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Matsyura, Alex, Kazimierz Jankowski, and Marina Matsyura. "BIRDS’ FLIGHT ENERGY PREDICTIONS AND APPLICATION TO RADAR-TRACKING STUDY." Biological Bulletin of Bogdan Chmelnitskiy Melitopol State Pedagogical University 3, no. 03 (October 28, 2013): 135. http://dx.doi.org/10.15421/20133_45.
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<p>In offered research, we propose to observe diurnal soaring birds to check, whether there the positions of birds in formations are such, that the wing tip interval and depth meet the predictions of aerodynamic theory for achievement of maximal conservation of energy or predictions of the hypothesis of communication. We also can estimate, whether adverse conditions of a wind influence the ability of birds to support formation. We can assume that windy conditions during flight might make precision flight more difficult by inducing both unpredictable bird and vortex positions. To this, we need to found change in wing-tip spacing variation with increasing wind speed, suggesting or rejecting that in high winds bird skeins maintained similar variation to that on calm days. The interrelation between variation of mean depth and wind speed should prove this hypothesis. Little is known about the importance of depth, but in high winds the vortex is likely to break up more rapidly and its location become unpredictable the further back a bird flies; therefore, a shift towards skeins with more regular depths at high wind speeds may compensate for the unpredictability of the vortex locations. Any significant relationship between the standard deviation of wing-tip spacing and wind speed suggests that wind has a major effect on optimal positioning.</p> <p>Results of proposed study will be used also as the auxiliary tool in radar research of bird migration, namely in research of flight features of soaring birds. It is extremely important to determine all pertinent characteristics of flock for model species, namely flocking birds.</p> <p><em>Kew words: birds, flock, radar, flight</em></p><p> </p>
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Mandelbaum, R. "Reap the wild wind [offshore wind farm]." IEEE Spectrum 39, no. 10 (October 2002): 34–39. http://dx.doi.org/10.1109/mspec.2002.1038567.
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Bradley, Stuart, and Alexander Strehz. "Corrections to sodar Doppler winds due to wind drift." Meteorologische Zeitschrift 24, no. 6 (November 5, 2015): 605–14. http://dx.doi.org/10.1127/metz/2014/0627.
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Edwards, Susan. "The wild west wind." Women & Performance: a journal of feminist theory 10, no. 1-2 (January 1999): 277–90. http://dx.doi.org/10.1080/07407709908571306.
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Andreas, Edgar L., and Larry Mahrt. "On the Prospects for Observing Spray-Mediated Air–Sea Transfer in Wind–Water Tunnels." Journal of the Atmospheric Sciences 73, no. 1 (December 21, 2015): 185–98. http://dx.doi.org/10.1175/jas-d-15-0083.1.
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Abstract Nature is wild, unconstrained, and often dangerous. In particular, studying air–sea interaction in winds typical of tropical cyclones can place researchers, their instruments, and even their research platforms in jeopardy. As an alternative, laboratory wind–water tunnels can probe 10-m equivalent winds of hurricane strength under conditions that are well constrained and place no personnel or equipment at risk. Wind–water tunnels, however, cannot simulate all aspects of air–sea interaction in high winds. The authors use here the comprehensive data from the Air–Sea Interaction Salt Water Tank (ASIST) wind–water tunnel at the University of Miami that Jeong, Haus, and Donelan published in this journal to demonstrate how spray-mediated processes are different over the open ocean and in wind tunnels. A key result is that, at all high-wind speeds, the ASIST tunnel was able to quantify the so-called interfacial air–sea enthalpy flux—the flux controlled by molecular processes right at the air–water interface. This flux cannot be measured in high winds over the open ocean because the ubiquitous spray-mediated enthalpy transfer confounds the measurements. The resulting parameterization for this interfacial flux has implications for modeling air–sea heat fluxes from moderate winds to winds of hurricane strength.
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Khaghaninia, S., S. Mohammadi, A. Srafrazi, K. Nejad, and R. Zahiri. "Geometric Morphometric Study on Geographic Dimorphism of Coding Moth Cydia Pomonella (Lepidoptera, Tortricidae) from North West of Iran." Vestnik Zoologii 45, no. 5 (January 1, 2011): e-20-e-28. http://dx.doi.org/10.2478/v10058-011-0028-z.
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Geometric Morphometric Study on Geographic Dimorphism of Coding MothCydia Pomonella(Lepidoptera, Tortricidae) from North West of IranDuring years 2003-2004, nine geographical populations of codling moth Cydia pomonella (Linnaeus) from 4 north western provinces of Iran were collected. By preparing 575 images from fore wings and 564 from hind wings, a total of 15 and 11 landmarks were determined for fore and hind wings, respectively. With transforming of landmark's geometrical data into partial warp scores, 26 and 18 scores were obtained for fore and hind wings, respectively. Canonical correlation analysis (CCA) revealed significant correlation between environmental parameters and wing shape variables. Among environmental parameters, wind speed showed the highest correlation with wing shape variables whereas, the correlation between latitude, relative humidity as well as amount of precipitation and wing shape variables was low. Considering the effect of various environmental parameters on wing shape, wind speed was determined as important parameter affecting geographic dimorphism. Among the populations collected from different regions, two geographic population pairs; Meshkinshahr-Mahneshan and Zandjan-Khoramdareh were selected as representative of low and high windy regions, respectively. Relative warp analysis (RWA) of fore and hind wings shape variables in the areas with high and low wind showed shorter and wider fore wings as well as slender and narrower hind wings in populations from high windy regions compared with populations from low wind regions. Centroid size of fore and hind wings in high windy area populations were smaller compared with those from low windy ones as revealed by t-test. The results showed aerodynamic shape and small size of wings are as adapted traits for powerful flight and its control in high windy regions.
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Rehman, Shafiqur, Kashif Irshad, Nasiru I. Ibrahim, Ali AlShaikhi, and Mohamed A. Mohandes. "Offshore Wind Power Resource Assessment in the Gulf of North Suez." Sustainability 15, no. 21 (October 25, 2023): 15257. http://dx.doi.org/10.3390/su152115257.
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Growing population, industrialization, and power requirements are adversely affecting the environment through increased greenhouse gases resulting from fossil fuel burning. Global greenhouse gas mitigation targets have led nations to promote clean and self-renewable sources of energy to address this environmental issue. Offshore wind power resources are relatively more attractive due to high winds, less turbulence, minimal visualization effects, and no interaction of infrastructure. The present study aims at conducting an offshore wind power resource assessment (OWPRA) at some locations in the Gulf of North Suez. For this purpose, the long-term hourly mean wind speed (WS) and wind direction above mean sea level (AMSL), as well as temperature and pressure data near the surface, are used. The data is obtained from ERA5 (fifth generation global climate reanalysis) at six (L1–L6) chosen offshore locations. The data covers a period of 43 years, between 1979 and 2021. The WS and direction are provided at 100 m AMSL, while temperature and pressure are available near water-surface level. At the L1 to L6 locations, the log-term mean WS and wind power density (WPD) values are found to be 7.55 m/s and 370 W/m2, 6.37 m/s and 225 W/m2, 6.91 m/s and 281 W/m2, 5.48 m/s and 142 W/m2, 4.30 m/s and 77 W/m2, and 5.03 and 115 W/m2 and at 100 m AMSL, respectively. The higher magnitudes of monthly and annual windy site identifier indices (MWSI and AWSI) of 18.68 and 57.41 and 12.70 and 42.94 at the L1 and L3 sites, and generally lower values of wind variability indices, are indicative of a favorable winds source, which is also supported by higher magnitudes of mean WS, WPD, annual energy yields, plant capacity factors, and wind duration at these sites. The cost of energy for the worst and the best cases are estimated as 10.120 USD/kWh and 1.274 USD/kWh at the L5 and L1 sites, corresponding to wind turbines WT1 and WT4. Based on this analysis, sites L1, L3, and L2 are recommended for wind farm development in order of preference. The wind variability and windy site identifier indices introduced will help decision-makers in targeting potential windy sites with more confidence.
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Wiegel, R. L. "WIND WAVES AND SWELL." Coastal Engineering Proceedings 1, no. 7 (January 29, 2011): 1. http://dx.doi.org/10.9753/icce.v7.1.
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Winds blowing over the water surface generate waves. In general the higher the wind velocity, the larger the fetch over which it blows, and the longer it blows the higher and longer will be the average waves . Waves still under the action of the winds that created them are called wind waves, or a sea. They are forced waves rather than free waves. They are variable in their direction of advance (Arthur, 1949). They are irregular in the direction of propagation. The flow is rotational due to the shear stress of the wind on the water surface and it is quite turbulent as observations of dye in the water indicates. After the waves leave the generating area their characteristics become somewhat different, principally they are smoother, losing the rough appearance due to the disappearance of the multitude of smaller waves on top of the bigger ones and the whitecaps and spray. When running free of the storm the waves are known as swell. In Fig. 1 are shown some photographs taken in the laboratory of waves still rising under the action of wind and this same wave system after it has left the windy section of the wind-wave tunnel. It can be seen thati-the freely running swell has a smoother appearance than the waves in the windy section. The motion of the swell is nearly irrotational and nonturbulent, unless the swell runs into other regions where the water is in turbulent motion. Turbulence is a property of the fluid rather than of the wave motion. After the waves have travelled a distance from the generating area they have lost some energy due to air resistance, internal friction, and by large scale turbulent scattering if they run into other storm areas, and the rest of the energy has become spread over a larger area due to the dispersive and angular spreading characteristics of water gravity waves. All of these mechanisms lead to a decrease in energy density. Thus, the waves become lower in height. In addition, due to their dispersive characteristic the component wave periods tend to segregate in such a way that the longest waves lead the main body of waves and the shortest waves form the tail of the main body of waves. Finally, the swell may travel through areas where winds are present, adding new wind waves to old swell, and perhaps directly increasing or decreasing the size of the old swell.
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Darbandi, Masoud, Hossein Salemkar, Ali Behrouzifar, and Bagher Abrar. "CFD Simulation of Natural Draught Cooling Tower Wind-Covering." Applied Mechanics and Materials 307 (February 2013): 279–84. http://dx.doi.org/10.4028/www.scientific.net/amm.307.279.
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Past experiences have shown that a local wind can considerably affect the performances of powerplant cooling towers and factory chimneys. In thermal powerplants, the performance of Rankin cycles would reduce if the temperature of its condenser increases. This issue is very important to powerplants located in countries with strong local winds. To remedy the mal-performance of a natural cooling tower in windy conditions, it is required to understand the physics of flow around cooling towers more clearly. One adverse physics is known as the wind covering problem which can drastically affect the natural draught through a cooling tower in windy conditions. In this paper, we focus on wind-covering problem and its adverse impact on a real natural draught cooling tower. Contrary to the past studies, we show that wind can generally affect either positively or negatively in cooling tower performances. Surprisingly, the positive and negative roles can simultaneously occur in most times. In this paper, we use computational fluid dynamics tool to quantify the positive and negative impacts of wind on natural draught flow through dry cooling towers.
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Ni, Weicheng, Ad Stoffelen, Kaijun Ren, Xiaofeng Yang, and Jur Vogelzang. "SAR and ASCAT Tropical Cyclone Wind Speed Reconciliation." Remote Sensing 14, no. 21 (November 2, 2022): 5535. http://dx.doi.org/10.3390/rs14215535.
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Wind speed reconciliation across different wind sources is critically needed for extending available satellite wind records in Tropical Cyclones. The deviations between wind references of extremes, such as the moored buoy data and dropsonde wind estimates for guidance on geophysical model function development, are one of the main causes of wind speed differences for wind products, for instance, the overestimation of Synthetic Aperture Radars (SARs) relative to ASCAT winds. The study proposes a new wind speed adjustment to achieve mutual adjustment between ASCAT CMOD7 winds and simultaneous SAR wind speeds. The so-called CMOD7D-v2 adjustment is constructed based on the statistical analysis of SAR and ASCAT Tropical Cyclone acquisitions between 2016 and 2021, showing a satisfactory performance in wind speed reconciliation for winds with speeds higher than 14 m/s. Furthermore, the error characteristics of the CMOD7D-v2 adjustment for Tropical Cyclone winds are analyzed using the Triple Collocation analysis technique. The analysis results show that the proposed wind adjustment can reduce ASCAT wind errors by around 16.0% when adjusting ASCAT winds to SAR wind speeds. In particular, when downscaling SAR winds, the improvement in ASCAT wind errors can be up to 42.3%, effectively alleviating wind speed differences across wind sources. Furthermore, to avoid the impacts of large footprints by ASCAT sensors, wind speeds retrieved from SAR VV signals (acting as a substitute for ASCAT winds) are adjusted accordingly and compared against SAR dual-polarized winds and collocated Stepped Frequency Microwave Radiometer (SFMR) observations. We find that the bias values of adjusted winds are lower than products from other adjustment schemes by around 5 m/s at the most extreme values. These promising results verify the plausibility of the CMOD7D-v2 adjustment, which is conducive to SAR and ASCAT wind speed comparisons and extreme wind analysis in Tropical Cyclone cases.
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Xue, Yiwei, and Miao Wei. "Travel with the Wild Wind." Chinese Literature Today 9, no. 2 (July 2, 2020): 46–47. http://dx.doi.org/10.1080/21514399.2020.1851964.
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Dillon, Dennis. "Making the Wild Wind Visible." Journal of Library Administration 28, no. 1 (June 1999): 47–61. http://dx.doi.org/10.1300/j111v28n01_05.
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Müller, Regine. "NEUER WIND in WINDY CITY." Opernwelt 64, no. 2 (2023): 62–63. http://dx.doi.org/10.5771/0030-3690-2023-2-062.
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Seit 2021 ist ENRIQUE MAZZOLA Music Director der Lyric Opera of Chicago, dem zweitgrößten Opernhaus der USA. Sein Ziel ist es, alle gesellschaftlichen Gruppen zu begeistern. Ein Anfang ist gemacht. Eine Reportage VON REGINE MÜLLER «Es gibt eine afroamerikanische Community, eine asiatische, eine polnische – Chicago ist nach Warschau die zweitgrößte polnische Stadt! – und viele andere mehr.»
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Kim, Hyungkyoo, and Elizabeth Macdonald. "Wind and the city: An evaluation of San Francisco’s planning approach since 1985." Environment and Planning B: Urban Analytics and City Science 44, no. 1 (July 28, 2016): 10–32. http://dx.doi.org/10.1177/0265813515607474.
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In 1985, San Francisco adopted a downtown plan on ground-level wind currents intended to mitigate the negative effects of wind on pedestrians’ perceived comfort in public open spaces. The plan mandates that new buildings in designated parts of the city associated with high density or development potential be designed or adopt measures to not cause wind in excess of accepted comfort levels. This study examines whether and to what degree the plan has successfully shaped an urban form that mitigates wind by comparing the ground-level wind environment in 1985 and 2013. A series of wind tunnel tests found that during San Francisco’s windiest season when the westerly winds are prevalent, the overall mean wind speed ratio measured at 318 locations in four areas of the city dropped by 22%. However, there still exist many excessively windy places that are associated with specific urban form conditions, including streets oriented to have direct exposure to westerly winds, flat façades on high-rise buildings, and horizontal street walls where building façades align. Recommendations based on the findings include incorporating more tangible guidance on the built form conditions, expanding the plan’s reach to cover more parts of the city, and learning from strategies used elsewhere. By evaluating the urban form impacts of a wind mitigation policy that has been in place for 30 years, the research offers insights for other cities that have implemented or plan to adopt similar approach and sheds light on issues related to wind comfort in high-density urban areas.
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Wang, Xiaochun, Tong Lee, and Carl Mears. "Evaluation of Blended Wind Products and Their Implications for Offshore Wind Power Estimation." Remote Sensing 15, no. 10 (May 18, 2023): 2620. http://dx.doi.org/10.3390/rs15102620.
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The Cross-Calibrated Multi-Platform (CCMP) wind analysis is a satellite-based blended wind product produced using a two-dimensional variational method. The current version available publicly is Version 2 (CCMP2.0), which includes buoy winds in addition to satellite winds. Version 3 of the product (CCMP3.0) is being produced with several improvements in analysis algorithms, without including buoy winds. Here, we compare CCMP3.0 with a special version of CCMP2.0 that did not include buoy winds, so both versions are independent of buoy measurements. We evaluate them using wind data from buoys around the coasts of the United States and discuss the implications for the wind power industry and offshore wind farms. CCMP2.0 uses ERA-Interim 10 m winds as the background to fill observational gaps. CCMP3.0 uses ERA5 10 m neutral winds as the background. Because ERA5 winds are biased towards lower values at higher wind conditions, CCMP3.0 corrected this bias by matching ERA5 wind speeds with satellite scatterometer wind speeds using a histogram matching method. Our evaluation indicates that CCMP3.0 has better agreement with the independent buoy winds, primarily for higher winds (>10 m/s). This is reflected by the higher correlation and lower root-mean-squared differences of CCMP3.0 versus buoy winds, especially for higher wind conditions. For the U.S. coastal region (within 200 km), the mean wind speed of CCMP3.0 is enhanced by 1–2%, and the wind speed standard deviation is enhanced by around 3–5%. These changes in wind speed and its standard deviation from CCMP2.0 to CCMP3.0 cause an 8–12% increase in wind power density. The wind power density along the U.S. coastal region is also correlated with various climate indices depending on locations, providing a useful approach for predicting wind power on subseasonal to interannual timescales.
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Fukumura, Keigo, Missagh Mehdipour, Ehud Behar, Chris Shrader, Mauro Dadina, Demosthenes Kazanas, Stefano Marchesi, and Francesco Tombesi. "Dual Role of Accretion Disk Winds as X-Ray Obscurers and UV Line Absorbers in AGN." Astrophysical Journal 968, no. 2 (June 1, 2024): 70. http://dx.doi.org/10.3847/1538-4357/ad435a.
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Abstract X-ray obscuration of active galactic nuclei (AGNs) is considered in the context of ionized winds of stratified structure launched from accretion disks. We argue that a Compton-thick layer of a large-scale disk wind can obscure continuum X-rays and also lead to broad UV absorption, such as in the blue wing of C iv; the former originates from the inner wind and the latter from the outer wind, as a dual role. Motivated by a number of lines of observational evidence showing strong AGN obscuration phenomena in Seyfert 1 AGNs such as NGC 5548, we demonstrate in this work, by utilizing a physically motivated wind model coupled to post-process radiative transfer calculations, that an extended disk wind under certain physical conditions (e.g., morphology and density) could naturally cause a sufficient obscuration qualitatively consistent with UV/X-ray observations. Predicted UV/X-ray correlation is also presented as a consequence of variable spatial size of the wind in this scenario.
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VIDELER, JOHN, and ALEX GROENEWOLD. "Field Measurements of Hanging Flight Aerodynamics in the Kestrel Falco Tinnunculus." Journal of Experimental Biology 155, no. 1 (January 1, 1991): 519–30. http://dx.doi.org/10.1242/jeb.155.1.519.
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Hunting kestrels were observed to hang, almost without wing-flapping, in fixed positions over a sea dike. The height and position with respect to the dike profile, the wind direction and velocity and the percentage of hunting time without wing beating were recorded in 429 cases. The vertical wind angle, θ, the wind speed and its horizontal direction were measured at 13 heights up to 8.8m above the windward slope, the top and the leeward slope of the dike under various wind conditions in 225 cases. These wind profile measurements were used to estimate 6 and wind speed near the hanging birds. Kestrels hanging more than 90% of the hunting time preferred a position 6.5±1.5m (S.D.) over the windward slope with sea winds blowing at 8.7±1.5ms−1 (S.D.) perpendicular (±30°) to the longitudinal dike axis. For these birds angle θ was approximately 6–7°. These angles are larger than expected from aerodynamic models and windtunnel measurements. The minimum gliding angle for a kestrel under steady conditions is estimated to be 5°. Hanging kestrels save two-thirds of the energy used during normal windhovering but have to spend 1.6 times more time to catch the same number of voles.
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Chen, Sina, Ari Laor, Ehud Behar, Ranieri D. Baldi, Joseph D. Gelfand, Amy E. Kimball, Ian M. McHardy, Gabor Orosz, and Zsolt Paragi. "Windy or Not: Radio Parsec-scale Evidence for a Broad-line Region Wind in Radio-quiet Quasars." Astrophysical Journal 975, no. 1 (October 23, 2024): 35. http://dx.doi.org/10.3847/1538-4357/ad74fc.
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Abstract Does a broad-line region (BLR) wind in radio-quiet (RQ) active galactic nuclei (AGN) extend to parsec scales and produce radio emission? We explore the correlations between a parsec-scale radio wind and the BLR wind in a sample of 19 RQ Palomar–Green quasars. The radio wind is defined based on the spectral slope and the compactness of the emission at 1.5–5 GHz, and the BLR wind is defined by the excess blue wing in the C iv emission line profile. The five objects with both radio and BLR wind indicators are found at high Eddington ratios, L/L Edd (≥0.66), and eight of the nine objects with neither radio nor BLR winds reside at low L/L Edd (≤0.28). This suggests that the BLR wind and the radio wind in RQ AGN are related to a radiation-pressure-driven wind. Evidence for free–free absorption by AGN photoionized gas, which flattens the spectral slope, is found in two objects. Radio outflows in three low-L/L Edd (0.05–0.12) objects are likely from a low-power jet, as suggested by additional evidence. The presence of a mild equatorial BLR wind in four intermediate-L/L Edd (0.2–0.4) objects can be tested with future spectropolarimetry.
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Carroll, Paula, Lucy Cradden, and Mícheál Ó hÉigeartaigh. "High Resolution Wind Power and Wind Drought Models." International Journal of Thermal and Environmental Engineering 16, no. 1 (August 9, 2018): 27–36. http://dx.doi.org/10.5383/ijtee.16.01.004.
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Yuan, Jianhui, Jixin Liu, Changcheng Li, and Zheng Zhao. "Numerical Study of Aircraft Wake Vortex Evolution under the Influence of Vertical Winds." Applied Sciences 14, no. 1 (December 21, 2023): 86. http://dx.doi.org/10.3390/app14010086.
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Separating wake vortices is crucial for aircraft landing safety and essential to airport operational efficiency. Vertical wind, as a typical atmospheric condition, plays a significant role, and studying the evolution characteristics of wake vortices under this condition is of paramount importance for developing dynamic wake separation systems. In this study, we employed the SST k-ω turbulence model based on an O-Block structured grid to numerically simulate the simplified wing model. We analyzed the variations in the wake vortex structure and parameters of the Airbus A320 during the near-field phase under different vertical wind directions and speeds. The results indicate that favorable vertical winds cause a “flattening” deformation in the wake vortex. Vertical winds reduce the initial vortex strength, accelerate the rate of vortex decay, and influence the trajectory of the vortex core. Notably, under wind speeds of 1~3 m/s, the decay rate is more significant than under 4 m/s. When vertical wind speeds are substantial, it can lead to irregular motion and interactions within the vortex core, forming secondary vortices.
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Massa, Derek, and Raman K. Prinja. "UV Wind Variability in B Supergiants and its Implications for Wind Structures." International Astronomical Union Colloquium 169 (1999): 214–17. http://dx.doi.org/10.1017/s0252921100072018.
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AbstractWe discuss why B supergiant winds are particularly well suited for wind studies, and present or refer to dynamic spectra which suggest the presence of disks, bifurcated winds, shock formation, rotationally modulated winds and the spontaneous generation of wind enhancements. They underscore the strength and richness of wind variability in B supergiants and the challenges these phenomena present to theoretical studies of stellar winds.
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Houston, Adam L., Roger J. Laurence, Tevis W. Nichols, Sean Waugh, Brian Argrow, and Conrad L. Ziegler. "Intercomparison of Unmanned Aircraftborne and Mobile Mesonet Atmospheric Sensors." Journal of Atmospheric and Oceanic Technology 33, no. 8 (August 2016): 1569–82. http://dx.doi.org/10.1175/jtech-d-15-0178.1.
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AbstractResults are presented from an intercomparison of temperature, humidity, and wind velocity sensors of the Tempest unmanned aircraft system (UAS) and the National Severe Storms Laboratory (NSSL) mobile mesonet (NSSL-MM). Contemporaneous evaluation of sensor performance was facilitated by mounting the Tempest wing with attached sensors to the NSSL-MM instrument rack such that the Tempest and NSSL-MM sensors could collect observations within a nearly identical airstream. This intercomparison was complemented by wind tunnel simulations designed to evaluate the impact of the mobile mesonet vehicle on the observed wind velocity.The intercomparison revealed strong correspondence between the temperature and relative humidity (RH) data collected by the Tempest and the NSSL-MM with differences generally within sensor accuracies. Larger RH differences were noted in the presence of heavy precipitation; however, despite the exposure of the Tempest temperature and humidity sensor to the airstream, there was no evidence of wet bulbing within precipitation. Wind tunnel simulations revealed that the simulated winds at the location of the NSSL-MM wind monitor were ~4% larger than the expected winds due to the acceleration of the flow over the vehicle. Simulated vertical velocity exceeded 1 m s−1 for tunnel inlet speeds typical of a vehicle moving at highway speeds. However, the theoretical noncosine reduction in winds that should result from the impact of vertical velocity on the laterally mounted wind monitor was found to be negligible across the simulations. Comparison of the simulated and observed results indicates a close correspondence, provided the crosswind component of the flow is small.
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Grewing, Michael. "Wind Features and Wind Velocities." Symposium - International Astronomical Union 131 (1989): 241–50. http://dx.doi.org/10.1017/s0074180900138434.
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Fast winds have been detected in the spectra of many nuclei of planetary nebulae (PNNi). The wind velocities range from about 600 km/s to roughly 4000 km/s. While these winds add little to the mass of the nebular shells they may significantly effect their internal kinematics.By studying the emission from the faint outer envelopes of PNe one can infer also the wind properties of the progenitors of the current nuclei. This will in the end allow to test quantitatively current models of the origin of PNe.
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Tian, Wei, Ahmet Ozbay, and Hui Hu. "A wind tunnel study of wind loads on a model wind turbine in atmospheric boundary layer winds." Journal of Fluids and Structures 85 (February 2019): 17–26. http://dx.doi.org/10.1016/j.jfluidstructs.2018.12.003.
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Schmidlin, PhD, Thomas W., Barbara O. Hammer, MA, Paul S. King, BS, L. Scott Miller, PhD, Gregory Thumann, MS, and Helene Wetherington, MA. "Determining critical wind speeds for overturning two types of ambulances and a large city bus." Journal of Emergency Management 3, no. 2 (March 1, 2005): 21. http://dx.doi.org/10.5055/jem.2005.0016.
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Two types of ambulances and a city bus were modeled in a wind tunnel for the minimum wind speed required to upset the stationary vehicles. The Type I ambulance was vulnerable to upset with wind speeds of 135 to 150 mph on the vehicle over wind angles of 40° to 145°. The Type II ambulance was vulnerable to upset with wind speeds of 140 to 170 mph over wind angles of 30° to 145°. The 40-passenger city bus was vulnerable to upset with wind speeds of 60 to 75 mph over wind angles of 35° to 145°. These results showed ambulances were more stable in high winds than common passenger vehicles, but the city bus was very vulnerable in high winds. Testing showed that moving ambulances can be driven at low speeds in minimal hurricane-force winds without exceeding the upset wind speeds on the vehicles. This information provides guidance for safe operation of these vehicles during high winds including hurricanes, thunderstorms, and extra-tropical cyclones.
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Faig Bayramova, Ulker. "Wind analysis at Ganja International Airport." SCIENTIFIC WORK 61, no. 12 (December 25, 2020): 162–65. http://dx.doi.org/10.36719/2663-4619/61/162-165.
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The article reviews wind conditions at Ganja International Airport and specifies the maximum winds observed during the month and the direction of the winds. The direction of the mean, maximum wind speed of the prevailing wind was analyzed. Based on our analysis, we can see that the prevailing wind direction isnortheast and the maximum speed was recorded in March. Key words: wind, temperature, aviation, wind rose, visibility
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Monahan, Adam H. "The Temporal Autocorrelation Structure of Sea Surface Winds." Journal of Climate 25, no. 19 (April 5, 2012): 6684–700. http://dx.doi.org/10.1175/jcli-d-11-00698.1.
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Abstract The temporal autocorrelation structures of sea surface vector winds and wind speeds are considered. Analyses of scatterometer and reanalysis wind data demonstrate that the autocorrelation functions (acf) of surface zonal wind, meridional wind, and wind speed generally drop off more rapidly in the midlatitudes than in the low latitudes. Furthermore, the meridional wind component and wind speed generally decorrelate more rapidly than the zonal wind component. The anisotropy in vector wind decorrelation scales is demonstrated to be most pronounced in the storm tracks and near the equator, and to be a feature of winds throughout the depth of the troposphere. The extratropical anisotropy is interpreted in terms of an idealized kinematic eddy model as resulting from differences in the structure of wind anomalies in the directions along and across eddy paths. The tropical anisotropy is interpreted in terms of the kinematics of large-scale equatorial waves and small-scale convection. Modeling the vector wind fluctuations as Gaussian, an explicit expression for the wind speed acf is obtained. This model predicts that the wind speed acf should decay more rapidly than that of at least one component of the vector winds. Furthermore, the model predicts a strong dependence of the wind speed acf on the ratios of the means of vector wind components to their standard deviations. These model results are shown to be broadly consistent with the relationship between the acf of vector wind components and wind speed, despite the presence of non-Gaussian structure in the observed surface vector winds.
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Liu, Tianshu, RS Vewen Ramasamy, Ryne Radermacher, William Liou, and David Moussa Salazar. "Oscillating-wing unit for power generation." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 233, no. 4 (September 19, 2018): 510–29. http://dx.doi.org/10.1177/0957650918790116.
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This paper describes an exploratory study of a nonconventional wind power converter with a pair of oscillating wings, which is called an oscillating-wing unit. The working principles of the oscillating-wing unit are described, including the aerodynamic models, kinematical, and dynamical models. The performance of the oscillating-wing unit is evaluated through computational simulations and the power scaling in comparison with conventional horizontal-axis wind turbines. Then, a model oscillating-wing unit is designed, built, and tested in a wind tunnel to examine the feasibility of the oscillating-wing unit in extraction of the wind energy in comparison with the theoretical analysis. The theoretical analysis and experimental data indicate that the oscillating-wing unit has the power efficiency comparable to the conventional horizontal axis wind turbine and it can operate at low wind speeds.
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OKUBO, Hiroshi, Ryo HATAKEYAMA, Hidemi ONODERA, Tsuyoshi SATO, Hironori FUJII, Yusuke MARUYAMA, and Makoto IWAHARA. "Airborne Wind Power Generation Using a Straight Wing Vertical Axis Wind Turbine." Proceedings of Conference of Kanto Branch 2019.25 (2019): 18E16. http://dx.doi.org/10.1299/jsmekanto.2019.25.18e16.
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Kuchera, Evan L., and Matthew D. Parker. "Severe Convective Wind Environments." Weather and Forecasting 21, no. 4 (August 1, 2006): 595–612. http://dx.doi.org/10.1175/waf931.1.
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Abstract Nontornadic thunderstorm winds from long-lived, widespread convective windstorms can have a tremendous impact on human lives and property. To examine environments that support damaging wind producing convection, sounding parameters from Rapid Update Cycle model analyses (at 3-hourly intervals) from 2003 were compared with 7055 reports of damaging winds and 377 081 occurrences of lightning. Ground-relative wind velocity was the most effective at discriminating between damaging and nondamaging wind convective environments. Steep surface-based lapse rates (a traditional damaging wind parameter) generally did not discriminate between damaging and nondamaging wind convective environments. Other parameters, such as convective available potential energy, humidity aloft, and lapse rates aloft were moderately discriminating. This paper presents a composite damaging wind algorithm in which the two most discriminatory parameters were combined, yielding more skill than any individual parameter. Damaging wind environments are then examined further through a selection of cases that highlight common severe wind ingredients and failure modes. A primary result is that, even in seemingly favorable environments, when the winds at the top of the inflow layer were either parallel to the convective line or blowing from warm to cold over a front, damaging winds were less likely. In the former case, it appears that the downdraft winds and the cold pool’s gust-front-normal flow are not additive. In the latter case, it appears that convection becomes elevated and does not produce downdrafts that reach the surface. Combining the most discriminatory severe wind parameters with knowledge of these severe wind failure modes may help to improve the situational awareness of forecasters.
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Shtanko, Oleksandr, Maryna Litvinova, Iryna Zorina, Svitlana Karpova, and Roman Avdiunin. "Improving the oscillating wind turbine model." Eastern-European Journal of Enterprise Technologies 3, no. 8 (123) (June 30, 2023): 46–53. http://dx.doi.org/10.15587/1729-4061.2023.281228.
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Disadvantages in the structure of the most common rotary wind generators limit their use. This motivates the development of alternative types of wind turbines, the most promising of which are oscillating wind generators. The object of the study is the structure of an oscillating type wind generator, which provides self-oscillating movement of the blade-wing. The design of the wind generator uses a modified wing shape to provide maximum lift. For this purpose, added elements are the tip and flap, which affect the shape of the wing, its angle of attack, and regulate the direction of the lifting force. The principle of attaching the tip and flap to the wing using spiral springs has been developed. The structure also includes locking magnets that affect the movement of the wing during a turn. The mechanism that drives the self-oscillating mode of operation of the wind turbine was described. This mode occurs under the action of the inertial force of the movement of the wing, the force of elasticity, the repulsive force of the magnets, and the pressure force of the air flow. A computer simulation of the wind generator was carried out using the Ansys CFX software package. The model of the flow around an absolutely rigid body at small values of the Reynolds number was applied. The resulting dynamics of the horizontal movement of the wing of the wind turbine make it possible to use it for energy generation already at a wind speed of 2 m/s. The low cost of the wing and the automatic regulation of its movement make it possible to install many wings to increase the power of the wind generator. Thus, the improved wind turbine is low-cost, harmless to birds, has self-regulation of wing movement and can use the low-speed component of the wind, which significantly expands the geography of its operation. It is possible to transfer the proposed technological solutions for the construction of hydroelectric generators
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Hodges, Laurie, and James R. Brandle. "Windbreaks: An Important Component in a Plasticulture System." HortTechnology 6, no. 3 (July 1996): 177–81. http://dx.doi.org/10.21273/horttech.6.3.177.
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Windbreaks reduce wind speed and modify the microclimate in sheltered areas. Many producers use wind barriers in their production systems, but few producers recognize all of the benefits available or understand the principles involved in windbreak function and design. Wind has direct and indirect effects on plant growth and development. Direct effects include soil abrasion, increased transpiration, and lodging. Indirect effects are based on changes in the crop microclimate, which influence plant growth and yield. Windbreaks increase soil and air temperatures and can extend the growing season in sheltered areas, resulting in increased crop development, earlier crop maturity, and market advantage. Plant-water relations and irrigation efficiency are improved by shelter. Overall, modifications to the microclimate in sheltered areas contribute to 5% to 50% higher crop yields. Winds in excess of about 5 m·s−1 (1.0 m·s−1 = 2.25 miles/h; miles/h × 0.447 = m·s−1) result in wind erosion and soil abrasion and may cause a loss of crop stand. Wind speeds below 5 m·s−1 may have an equally adverse impact on crop quality and marketable yield. In both cases, wind-breaks can reduce damage effectively in sheltered areas. Wind protection reduces certain problems associated with plasticulture under windy conditions.
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Tursunova, Aziza, Saodat Bozorova, Khusniya Ibragimova, Javokhir Bobokulov, and Shukhrat Abdullaev. "Researching localization of vertical axis wind generators." E3S Web of Conferences 417 (2023): 03005. http://dx.doi.org/10.1051/e3sconf/202341703005.
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The paper analyses the economic efficiency of using wind power plants in mountainous areas and small residential areas as well as the results of using vertical axis wind devices in areas with low-speed winds. So it became possible to obtain the necessary electrical energy in the less windy regions of Uzbekistan by using vertical axis wind generators. In recent years the demand for electricity is increasing gradually as a result of the sharp growth of direct production enterprises and population consumption. This demand can be compensated by using not only traditional energy sources but also non-traditional energy sources. The use of wind energy is to a certain extent the basis of energy production. Nurato district of Navoi region of Uzbekistan was selected as an object. The problems of saving and shortage of electric energy will be avoided by using the vertical axis wind generator in the regions. By moving the rotor of the wind generator the wind energy is converted into mechanical energy, which generates electrical energy through the generator. Electric power from the generator is provided by a controller that serves to monitor the charge level of the accumulator and is sent to the accumulator through the controller.
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Shen, Xiong, Yaolong Wang, Jiarui Xu, and Tiantian Huang. "A Study on Whether a ‘Maze’-like Layout Contributes to the Improvement of Wind Environments in Traditional Coastal Villages—A Validation Study Based on Numerical Simulation." Buildings 14, no. 9 (September 6, 2024): 2805. http://dx.doi.org/10.3390/buildings14092805.
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The coastal regions of Fujian, characterized by a subtropical maritime monsoon climate, experience a high frequency of windy days throughout the year, which significantly impacts residents’ lives. Local traditional villages, through long-term practical exploration, have developed a unique “maze-like” spatial layout adapted to withstand harsh wind conditions. This study aims to quantitatively analyze the climatic adaptability advantages of this traditional layout, providing theoretical support for the protection of historical cultural heritage and guidance for modern village construction. The methodology includes field wind measurement for data acquisition, construction of current and regularized divergent models, and comparative numerical simulations under scenarios of strong winter winds and typhoons. The results indicate that wind speeds within traditional villages are generally lower. The layout’s nonlinear roads and clusters of buildings form multiple buffer zones that effectively reduce wind speeds. In contrast, areas in the divergent model experience excessively high wind speeds, impacting outdoor activity safety and comfort. The traditional “maze-like” layout encapsulates the climate adaptation wisdom of ancestors, enhancing wind environment regulation, thermal comfort, and disaster resilience. This layout concept merits promotion and innovative application in the new era to construct livable, green, and sustainable human environments.
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Mahrt, Larry. "Surface Wind Direction Variability." Journal of Applied Meteorology and Climatology 50, no. 1 (January 1, 2011): 144–52. http://dx.doi.org/10.1175/2010jamc2560.1.
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Abstract Common large shifts of wind direction in the weak-wind nocturnal boundary layer are poorly understood and are not adequately captured by numerical models and statistical parameterizations. The current study examines 15 datasets representing a variety of surface conditions to study the behavior of wind direction variability. In contrast to previous studies, the current investigation directly examines wind direction changes with emphasis on weak winds and wind direction changes over smaller time periods of minutes to tens of minutes, including large wind direction shifts. A formulation of the wind direction changes is offered that provides more realistic behavior for very weak winds and for complex terrain.
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Ricciardulli, Lucrezia, Carl Mears, Andrew Manaster, and Thomas Meissner. "Assessment of CYGNSS Wind Speed Retrievals in Tropical Cyclones." Remote Sensing 13, no. 24 (December 16, 2021): 5110. http://dx.doi.org/10.3390/rs13245110.
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The NASA CYGNSS satellite constellation measures ocean surface winds using the existing network of the Global Navigation Satellite System (GNSS) and was designed for measurements in tropical cyclones (TCs). Here, we focus on using a consistent methodology to validate multiple CYGNSS wind data records currently available to the public, some focusing on low to moderate wind speeds, others for high winds, a storm-centric product for TC analyses, and a wind dataset from NOAA that applies a track-wise bias correction. Our goal is to document their differences and provide guidance to users. The assessment of CYGNSS winds (2017–2020) is performed here at global scales and for all wind regimes, with particular focus on TCs, using measurements from radiometers that are specifically developed for high winds: SMAP, WindSat, and AMSR2 TC-winds. The CYGNSS high-wind products display significant biases in TCs and very large uncertainties. Similar biases and large uncertainties were found with the storm-centric wind product. On the other hand, the NOAA winds show promising skill in TCs, approaching a level suitable for tropical meteorology studies. At the global level, the NOAA winds are overall unbiased at wind regimes from 0–30 m/s and were selected for a test assimilation into a global wind analysis, CCMP, also presented here.
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Obukhov, S. G. "DYNAMIC WIND SPEED MODEL FOR SOLVING WIND POWER PROBLEMS." Eurasian Physical Technical Journal 17, no. 1 (June 2020): 77–84. http://dx.doi.org/10.31489/2020no1/77-84.
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Pereyra-Castro, Karla, Ernesto Caetano, Oscar Martínez-Alvarado, and Ana L. Quintanilla-Montoya. "Wind and Wind Power Ramp Variability over Northern Mexico." Atmosphere 11, no. 12 (November 27, 2020): 1281. http://dx.doi.org/10.3390/atmos11121281.
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The seasonal and diurnal variability of the wind resource in Northern Mexico is examined. Fourteen weather stations were grouped according to the terrain morphology and weather systems that affect the region to evaluate the impact on wind ramps and high wind persistent events. Four areas driven by weather systems seasonality are identified. Wind power ramps and persistent generation events are produced by cold fronts in winter, while mesoscale convective systems and local circulations are dominant in summer. Moreover, the 2013 wind forecast of the Rapid Refresh Model (RAP) and the North American Mesoscale Forecast System (NAM) forecast systems were also assessed. In general, both systems have less ability to predict mesoscale events and local circulations over complex topography, underestimating strong winds and overestimating weak winds. Wind forecast variations in the mesoscale range are smoother than observations due to the effects of spatial and temporal averaging, producing fewer wind power ramps and longer lasting generation events. The study carried out shows the importance of evaluating operational models in terms of wind variability, wind power ramps and persistence events to improve the regional wind forecast. The characteristics of weather systems and topography of Mexico requires model refinements for proper management of the wind resource.
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Brill, Keith F. "Revisiting an Old Concept: The Gradient Wind*." Monthly Weather Review 142, no. 4 (March 27, 2014): 1460–71. http://dx.doi.org/10.1175/mwr-d-13-00088.1.
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Abstract The gradient wind is defined as a horizontal wind having the same direction as the geostrophic wind but with a magnitude consistent with a balance of three forces: the pressure gradient force, the Coriolis force, and the centrifugal force arising from the curvature of a parcel trajectory. This definition is not sufficient to establish a single way of computing the gradient wind. Different results arise depending upon what is taken to be the parcel trajectory and its curvature. To clarify these distinctions, contour and natural gradient winds are defined and subdivided into steady and nonsteady cases. Contour gradient winds are based only on the geostrophic streamfunction. Natural gradient winds are obtained using the actual wind. Even in cases for which the wind field is available along with the geostrophic streamfunction, it may be useful to obtain the gradient wind for comparison to the existing analyzed or forecast wind or as a force-balanced reference state. It is shown that the nonanomalous (normal) solution in the case of nonsteady natural gradient wind serves as an upper bound for the actual wind speed. Otherwise, supergradient wind speeds are possible, meaning that a contour gradient wind or the steady natural gradient wind used as an approximation for an actual wind may not be capable of representing the full range of actual wind magnitude.
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Weiss, Robin A., and Jonathan L. Heeney. "An ill wind for wild chimps?" Nature 460, no. 7254 (July 2009): 470–71. http://dx.doi.org/10.1038/460470a.
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Wu, Jin. "Wind-Stress Coefficients at Light Winds." Journal of Atmospheric and Oceanic Technology 5, no. 6 (December 1988): 885–88. http://dx.doi.org/10.1175/1520-0426(1988)005<0885:wscalw>2.0.co;2.
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Gideon, Samuel, and Mimie Purnama. "PENEMPATAN TURBIN ANGIN OPTIMAL UNTUK GEDUNG PUSAT PEMBELAJARAN ARNTZ-GEISE 2 UNIVERSITAS KATOLIK PARAHYANGAN, BANDUNG UNTUK MENGHASILKAN ENERGI BERSIH SEPANJANG TAHUN." Riset Arsitektur (RISA) 8, no. 04 (October 4, 2024): 388–405. https://doi.org/10.26593/risa.v8i04.8586.388-405.
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Abstract-In today’s climate condition, green building technologi is no longer a luxury but a necessity. Wind is one of the natural resources that we can harvest using wind turbines to generate clean energy. Unfortunately, winds that blows in cities on tropical countries tends to have less speed than ones that blows in other climates and areas. Fortunately, winds speed can be manipulated through building orientation and forms to produce high speed winds that can be used by wind turbines to generate clean energy. There are many wind phenomenons that occurs due to building orientation and form, some of these phenomenons are: Wind Tunnel Effect, Cumulative Effect, and winds on the peaks of buildings. Other than that, buildings that have sharp edges tend to produce higher wind speeds than those that have curved edges. Pusat Pembelajaran Arntz-Geise 2 (PPAG 2) UNPAR, Bandung is a building that can produce these 4 phenomenons in order to generate high speed winds through its form and orientation. This evaluative research will analyze PPAG 2’s form againts winds that it will experience and evaluate where in the building are optimal spots to install wind turbines. The wind datas that will be used is a daily data throughout 2021. Those data will then be used as a base for wind simulations using the Computational Fluid Dynamics (CFD) Software. The results from the simulation will be analyzed to determine the optimal placements of wind turbines in order for PPAG 2 to generate clean energy year-round. The result of this research says that all outer edges of PPAG 2 is suitable for wind turbine placements, along with the top of both towers and the bridge connecting the northern and souther tower. Keywords: Wind Turbine, PPAG 2, placement, year-round, clean energy
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Xie, Jia Li, and Cun Ming Ma. "Research on Influences of Wind Screens on Wind-Resistant Capability for Long Span Suspension Bridges." Advanced Materials Research 774-776 (September 2013): 73–77. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.73.
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As long span suspension bridges have high towers, large flexibility and low damping, it is a must to consider the wind-resistant stability in bridge designs, especially for sea-crossing bridges where there are always strong winds. To ensure the traffic safety under strong winds, wind screens are often installed on the bridge deck to reduce the wind speed over the roadway. In order to analyze the influence of wind screens on wind-resistant capability and driving security for long span suspension bridges, CFD wind tunnel technique is adopted to analyze the flutter stability, the buffeting displacement and the wind environment of the bridge deck with and without wind screens. According to the analysis, the installation of wind screens could effectively reduce the wind speed over the roadway, but it would also weaken the wind-resistant capability of the bridge. The analysis results could be used as reference for the wind-resistant capability optimization and the wind screen design for long span suspension bridges.
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Seefeldt, Mark W., John J. Cassano, and Thomas R. Parish. "Dominant Regimes of the Ross Ice Shelf Surface Wind Field during Austral Autumn 2005." Journal of Applied Meteorology and Climatology 46, no. 11 (November 1, 2007): 1933–55. http://dx.doi.org/10.1175/2007jamc1442.1.
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Abstract An analysis of the surface wind field across the Ross Ice Shelf, Antarctica, is conducted for austral autumn 2005. The airflow is divided into dominant wind regimes identifying similar wind patterns and the associated typical atmospheric forcing. The results of previous research and a seasonal analysis of the recently expanded network of automatic weather stations in the Ross Ice Shelf region are used to define the dominant wind regimes. Events composing each wind regime are identified by matching wind speed and wind direction observations at several automatic weather station sites for durations of at least 10 h. The four different dominant wind regimes are barrier wind, strong katabatic, weak katabatic, and light wind. Each wind regime is studied through the use of wind rose plots and sea level pressure fields from the Antarctic Mesoscale Prediction System. The sea level pressure fields are used to characterize the forcing of the surface wind field by synoptic pressure gradients. The four dominant wind regimes result in classifying less than 50% of the total hours for austral autumn 2005. The results indicate that previous studies of the Ross Ice Shelf surface wind field, focusing on katabatic winds and barrier winds, represent less than one-half of the observed winds. This study provides a better understanding of the composition of the surface wind field in Antarctica and more insight into the characteristics of the Ross Ice Shelf airstream.
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Monahan, Adam H. "Can We See the Wind? Statistical Downscaling of Historical Sea Surface Winds in the Subarctic Northeast Pacific." Journal of Climate 25, no. 5 (March 2012): 1511–28. http://dx.doi.org/10.1175/2011jcli4089.1.
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The statistical predictability of wintertime (December–February) monthly-mean sea surface winds (both vector wind components and wind speed) in the subarctic northeast Pacific off the west coast of Canada is considered, in the context of surface wind downscaling. Predictor fields (zonal wind, meridional wind, wind speed, and temperature) are shown to carry predictive information on the large scales (both vertical and horizontal) that are well simulated by numerical weather prediction and global climate models. It is found that, in general, the monthly mean vector wind components are more predictable by indices of the large-scale flow than by the monthly mean wind speed, with no systematic vertical variation in predictive skill for either across the depth of the troposphere. The difference in predictive skill between monthly-mean vector wind components and wind speed is interpreted in terms of an idealized model of the vector wind speed probability distribution, which demonstrates that for the conditions in the subarctic northeast Pacific, the sensitivity of mean wind speed to the standard deviations of vector wind component fluctuations (which are not well predicted) is greater than that to the mean vector wind components. It is demonstrated that this sensitivity is state dependent, and it is suggested that monthly mean wind speeds may be inherently more predictable in regions where the sensitivity to the vector wind component means is greater than that to the standard deviations. It is also demonstrated that daily wind fluctuations (both vector wind and wind speed) are generally more predictable than monthly-mean variability, and that monthly averages of the predicted daily winds generally represent the monthly-mean surface winds better than the predictions directly from monthly mean predictors.
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Shimada, Teruhisa. "Structures and Seasonal Variations of Surface Winds Blowing through the Tsushima Strait." Journal of Applied Meteorology and Climatology 49, no. 8 (August 1, 2010): 1714–27. http://dx.doi.org/10.1175/2010jamc2301.1.
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Abstract Surface winds blowing through the Tsushima Strait are statistically investigated using satellite wind measurements and atmospheric reanalysis data. This study first presents structures and seasonal variations of the northeasterly and southwesterly along-strait winds by imposing newly proposed conditions for defining them. Although the speeds of the northeasterly along-strait winds are generally high within the entire strait, the maximum wind speeds are located downwind of the two channels. The southwesterly along-strait winds start to accelerate at the west exit within the strait. Weak-wind regions are formed in the lee of Tsushima Island in both cases. The occurrence frequencies of the northeasterly and southwesterly along-strait winds are high (low) in the warm (cool) season. The northeasterly along-strait winds are more often observed than the southwesterly along-strait winds. The frequency of the northeasterly along-strait wind is extraordinarily high in September, but the averaged wind speed is comparable to those in the other months. Most of the southwesterly along-strait wind cases fall within low-Froude-number regimes, suggesting the significant effects of Tsushima Island on the wind in the strait. Synoptic situations favorable for the along-strait winds are investigated. Correlations between the along-strait wind component and sea level pressure (SLP) indicate that the along-strait winds are induced by SLP perturbations primarily over the Japan Sea and secondarily on the south of the strait. In addition, cluster analysis of the SLP fields shows four representative SLP fields favorable for the along-strait winds and their monthly occurrence frequencies.
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Butler, Bret, Steve Quarles, Christine Standohar-Alfano, Murray Morrison, Daniel Jimenez, Paul Sopko, Cyle Wold, et al. "Exploring fire response to high wind speeds: fire rate of spread, energy release and flame residence time from fires burned in pine needle beds under winds up to 27 ms−1." International Journal of Wildland Fire 29, no. 1 (2020): 81. http://dx.doi.org/10.1071/wf18216.
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The relationship between wildland fire spread rate and wind has been a topic of study for over a century, but few laboratory studies report measurements in controlled winds exceeding 5ms−1. In this study, measurements of fire rate of spread, flame residence time and energy release are reported for fires burning under controlled atmospheric conditions in shallow beds of pine needles subject to winds ranging from 0 to 27ms−1 (measured 5m above ground level). The data suggested that under constant flow conditions when winds are less than 10ms−1, fire rate of spread increases linearly at a rate of ~3% of the wind speed, which generally agrees with other laboratory-based models. When wind speed exceeds 10ms−1, the fire rate of spread response to wind remains linear but with a much stronger dependence, spreading at a rate of ~13% of the wind speed. Radiative and convective heating correlated directly to wind speed, with radiant heating increasing approximately three-fold as much as convective heating over the range of winds explored. The data suggested that residence time is inversely related to wind speed and appeared to approach a lower limit of ~20s as wind exceeded 15ms−1. Average flame residence time over the range of wind speeds was nominally 26s.
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Sun, Cangjie, and Adam H. Monahan. "Statistical Downscaling Prediction of Sea Surface Winds over the Global Ocean." Journal of Climate 26, no. 20 (October 4, 2013): 7938–56. http://dx.doi.org/10.1175/jcli-d-12-00722.1.
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Abstract The statistical prediction of local sea surface winds from large-scale, free-tropospheric fields is investigated at a number of locations over the global ocean using a statistical downscaling model based on multiple linear regression. The predictands (the mean and standard deviation of both vector wind components and wind speed) calculated from ocean buoy observations on daily, weekly, and monthly scales are regressed on upper-level predictor fields from reanalysis products. It is found that in general the mean vector wind components are more predictable than mean wind speed in the North Pacific and Atlantic, while in the tropical Pacific and Atlantic the difference in predictive skill between mean vector wind components and wind speed is not substantial. The predictability of wind speed relative to vector wind components is interpreted by an idealized model of the wind speed probability density function, which indicates that in the midlatitudes the mean wind speed is more sensitive to the vector wind standard deviations (which generally are not well predicted) than to the mean vector winds. In the tropics, the mean wind speed is found to be more sensitive to the mean vector winds. While the idealized probability model does a good job of characterizing month-to-month variations in the mean wind speed in terms of the vector wind statistics, month-to-month variations in the standard deviation of speed are not well modeled. A series of Monte Carlo experiments demonstrates that the inconsistency in the characterization of wind speed standard deviation is the result of differences of sampling variability between the vector wind and wind speed statistics.
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Poulain, Pierre-Marie, Riccardo Gerin, Elena Mauri, and Romain Pennel. "Wind Effects on Drogued and Undrogued Drifters in the Eastern Mediterranean." Journal of Atmospheric and Oceanic Technology 26, no. 6 (June 1, 2009): 1144–56. http://dx.doi.org/10.1175/2008jtecho618.1.
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Abstract The wind effects on drogued and undrogued drifters are assessed using Coastal Ocean Dynamics Experiment (CODE) and Surface Velocity Program (SVP) drifter datasets and ECMWF wind products in the eastern Mediterranean. Complex and real linear regression models are used to estimate the relative slip of undrogued SVP drifters and to extract the wind-driven currents from the drifter velocities. The frequency response of the wind-driven currents is studied using cross-spectral analysis. By comparing the velocities of cotemporal and nearly collocated undrogued and drogued SVP drifters, it appears that undrogued SVP drifters have a general downwind slippage of about 1% of the wind speed. Time-lagged complex correlations and cross-spectral results show that the wind response is almost simultaneous. The velocities of SVP drifters drogued to 15 m are poorly correlated with the winds (R2 ≈ 3%): wind-driven currents have a magnitude of 0.7% of the wind speed and are 27°–42° to the right of the wind. For undrogued SVP drifters, the correlation with the winds increases to R2 ≈ 22% and the angle between winds and currents decreases to 17°–20°. The magnitude of the wind-driven currents is about 2% of the wind speed. For CODE designs, wind-driven currents are 1% of the wind speed at an angle of about 28° to the right of the wind (R2 ≈ 8%). Spectral and cospectral analyses reveal that the drifters sampled more anticyclonic than cyclonic motions. The inner coherence spectra show that wind and currents are more correlated at temporal scales spanning 3–10 days. They also confirm that the wind response is quasi-simultaneous and that currents are generally to the right of the wind.
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Bentamy, Abderrahim, Semyon A. Grodsky, Gildas Cambon, Pierre Tandeo, Xavier Capet, Claude Roy, Steven Herbette, and Antoine Grouazel. "Twenty-Seven Years of Scatterometer Surface Wind Analysis over Eastern Boundary Upwelling Systems." Remote Sensing 13, no. 5 (March 3, 2021): 940. http://dx.doi.org/10.3390/rs13050940.
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More than twelve satellite scatterometers have operated since 1992 through the present, providing the main source of surface wind vector observations over global oceans. In this study, these scatterometer winds are used in combination with radiometers and synthetic aperture radars (SAR) for the better determination and characterization of high spatial and temporal resolution of regional surface wind parameters, including wind speed and direction, wind stress components, wind stress curl, and divergence. In this paper, a 27-year-long (1992–2018) 6-h satellite wind analysis with a spatial resolution of 0.125° in latitude and longitude is calculated using spatial structure functions derived from high-resolution SAR data. The main objective is to improve regional winds over three major upwelling regions (the Canary, Benguela, and California regions) through the use of accurate and homogenized wind observations and region-specific spatial and temporal wind variation structure functions derived from buoy and SAR data. The long time series of satellite wind analysis over the California upwelling, where a significant number of moorings is available, are used for assessing the accuracy of the analysis. The latter is close to scatterometer wind retrieval accuracy. This assessment shows that the root mean square difference between collocated 6-h satellite wind analysis and buoys is lower than 1.50 and 1.80 m s−1 for offshore and nearshore locations, respectively. The temporal correlation between buoy and satellite analysis winds exceeds 0.90. The analysis accuracy is lower for 1992–1999 when satellite winds were mostly retrieved from ERS-1 and/or ERS-2 scatterometers. To further assess the improvement brought by this new wind analysis, its data and data from three independent products (ERA5, CMEMS, and CCMP) are compared with purely scatterometer winds over the Canary and Benguela regions. Even though the four products are generally similar, the new satellite analysis shows significant improvements, particularly in the upwelling areas.