weakly stable layers. On the other hand, close to the lake's shoreline the ABL was found to be stabilized down to very low heights, as an effect of the onshore advection of cold air by the lake breeze. Airborne potential temperature observations were mapped over high-resolution 3-D grids for each valley section explored by the flights, using a geostatistical technique called residual kriging (RK). RK-regridded fields revealed fine-scale features and inhomogeneities of ABL thermal structures associated with the complex thermally-driven wind field developing in the valleys. The combined analysis of surface observations and RK-interpolated fields revealed an irregular propagation of the lake-breeze front in the lower part of the valley, and cross-valley thermal asymmetries amenable both to the differential solar heating of the valley slopes and to the valley curvature in its upper part. The overflowing of the potentially cooler Ora del Garda air from the Lakes Valley in the afternoon produces a strong katabatic wind at the bottom of the underlying Adige Valley, which blows in cross-valley (i.e. westerly) direction and impinges on the opposite eastern valley sidewall. RK-regridded potential temperature field highlighted that this phenomenon gives origin to a "hydraulic jump" flow structure in the urban area north of the city of Trento, leading to the down-stream formation of a ∼1300 m deep well-mixed layer. The improved knowledge of the typical Ora del Garda flow patterns and associated ABL structures, deriving from the combined analysis of surface and airborne observations, has practical application in air quality forecasting for the study area, for it helps in the understanding of pollution transport and dispersion processes by thermally-driven winds in the region. Moreover, 3-D meteorological fields produced by RK are likely to be an excellent basis for comparison with results from high-resolution numerical simulations, as they provide a degree of spatial detail that is fully comparable to the spatial scales resolved by large-eddy simulations.
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Muñoz, Ricardo C., Mark J. Falvey, Marcelo Araya, and Martin Jacques-Coper. "Strong Down-Valley Low-Level Jets over the Atacama Desert: Observational Characterization." Journal of Applied Meteorology and Climatology 52, no. 12 (December 2013): 2735–52. http://dx.doi.org/10.1175/jamc-d-13-063.1.
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AbstractThe near-surface wind and temperature regime at three points in the Atacama Desert of northern Chile is described using two years of multilevel measurements from 80-m towers located in an altitude range between 2100 and 2700 m MSL. The data reveal the frequent development of strong nocturnal drainage flows at all sites. Down-valley, nose-shaped wind speed profiles are observed, with maximum values occurring at heights between 20 and 60 m AGL. The flow intensity shows considerable interdaily variability and a seasonal modulation of maximum speeds, which in the cold season can attain hourly average values of more than 20 m s−1. Turbulent mixing appears to be important over the full tower layer, affecting the curvature of the nighttime temperature profile and possibly explaining the observed increase of surface temperatures in the down-valley direction. Nocturnal valley winds and temperatures are weakly controlled by upper-air conditions observed at the nearest aerological station. Estimates of terms in the momentum budget for the development and quasi-stationary phases of the down-valley flows suggest that the pressure gradient force due to the near-surface cooling along the sloping valley axes plays an important role in these drainage flows. A scale for the jet nose height of equilibrium turbulent down-slope jets is proposed that is based on surface friction velocity and surface inversion intensity. At one of the sites, this scale explains about 70% of the case-to-case observed variance of jet nose heights. Further modeling and observations are needed, however, to define better the dynamics, extent, and turbulence structure of this flow system, which has significant wind-energy, climatic, and environmental implications.
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Li, Yang, Outing Li, Feng Wu, Shiyi Ma, Linjun Shi, and Feilong Hong. "Multi-Objective Capacity Optimization of Grid-Connected Wind–Pumped Hydro Storage Hybrid Systems Considering Variable-Speed Operation." Energies 16, no. 24 (December 17, 2023): 8113. http://dx.doi.org/10.3390/en16248113.
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The coordination of pumped storage and renewable energy is regarded as a promising avenue for renewable energy accommodation. Considering wind power output uncertainties, a collaborative capacity optimization method for wind–pumped hydro storage hybrid systems is proposed in this work. Firstly, considering the fluctuation of wind power generation caused by the natural seasonal weather and inherent uncertainties of wind power outputs, a combined method based on the generative adversarial network and K-means clustering algorithm is presented to construct wind power output scenarios. Then, a multi-objective wind–pumped storage system capacity optimization model is established with three objectives consisting of minimizing the levelized cost of energy, minimizing the net load peak–valley difference of regional power grids, and minimizing the power output deviation of hybrid systems. An inner and outer nested algorithm is proposed to obtain the Pareto frontiers based on the strength of the Pareto evolutionary algorithm II. Finally, the complementarity of wind power and pumped storage is illustrated through an analysis of numerical examples, and the advantages of variable-speed pumped storage in complementary operation with wind power over fixed-speed units are verified.
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Ju, Liwei, Zhongfu Tan, Huanhuan Li, Xiaobao Yu, and Huijuan Zhang. "Multiobjective Synergistic Scheduling Optimization Model for Wind Power and Plug-In Hybrid Electric Vehicles under Different Grid-Connected Modes." Mathematical Problems in Engineering 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/179583.
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In order to promote grid’s wind power absorptive capacity and to overcome the adverse impacts of wind power on the stable operation of power system, this paper establishes benefit contrastive analysis models of wind power and plug-in hybrid electric vehicles (PHEVs) under the optimization goal of minimum coal consumption and pollutant emission considering multigrid connected modes. Then, a two-step adaptive solving algorithm is put forward to get the optimal system operation scheme with the highest membership degree based on the improvedεconstraints method and fuzzy decision theory. Thirdly, the IEEE36 nodes 10-unit system is used as the simulation system. Finally, the sensitive analysis for PHEV’s grid connected number is made. The result shows the proposed algorithm is feasible and effective to solve the model. PHEV’s grid connection could achieve load shifting effect and promote wind power grid connection. Especially, the optimization goals reach the optimum in fully optimal charging mode. As PHEV’s number increases, both abandoned wind and thermal power generation cost would decrease and the peak and valley difference of load curve would gradually be reduced.
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Jiang, Qingfang, and James D. Doyle. "Diurnal Variation of Downslope Winds in Owens Valley during the Sierra Rotor Experiment." Monthly Weather Review 136, no. 10 (October 2008): 3760–80. http://dx.doi.org/10.1175/2008mwr2469.1.
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The impact of diurnal forcing on a downslope wind event that occurred in Owens Valley in California during the Sierra Rotors Project (SRP) in the spring of 2004 has been examined based on observational analysis and diagnosis of numerical simulations. The observations indicate that while the upstream flow was characterized by persistent westerlies at and above the mountaintop level the cross-valley winds in Owens Valley exhibited strong diurnal variation. The numerical simulations using the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) capture many of the observed salient features and indicate that the in-valley flow evolved among three states during a diurnal cycle. Before sunrise, moderate downslope winds were confined to the western slope of Owens Valley (shallow penetration state). Surface heating after sunrise weakened the downslope winds and mountain waves and eventually led to the decoupling of the well-mixed valley air from the westerlies aloft around local noon (decoupled state). The westerlies plunged into the valley in the afternoon and propagated across the valley floor (in-valley westerly state). After sunset, the westerlies within the valley retreated toward the western slope, where the downslope winds persisted throughout the night.
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Zhong, Shiyuan, and C. David Whiteman. "Downslope Flows on a Low-Angle Slope and Their Interactions with Valley Inversions. Part II: Numerical Modeling." Journal of Applied Meteorology and Climatology 47, no. 7 (July 1, 2008): 2039–57. http://dx.doi.org/10.1175/2007jamc1670.1.
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Abstract The characteristics of well-developed downslope winds observed by tethered balloon soundings at multiple locations over a low-angle slope in the Salt Lake Valley are studied using the Regional Atmospheric Modeling System (RAMS). The model successfully simulated the key properties of the observed wind and temperature structure and evolution and provided insight into the forcing mechanisms. The results show that, although the slope angle is only 1.6°, the buoyancy force associated with the local temperature perturbation caused by nocturnal cooling of the slope surface is capable of producing the unusually strong and deep downslope winds observed by the tethersondes. The hypothesis that the flow is produced locally by the temperature deficit is further confirmed by analysis of the momentum budget that indicates a very small contribution from advection to the downslope mass flux. The analysis also reveals the importance of the along-slope pressure gradient force, which has been neglected by some previous investigators. On an isolated slope, the pressure gradient force, which develops as the downslope-flow layer deepens with downslope distance, is important mostly in the upper part of the downslope wind layer where it counterbalances the buoyancy force. On a slope in a valley, the pressure gradient force interacts with the valley inversion to produce intermittency in the downslope jet and may also significantly slow the flow as the inversion strengthens during the night. The simulations for two different observational nights indicate that the maximum downslope wind speed is sensitive to ambient stability, with near-neutral ambient stability yielding a stronger downslope jet than does a more stable ambient atmosphere. Sensitivity studies suggest that an increase in down-valley winds leads to a decrease in the maximum downslope wind speed and an increase in the thickness of the downslope wind layer. An increase in slope roughness, on the other hand, increases the height of the downslope jet but has little effect on other properties. The downslope wind is stronger over a gentle 1.6° slope than over a much steeper slope of 11°, mainly because of the combination of the stronger buoyancy and weaker pressure gradient over the gentle slope.
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Giovannini, Lorenzo, Lavinia Laiti, Stefano Serafin, and Dino Zardi. "The thermally driven diurnal wind system of the Adige Valley in the Italian Alps." Quarterly Journal of the Royal Meteorological Society 143, no. 707 (July 2017): 2389–402. http://dx.doi.org/10.1002/qj.3092.
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Teh, Jiashen. "Adequacy Assessment of Wind Integrated Generating Systems Incorporating Demand Response and Battery Energy Storage System." Energies 11, no. 10 (October 4, 2018): 2649. http://dx.doi.org/10.3390/en11102649.
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The demand response and battery energy storage system (BESS) will play a key role in the future of low carbon networks, coupled with new developments of battery technology driven mainly by the integration of renewable energy sources. However, studies that investigate the impacts of BESS and its demand response on the adequacy of a power supply are lacking. Thus, a need exists to address this important gap. Hence, this paper investigates the adequacy of a generating system that is highly integrated with wind power in meeting load demand. In adequacy studies, the impacts of demand response and battery energy storage system are considered. The demand response program is applied using the peak clipping and valley filling techniques at various percentages of the peak load. Three practical strategies of the BESS operation model are described in this paper, and all their impacts on the adequacy of the generating system are evaluated. The reliability impacts of various wind penetration levels on the generating system are also explored. Finally, different charging and discharging rates and capacities of the BESS are considered when evaluating their impacts on the adequacy of the generating system.
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Vogt, Siegfried, and Genevieve Jaubert. "Foehn in the Rhine Valley as seen by a wind-profiler-RASS system and comparison with the nonhydrostatic model Meso-NH." Meteorologische Zeitschrift 13, no. 3 (July 5, 2004): 165–74. http://dx.doi.org/10.1127/0941-2948/2004/0013-0165.
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Yu, Changle, Su Zhang, Jianhua Shen, Wenwen Li, Yanchen Ji, and Junqi Wang. "Research on the Optimal Capacity Configuration Method of Park-type Wind-photovoltaic Storage Complementary Power Generation System." Journal of Physics: Conference Series 2503, no. 1 (May 1, 2023): 012042. http://dx.doi.org/10.1088/1742-6596/2503/1/012042.
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Abstract At present, China’s installed renewable energy capacity is growing at a fast rate, and reasonable allocation of the wind turbine, photovoltaic, and energy storage capacity is a prerequisite to ensure the economic and reliable operation of the system. For the park-type grid-connected operation of the wind-photovoltaic storage system, in order to improve the stability of the system and make full use of the distribution grid resources, the operation strategy of the park-type wind-photovoltaic storage system is proposed, and the model of wind-photovoltaic storage is established respectively, and the economy and reliability of the system are considered comprehensively. The objective function of capacity configuration and the constraints of power system operation specification are set up, combined with the time-of-use electricity price, the charging of energy storage battery is preferred at the low valley, and the objective function is solved by a genetic algorithm according to the energy use characteristics of the park, and three configuration schemes are selected from the Pareto front solution. Finally, through the typical day analysis, the results show that the wind-photovoltaic storage capacity allocation method can effectively improve the economy of park operation and the quality of the park power supply.
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Zhao, Zhan, Shu-Hua Chen, Michael J. Kleeman, Mary Tyree, and Dan Cayan. "The Impact of Climate Change on Air Quality–Related Meteorological Conditions in California. Part I: Present Time Simulation Analysis." Journal of Climate 24, no. 13 (July 1, 2011): 3344–61. http://dx.doi.org/10.1175/2011jcli3849.1.
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Abstract This study investigates the impacts of climate change on meteorology and air quality conditions in California by dynamically downscaling Parallel Climate Model (PCM) data to high resolution (4 km) using the Weather Research and Forecast (WRF) model. This paper evaluates the present years’ (2000–06) downscaling results driven by either PCM or National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) reanalysis data. The analyses focused on the air quality–related meteorological variables, such as planetary boundary layer height (PBLH), surface temperature, and wind. The differences of the climatology from the two sets of downscaling simulations and the driving global datasets were compared, which illustrated that most of the biases of the downscaling results were inherited from the driving global climate model (GCM). The downscaling process added mesoscale features but also introduced extra biases into the driving global data. The main source of bias in the PCM data is an imprecise prediction of the location and strength of the Pacific subtropical high (PSH). The analysis implied that using simulation results driven by PCM data as the input for air quality models will likely underestimate air pollution problems in California. Regional-averaged statistics of the downscaling results were estimated for two highly polluted areas, the South Coast Air Basin (SoCAB) and the San Joaquin Valley (SJV), by comparing to observations. The simulations driven by GFS data overestimated surface temperature and wind speed for most of the year, indicating that WRF has systematic errors in these two regions. The simulation matched the observations better during summer than winter in terms of bias. WRF has difficulty reproducing weak surface wind, which normally happens during stagnation events in these two regions. The shallow summer PBLH in the Central Valley is caused by the dominance of high pressure systems over the valley and the strong valley wind during summer. The change of meteorology and air quality in California due to climate change will be explored in Part II of this study, which compares the future (2047–53) and present (2000–06) simulation results driven by PCM data and is presented in a separate paper.
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Guardans, R., and I. Palomino. "Description of Wind Field Dynamic Patterns in a Valley and Their Relation to Mesoscale and Synoptic-Scale Meteorological Situations." Journal of Applied Meteorology 34, no. 1 (January 1, 1995): 49–67. http://dx.doi.org/10.1175/1520-0450-34.1.49.
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Abstract A large set of hourly meteorological data from seven towers deployed in Montesina Valley (Cordoba, Spain) is studied in relation to the prevailing synoptic situation. The complete collection of daily synoptic maps for 1985-90 has been classified in seven basic weather patterns. First-order transition probabilities and weatherpattern persistences have been calculated for each of the patterns. The behavior of the local valley wind field is described as a function of the synoptic patterns. The work reported here, based on observations of the characteristic time and space patterns of flow in the valley under different synoptic conditions, has made it possible to obtain a set of empirical rules and regression functions to produce forecasts of the local wind field as a function of the synoptic situation and the hour of the day to be used in the emergency plans. The result of this work is currently being implemented in an atmospheric dispersion module of an expert system that will be used as a tool to predict the evolution of accidental and routine hazardous emissions to the atmosphere in complex terrain such as valleys and coastal areas.
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Li, Liangkai, Jingguang Huang, Zhenxing Li, and Hao Qi. "Optimized Dispatch of Regional Integrated Energy System Considering Wind Power Consumption in Low-Temperature Environment." Energies 16, no. 23 (November 27, 2023): 7791. http://dx.doi.org/10.3390/en16237791.
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The wind abandonment phenomenon of cogeneration units in regional integrated energy systems (RIES) under the operation mode of “heat for electricity” and the improvement in the operation efficiency of the energy storage system under a low-temperature environment are problems that need to be solved urgently. To this end, a regional integrated energy system optimization scheduling method based on fine energy storage and wind power consumption is proposed in the paper. First, a fine energy storage model more adapted to a low-temperature environment is established on the power side to accurately simulate the actual working state of the energy storage components and quantify the uncertainty of the wind power output using the conditional value-at-risk (CVaR) theory. Then, a combined heat and power demand response mechanism is introduced on the load side to reduce the peak-to-valley difference in the heat and power loads, it is realized to promote the system’s consumption of wind power without increasing the transmission power of the contact line. Finally, the example is solved on the MATLAB platform with the objective of minimizing the total cost of the RIES optimal dispatch. The simulation results show that the proposed model is not only more adaptable to a low-temperature environment compared with the traditional model but also reduces the overall cost of the system by 2.58% while realizing the complete consumption of wind power. This innovative study provides a feasible and efficient solution to improve the performance of integrated energy systems, especially the operation capability in extreme environments.
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Serafin, Stefano, and Dino Zardi. "Daytime Heat Transfer Processes Related to Slope Flows and Turbulent Convection in an Idealized Mountain Valley." Journal of the Atmospheric Sciences 67, no. 11 (November 1, 2010): 3739–56. http://dx.doi.org/10.1175/2010jas3428.1.
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Abstract The mechanisms governing the daytime development of thermally driven circulations along the transverse axis of idealized two-dimensional valleys are investigated by means of large-eddy simulations. In particular, the impact of slope winds and turbulent convection on the heat transfer from the vicinity of the ground surface to the core of the valley atmosphere is examined. The interaction between top-down heating produced by compensating subsidence in the valley core and bottom-up heating due to turbulent convection is described. Finally, an evaluation of the depth of the atmospheric layer affected by the slope wind system is provided.
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Robak, Sylwester, Robert Raczkowski, and Michał Piekarz. "Development of the Wind Generation Sector and Its Effect on the Grid Operation—The Case of Poland." Energies 16, no. 19 (September 25, 2023): 6805. http://dx.doi.org/10.3390/en16196805.
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One of the main factors for changes in the structure of the energy mix in Poland is the development of renewable energy sources, in particular wind generation. In 2009–2020, the installed capacity of wind sources in Poland increased more than ninefold. At the same time, new legislation significantly curbed the development of onshore wind farms. Further development of wind energy in Poland will rely largely on offshore wind farms. The current state of development of wind power in Poland allows for analyses of the onshore part of wind energy development in Poland. The paper aims to conduct a detailed analysis of the Polish wind sector from an electric power generation perspective. This article presents a comprehensive discussion of the development of onshore wind generation in Poland. In particular, analyses address the production of electric power from wind. Various time horizons are taken into account, as well as the correlation of wind generation with demand for power in the Polish Power System (PPS). The results of the analysis indicate a high variability of wind generation throughout the month or year. The largest wind generation occurred during the night valley, which makes it difficult to operate the power system. In the winter months, wind generation is much greater than in the summer months. Monthly average values of the capacity factor for onshore wind farms (WFs) vary from 0.14 in August to 0.48 in February. Moreover, the coefficient of determination R2 close to zero shows a lack of correlation between offshore wind power generation and real power demand in the PPS. The studied high variability of wind generation in PPS can be mitigated by the wide use of electricity storage systems. Moreover, the obtained results can be part of a model to describe the energy mix in Poland.
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Weigel, Andreas P., Fotini K. Chow, Mathias W. Rotach, Robert L. Street, and Ming Xue. "High-Resolution Large-Eddy Simulations of Flow in a Steep Alpine Valley. Part II: Flow Structure and Heat Budgets." Journal of Applied Meteorology and Climatology 45, no. 1 (January 1, 2006): 87–107. http://dx.doi.org/10.1175/jam2323.1.
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Abstract This paper analyzes the three-dimensional flow structure and the heat budget in a typical medium-sized and steep Alpine valley—the Riviera Valley in southern Switzerland. Aircraft measurements from the Mesoscale Alpine Programme (MAP)-Riviera field campaign reveal a very pronounced valley-wind system, including a strong curvature-induced secondary circulation in the southern valley entrance region. Accompanying radio soundings show that the growth of a well-mixed layer is suppressed, even under convective conditions. Our analyses are based on the MAP-Riviera measurement data and the output of high-resolution large-eddy simulations using the Advanced Regional Prediction System (ARPS). Three sunny days of the measurement campaign are simulated. Using horizontal grid spacings of 350 and 150 m (with a vertical spacing as fine as 20 m), the model reproduces the observed flow features very well. The ARPS output data are then used to calculate the components of the heat budget of the valley atmosphere, first in profiles over the valley base and then as averages over almost the entire valley volume. The analysis shows that the suppressed growth of the well-mixed layer is due to the combined effect of cold-air advection in the along-valley direction and subsidence of warm air from the free atmosphere aloft. It is further influenced by the local cross-valley circulation. This had already been hypothesized on the basis of measurement data and is now confirmed through a numerical model. Averaged over the entire valley, subsidence turns out to be one of the main heating sources of the valley atmosphere and is of comparable magnitude to turbulent heat flux divergence. On the mornings of two out of the three simulation days, this subsidence is even identified as the only major heating source and thus appears to be an important driving mechanism for the onset of thermally driven upvalley winds.
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Truccolo, Eliane Cristina. "Assessment of the wind behavior in the northern coast of Santa Catarina." Revista Brasileira de Meteorologia 26, no. 3 (September 2011): 451–60. http://dx.doi.org/10.1590/s0102-77862011000300011.
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The spatial and temporal coherence of wind characteristics of coastal areas of Navegantes and Praia Grande, SC, 100 km apart each other, were assessed. Despite the relatively short distance, the oceanographic and geomorphological characteristics are different and can change the local and synoptic wind behavior, which are important for the understanding of the factors controlling the hydrodynamics and water quality of coastal environments. The comparison was performed through statistical analysis in the time and frequency domain, over a data set comprising hourly records from July to December, 1996. Both stations presented similarities regarding the north-south wind component. Therefore, quite different behavior is noticed for the east-west wind component, such as the breeze effect. The north-south wind pattern in Praia Grande is similar to the general wind regime for the Brazilian south-southwest areas, with dominance of northerly winds, and with southerly winds during the passage of cold-front systems, with small account of land-sea breeze. On the other hand, the breeze is the main factor contributing for the wind kinetics for the Navegantes area. We suggest that this differentiation is partially due to the combination of the mountain-valley circulation system of Vale do Itajaí with the breeze system, indicating a strong role of the local geomorphology on the wind regime. Additionally, it is may be possible that the sea surface temperature can also contribute, since there is a general trend of smaller temperatures southwards, though increasing the thermal gradient between the land and the sea.
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Rendón, Angela M., Juan F. Salazar, Carlos A. Palacio, Volkmar Wirth, and Björn Brötz. "Effects of Urbanization on the Temperature Inversion Breakup in a Mountain Valley with Implications for Air Quality." Journal of Applied Meteorology and Climatology 53, no. 4 (April 2014): 840–58. http://dx.doi.org/10.1175/jamc-d-13-0165.1.
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AbstractMany cities located in valleys with limited ventilation experience serious air pollution problems. The ventilation of an urban valley can be limited not only by orographic barriers, but also by urban heat island–induced circulations and/or the capping effect of temperature inversions. Furthermore, land-use/-cover changes caused by urbanization alter the dynamics of temperature inversions and urban heat islands, thereby affecting air quality in an urban valley. By means of idealized numerical simulations, it is shown that in a mountain valley subject to temperature inversions urbanization can have an important influence on air quality through effects on the inversion breakup. Depending on the urban area fraction in the simulations, the breakup time changes, the cross-valley wind system can evolve from a confined to an open system during the daytime, the slope winds can be reversed by the interplay between the urban heat island and the temperature inversion, and the breakup pattern can migrate from one dominated by the growth of the convective boundary layer to one also involving the removal of mass from the valley floor by the upslope winds. The analysis suggests that the influence of urbanization on the air quality of an urban valley may lead to contrasting and possibly counterintuitive effects when considering temperature inversions. More urban land does not necessarily imply worse air quality, even when considering that the amount of pollutants emitted grows with increased urbanization.
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Wang, Zhenghao, Yonghui Liu, Zihao Yang, and Wanhao Yang. "Load Frequency Control of Multi-Region Interconnected Power Systems with Wind Power and Electric Vehicles Based on Sliding Mode Control." Energies 14, no. 8 (April 19, 2021): 2288. http://dx.doi.org/10.3390/en14082288.
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In recent years, wind power systems have been used extensively, which not only improve the efficiency of current conventional power generation systems, but also can save traditional fossil fuel resources. However, considering the instability of wind power, after being grid connected, it can easily cause an impact on the stability of the grid operation. Considering the above problems, this paper considers to make full use of the energy storage part of electric vehicles (EVs) to increase the stability of grid operation. Based on the mathematical model, this paper studies the load frequency control (LFC) problem of a multi-region interconnected power system with wind power and EVs. First, since the system states are difficult to be monitored, a state observer is designed to estimate the state. Based on this, the integral sliding mode controller (SMC) is designed to realize the LFC of the interconnected power system. Meanwhile, to obtain better control performance, this paper further analyzes and optimizes the controller parameters based on Lyapunov stability theory. At last, simulations are carried out for the power systems with two regions in Simulink. The results show that the designed controllers are effective to compensate the load demand disturbances. In addition, it is demonstrated that the battery storage of EVs can play the role of peak-shaving and valley-filling in LFC.
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Hu, Wei, Xinyan Zhang, Lijuan Zhu, and Zhenen Li. "Optimal Allocation Method for Energy Storage Capacity Considering Dynamic Time-of-Use Electricity Prices and On-Site Consumption of New Energy." Processes 11, no. 6 (June 5, 2023): 1725. http://dx.doi.org/10.3390/pr11061725.
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Configuring energy storage devices can effectively improve the on-site consumption rate of new energy such as wind power and photovoltaic, and alleviate the planning and construction pressure of external power grids on grid-connected operation of new energy. Therefore, a dual layer optimization configuration method for energy storage capacity with source load collaborative participation is proposed. The external model introduces a demand-side response strategy, determines the peak, flat, and valley periods of the time-of-use electricity price-based on the distribution characteristics of load and new energy output, and further aims to maximize the revenue of the wind and solar storage system. With the peak, flat, and valley electricity price as the decision variable, an outer optimization model is established. Based on the optimized electricity price, the user’s electricity consumption in each period is adjusted, and the results are transmitted to the inner optimization model. The internal model takes the configuration power and energy storage capacity in the wind and solar storage system as decision variables, establishes a multi-objective function that comprehensively considers the on-site consumption rate of new energy and the cost of energy storage configuration, and feeds back the optimization results of the inner layer to the outer layer optimization model. Use ISSA-MOPSO algorithm to solve the optimized configuration model. Finally, the rationality of the proposed model and algorithm in terms of on-site consumption rate and economy of new energy is verified through numerical examples.
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Ortiz-Amezcua, Pablo, Alodía Martínez-Herrera, Antti J. Manninen, Pyry P. Pentikäinen, Ewan J. O’Connor, Juan Luis Guerrero-Rascado, and Lucas Alados-Arboledas. "Wind and Turbulence Statistics in the Urban Boundary Layer over a Mountain–Valley System in Granada, Spain." Remote Sensing 14, no. 10 (May 11, 2022): 2321. http://dx.doi.org/10.3390/rs14102321.
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Urban boundary layer characterization is currently a challenging and relevant issue, because of its role in weather and air quality modelling and forecast. In many cities, the effect of complex topography at local scale makes this modelling even more complicated. This is the case of mid-latitude urban areas located in typical basin topographies, which usually present low winds and high turbulence within the atmospheric boundary layer (ABL). This study focuses on the analysis of the first ever measurements of wind with high temporal and vertical resolution throughout the ABL over a medium-sized city surrounded by mountains in southern Spain. These measurements have been gathered with a scanning Doppler lidar system and analyzed using the Halo lidar toolbox processing chain developed at the Finnish Meteorological Institute. We have used the horizontal wind product and the ABL turbulence classification product to carry out a statistical study using a two-year database. The data availability in terms of maximum analyzed altitudes for statistically significant results was limited to around 1000–1500 m above ground level (a.g.l.) due to the decreasing signal intensity with height that also depends on aerosol load. We have analyzed the differences and similarities in the diurnal evolution of the horizontal wind profiles for different seasons and their modelling with Weibull and von Mises probability distributions, finding a general trend of mean daytime wind from the NW with mean speeds around 3–4 m/s at low altitudes and 6–10 m/s at higher altitudes, and weaker mean nocturnal wind from the SE with similar height dependence. The highest speeds were observed during spring, and the lowest during winter. Finally, we studied the turbulent sources at the ABL with temporal (for each hour of the day) and height resolution. The results show a clear convective activity during daytime at altitudes increasing with time, and a significant wind-shear-driven turbulence during night-time.
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Grubišić, Vanda, and Brian J. Billings. "The Intense Lee-Wave Rotor Event of Sierra Rotors IOP 8." Journal of the Atmospheric Sciences 64, no. 12 (December 1, 2007): 4178–201. http://dx.doi.org/10.1175/2006jas2008.1.
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Abstract A large-amplitude lee-wave rotor event observationally documented during Sierra Rotors Project Intensive Observing Period (IOP) 8 on 24–26 March 2004 in the lee of the southern Sierra Nevada is examined. Mountain waves and rotors occurred over Owens Valley in a pre-cold-frontal environment. In this study, the evolution and structure of the observed and numerically simulated mountain waves and rotors during the event on 25 March, in which the horizontal circulation associated with the rotor was observed as an opposing, easterly flow by the mesonetwork of surface stations in Owens Valley, are analyzed. The high-resolution numerical simulations of this case, performed with the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) run with multiple nested-grid domains, the finest grid having 333-m horizontal spacing, reproduced many of the observed features of this event. These include small-amplitude waves above the Sierra ridge decoupled from thermally forced flow within the valley, and a large-amplitude mountain wave, turbulent rotor, and strong westerlies on the Sierra Nevada lee slopes during the period of the observed surface easterly flow. The sequence of the observed and simulated events shows a pronounced diurnal variation with the maximum wave and rotor activity occurring in the early evening hours during both days of IOP 8. The lee-wave response, and thus indirectly the appearance of lee-wave rotor during the core IOP 8 period, is found to be strongly controlled by temporal changes in the upstream ambient wind and stability profiles. The downstream mountain range exerts strong control over the lee-wave horizontal wavelength during the strongest part of this event, thus exhibiting the control over the cross-valley position of the rotor and the degree of strong downslope wind penetration into the valley.
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Lyza, Anthony W., and Kevin R. Knupp. "A Background Investigation of Tornado Activity across the Southern Cumberland Plateau Terrain System of Northeastern Alabama." Monthly Weather Review 146, no. 12 (November 26, 2018): 4261–78. http://dx.doi.org/10.1175/mwr-d-18-0300.1.
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Abstract The effects of terrain on tornadoes are poorly understood. Efforts to understand terrain effects on tornadoes have been limited in scope, typically examining a small number of cases with limited observations or idealized numerical simulations. This study evaluates an apparent tornado activity maximum across the Sand Mountain and Lookout Mountain plateaus of northeastern Alabama. These plateaus, separated by the narrow Wills Valley, span ~5000 km2 and were impacted by 79 tornadoes from 1992 to 2016. This area represents a relative regional statistical maximum in tornadogenesis, with a particular tendency for tornadogenesis on the northwestern side of Sand Mountain. This exploratory paper investigates storm behavior and possible physical explanations for this density of tornadogenesis events and tornadoes. Long-term surface observation datasets indicate that surface winds tend to be stronger and more backed atop Sand Mountain than over the adjacent Tennessee Valley, potentially indicative of changes in the low-level wind profile supportive to storm rotation. The surface data additionally indicate potentially lower lifting condensation levels over the plateaus versus the adjacent valleys, an attribute previously shown to be favorable for tornadogenesis. Rapid Update Cycle and Rapid Refresh model output indicate that Froude numbers for the plateaus in tornadic environments are likely supportive of enhanced low-level flow over the plateaus, which further indicates the potential for favorable wind profile changes for tornado production. Examples of tornadic storms rapidly acquiring increased low-level rotation while reaching the plateaus of northeast Alabama are presented. The use of this background to inform the VORTEX-SE 2017 field campaign is discussed.