Search

Wind speed changes from one region to another due to several influencing variables. In this article, a software method has been proposed to determine the future wind speed at any time and under any conditions. Neural Networks were used with engineering data regarding the method of education, training algorithms, and different activation functions between the input and output layers, each according to the nature of the data that would be generated. Backpropagation Neural was used with three variables chosen to be the inputs for the learning and training network (wind speed, humidity, and time), which are considered the most important in determining the proposed or expected speed at the relevant time and place. The hidden layer consists of 10 neurons, which are determined according to the precision of output. After comparing the measurements from the weather system with the expected values, a very tiny percentage of error was found since these readings are regarded as acceptable and aid in the problem-solving process for running companies and researchers. The error rate recorded in this work ranged between (3 * 10-3 and 3 * 10-5), and the average number of attempts for the training and examination process reached 33 attempts, as it is known that neural networks carry out the training process based on specific mathematical functions and closed loops that depend on the lowest possible error rate. [ABSTRACT FROM AUTHOR]

The waters of the Seram Sea and Buru Island are comparatively rich in resources and productivity. However, many fishermen continue to rely on intuition or instinct to locate fishing spots. Therefore, understanding the significance of oceanographic parameters as indicators of water's primary productivity is crucial. This study utilizes data from January 2010 to December 2020, including oceanographic parameters such as sea surface temperature (SST) and chlorophyll-a concentration from AQUA-MODIS satellite imagery, wind data from ECMWF reanalysis, and fish catch data from Fishing Spot Galala-Hative Kecil. The research aimed to examine the variability of sea surface temperature, chlorophyll-a, and surface winds, and their relationship with the upwelling phenomenon in Seram Sea waters and Buru Island. Data were processed spatially using script methods in the Grads 2.2.1 application and temporally using statistical methods in MS Excel, followed by correlation analysis using Pearson correlation. The results indicate that sea surface temperature, chlorophyll-a, and winds exhibit greater variability from May to August. Upwelling potential in these waters occurs from June to August and continues through September and October, characterized by strong upwelling. This is evidenced by low sea surface temperatures ranging from 26°C to 27.7°C, chlorophyll-a concentrations ranging from 0.5 to 1.2mg/l, and wind speeds during this period ranging from 3.9 to 6.4m/s. Additionally, correlation tests reveal that sea surface temperature and chlorophyll-a in the study area from May to August have a linear correlation with fish catch (CPUE), with values of 0.52 and 0.56, respectively. [ABSTRACT FROM AUTHOR]

Background: Pigeon pea (Cajanus cajan, Mayer) is the member of Asian Cajanus crop and also reffered as Tur and Arhar and commonly grown in Kharif session in Indian subcontinent.). In India, around 250 known species of insect pests have been identified to affect pigeon pea crops at different growth stages. The leaf webber and leaf roller are notable insect pests that pose a significant threat to pigeonpea, particularly during its vegetative stage. The leaf webber and leaf roller, among various insect pests, are notably visible and pose a threat to pigeonpea. These insects target the pigeonpea plant during its vegetative stage. Specifically, the leaf webber, identified as Grapholita (Pammene) critica, Meyrick (Lepidoptera: Tortricidae), has been acknowledged as a significant constraint affecting pigeonpea production. The aim of this investigation is to assess the relationship between the incidence of leaf roller and leaf webber and various abiotic factors, including temperature, relative humidity, wind velocity and rainfall. Methods: The research, spanning Kharif 2021-22 and 2022-23, at Entomological Research Block in BUAT, Banda. It aimed to observe leaf roller and leaf webber incidence in pigeon pea alongside weather conditions. 'IPA-203' pigeon pea variety was manually sown in 200 m2 plots on July 12, 2021 (first year) and July 18, 2022 (second year). Standard agronomic practices were adhered to and no insecticides were used on the crop. Result: Over the two-year observation period, the larval population of G. critica on pigeon pea plants commenced during the 34th SMW, peaking at 4.90 larvae plant-1 in the 45th SMW. Simultaneously, C. soyella infestation initiated in the 34th SMW, steadily increasing until the 42nd SMW, reaching its peak larval count at 3.03. [ABSTRACT FROM AUTHOR]

Abstract When evaluating the fragility of structures in response to wind loads, vulnerability analyses are often conducted under intact conditions. Therefore, the actual strength of aged transmission towers may be compromised, resulting in severe damage. Especially for steel structures used over a long period in coastal areas, there is a potential for performance degradation due to corrosion. One of the high-voltage transmission towers, the 765 kV transmission tower, is taller than other towers, making it more vulnerable to strong winds in the event of corrosion. In this study, the structural performance degradation of 765 kV transmission towers in coastal regions based on their service life was investigated. Capacity distributions were provided considering the uncertainties in various parameters, such as the wind attack angle and material properties. A fragility assessment process that accounts for uncertainties in the wind conditions and aerodynamic parameters is proposed. Using the research results, we created limit-collapsed surfaces to evaluate the structural safety of transmission towers based on their service life, wind speed, and wind attack angle. The results showed a quantitative decrease in structural safety due to corrosion depending on the service life, with the most unfavorable wind attack angle being 0°. The proposed limit-collapsed surface can help efficiently evaluate structural conditions considering wind speed, wind attack angle, and service life. Hence, this study can serve as a basis for the structural evaluation of modern transmission towers to avoid power disruptions in major cities. [ABSTRACT FROM AUTHOR]

A fire in the cargo compartment has a major impact on civil aviation flight safety, and according to the airworthiness clause of the CCAR-25, the detector must sound an alarm within 1 min of a fire in the cargo compartment. As for the cargo compartment of large transport aircrafts, the internal space is high and open, and the smoke movement speed becomes slower with significant cooling in the process of diffusion. Hysteresis can occur in smoke detectors because of their internal labyrinth structure, which causes the detector's internal and external response signals to be out of sync. This research employs a numerical simulation to examine the detector response parameters under an ambient wind speed of 0.1–0.2 m/s and fits a Cleary two-stage hysteresis model, where τ1= 0.09u−1.43 and τ2= 0.67u−1.59. Finally, multiple full-scale cargo cabin experiments were conducted to validate the prediction model. The results show that the model's predicted alarm range is 43.1 s to 49.0 s, and the actual alarm time obtained by the experiment falls within this interval, confirming the model's accuracy and providing theoretical support for the structural design and layout of the aircraft cargo cabin smoke detector. [ABSTRACT FROM AUTHOR]

The natural ventilation model plays a crucial role in greenhouse environmental control. It has been extensively studied by previous researchers, but it is limited to low-altitude areas. This study established a numerical model of single-span plastic greenhouses in high-altitude areas. The model was validated using measured data, showing a good agreement between the measured and simulated values. By setting boundary conditions based on on-site monitoring data, ventilation rates were extracted under different conditions for numerical simulations. Through nonlinear fitting, an empirical formula for natural ventilation rates, with a determination coefficient (R2) of 0.9724, was derived. The formula was validated through an energy balance analysis of indoor air. Different ventilation opening sizes were simulated to derive an empirical formula for natural ventilation rates based on opening size. Building on this, the relationship between plant height and ventilation rate was analyzed. As the dominant factors of natural ventilation change with environmental fluctuations, this study also proposed the threshold wind speed for wind pressure ventilation, thermal pressure ventilation, and coupled ventilation, filling the knowledge gap in relevant ventilation rate calculations. This is the first time that a natural ventilation model of single-span plastic greenhouses in high-altitude areas has been proposed, providing the basis in terms of modeling for the further development of local facility agriculture. [ABSTRACT FROM AUTHOR]

In this work, the inter-relationship among 10 morphological characters, 8 climatic parameters and the content of total anthocyanins in the cob core of PMV 581 purple maize, cultivated and produced in three different places in Huanuco–Peru region, has been reported. This study of morphological characters was carried out using standard descriptors, both for the plant and the cob. Data on climatic parameters were obtained from three meteorological stations near the test locations. The total anthocyanin content (Acy), expressed as the glucoside-3-cyanidin concentration, has been determined by the differential pH method. From the statistical treatment of the data obtained, the following descriptors were found to be the most representative, given that they are poorly correlated with each other, but in general, depending on the localities: i/ (morphological) grain weight per cob GWC, plant length PL and cob core weight CCW; ii/ (climatic) minimum temperature Tmin, wind speed v and relative humidity RH. Between both types of descriptors, the best correlations occur for (CCW vs. Tmin) and (GWC vs. v). On the other hand, the total anthocyanin content Acy correlates very well with the CCW and Tmin descriptors. So, the highest concentration of Acy (684.2 mg/100 g) and also the highest CCW (38.6 g/cob) have been obtained in cobs of Winchuspata (W-Q), the coldest (Tmin = 7.89 °C) of the considered localities. On the contrary, the lowest concentration of Acy (603.7 mg/100 g) and also the lowest CCW 25.4 g/cob) have been obtained in cobs of Pistaloli (P-SA), the warmest (Tmin = 19.96 °C) of the three locations. The highest GWC value (139.4 g/cob) has been obtained in cobs of Marabamba (M-Y) where the wind speed v (4.13 m/s) was the highest of the locations considered. On the contrary, the lowest value of GWC (79.6 g/cob) has been obtained for cobs of Pistaloli (P-SA) where v was the lowest (1.19 m/s). In this context, it is important to propose studies on climatic variations' impact on different crop cycles, investigating how different agronomic management practices and the use of genetic identification/expression tools can optimize the anthocyanin production of purple maize, in order to facilitate the selection of new varieties for specific climatic conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: The emergence of midge-borne diseases such as lumpy skin disease in Thailand highlights the necessity of understanding the seasonal abundance and spatial distribution of Culicoides biting midges. Population dynamics, species composition, and host preferences of Culicoides species were studied in Kanchanaburi, Thailand. Nine UV light traps were deployed to collect midges in nine animal sheds over the course of a year, revealing abundant species such as C. oxystoma Kieffer and C. peregrinus Kieffer, C. arakawae Arakawa, and C. imicola Kieffer. These species demonstrated preferences for different farm animals and peaked in trap captures from the late rainy season to early winter. Trap catches were positively influenced by relative humidity and temperature, while they exhibited a negative impact from wind speed. This study provides important data for disease management and prevention, emphasizing the impact of these vectors on both animal and human health. Overall, this research underscores the importance of ongoing studies into Culicoides behavior, ecology, and disease transmission potential to inform effective control strategies. Culicoides biting midges were collected using UV light traps from nine livestock farms in Kanchanaburi Province, Thailand. Collections were made one night per month from June 2020 to May 2021 to determine the seasonal changes and spatial distribution of the Culicoides assemblage. The influence of four environmental factors (temperature, rainfall, humidity, and wind speed), types of animals in each shed (cattle, pigs, and avians), and neighboring animals (those in the other sheds and their proximity) were assessed. A subsample of 130,670 out of a total of 224,153 specimens collected was identified and counted. The collections were predominantly female (76.9%), though males were also commonly collected (23.1%). The dominant species included C. peregrinus (97,098 individuals; 43.0%), C. oxystoma (55,579; 24.6%), C. arakawae (45,996; 20.4%), and C. imicola (15,703; 7.0%), while other species accounted for the remaining 9777 individuals (4.4%). Trap captures were strongly influenced by seasons and animal sheds. Cattle exhibited the greatest effect on the community, likely due to their large biomass. Humidity and temperature had a positive effect on trap captures, whereas wind speed exhibited a negative effect. Cattle positively influenced all major species, except for C. arakawae, which showed a positive association with avians. A "neighboring effect" was also observed. Additionally, the lowest dispersal ability of C. arakawae was suggested. [ABSTRACT FROM AUTHOR]

The internal to external pressure ratio in a large-span cylindrical roof building with a dominant gable opening fluctuates dramatically between 0 and 1, significantly impacted by the attenuation of internal pressure. Current theories usually assume this ratio equal to 1 and overlook the attenuation effect. This study investigates four cylindrical roof models with varying opening areas, scale ratios, and wind speeds by wind tunnel tests. It analyzes ratios of mean ( C ¯ p i / C ¯ p e ), fluctuating ( σ p i / σ p e ), and peak ( C ̂ p i / C ̂ p e ) internal to external pressure to pinpoint factors affecting the internal pressure attenuation. The results highlight that the most pronounced internal pressure attenuation is at the sideward opening. The vortex shedding around the opening is induced by the wind direction, scale ratio, and wind speed. The attenuation effect decreases with lower frequencies of periodic vortex shedding. This effect generally vanishes when the windward or leeward opening ratio (A1.5/V0) exceeds 0.57%. Empirical design formulas are proposed to predict ratios of internal to external pressure considering the attenuation effect. The inertia (CI) and loss coefficients (CL) affected by the internal pressure attenuation are analyzed to estimate the air slug inertia and damping through the opening. A governing equation, incorporating reduction coefficients ( C ¯ eddy , C ̃ eddy ) from empirical design formulas, is applied to precisely compute the attenuated internal pressure in the large-span cylindrical roof building with a dominant gable opening for engineering risk assessment. [ABSTRACT FROM AUTHOR]

This article investigates the impact of atmospheric turbulence on wind farms in mountainous regions using Scale-Adaptive Large-Eddy Simulation (SALES) combined with the immersed boundary method. An array of 25 Gaussian hills was considered to mimic the mountainous terrain, and three cases were simulated: atmospheric boundary layer flow over complex terrain, 25 full-scale turbines positioned on hilltops, and 125 full-scale turbines positioned across the mountainous landscape. These simulations captured the intrinsic spatial inhomogeneity caused by the complex topographic features of mountainous terrain, challenging the assumption of horizontally homogeneous atmospheric turbulence. This study emphasizes the significance of velocity gradient dynamics and stresses on surface mounted obstacles to evaluate data quality and uncertainty. However, it also considered more detailed comparisons with other methods, validation of topographic impact using experimental work with windbreak and isolated hill, and a comprehensive analysis of the results. The findings include significantly enhanced power production at hilltop turbine locations as compared to homogeneous terrain. Although wind turbines in windward and leeward directions experienced a reduced power output in the near-wake region, these local losses recovered globally by the enhanced vertical energy entrainment from higher altitudes. Additionally, the presence of mountains indicated an increase in the power density by up to five times compared to flat terrain. A wavelet-based autoencoder demonstrated superior performance in separating the harmonic component of time-varying mean and subgrid-scale fluctuations compared to constant and Gaussian weighting kernels. The study suggests wavelet filtering as a promising technique for subgrid-scale modeling, offering improvements not only in wind energy applications but also in other turbulence flow scenarios. [ABSTRACT FROM AUTHOR]

The main structure of the transmission tower consists of the tower body and the cross arm, which serve as vertical support and transverse extension, respectively. Compared with the tower body, due to the difference between the transverse and longitudinal projected areas of the cross-arm, the wind load distribution of the cross-arm is more complicated and requires more in-depth research. In this paper, wind tunnel force tests under skew wind were carried out on the 1:20 scaled rigid models of the tubular and the tubular-angle combined cross-arms. The tests consider four solidity ratios (0.2, 0.3, 0.4, and 0.5) under three wind speeds and 19 yaw angles. The aerodynamic force coefficients Ci, the skewed wind load factor Kθ, the transversal and longitudinal wind load distribution factor nX and nY, and the angle α between the transversal aerodynamic force coefficient (CX) and the resultant wind force coefficient (CR) were obtained and analyzed. It was found that the wind load coefficients decrease with increasing solidity ratio. The tested drag coefficient of the tubular cross-arm is larger than the combined cross-arm under the same solidity ratio. The nX of the tubular and combined cross-arm reaches the maximum range of 0.33–0.47 and 0.22–0.23 at 30° <θ < 45° and 30° < θ < 35°, respectively. The nY curves were ordered from large to small as follows: EN 50341-1, the tested tubular cross-arm, the tested combined cross-arm, and JEC-127-1979. At 55° < θ < 65°, the difference of α and θ for the tested tubular and combined cross-arm reaches the maximum of 10°–18° and 29°–32°, respectively, indicating that the lift force cannot be ignored and the assumption α = θ is not applicable. Reasonable nonlinear fitting functions are proposed to accurately calculate the wind load of the two types of cross-arms. [ABSTRACT FROM AUTHOR]

Ideal tree exhibits fractal characteristics, where the branch angle plays a significant role in shaping the morphology of trees, thereby influencing their wind resistance capabilities. Nevertheless, investigation into the aerodynamic effects of branch angle on trees with leaves remains relatively scarce. By subjecting various tree morphologies to controlled wind conditions, this study scrutinizes the aerodynamic responses and resulting loads experienced by one-order sympodial trees with differing branch angle configurations. The results reveal that the tree experiences unstable oscillations induced by irregular leaf vibration with an increase in wind speed, resulting in a rise in drag coefficient. Meanwhile, despite a higher drag force observed in the tree with higher branch angle at wind speeds below 20 m/s, the tree exhibits superior reconfiguration capabilities, enabling it to withstand stronger winds effectively. Subsequently, a reconfiguration process for the one-order sympodial tree is proposed, exhibiting a wavy streamlining effect. Finally, it is found that the sympodial tree structure can be regarded as a high-frequency filter to dissipate high-frequency branch vibration energy. The findings from this research endeavor hold significant implications for enhancing our understanding of the aerodynamics of trees with different morphology and the cultivation and selection of urban trees. [ABSTRACT FROM AUTHOR]

This study introduces an empirical model designed to predict the maximum values of time-dependent data across four turbulence-related fields: hydrogen combustion in renewable energy systems, urban microclimate effects on cultural heritage, shipping emissions, and road vehicle emissions. The model, which is based on the mean, standard deviation, and integral time scale, employs two parameters: a fixed exponent 'ν' (0.3) reflecting time scale sensitivity, and a variable parameter 'b' that accounts for application-specific uncertainties. Integrated into the Computational Fluid Dynamics (CFD) framework, specifically the Reynolds-Averaged Navier–Stokes (RANS) methodology, the model addresses the RANS approach's limitation in predicting extreme values due to its inherent averaging process. By incorporating the empirical model, this study enhances RANS simulations' ability to predict critical values, such as peak hydrogen concentrations and maximum urban wind speeds, which is essential for safety and reliability assessments. Validation against experimental and numerical data across the four fields demonstrates strong agreement, highlighting the model's potential to improve CFD-RANS predictions of extreme events. This advancement offers significant implications for future CFD-RANS applications, particularly in scenarios demanding fast and reliable maximum value predictions. [ABSTRACT FROM AUTHOR]

This study conducts a comprehensive evaluation of four scenario experiments using the CMA_WSP, WRF, and WRF_FITCH models to enhance forecasts of hub-height wind speeds at multiple wind farms in Northern China, particularly under significant wind speed fluctuations during high wind conditions. The experiments apply various wind speed calculation methods, including the Monin–Obukhov similarity theory (ST) and wind farm parameterization (WFP), within a 9 km resolution framework. Data from four geographically distinct stations were analyzed to assess their forecast accuracy over a 72 h period, focusing on the transitional wind events characterized by substantial fluctuations. The CMA_WSP model with the ST method (CMOST) achieved the highest scores across the evaluation metrics. Meanwhile, the WRF_FITCH model with the WFP method (FETA) demonstrated superior performance to the other WRF models, achieving the lowest RMSE and a greater stability. Nevertheless, all models encountered difficulties in predicting the exact timing of extreme wind events. This study also explores the effects of these methods on the wind power density (WPD) distribution, emphasizing the boundary layer's influence at the hub-heighthub-height of 85 m. This influence leads to significant variations in the central and coastal regions. In contrast to other methods that account for the comprehensive effects of the entire boundary layer, the ST method primarily relies on the near-surface 10 m wind speed to calculate the hub-height wind speed. These findings provide important insights for enhancing wind speed and WPD forecasts under transitional weather conditions. [ABSTRACT FROM AUTHOR]

Accurate forecasting of wind speeds is a crucial aspect of providing fine-scale professional meteorological services (such as wind energy generation and transportation operations etc.). This article utilizes CMA-MESO model forecast data and CARAS-SUR_1 km ground truth grid data from January, April, July, and October 2022, employing the random forest algorithm to establish and evaluate a downscaling correction model for near-surface 1 km resolution wind-speed grid forecast in the complex terrain area of northwestern Hebei Province. The results indicate that after downscaling correction, the spatial distribution of grid forecast wind speeds in the entire complex terrain study area becomes more refined, with spatial resolution improving from 3 km to 1 km, reflecting fine-scale terrain effects. The accuracy of the corrected wind speed forecast significantly improves compared to the original model, with forecast errors showing stability in both time and space. The mean bias decreases from 2.25 m/s to 0.02 m/s, and the root mean square error (RMSE) decreases from 3.26 m/s to 0.52 m/s. Forecast errors caused by complex terrain, forecast lead time, and seasonal factors are significantly reduced. In terms of wind speed categories, the correction significantly improves forecasts for wind speeds below 8 m/s, with RMSE decreasing from 2.02 m/s to 0.59 m/s. For wind speeds above 8 m/s, there is also a good correction effect, with RMSE decreasing from 2.20 m/s to 1.65 m/s. Selecting the analysis of the Zhangjiakou strong wind process on 26 April 2022, it was found that the downscaled corrected forecast wind speed is very close to the observed wind speed at the station and the ground truth grid points. The correction effect is particularly significant in areas affected by strong winds, such as the Bashang Plateau and valleys, which has significant reference value. [ABSTRACT FROM AUTHOR]

The primary focus of this article is to derive a solution to obtain the asymptotic turbulent dispersion parameter provided by the spectral Taylor statistical diffusion model. Unlike previous articles, which employed the Dirac delta function to solve the eddy diffusivity formula, in this study, we used the Dirac delta function properties to obtain directly the asymptotic turbulent dispersion parameter from the particles' spatial dispersion variance described in terms of the Eulerian turbulence spectrum and of the scale factor defined formally as the ratio between Lagrangian and Eulerian timescales. From the Kolmogorov 1941 theory, a detailed derivation for this scale factor is presented. Furthermore, using high mean wind speed data generated by local topographic features, a magnitude for the Kolmogorov constant for the neutral atmospheric boundary layer is evaluated. Thus, this magnitude when added to other values obtained from the selected studies found in the literature provides an average value for the Kolmogorov constant that agrees with large eddy simulation data results. Therefore, this average value allows to obtain a more reliable description of this scale factor. Finally, employing analytical formulations for the observed neutral turbulent spectra and for the velocity variances as well as turbulent statistical quantities measured in a surface neutral atmospheric boundary layer, a vertical dispersion parameter is derived. This vertical dispersion parameter when utilized in a simple Gaussian diffusion model is able to reproduce well contaminant observed concentrations.The Gaussian simulated concentrations also compare well with those simulated by a Lagrangian stochastic particle dispersion model that uses observed vertical spectral peak frequency values at distinct levels of the neutral surface boundary layer. Therefore, the present study shows that the observational determination of a single vertical spectral peak frequency is sufficient to obtain a realistic vertical dispersion parameter characterizing the dispersive effect in the turbulent environment of the surface neutral atmospheric boundary layer. [ABSTRACT FROM AUTHOR]

The radon concentration activity in buildings is influenced by various factors, including meteorological elements like temperature, pressure, and precipitation, which are recognized as significant influencers. The fluctuations of indoor radon in premises are related to seasonal change. This study aimed to understand better the effects of environmental parameters on indoor radon concentration levels in the Aksu school. Indoor and outdoor temperature differentials heavily influence diurnal indoor radon patterns. The analysis indicates that the correlation between indoor radon and outdoor temperature, dew point, and air humidity is weak and negligible for atmospheric pressure, wind speed, and precipitation, as determined by the obtained values of R2 and the Chaddock scale. The multiple regression model is characterized by the correlation coefficient rxy = 0.605, which corresponds to a close relationship on the Chaddock scale. [ABSTRACT FROM AUTHOR]

It is challenging to estimate how the climate of a region will change under global warming in the future. Among the essential climate variables, temperature, relative humidity and wind speed are very important, and their changes in relation to each other can have many consequences, such as increasing heat stress and evapotranspiration. In this research, we investigated future temperature, wind speed, and relative humidity in Iran. Five models, namely GFDL-ESM4, IPSL-CM6A-LR, MPI-ESM1-2-HR, MRI-ESM2-0, and UKESM1-0- LL from the Coupled Model Intercomparison Project Phase 6 (CMIP6) have been evaluated versus observations for 1990-2014. A multi-model ensemble was generated with the Integrated Weighted Mean (IWM) method from selected CMIP6 models, and the performances of individual CMIP6 and CMIP6-MME models in estimating temperature, wind speed, and relative humidity were investigated. The results showed that all five selected models are capable to reproduce the variables; however, the CMIP6-MME significantly improved the results. The CMIP6-MME showed good agreement with observational data both in terms of climatology and spatial distribution of each variable, and its performance is higher compared to individual models. We have used two Shared Socioeconomic Pathways (SSPs), namely SSP2-4.5 and SSP5-8.5, and three-time periods, namely near-term (2026-2050), midterm (2051-2075), and long-term (2076-2100) relative to the historical period (1990-2014). The results of this study showed that Iran will undergo changes in temperature, wind speed, and relative humidity spatial distribution in the future. The decrease in relative humidity and dryness of the air in the future can have important consequences for agriculture, food security, and water resources management. The findings of this study, in agreement with previous studies, emphasize the significant increase in temperature throughout Iran. Under the SSP2-4.5 (SSP5-8.5) scenario, the average annual temperature of the country increases by 1.40 (1.83), 2.34 (3.58), and 2.99 (5.58) degrees Celsius in the near (2026-2050), middle (2051-2075), and far (2076-2100) future, respectively. Along with the increasing trend of temperature in Iran, wind speed will decrease in most regions of the country in the middle and end of the 21st century under two SSP scenarios. This decreasing trend can be a result of decreasing atmospheric instability and increasing potential temperature. The northwest of Iran has shown the maximum increasing temperature and the maximum decreasing wind speed. The decrease in relative humidity in Iran has been evident since the 1990s, and the projection results indicate that it will decrease in large parts of Iran in the future. However, the relative humidity in the southeast of Iran shows an increasing rate in the future. Results of this study show that the heat stress will be significantly higher through SSP5-8.5 than SSP2-4.5 in the 21st century due to the decrease in wind speed and increase in temperature throughout Iran. Therefore, Iran should quickly move on to formulate and implement long-term adaptation plans for resilience against climate change. [ABSTRACT FROM AUTHOR]

Sea ice drift in the Arctic Ocean impacts ice mass balance, ocean currents, ice deformation, and freshwater output into lower latitudes. Satellite observation reveals that the Arctic sea ice drift has accelerated under global warming. Meanwhile, previous studies also found that local atmospheric intraseasonal oscillation modulates the Arctic sea ice drift. However, the mechanisms linking the Arctic sea ice drift change to the general warming and intraseasonal oscillation in the local atmosphere are not clearly addressed. Based on a sea ice‒ocean coupled model, this study finds that: (1) The atmospheric intraseasonal oscillation leads to a higher climatological sea ice drift speed despite it produces thicker ice in the Arctic marginal seas, since the elevating effect of increased wind speed yields the suppressing effect of increased ice thickness on sea ice drift speed. (2) The warming of local atmosphere results in substantial elevation of the Arctic sea ice drift speed through generating basin-scale reduction of sea ice thickness. Developing a more sophisticated sea ice dynamical equation may be an essential way to reduce the wide-existing positive bias in sea ice drift modeling. [ABSTRACT FROM AUTHOR]

The Turkana low-level jet stream (TJ) is important to climatic conditions over northern Kenya and East Africa. The representation of the TJ in climate models varies due to the TJ interaction with Turkana channel that is influenced by model resolution and influences the model representation of the regional climate. This study compares features of the TJ in CMIP6 AMIP model simulations with ERA5. Models reveal climatological wind speeds that match those of the reanalysis from the ERA5 at the jet entrance (13 m/s) but lower magnitudes of wind speed and vertical shears compared to ERA5 within the Turkana channel. The models with slowest wind speeds, have a flattened Turkana channel and fail to exhibit the terrain constriction at 37° E which otherwise aids in accelerating winds to form a jet core. Furthermore, they fail to represent the narrowing of the channel as in ERA5, thereby forming blocking walls in the channel, forcing vertical ascent and mixing, and weakening shear. This boosting of ascent motion promotes rainfall formation and enhances wet anomalies at the exit of the TJ when the jet stream is weaker. By applying a new narrowing index, we demonstrate the need to improve topography details in the CMIP6 models, particularly those with resolution coarser than 1.5°, in order to properly simulate the TJ and the observed rainfall over the northwestern areas of eastern Africa. [ABSTRACT FROM AUTHOR]

Highlights Mosquito adulticiding over operationally relevant areas is feasible using UASS. Wind speed plays an important role in the spray landing position, as expected based on previous studies using CASA. Results are based on both passive and active collectors, including flat cards, rotary impingers, and bottle brushes. Over 1900 total samples were collected in 8 trials, and elevated samplers allowed analysis of the descent of the droplet cloud. A spatially extensive experiment was designed to evaluate the effectiveness of Uncrewed Aerial Spray Systems (UASS) in mosquito adulticiding. The practice of adulticiding uses very fine droplets (DV0.5 <50µm). The objective is to fill a volume of air with fine droplets that a flying adult mosquito will encounter in flight. A field program was designed with samplers as far as 500 m downwind from the UASS flight line. A total of over 1900 samples were collected over the course of eight trials. Both passive and active collectors were deployed. Tests were conducted in the early morning and were generally successful in terms of meteorological conditions and data collection. Elevated samplers successfully tracked the descent of the spray cloud, and spray was collected from the most distant samplers. The known dependence of spray movement on wind speed that has been widely observed and codified into label language for Crewed Aerial Spray Aircraft (CASA) was observed. Very low wind speed conditions are problematic for adulticiding in general, and undesirable near-field deposition of adulticiding spray was observed in the data presented here under low wind speed conditions. It needs to be emphasized that much more data needs to be collected before statistically robust conclusions can be drawn. Generally, these data show that UASS can be used to disperse very fine spray droplets over areas representative of operational adulticiding. This paper presents and discusses spray movement and deposition, a second paper is in preparation comparing these data to existing models of spray dispersion and deposition from UASS spraying. A third paper examining mortality from UASS adulticiding has been published. [ABSTRACT FROM AUTHOR]

Spaceborne synthetic aperture radar (SAR) for measuring high winds is expected to reduce uncertainties in tropical cyclone (TC) intensity and structure estimation, yet the consistency of SAR observed winds equivalent to a 1-min sustained wind speed with the conventionally estimated 10-min maximum wind speed (Vmax10) remains to be assessed. This study compares SAR wind observations with western North Pacific best track estimates from the Japan Meteorological Agency (JMA) and the Joint Typhoon Warning Center (JTWC). Because SAR wind observations have a bias dependent on SAR incidence angle, a first order corrective term is proposed and used to correct SAR-derived maximum wind (SAR Vmax) tentatively. After this correction, conversion of SAR Vmax into SAR Vmax10 with Dvorak conversion tables revealed a mean difference between SAR Vmax10 and JMA Vmax10 (ΔVmax10) of -0.1 m s-1 and a mean absolute difference of 4.8 m s-1. ΔVmax10 is found to be correlated with current intensities and with subsequent intensity changes from the SAR observation time. Also, comparison of the JMA best track 50-kt wind radius (R50) with SAR wind speeds suggests that R50 is systematically underestimated. Aside from the SAR wind limitations, possible reasons for the observed discrepancies between SAR wind observations and best track estimates include biases in the Dvorak analysis and conventional surface wind products. Further accumulation of SAR wind observations with appropriate bias correction in the future is expected to contribute to a comprehensive evaluation and improvement of conventional Vmax estimation methods, which could also be useful to verify TC intensity forecasts. [ABSTRACT FROM AUTHOR]

In practical applications, the proton exchange membrane (PEM) fuel cell stack is often exposed to wind environment, and the speed and direction of the ambient wind are random. The performance variation of an open-cathode PEM fuel cell under various ambient wind directions and speeds was studied. The results show that when the ambient wind direction is opposite to the cathode reactant or from the side of stack, the stack temperature increases and the stack power decreases finally. Moreover, with the increase in the wind speed, the running time of the stack is shortened significantly. For the ambient wind in the same direction as the cathode gas, the stack power increases at a high current and decreases at a low current. For the given speed and direction of ambient wind, the increased air flow rate of fan could alleviate the interference of ambient wind on the stack performance and temperature. However, while the stack temperature is more than the allowable maximum operating temperature, the stack power declines even though the air flow rate of fan increases. [ABSTRACT FROM AUTHOR]

How might irrelevant events infiltrate voting decisions? The current research introduces a new mechanism—regulatory focus—by which incidental environmental factors can affect vote choice. Regulatory focus theory proposes that there are two fundamental psychological orientations in how people navigate their worlds: A prevention focus tunes cognition towards security, safety, protection, and risk aversion, whereas a promotion focus orients attention toward achieving growth and positive outcomes. We present a model for how wind speed on Election Day affects voting by shifting the regulatory focus of voters. We propose that increased wind speed shifts voters toward selecting prevention-focused options (e.g., restricting immigration, rejecting Brexit, rejecting Scottish Independence) over promotion-focused options (e.g., promoting immigration, favoring Brexit, favoring Scottish Independence). We further argue that wind speed only affects voting when an election clearly offers a choice between prevention and promotion-focused options. Using a mixed-method approach—archival analyses of the "Brexit" vote, the Scotland independence referendum, and 10 years of Swiss referendums, as well as one field study and one experiment—we find that individuals exposed to higher wind speeds become more prevention-focused and more likely to support prevention-focused electoral options. The findings highlight the political importance of incidental environmental factors. Practically, they speak to the benefit of absentee voting and expanding voting periods beyond traditional election days. [ABSTRACT FROM AUTHOR]

Wind energy is essential for sustainable energy development, providing a clean and reliable energy source through the wind turbine. However, the vortices and turbulence generated as wind passes through turbines reduce wind speed and increase turbulence, leading to significant power losses for downstream turbines in wind farms. This study investigates wake characteristics in wind turbines by examining the effects of different scale ratios on wake dynamics, using both experimental and numerical approaches, utilizing scaled-down models of the Aeolos H-20 kW turbine at scales of 1:33, 1:50, and 1:67. The experimental component involved wind tunnel tests in an open-circuit tunnel with adjustable wind speeds and controlled turbulence intensity. Additionally, Computational Fluid Dynamics (CFD) simulations were conducted using STAR-CCM+ (Version 15.06.02) to numerically analyze the wake characteristics. Prior to the simulation, a convergence test was performed by varying grid density and y+ values to establish optimized simulation settings essential for accurately capturing wake dynamics. The results were validated against experimental data, reinforcing the reliability of the simulations. Despite minor inconsistencies in areas affected by tower and nacelle interference, the overall results strongly support the methodology's effectiveness. The discrepancies between the experimental results and CFD simulations underscore the limitations of the rigid body assumption, which does not fully account for the deformation observed in the experiment. [ABSTRACT FROM AUTHOR]

This study investigates the influence of atmospheric stability and ground effects on wind turbine wake recovery, challenging the conventional linear relationship between turbulence intensity and wake expansion coefficient. Through comprehensive field measurements and numerical simulations, we demonstrate that the linear wake expansion assumption is invalid at far-wake locations under high turbulence conditions, primarily due to ground effects. We propose a novel nonlinear wake expansion model that incorporates both atmospheric stability and ground effects by introducing a logarithmic relationship between the wake expansion coefficient and turbulence intensity. Validation results reveal the superior prediction accuracy of the proposed model compared to typical engineering wake models, with root mean square errors of wake wind speed predictions ranging from 0.04 to 0.063. The proposed model offers significant potential for optimizing wind farm layouts and enhancing overall wind energy production efficiency. [ABSTRACT FROM AUTHOR]

Passively tuned mass dampers (TMDs) are known to effectively mitigate the vibration of wind turbines. However, existing literature predominantly examines their application in damping vibrations of the tower or platform, overlooking the potential benefits of installing TMDs on the turbine blades themselves. This study investigates the impact of wind and wave loads on TMD damping effectiveness and proposes a comprehensive damping strategy involving TMDs installed in both the nacelle and the blades. The design optimized the mass and stiffness of these TMDs to enhance their performance. Results indicate that, as wind speeds increased from 12 m/s to 24 m/s, the power spectral density at the tower's natural frequency (0.22 Hz) more than doubled. Notably, TMDs exhibited robust vibration damping capabilities under high wind speeds. Specifically, at wind speeds of 24 m/s, TMDs reduced anterior–posterior and lateral displacement at the tower top by 61.2% and 166.8%, respectively, when two TMDs were combined. Conversely, the study found that TMDs did not significantly improve vibration damping at lower to moderate wind speeds. This research underscores the importance of optimizing TMDs for high wind conditions to ensure wind turbine stability and mitigate potential vibration-related risks effectively under varying environmental loads, including wind and waves. It offers valuable insights for the refined design and deployment of TMDs in wind energy applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to determining the ampacity of DC and AC railway overhead contact lines, considering both operational and design factors. The ampacity of contact lines is influenced by several design parameters, including materials, cross section and the number of catenary and contact wires, etc. Additionally, the permissible long-term and short-term current values, which correspond to the permissible temperatures defined by EN 50119:2020, are affected by operational factors such as ambient temperature, solar radiation, heat exchange conditions, wind speed, wear of contact wires. Existing methods for determining the ampacity of overhead contact lines often fail to account adequately for these critical factors and lack the necessary procedures to calculate the 30 min ampacity required by EN 50119:2020. In response, the method proposed in this study adapts the procedures of IEEE 738-2012 to the specific needs of railway contact lines, taking into account the effect of contact wire wear on current distribution and overall ampacity. The proposed method offers a more realistic and practical approach to determining the ampacity of contact lines, thereby enhancing the reliability and efficiency of the traction power supply infrastructure. This method could be useful for railway infrastructure managers to ensure the safe and efficient operation under varying environmental and operational conditions. [ABSTRACT FROM AUTHOR]

This research study aims to develop a system which ensures the mobility of a floating dock and its stability in position during docking operations. The dock is designed for operation in a river canal. In order to dock a ship, it is moved away from the quay over a dock trench. Initial requirements and design criteria for the system were determined. The most important of them include docking in the maximum weather conditions, corresponding to a wind speed of 5° Beaufort (5°B), and a zero-emission target for the power supply system (use of a renewable energy source). A wire and winch system was designed to move the dock and stabilise it in position during docking operations. The system comprises mooring wires which are tied to bollards on both quays, and wire winches mounted on both sides of the dock. The wire winches are hydraulically driven, and the hydraulic pumps, run by electric motors, are powered with batteries charged using photovoltaic panels. Statistical environmental parameters (wind, river current) were analysed and the probability of certain mooring wire loads and the corresponding wire winch power output were quantified. Based on these calculations, the power of photovoltaic panels and capacity of the batteries required to power the dock moving system were determined. This paper discusses the system design as well as the results of trials. [ABSTRACT FROM AUTHOR]

Water scarcity is a serious threat to the survival and development of mankind. Interfacial solar steam generation (ISSG) can alleviate the global freshwater shortage by converting sustainable solar power into thermal energy for desalination. ISSG possesses many advantages such as high photothermal efficiency, robust durability, and environmental friendliness. However, conventional evaporators suffered from huge heat losses in the evaporation process due to the lack of efficient thermal management. Herein, hydrophilic Tencel yarn is applied to fabricate a three-dimensional double-layer fabric evaporator (DLE) with efficient multi-stage thermal management. DLE enables multiple solar absorptions, promotes cold evaporation, and optimizes thermal management. The airflow was utilized after structure engineering for enhanced energy evaporation efficiency. The evaporation rate can reach 2.86 kg·m−2·h−1 under 1 sun (1 kW·m−2), and 6.26 kg·m−2·h−1 at a wind speed of 3 m·s−1. After a long duration of outdoor operation, the average daily evaporation rate remains stable at over 8.9 kg·m−2, and the removal rate of metal ions in seawater reaches 99%. Overall, DLE with efficient and durable three-dimensional multi-stage thermal management exhibits excellent practicality for solar desalination. [ABSTRACT FROM AUTHOR]

In recent years, wind power generation has been promoted as a countermeasure to global environmental problems. However, the introduction of many wind power generators into the power system may cause system frequency fluctuations. This paper proposes a control method to reduce system frequency fluctuations by using the rotor kinetic energy (RKE) of a variable speed wind turbine (VSWT). When the frequency falls, this method suppresses fluctuations by consuming RKE to increase VSWT power generation, and when it rises, it decreases VSWT power generation by accumulating RKE. The effectiveness of this method is confirmed through simulations using PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

The instability of the increasingly important photovoltaic (PV) electricity generation in Korea due to a dependence on meteorological conditions is an emerging problem. In this study, we examined the influence of various meteorological conditions on the prediction accuracy of PV generation and module temperature. The predictions were based on weather data acquired from the Korea Meteorological Administration and compared with actual PV generation data from the Dangjin coal yard PV power facility. The results were analyzed on the basis of meteorological conditions, insolation, ambient temperature, and wind velocity. [ABSTRACT FROM AUTHOR]

Tropical cyclones (TC) are common high-impact weather events in the southeastern United States. One of the most intense TCs to hit north-central Florida in recent decades was Hurricane Frances (2004), which resulted in over $10B in damages. Given the growing concern about the relationship between anthropogenic climate change, precipitation, and TCs, we investigated how a Hurricane Frances-like event would affect north-central Florida in the late 21st century under an RCP-8.5 scenario. Using a 'pseudo' global warming dataset based on the high-resolution Weather Research and Forecasting (WRF) model, we explore historical and future simulations of Hurricane Frances's path, precipitation rates, and wind speeds. We discover that, across north-central Florida sub-daily to daily rainfall totals in the future simulation exceed that of the historical, having return period events in some cases reaching 500-year thresholds. We also find more broadly across the spatial domain of the hurricane that rainfall rates in all temporal categories and total rainfall accumulation increased significantly. Results for wind speeds were mixed, with an evident expansion of tropical storm winds, but a slight contraction of the spatial extent of strongest winds at the surface. We discuss the implications of these findings for decision-makers in Florida. [ABSTRACT FROM AUTHOR]

Sea spray particles play a key role in transferring momentum, heat, and gas across the atmosphere–ocean interface at high wind speeds and represent an important source of cloud condensation nuclei which affect the genesis, chemistry, and radiative properties of marine clouds. Here, we present direct measurements of sea spray particle fluxes obtained using an eddy covariance technique through the use of a newly developed high temporal resolution optical particle counter. With this instrumentation measurements were made over the coastal ocean during a 5-week field campaign conducted at an observation pier from November to December 2021. Our optical particle counter was capable of measuring size spectra at a rate of 10 Hz in 8 channels covering a range of mean radii between 0.3 and 15. The power spectra of particle number density followed the Kolmogorov −2/3 power law. The shape of the cospectrum of the particle number density flux was basically similar to that of the cospectra of the heat and gas fluxes. The measured sea spray particle fluxes at mean wind speeds of up to 21 m s−1 were dominated by an upward flux, which likely represents aerosol production caused by the bursting of bubbles at the ocean surface. [ABSTRACT FROM AUTHOR]

Near-surface ocean wind measurements are important for weather forecasting, determining surface transports, and estimating air-sea interactions; however, in-situ wind observations are often limited. Previous studies indicate that the equilibrium range of the surface gravity wave spectrum can be used to estimate surface wind velocity. This approach is tested using spectral wave measurements from the Coastal Data Information Program (CDIP) buoy array off Monterey, California. Quality controlled wind vectors inferred from wave spectra are statistically compared to measurements from a nearby National Data Buoy Center (NDBC) buoy, demonstrating strong agreement with the control observations with root mean square errors for speed and direction of 1.8 m/s for all wind speeds and 13.2° for wind speeds greater than 7 m/s. We expand this estimation method to account for biofouling, which causes high-frequency damping of the wave spectrum, and the effects of form factor, which impact the platform's dynamic response to high-frequency waves. The method produces wind-proxy measurements solely from wave spectra and wave-based drag parametrizations, making it useful for operational integration. This work demonstrates the ability to make robust wind velocity estimates using wave data from multiple sources, increasing the coverage of wind information over the coastal and open ocean. [ABSTRACT FROM AUTHOR]

The generation of ocean surface waves by wind has been studied for a century, giving rise to wave forecasting and other crucial applications. However, the reacting force of swell waves on the turbulence in the marine atmospheric boundary layer (ABL) remains unknown partly due to the unclear magnitude and profile of wave-coherent (WC) stress. In this study, the intersection frequency between the energy-containing range and inertial subrange range in the turbulent spectra is identified based on the attached eddy model (AEM), as the intersection modulated by swell wave could help to comprehend the physical process between the ocean surface wave and the marine ABL. Using observations from a fixed platform located in the South China Sea, this study shows that the intersection when the WC stress accounts for a lower proportion of the total wind stress (<10%) follows U/(2πz) given by AEM, where U is the wind speed and z is the height. While the intersection depends on the drag coefficient of WC stress for the case, WC stress accounts for a large part of the total wind stress (>10%). Considering the unclear magnitude and profile of WC stress, this study derives a new function to depict the WC stress. Significance Statement: Turbulence located in the energy-containing range of the spectra is the primary source of momentum, heat, and water vapor fluxes between the ocean and marine atmospheric boundary layer (ABL). Thus, a better understanding of the turbulent structure within the wave boundary layer can help us accurately parameterize those fluxes. In addition to absorbing energy from the marine ABL, waves, especially swell waves, influence the turbulent structure. However, until now, the turbulent structure is unclear due to the unclear wave-coherent stress size and profile. In this study, a function that can depict the wave-coherent stress is proposed. We found that the wave-coherent stress can modulate the intersection between the energy-containing range and the inertial subrange range in the turbulent spectra. [ABSTRACT FROM AUTHOR]

The state of Hawaii is a series of mountainous islands with a topography that is much more complex than the simple isolated hills and escarpments included in ASCE standard ASCE/SEI 7-22 (Minimum design loads and associated criteria for buildings and other structures, ASCE 7). Hawaii state and county building codes have incorporated topographic wind speed mapping since 2007. In 2010, ASCE 7-10 recognized Hawaii as a special wind region. The design wind speed maps, Kzt maps, and site-specific directionality factors as adopted in Hawaii's state building codes constituted the "special Kzt topographic effect adjustments" of the authority having jurisdiction that were referenced in ASCE 7-10. In ASCE 7-16 and ASCE 7-22, microzoned wind speed maps for Hawaii, including the effect of topography and directionality, were incorporated for strength design return periods. This paper provides information on the development of an improved generation of higher-resolution basic design wind speed maps for the state of Hawaii, including better accuracy of topographic and directionality effects. The digital format of these wind speed maps can be readily incorporated into the ASCE 7 digital hazard tool interfaces. [ABSTRACT FROM AUTHOR]

Tropical cyclone (TC) winds control design wind speeds for much of the eastern United States. Those winds are likely to intensify with climate change, but climate change was not considered in the ASCE 7-22 design wind speed maps, potentially causing many structures to be designed with unacceptably high levels of risk. In this study, we investigate (1) the increases in design wind speed due to climate change; and (2) the resulting risk to structures if climate change is not considered. We estimated the design wind speeds for US counties affected by TCs along the Gulf and Atlantic coasts using nonstationary methods based on a set of synthetic TCs (1,000–1,500 year simulations) downscaled from the latest global climate projections (CMIP6) for the high-emissions scenario (SSP5-8.5). It was found that over the 21st century, 50-year return period winds would increase by an average of around 10% along the US Gulf and Atlantic coasts. Depending on the risk category, design lifetime, and year of construction, design wind speeds (targeting lifetime exceedance probability) are projected to increase by an average of 3%–6% for all counties studied and 6%–15% for coastal counties. For Risk Category II–IV structures, depending on the design lifetime and year of construction, 8%–36% of all counties studied and 25%–66% of coastal counties would experience projected lifetime exceedance probabilities that were at least two risk categories too low; for example, in up to 26% of all counties studied and 54% of coastal counties, a Risk Category III structure would be effectively designed as Risk Category I or lower. [ABSTRACT FROM AUTHOR]

Recruitment is a critical process in the dynamics of fish populations since it represents the abundance of new fish that enter a population each year. In Ekman‐type upwelling ecosystems, wind is a critical factor for small pelagic fish recruitment, as it controls food availability and physical constraints such as turbulence and offshore advection. In this study, we evaluate the effect of wind, chlorophyll‐a, and spawning biomass as independent variables on anchovy recruitment. Using generalized additive models (GAMs), we tested (i) the significance of each factor, (ii) the shape of the relationship between recruitment and predictors variables, (iii) recruitment regimes in the series, and (iv) whether extended windy events are associated with low recruitment levels potentially related to offshore transport of early life stages. The study period spanned from 1990 to 2021, focusing on the austral spring in south‐central Chile (35–40°S) when both upwelling and anchovy spawning are maximized. GAMs revealed a parabolic relationship between the velocity of upwelling‐favorable winds and anchovy recruitment. Maximized recruitment occurred at wind speeds around 6 m s−1 but decreased with winds above 7 m s−1 and below 5 m s−1, and during periods of extended windy events (i.e., those lasting more than 15 days). Chlorophyll‐a showed no significance on anchovy recruitment, suggesting that phytoplankton were not a limiting factor for anchovy early survival. We also found that anchovy recruitment regimes were associated with specific wind intensities. We discussed the pertinence of incorporating a recruitment index based on wind in the fishery management of the anchovy in south‐central Chile. [ABSTRACT FROM AUTHOR]

Tropical cyclone intensification is simulated with a cloud-resolving model under idealized conditions of constant SST and unidirectional environmental vertical wind shear maximized in the middle troposphere. The intensification process commonly involves a sharp transition to relatively fast spinup before the surface vortex achieves hurricane-force winds in the azimuthal mean. The vast majority of transitions fall into one of two categories labeled S and A. Type S transitions initiate quasi-symmetric modes of fast spinup. They occur in tropical cyclones after a major reduction of tilt and substantial azimuthal spreading of inner-core convection. The lead-up also entails gradual contractions of the radii of maximum wind speed rm and maximum precipitation. Type A transitions begin before an asymmetric tropical cyclone becomes vertically aligned. Instead of enabling the transition, alignment is an essential part of the initially asymmetric mode of fast spinup that follows. On average, type S transitions occur well after and type A transitions occur once the cyclonically rotating tilt vector becomes perpendicular to the shear vector. Prominent temporal peaks of lower-tropospheric CAPE and low-to-midlevel relative humidity averaged over the entire inner core of the low-level vortex characteristically coincide with type S but not with type A transitions. Prominent temporal peaks of precipitation and midlevel vertical mass flux in the meso-β-scale vicinity of the convergence center characteristically coincide with type A but not with type S transitions. Despite such differences, in both cases, the transitions tend not to begin before the distance between the low-level convergence and vortex centers divided by rm reduces to unity. [ABSTRACT FROM AUTHOR]

The issue of pedestrian-level wind environments around high-rise buildings is closely related to the comfort and safety of human settlements. In this paper, we study the effects of different wind direction angles and spacing ratios on the wind environment at pedestrian heights around buildings arranged in an equilateral triangle configuration. Three-dimensional steady-state numerical simulation was employed, with the standard k-ε model selected as the turbulence model. Wind speed ratios and different area ratio parameters are used to quantitatively express the degree and range of influence of wind speed by buildings. The results show that the maximum wind speed ratio at the corner of a building is greatly affected by the wind direction angle, with 45°, 135°, and 157.5° being the unfavorable wind direction angles. Conversely, the area ratio of different areas is greatly affected by the spacing ratio. As the spacing ratio increases, the mutual interference effect between buildings weakens, resulting in a better pedestrian wind environment. Owing to the unique layout of the building group, different degrees of ventilation corridors are formed among the three buildings. The wind speed amplification effect in the corridors is more significant, and the areas with poor wind environments are concentrated in these corridors. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The main aim of this research is to analyze the characteristics of the wind speed and wind power density in Baghdad City within micro-scale meteorological conditions at Mustansiriyah University Meteorological Station (MUMS). Temperature, atmospheric pressure and wind speed data were taken for one year (2016) measured at a height of 18 m above the earth's surface. Hourly, monthly, and seasonal changes in wind speed at an altitude of 30 m were estimated using a power law. The mean diurnal and monthly air density was calculated. Different statistical distributions were used, including the Rayleigh, Gamma and Weibull distributions, and the best distribution function was selected to evaluate the wind power density in the study area. The results showed the highest monthly mean of wind speed recorded in June and July. Therefore, these months have the highest wind power density. The lowest monthly mean of wind speed and wind power density was observed in December. The maximum and minimum values of air density were recorded in December, January and July, August, respectively. The monthly variation of the shape parameter (k) ranges between 0.99 - 1.81, while the monthly variation of the scale parameter(c) ranges between 1.07 - 2.3 m s-1. It was also found that the Weibull distribution was more accurate than the Rayleigh and Gamma distributions. The prevailing wind direction is northeast (NE) and east-northeast (ENE) most of the time. The research results showed that the study area is not suitable for using wind energy to generate energy. [ABSTRACT FROM AUTHOR]

Rice cultivation in Madurai district, Tamil Nadu, spans distinct cropping seasons: Kar (May -- Jun), Semi-dry (Jul - Aug), Samba/ Late Samba (Aug - Sep), and Navarai (Dec - Jan), each with unique weather conditions and rice varieties. This study explores the correlation between weather parameters temperature, rainfall, humidity, sunshine hours, and wind speed and rice blast disease severity from 2021 to 2023. Using multiple linear regression with ordinary least squares (OLS), the analysis achieves high predictive accuracy (R² = 0.98). Results show that the maximum temperatures correlated negatively with disease severity (r = -0.869 to -0.892), while rainfall (r = 0.768 to 0.804) and wind speed (r = 0.766 to 0.938) correlated positively during the semi-dry season. Relative humidity exhibits varying impacts across seasons. These findings underscore the importance of tailored disease management strategies, such as targeted fungicidal applications during warmer seasons and optimized water management in others. By elucidating these dynamics, the study enhances understanding of weather-disease interactions, providing actionable insights to optimize disease management and enhance crop resilience in Madurai district. [ABSTRACT FROM AUTHOR]

Atmospheric stability is considered as one of the most important factors affecting the increase or decrease in wind speed in the atmosphere and thus affects the wind energy density. This study aims to analyze the stability of the atmospheric conditions in southern part of Iraq, specifically in the Ali Al-Gharbi region, using one of methods to determine atmospheric stability called Monin-Obukhov length . Field data of horizontal and vertical wind speed and air temperature collected at three heights (10m, 30m, and 50m) in 2017 from tower installed in Ali Al-Gharbi region. The results show that the vertical wind speed increases with height up to 30 m and decreases at 50 m, while the horizontal wind speed increases as the height increases. The friction velocity, surface heat flux, momentum flux and shear stress were calculated and the stability conditions were determined. Results revealed that stable atmospheric condition was the most frequent with about 59% occasions occurring during the year followed by unstable (40%) and neutral (1%) conditions. The highest wind energy density was in stable conditions (0 ≤ L< 200), with percentage (58% - 57%) in spring season at both heights 10m and 50m, respectively, followed by unstable conditions (-200 < L ≤ 0), while the lowest wind energy density was in neutral conditions (-200 ≤ L ≥ 200) with percentage (1.3% - 0.8%) in autumn season. [ABSTRACT FROM AUTHOR]

The unpredictability and instability of wind have hindered the development and utilization of wind power. To harness wind energy and ensure a secure and stable power grid after wind power integration, precise predictions of wind power generation are imperative. Here, we apply one-year data from a coastal wind farm in Zhejiang to train a Random Forest (RF) model for predicting wind power generation. The results indicate that the RF model (mean bias (MB) 1.33) outperforms traditional linear models (MB 87.70). An evaluation of prediction-measurement bias shows a strong agreement between the RF model's predictions and actual measurements (MB 1.33), especially when wind speeds exceed 5.7 m/s. While the Weather Research and Forecasting (WRF) model yields less accurate results (R2 0.65) compared to using measured wind velocity data (R2 0.97) for wind power prediction, it remains acceptable as it can capture and forecast peak generating power, meeting daily management requirements. Therefore, our machine learning-based approach offers practical guidance for reducing wind power generation uncertainties. Enhancing wind velocity forecasting through the WRF model could further improve the RF model's accuracy in predicting wind power generation. Our study also verified the future application of RF model in coastal areas of China. [ABSTRACT FROM AUTHOR]

This paper is dedicated to correcting the WAM/ICON numerical wave model predictions by reducing the residue between the model's predictions and the actual buoy observations. The two parameters used in this paper are significant wave height and wind speed. The paper proposes two machine learning models to solve this task. Both models are multioutput models and correct the significant wave height and wind speed simultaneously. The first machine learning model is based on gradient boosted trees, which is trained to predict the residue between the model's forecasts and the actual buoy observations using the other parameters predicted by the numerical model as inputs. This paper demonstrates that this model can significantly reduce errors for all used geographical locations. This paper also uses SHapley Additive exPlanation values to investigate the influence that the numerically predicted wave parameters have when the machine learning model predicts the residue. To design the second model, it is assumed that the residue can be modelled as noise added to the actual values. Therefore, this paper proposes to use the denoising autoencoder to remove this noise from the numerical model's prediction. The results demonstrate that denoising autoencoders can remove the noise for the wind speed parameter, but their performance is poor for the significant wave height. This paper provides some explanations as to why this may happen. [ABSTRACT FROM AUTHOR]

In efforts to fulfill the objectives of taking part in pragmatic cooperation in the Arctic, constructing the "Silk Road on Ice", and ensuring ships' safety and risk assessment in the Arctic, the two biggest hazards, which concern ships' navigation in the Arctic, are wind and sea ice. Sea ice can result in a ship being besieged or crashing into an iceberg, endangering both human and property safety. Meanwhile, light winds can assist ships in breaking free of a sea-ice siege, whereas strong winds can hinder ships' navigation. In this work, we first calculated the spatial and temporal characteristics of a number of indicators, including Arctic wind speed, sea-ice density, the frequency of different wind directions, the frequency of a sea-ice density of less than 20%, the frequency of strong winds of force six or above, etc. Using the ERA5 wind field and the SSMI/S sea-ice data, and applying statistical techniques, we then conducted a joint analysis to determine the correlation coefficients between the frequencies of various wind directions, the frequency of strong winds and its impact on the density of sea ice, the frequency of a sea-ice concentration (SIC) of less than 20%, and the correlation coefficient between winds and sea-ice density. In doing so, we determined importance of factoring the wind's contribution into sea-ice analysis. [ABSTRACT FROM AUTHOR]

The global transition to renewables in response to climate change has largely been supported by the expansion of wind power capacity and improvements in turbine technology. This is being made possible mainly due to improvements in the design of highly efficient turbines exceeding a 10 MW rated power. Apart from power efficiency, wind turbines must withstand the mechanical stress caused by wind–hydro conditions. Such comprehensive structural analysis has rarely been performed previously, especially for large-scale wind turbines under real environmental conditions. The present work analyzes the energy production and structural performance of an NREL-IEA 15 MW wind turbine using measured wind and hydro data. First of all, an optimum operating range is determined in terms of the wind speed and blade pitch angle to maximize the power coefficient. Then, at this optimum range, a detailed breakdown of the forces and moments acting on different components of the wind turbine is presented. It was found that wind speeds of 9 to 12 m/s are best suited for this wind turbine, as the power coefficient is at its maximum and the mechanical loads on all components are at a minimum. The loads are at a minimum due to the optimized blade pitch angle. The bending force on a monopile foundation (fixed on the seabed) is found to be at a maximum and corresponds to nearly 2000 kN. The maximum blade force is nearly 700 kN, whereas on the tower it is almost 250 kN. The maximum force on the tower occurs at a point which is found to be undersea, whereas above-sea, the maximum force on the tower is nearly 20% less than the undersea maximum force. Finally, seasonal and annual energy production is also estimated using locally measured wind conditions. [ABSTRACT FROM AUTHOR]