High Wind Speeds Research Articles

Experimental investigation of the occurrence of transonic flow effects on the FFA-W3-211 airfoil

For the largest wind turbines currently designed, when operating at rated power and at high wind speeds, the tip airfoils can experience large negative angles of attack. For these conditions and in combination with turbulence, the airfoils are at risk of reaching locally supersonic flow, even at low free-stream Mach numbers. The possibility of shock wave formation and its consequences endangers the lifetime of these largest rotating machines ever built. So far only numerical analyses of this challenge have been attempted with significant modelling uncertainty. Here, for the first time, a wind turbine airfoil (the FFA-W3-211, used at the blade tip of the IEA 15MW reference wind turbine) is studied under transonic conditions using experimental techniques. Schlieren visualization and Particle Image Velocimetry were employed for free-stream Mach numbers of 0.5 and 0.6 and various angles of attack. It was shown that calculations based on isentropic flow theory and compressibility corrections were able to predict the situations where supersonic flow occurred. However, they could not predict the frequency of occurrence and whether shock waves were formed. In conclusion, an unsteady characterization of such airfoil behavior in transonic flow seems to be warranted.

Resolution Dependence of Extreme Wind Speed Projections in the Great Lakes Region

Abstract The effect of anthropogenic climate change on extreme near-surface wind speeds is uncertain. Observed trends are weak and difficult to disentangle from internal variability, and model projections disagree on the sign and magnitude of trends. Standard coarse-resolution climate models represent the fine structures of relevant physical phenomena such as extratropical cyclones (ETCs), upper-level jet streaks, surface energy fluxes, and land surface variability less skillfully than their high-resolution counterparts. Here, we use simulations with the NCAR Community Earth System Model with both uniform (110 km) resolution and the variable-resolution configuration (VR-CESM-SONT, from 110 to 7 km) to study the effect of refined spatial resolution on projections of extreme strong and weak wind speeds in the Great Lakes region under end-of-century RCP8.5 forcing. The variable-resolution configuration projects strengthening of strong-wind events in the refined region with the opposite occurring in the uniform-resolution simulation. The two configurations provide consistent changes to synoptic-scale circulations associated with high-wind events. However, only the variable-resolution configuration projects weaker static stability, enhanced turbulent vertical mixing, and consequentially enhanced surface wind speeds because boundary layer dynamics are better captured in the refined region. Both models project increased frequency of extreme weak winds, though only VR-CESM-SONT resolves the cold-season inversions and summertime high temperatures associated with stagnant wind events. The identifiable mechanism of the changes to strong winds in VR-CESM-SONT provides confidence in its projections and demonstrates the value of enhanced spatial resolution for the study of extreme winds under climate change. Significance Statement In this study, we compare climate change projections of high and low extreme wind speeds in the Great Lakes region between a standard coarse-resolution simulation and a high-resolution simulation performed using the same climate model. The fine-resolution simulation projects strengthening high wind speeds, opposite to the coarse-resolution simulation. Both project increasing frequency of extreme weak winds, but the human-health-related impacts of stagnant winds are only captured at fine resolution. The changes in the coarse-resolution simulation are explained by changes to large-scale circulation, while the fine-resolution changes are linked to local processes the coarse model does not resolve. This helps explain the diverging projections of strong winds and gives greater credibility to the fine-resolution simulation.

UNICO: an open-source controller optimized for stall-regulated wind turbines

Stall regulation turbines still represent the preferred solution for small wind turbines. In stall-controlled rotors the controller plays a key role but, differently from pitch-based ones, no open-source controller was available to date. The study presents the UNICO (UNIfi research COntroller) controller, which has been specifically developed for variable speed stall-regulated turbines. The controller has been developed in MATLAB® Simulink® and a dynamic link library (.dll) has been generated, which can be coupled with common simulation codes such as OpenFAST and QBlade using a Bladed-style interface. UNICO includes features that are specifically tailored to variable-speed stall-regulated turbines. For below-rated conditions, the controller employs either the commonly used k-ω2 law or a tracking of the optimal tip speed ratio. For above-rated conditions, a PI controller is used to track a user-imposed reference speed. The reference speed is set to decrease linearly with wind speed, providing a safety margin for turbine operation at higher wind speeds. UNICO has been tested on a 50-kW stall-regulated reference turbine. Preliminary results show how the proposed controller can achieve better overall performance in comparison to the simplified control laws implemented in state-of-the-art codes. Additionally, the rotor speed can be controlled in above-rated conditions, providing an increased run away safety margin.

Future Changes in Regional Tropical Cyclone Wind, Precipitation, and Flooding Using Event‐Based Downscaling

AbstractUnderstanding changes in the hazard component of climate risk is important to inform societal resilience planning in a changing climate. Here, we examine local changes in wind speed, rainfall, and flooding related to tropical cyclones (TCs) and compare them across statistical and dynamical modeling approaches. Our focus region is the Delaware River Basin, located in the northeastern United States. We pair event‐based downscaling with large ensemble climate model information to capture the details of extreme TC wind, rain, and flooding, and their likelihood, in a changing climate. We identify local TCs in the Community Earth System Model 2 Large Ensemble (CESM2‐LENS). We find fewer TCs in the future, but these future storms have higher wind speeds and are wetter. We also find that TCs produce heavier 3‐day precipitation distributions than all other summertime weather events, with TCs constituting a larger percentage of the upper tail of the full precipitation distribution. With this information, we identify a small collection of 200‐year return events and compare the resulting TC rain and wind across dynamical and statistical downscaling methods. We find that dynamical downscaling produces peak rain rates far higher than CESM or the statistical downscaling method. It can also produce quite different future changes in precipitation totals for the small set of events considered here. This leads to vastly different flood responses. Overall, our results highlight the need to interpret future changes of event‐based simulations in the context of downscaling method limitations.

Deviation of drive torque and rotational speed of a wind turbine drivetrain between test bench and wind turbine simulations

Wind turbines are a major contributor to a clean and independent energy mix in the future and therefore need to have as little downtime as possible. Downtime can be minimised by increasing the robustness of the wind turbine. The drivetrain is one of the major contributors of downtime in wind turbines. One way of increasing the robustness of wind turbine drivetrains is extensive drivetrain testing and loop-back optimization of the design and control. On the drivetrain test bench torque and other wind loads are applied. To ensure that the drivetrain reaction to the loads is the same as of the erected wind turbine the accuracy of the application of the loads needs to be sufficient. Only if the reaction loads of the drivetrain are similar to the rotor loads of the erected wind turbine a robustness increase can be achieved via the loop-back optimization after the tests. This paper therefore quantifies the deviations occurring in torque and rotational speed of the hub between the erected wind turbine and the test bench for a specific wind turbine. To do so the results of a test bench simulation are compared to results of an aerodynamic simulation of the wind turbine. For the investigated wind turbine drivetrain, the deviation in drive torque increases slightly with higher windspeeds. The torque values are maximum 2 % higher at the wind turbine compared to the rated torque. The rotational speed values are represented very well regarding the time series as well as the occurring frequencies. The speed values deviate maximum 0.5 % compared to the rated speed. The deviations are a result of differences in an underestimation of the drivetrain efficiency in the aerodynamic simulation and the inertia of the drivetrain on the test bench and wind turbine. Since the deviations are small the abstraction losses at the test bench regarding torque and speed are acceptable.

Influences of Solar Wind Parameters on Energetic Electron Fluxes at Geosynchronous Orbit Revealed by the Deep SHAP Method

AbstractSolar wind is an intermediary in energy transfer from the Sun into the Earth's magnetosphere, and is considered as a decisive driver of energetic electron dynamics at the geosynchronous orbit (GEO). Based on machine learning technology, several models driven by solar wind parameters have been established to predict GEO electron fluxes. However, the relative contributions of different solar wind parameters on GEO electron fluxes are still unclear. Recently, a feature attribution method, Deep SHapley Additive exPlanations (Deep SHAP) is proposed to open black boxes of machine learning models. In this study, we use the Deep SHAP method to quantify contributions of different solar wind parameters with an artificial neural network (ANN) model. Backpropagating the prediction results of this ANN model from 2011 to 2020, SHAP values for four solar wind parameters (interplanetary magnetic field (IMF) BZ, solar wind speed, solar wind dynamic pressure, and proton density) are calculated and comprehensively analyzed. The results suggest that solar wind speed with a lag of 1 day is the most important driver. We further investigate relative roles of different parameters in three specific electron fluxes variation events (corresponding to electron fluxes reaching a local maximum, a local minimum, and unchanged, respectively). The results suggest that high solar wind speed and southward IMF BZ (high dynamic pressures) facilitate increases (decreases) of electron fluxes. These findings help reveal the underlying physical mechanisms of GEO electron dynamics and help develop more accurate prediction models for GEO electron fluxes.

Hydrodynamic Response of Semi-Submersible FOWT Floaters: A Numerical Investigation of Wave and Mooring Parameter Dependencies

Floating wind turbines have enormous potential in harnessing high wind speeds in deep ocean locations. Compared with bottom-fixed technology, the latter is limited by the depth to which it can be installed. These turbines are designed to be deployed in deep waters and rely on specialized floaters such as spar buoys, semi-submersibles, and tension leg platforms to provide structural support. These floaters are tethered to the seabed using mooring lines, which regulate their movements and maintain stability. However, the existing literature lacks in-depth studies that comprehensively analyze how waves and mooring lines impact the motion of a semi-submersible floater. To address this gap, computational fluid dynamics (CFD) simulations are conducted using the overset methodology to replicate the actual loads experienced by semi-submersible floaters accurately. The study accurately predicts the six degrees of freedom (DOF) of the platform’s motion. The mooring lines are modeled using static or moving boundaries, and their interaction with the floater surface has been modeled using contact forces. The approach can simulate the impact of waves and mooring lines on the floater’s motion. The study uses the specifications depicted in the OC5 semi-submersible platform with mooring in test conditions and compares it with available experimental data to validate the numerical model. Once validated, the model is used to explore the hydrodynamic behavior of the floating structure across a range of waves characterized by varying amplitudes, periods, and directions. Similarly, in the case of the mooring lines, variations in critical parameters such as stiffness, pre-tension, and free length are introduced. This systematic manipulation of parameters enables a comprehensive investigation into their respective impacts on the dynamic response and motion of the floating platform.

Stagnation of Eddy Kinetic Energy After Summer Monsoon Onset in the South China Sea

AbstractThe monsoon is the primary force behind the upper‐layer circulation system and regulates eddy activity in the South China Sea (SCS). Using satellite observations and a state‐of‐the‐art oceanic reanalysis, this study examines transferring processes of eddy kinetic energy (EKE) during the SCS Summer Monsoon (SCSSM) onset (20th May on average). The SCSSM onset transforms surface winds from easterly to southwesterly, increasing EKE in the southwestern SCS by surface wind work. Despite the persistent energy input from wind work, EKE growth ceases during the first 20 days after SCSSM onset. An EKE budget analysis suggests that most energy input dissipates in the mixed layer due to the high wind speed, which explains the EKE stagnation. Additionally, eddy‐mean flow interactions transfer kinetic energy from eddies to mean flows during the SCSSM onset. The Vietnam coastal upwelling system provides available potential energy to EKE on the offshore side through buoyancy work. Our study reveals energy‐transferring processes from the summer monsoon to eddy activity and dissipation in the SCS, with implications for understanding multiscale dynamic evolutions during the monsoon transition.

Comparative Analysis of Indoor Air Quality in Coal Mining Communities During Wet and Dry Seasons in the Coal Mining Belt of Kogi East, Nigeria

This study investigates the indoor air quality in coal mining communities during wet and dry seasons in the coal mining belt of Kogi East, Kogi State, Nigeria. The research was conducted at selected coal mining sites, specifically the Ika-Ogboyaga and Okaba mine sites, using a randomized sampling method. Indoor air quality data were collected from fifteen households in Ika and Odele villages within a 500-meter radius of the mining sites. Monitoring was performed using the Gasman autosampler to measure concentrations of nitrogen dioxide (NO₂), sulphur dioxide (SO₂), carbon monoxide (CO), hydrogen sulphide (H₂S), and particulate matter (PM₂.5 and PM₁₀). Data collection spanned 7 days each for the wet season (October 2022) and the dry season (February 2023), with measurements taken thrice daily. Meteorological parameters such as temperature, wind speed, wind direction, and relative humidity were also recorded. The results indicated higher pollutant concentrations during the dry season. For instance, PM₂.5 levels in Ika during the wet season were 45.3±0.25 μg/m³ (morning), 74.6±0.49 μg/m³ (afternoon), and 56.26±0.1 μg/m³ (evening), while dry season values were 48.32±1.74 μg/m³ (morning), 74.12±0.30 μg/m³ (afternoon), and 56.9±0.75 μg/m³ (evening). Similarly, PM₁₀ levels in Ika during the wet season were 73.61±1.44 μg/m³ (morning), 105.53±0.44 μg/m³ (afternoon), and 99.01±0.5 μg/m³ (evening), whereas dry season values were 75.47±0.70 μg/m³ (morning), 102.08±1.48 μg/m³ (afternoon), and 96.98±1.33 μg/m³ (evening). CO concentrations in Ika during the wet season were 4.22±0.22 ppm (morning), 6.13±0.3 ppm (afternoon), and 3.1±0.05 ppm (evening), and during the dry season, they were 5.55±1.74 ppm (morning), 8.11±1.46 ppm (afternoon), and 7.04±1.184 ppm (evening). Meteorological analysis showed that the dry season had higher wind speeds (2-4 m/s) compared to the wet season (0-2 m/s), and lower relative humidity (mean of 51.18%) compared to the wet season (mean of 77.55%). Air Quality Index (AQI) values indicated that PM₂.5 levels in both seasons were unhealthy (155.8-156.4 in the wet season and 151-200 in the dry season), while PM₁₀ levels were moderate (65.5-66.9 in the wet season and 51-100 in the dry season). CO, NO₂, and SO₂ levels generally remained within permissible limits set by the World Health Organization (WHO). Statistical analysis revealed significant seasonal variations in the concentrations of the monitored pollutants, with higher levels typically recorded during the dry season.

Characteristics of new particle formation events occurred over the Yellow Sea in Springtime from 2019 to 2022

Characteristics of atmospheric new particle formation (NPF) events were investigated using the data obtained from the ship measurement campaign named Yellow Sea Air Quality (YES-AQ) over the Yellow Sea during the springtime from 2019 to 2022. NPF events occurred 15 times for the valid 128 observation days for the four-year period, and the average and standard deviation formation rate (FR) and growth rate (GR) of the NPF events were 2.38 ± 1.53 cm−3 s−1 and 4.11 ± 2.81 nm h−1, respectively. The FR and GR were close to those in urban regions, implying the unique characteristics of the Yellow Sea. Owing to the NPF events, the number concentrations of total aerosols and nucleation mode particles increased by approximately 7850 and 6002 cm−3, respectively, and those of cloud condensation nuclei at 0.2% and 0.6% supersaturation increased by about 1269 and 3269 cm−3, respectively. The NPF events mostly occurred under the meteorological conditions of low temperature and relative humidity as well as high solar radiation and wind speed. These meteorological conditions appeared predominantly when the air mass originated from the continent north of the Korean Peninsula. The current analyses based on the data measured repeatedly during a specific period each year, which were not well conducted in other maritime NPF studies, highlight the reliability of the presented characteristics of NPF events over the Yellow Sea.

Influence of climate extremes on long-term changes in cyanobacterial blooms in a eutrophic and shallow lake

Climate change and human activities have crucial effects on the variations in phytoplankton blooms in lakes worldwide. A record-breaking heatwave and drought event was reported in the middle and lower reaches of the Yangtze River during the summer of 2022, but only little is known about how cyanobacterial blooms in lakes respond to such climate extremes. Here, we utilized MODIS images to generate the area, occurrence, and initial blooming date (IBD) of cyanobacterial blooms in Lake Chaohu from 2000 to 2022. We found that the area and occurrence of cyanobacterial blooms were largely reduced. At the same time, the IBD was delayed in 2022 compared with the previous 20 years. The annual occurrence and mean area of cyanobacterial blooms in 2022 were 17 % and 23.1 km2, respectively, which were the lowest reported levels since the 21st century. The IBD in 2022 was four months late compared with the IBD in 2020. The high wind speed in spring delayed the spring blooms in 2022. The record-breaking heatwaves and drought from June to August reduced the blooms by influencing the growth of cyanobacteria and reducing the flow of nutrients from the watershed into the lake. This study highlights the compound impact of heatwave and drought climate events on reducing cyanobacterial blooms in a long-term period, enhancing additional understanding of the changes in phytoplankton blooms in lakes.

The Arctic marine soundscape of the Amundsen Gulf, Western Canadian Arctic

The underwater soundscape, a habitat component for Arctic marine mammals, is shifting. We examined the drivers of the underwater soundscape at three sites in the Amundsen Gulf, Northwest Territories, Canada from 2018 to 2019 and estimated the contribution of abiotic and biotic sources between 20 Hz and 24 kHz. Higher wind speeds and the presence of bearded seal (Erignathus barbatus) vocalizations led to increased SPL (0.41 dB/km/h and 3.87 dB, respectively), while higher ice concentration and air temperature led to decreased SPL (−0.39 dB/% and − 0.096 dB/°C, respectively). Other marine mammals did not significantly impact the ambient soundscape. The presence of vessel traffic led to increased SPLs (12.37 dB) but was quieter at distances farther from the recorder (−2.57 dB/log m). The presence of high frequency and broadband signals produced by ice led to increased SPLs (7.60 dB and 10.16 dB, respectively).

The multiscale variability of global extreme wind and wave events and their relationships with climate modes

Extreme winds and waves threaten human life, property security, infrastructure, and marine engineering. Persistent extreme wind events (EWiEs) and extreme wave events (EWaEs) can cause more significant impacts and destruction than short-term or instantaneous extreme events. This study defines an EWiE (EWaE) as a prolonged discrete event characterized by abnormally high wind speeds (significant wave heights). The climatological characteristics, spatiotemporal variability, and long-term trends of EWaEs and EWiEs globally are studied utilizing ERA5 reanalysis datasets from 1940 to 2021. The climatological mean characteristics of EWiEs and EWaEs are generally similar: extratropical regions exhibit high intensities, high counts, and short durations, whereas tropical regions are characterized by weak intensities, low counts, and long durations. The count and duration of EWaEs have significantly increased globally, with the greatest rate in the equatorial Pacific Ocean, where the count of events has increased by more than 2.1/decade and the duration by more than 7.2 h/decade. Furthermore, the Southern Annular Mode (SAM) exhibits a significant positive correlation with the count and duration of EWaEs in the eastern Pacific and Southern Oceans. In the Southern Hemisphere at 0–30°S, the Atlantic Multidecadal Oscillation (AMO) shows a significant positive correlation with the count of EWaEs and EWiEs.

Estimating Fire Radiative Energy Density with Repeat-Pass Aerial Thermal-Infrared Imaging of Actively Progressing Wildfires

Studies on estimating cumulative fire intensity from spreading wildland fires based on fire radiative energy density (FRED) have primarily been conducted through controlled experiments. The objective of this study was to assess the potential for estimating FRED for freely-burning wildfires at landscape scales. Airborne thermal infrared image sequences collected 8 and 9 December 2017 during the Thomas Fire were used for surface temperature derivation and FRED estimation. Sensitivity of varying ambient temperatures, and a newly developed method that adjusts for ash radiances on fire radiative flux density (FRFD) and FRED estimates were tested. Pixel-level image classification was run to identify FRFD time sequences that were complete or incomplete because of cloud obscuration and provided the basis for an obscuration gap filling technique. Variations in estimated ambient temperature used to estimate FRFD had little impact on FRED estimates, while our ash adjustment led to notable differences. An exponential decay model characterized FRFD time sequences well, providing a basis for gap filling irregular sequences caused by atmospheric obscuration. FRED estimates were regressed on rate of spread (ROS) magnitudes and found to be positively and significantly correlated. FRED magnitudes were higher on 9 December when the Thomas Fire burned under higher wind speeds and lower relative humidity levels (Santa Ana weather conditions) than on 8 December.

Wind as a Driver of Peat CO2 Dynamics in a Northern Bog.

The online version contains supplementary material available at 10.1007/s10021-024-00904-1.

Characterization of 21 years of dust events across four West Texas regions

Dust events are caused by strong winds that lift dust particles into the air. Due to surrounding deserts and agriculture, West Texas experiences many dust events. This study examines dust events that occurred between 2000 and 2020 across four locations: Amarillo, Lubbock, Midland, and El Paso. A total of 1,834 dust events were identified across the four locations with an average of 22 dust events annually. 227 dust events were observed in Amarillo, 609 in Lubbock, 545 in Midland, and 453 dust events were observed in El Paso. A slight increasing trend of dust events over time was observed for Amarillo, Lubbock, and Midland while El Paso showed a decreasing trend. Most dust events occurred during the spring to early summer months and they lasted an hour or less. Many dust events occurred during times of drought and periods of La Niña. Separation of the dust events based on the meteorological disturbance that caused them (convective vs. synoptic) showed that synoptic disturbances contribute to >60 % of the dust events, while convective disturbances were responsible for most of the remaining. Synoptic disturbances were predominately in spring while convective disturbances were common in the early summer months. A comparison of meteorological parameters measured during each disturbance shows that synoptic dust events were associated with lower temperatures, dew point, and relative humidity, but with higher wind speeds and gusts.

Association between synoptic types in Beijing and acute myocardial infarction hospitalizations: A comprehensive analysis of environmental factors

BackgroundEnvironmental factors like air pollution and temperature can trigger acute myocardial infarction (AMI). However, the link between large-scale weather patterns (synoptic types) and AMI admissions has not been extensively studied. This research aimed to identify the different synoptic air types in Beijing and investigate their association with AMI occurrences. MethodsWe analyzed data from Beijing between 2013 and 2019, encompassing 2556 days and 149,632 AMI cases. Using principal component analysis and hierarchical clustering, classification into distinct synoptic types was conducted based on weather and pollution measurements. To assess the impact of each type on AMI risk over 14 days, we employed a distributed lag non-linear model (DLNM), with the reference being the lowest risk type (Type 2). ResultsFour synoptic types were identified: Type 1 with warm, humid weather; Type 2 with warm temperatures, low humidity, and long sunshine duration; Type 3 with cold weather and heavy air pollution; and Type 4 with cold temperatures, dryness, and high wind speed. Type 4 exhibited the greatest cumulative relative risk (CRR) of 1.241 (95%CI: 1.150, 1.339) over 14 days. Significant effects of Types 1, 3, and 4 on AMI events were observed at varying lags: 4–12 days for Type 1, 1–6 days for Type 3, and 1–11 days for Type 4. Females were more susceptible to Types 1 and 3, while individuals younger than 65 years old showed increased vulnerability to Types 3 and 4. ConclusionAmong the four synoptic types identified in Beijing from 2013 to 2019, Type 4 (cold, dry, and windy) presented the highest risk for AMI hospitalizations. This risk was particularly pronounced for males and people under 65. Our findings collectively highlight the need for improved methods to identify synoptic types. Additionally, developing a warning system based on these synoptic conditions could be crucial for prevention.

Benefits Availed and Constraints Faced by Beneficiaries of Jalasamrudhi, Project, Thiruvananthapuram

The study analysed the benefits availed and constraints faced by beneficiaries of Jalasamrudhi Project, Thiruvananthapuram. A systematic sampling technique was adopted for the data collection and information was collected from 80 beneficiaries of the project, thus making the total sample size 80. The farmers responded to the benefits availed and the constraints were ranked using Garrett ranking technique. The respondents benefitted from increase in ground water table level, market and non- market benefits. The major constraints faced by the beneficiaries were crop loss due to high speed wind, pests and climate change, followed by non-availability of inputs and non- availability of subsidy on time, lack of technical guidance. The primary suggestion from beneficiary farmers was to ensure continuity and follow-up, increase the project period from 5 to 10 years and ensure better infrastructure facilities to improve the effectiveness of the project.

Seasonal change and influence of environmental variables on host-seeking activity of the biting midge Culicoides sonorensis at a southern California dairy, USA

BackgroundAs a primary vector of bluetongue virus (BTV) in the US, seasonal abundance and diel flight activity of Culicoides sonorensis has been documented, but few studies have examined how time of host-seeking activity is impacted by environmental factors. This knowledge is essential for interpreting surveillance data and modeling pathogen transmission risk.MethodsThe diel host-seeking activity of C. sonorensis was studied on a California dairy over 3 years using a time-segregated trap baited with CO2. The relationship between environmental variables and diel host-seeking activity (start, peak, and duration of activity) of C. sonorensis was evaluated using multiple linear regression. Fisher’s exact test and paired-sample z-test were used to evaluate the seasonal difference and parity difference on diel host-seeking activity.ResultsHost-seeking by C. sonorensis began and reached an activity peak before sunset at a higher frequency during colder months relative to warmer months. The time that host-seeking activity occurred was associated low and high daily temperature as well as wind speed at sunset. Colder temperatures and a greater diurnal temperature range were associated with an earlier peak in host-seeking. Higher wind speeds at sunset were associated with a delayed peak in host-seeking and a shortened duration of host-seeking. Parous midges reached peak host-seeking activity slightly later than nulliparous midges, possibly because of the need for oviposition by gravid females before returning to host-seeking.ConclusionsThis study demonstrates that during colder months C. sonorensis initiates host-seeking and reaches peak host-seeking activity earlier relative to sunset, often even before sunset, compared to warmer months. Therefore, the commonly used UV light-baited traps are ineffective for midge surveillance before sunset. Based on this study, surveillance methods that do not rely on light trapping would provide a more accurate estimate of host-biting risk across seasons. The association of environmental factors to host-seeking shown in this study can be used to improve modeling or prediction of host-seeking activity. This study identified diurnal temperature range as associated with host-seeking activity, suggesting that Culicoides may respond to a rapidly decreasing temperature by shifting to an earlier host-seeking time, though this association needs further study.Graphical

Model development and preliminary study of the concentrated-radiative cooling based thermoelectric generator

Photovoltaic (PV) cells, widely adopted in solar energy applications, achieve a maximum efficiency of only 30 % and remain inactive during nighttime. In contrast, solar-thermal power generation has surpassed 50 % efficiency. To address these limitations, we introduce the Solar- Radiative cooling -Thermoelectric system (Solar-RC-TE), integrating solar energy, radiative cooling (RC), and thermoelectric power generation. This system enhances energy density, reduces consumption, lowers costs, and minimizes environmental impact while enabling nighttime power generation. For the optimization of the Solar-RC-TE model to further improve power generation efficiency, we employ the comprehensive three-dimensional methodology of COMSOL, considering material properties, structural configurations, and environmental factors. Research findings reveal that a 710 mm × 710 mm radiative cooling film can generate 386.12 mV of voltage on the thermoelectric generator (TEG). Environmental factors, such as increased solar irradiance, lead to temperature elevation, affecting efficiency. Overheating and higher wind speeds also contribute to decreased TEG efficiency. Regarding materials, improving the thermoelectric figure of merit (ZT) and film emissivity positively impact power generation efficiency. Elevating the film emissivity from 0.7 to 0.89 significantly enhances performance by 1.2 %. These outcomes provide a tangible and practical solution for addressing energy crises and environmental concerns.