scholarly journals Spatiotemporal Characteristics of Near-Surface Wind in Shenzhen

2020 ◽  
Vol 12 (2) ◽  
pp. 739 ◽  
Author(s):  
Cheng Liu ◽  
Qinglan Li ◽  
Wei Zhao ◽  
Yuqing Wang ◽  
Riaz Ali ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Surface Wind ◽  
Prevailing Wind ◽  
Average Wind Speed ◽  
Near Surface ◽  
Average Wind ◽  
Prevailing Wind Direction ◽  
Seasonal Wind ◽  
The Mean

The spatiotemporal characteristics of near-surface wind in Shenzhen were investigated in this study by using hourly observations at 92 automatic weather stations (AWSs) from 2009 to 2018. The results show that during the past 10 years, most of the stations showed a decreasing trend in the annual mean of the 10 min average wind speed (avg-wind) and the mean of the 3 s average wind speed (gust wind). Over half of the decreasing trends at the stations were statistically significant (p < 0.05). Seasonally, the decrease in wind speed was the most severe in spring, followed by autumn, winter, and summer. The distribution of wind speed tends to be greater in the east and coastal areas for both avg-wind and gust wind. From September to March of the following year, the prevailing wind direction in Shenzhen was northerly, and from April to August, the prevailing wind direction was southerly. The seasonal wind speed distribution exhibited two different types, spring–summer type and autumn–winter type, which may be induced by their different prevailing wind directions. The analysis by the empirical orthogonal function (EOF) method confirmed the previous findings that the mean wind speed was decreasing in Shenzhen and that two different seasonal wind speed spatial distribution patterns existed. Such a study could provide references for wind forecasting and risk assessment in the study area.

scholarly journals Caracterização da Velocidade e Direção do Vento em Mossoró/RN (Characterization of Wind Speed and Direction in Mossoró/RN)

2014 ◽  
Vol 7 (4) ◽  
pp. 746
Author(s):  
Giuliana Mairana de Morais ◽  
José Espínola Sobrinho ◽  
Wesley De Oliveira Santos ◽  
Danielly De Oliveira Costa ◽  
Saulo Tasso Araújo da Silva ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Agricultural Activities ◽  
Prevailing Wind ◽  
Average Wind Speed ◽  
Average Wind ◽  
Prevailing Wind Direction ◽  
Automatic Station ◽  
Semi Arid

O vento é de grande importância para muitas atividades humanas, especialmente para as atividades agropecuárias. O objetivo desse trabalho foi caracterizar a velocidade e a direção predominante do vento para Mossoró/RN, no período de janeiro de 2000 a dezembro de 2012. Foram analisados dados da velocidade média do vento a 10 m e 2 m de altura e direção predominante do vento para o período de 24 horas. Os dados foram coletados por uma Estação Meteorológica Automática, localizada na UFERSA (Universidade Federal Rural do Semi-Árido), em Mossoró/RN. Os valores da velocidade média do vento tendem a aumentar no segundo semestre do ano, tendo uma queda nos seus valores no primeiro semestre. Os valores médios de velocidade do vento para o período estudado foram de 3,32 m s-1 para 10 m e de 2,30 m s-1 para 2 m de altura, já as velocidades máximas instantânea do período estudado foram de 13,04 m s-1 para 10 m e de 9,40 m s-1 para 2 m de altura. A direção predominante do vento ficou na maioria dos meses entre sudeste (SE) e leste (E).   ABSTRACT The wind is of great importance to many human activities, especially for agricultural activities. The aim of this study was to characterize the speed and direction of the prevailing wind to Mossoró/RN, from January 2000 to December 2012. The datas from the average wind speed at 10 m and 2 m in height and the prevailing wind direction for the period of 24 hours. Data were collected by an Automatic Weather Station, located in UFERSA (Federal Rural University of the Semi - Arid), in Mossoró/RN. The values of average wind speed tend to increase in the second half of the year, with a fall in values in the first half. The average wind speed for the study period were 3.32 m s-1 to 10 m and 2.30 m s-1 to 2 m high, since the instantaneous speeds of the study period were 13.04 m s-1 to 10 m and 9.40 m s-1 to 2 m in height. The predominant wind direction was in most months between southeast (SE) and east (E).   Keywords: Climate, Anemometer, Automatic Station. 

Wind analysis at Ganja International Airport

2020 ◽  
Vol 61 (12) ◽  
pp. 162-165
Author(s):  
Ulker Faig Bayramova ◽  
Keyword(s):  
Wind Speed ◽  
Key Words ◽  
Wind Direction ◽  
Maximum Speed ◽  
Prevailing Wind ◽  
Wind Rose ◽  
International Airport ◽  
Wind Analysis ◽  
Prevailing Wind Direction ◽  
The Mean

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

scholarly journals Properties of the Wind Field within the Oklahoma City Park Avenue Street Canyon. Part I: Mean Flow and Turbulence Statistics

2007 ◽  
Vol 46 (12) ◽  
pp. 2038-2054 ◽  
Author(s):  
M. A. Nelson ◽  
E. R. Pardyjak ◽  
J. C. Klewicki ◽  
S. U. Pol ◽  
M. J. Brown
Keyword(s):  
Wind Direction ◽  
Street Canyon ◽  
Sonic Anemometer ◽  
Surface Wind ◽  
Oklahoma City ◽  
Prevailing Wind ◽  
Advective Transport ◽  
Mean Flow ◽  
Prevailing Wind Direction ◽  
The Mean

Abstract Velocity data were obtained from sonic anemometer measurements within an east–west-running street canyon located in the urban core of Oklahoma City, Oklahoma, during the Joint Urban 2003 field campaign. These data were used to explore the directional dependence of the mean flow and turbulence within a real-world street canyon. The along-canyon vortex that is a key characteristic of idealized street canyon studies was not evident in the mean wind data, although the sensor placement was not optimized for the detection of such structures. Instead, surface wind measurements imply that regions of horizontal convergence and divergence exist within the canopy, which are likely caused by taller buildings diverting the winds aloft down into the canopy. The details of these processes appear to be dependent on relatively small perturbations in the prevailing wind direction. Turbulence intensities within the canyon interior appeared to have more dependence on prevailing wind direction than they did in the intersections. Turbulence in the intersections tended to be higher than was observed in the canyon interior. This behavior implies that there are some fundamental differences between the flow structure found in North American–style cities where building heights are typically heterogeneous and that found in European-style cities, which generally have more homogeneous building heights. It is hypothesized that the greater three-dimensionality caused by the heterogeneous building heights increases the ventilation of the urban canopy through mean advective transport as well as enhanced turbulence.

scholarly journals Snow density along the route traversed by the Japanese-Swedish Antarctic Expedition 2007/08

2012 ◽  
Vol 58 (209) ◽  
pp. 529-539 ◽  
Author(s):  
Shin Sugiyama ◽  
Hiroyuki Enomoto ◽  
Shuji Fujita ◽  
Kotaro Fukui ◽  
Fumio Nakazawa ◽  
...  
Keyword(s):  
Wind Speed ◽  
Surface Wind ◽  
Coastal Region ◽  
Snow Density ◽  
Syowa Station ◽  
Near Surface ◽  
A Value ◽  
Surface Snow ◽  
The Mean ◽  
The Antarctic

AbstractDuring the Japanese-Swedish Antarctic traverse expedition of 2007/08, we measured the surface snow density at 46 locations along the 2800 km long route from Syowa station to Wasa station in East Antarctica. The mean snow density for the upper 1 (or 0.5) m layer varied from 333 to 439 kg m-3 over a region spanning an elevation range of 365-3800 ma.s.l. The density variations were associated with the elevation of the sampling sites; the density decreased as the elevation increased, moving from the coastal region inland. However, the density was relatively insensitive to the change in elevation along the ridge on the Antarctic plateau between Dome F and Kohnen stations. Because surface wind is weak in this region, irrespective of elevation, the wind speed was suggested to play a key role in the near-surface densification. The results of multiple regression performed on the density using meteorological variables were significantly improved by the inclusion of wind speed as a predictor. The regression analysis yielded a linear dependence between the density and the wind speed, with a coefficient of 13.5 kg m-3 (m s-1)-1. This relationship is nearly three times stronger than a value previously computed from a dataset available in Antarctica. Our data indicate that the wind speed is more important to estimates of the surface snow density in Antarctica than has been previously assumed.

Characteristics of the Mean Wind Speed Based on Field Measurement at Aizhai Bridge Gorge

2014 ◽  
Vol 521 ◽  
pp. 113-116
Author(s):  
Hong Xin Sun ◽  
Tao Yu ◽  
Xiu Yong Wang
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Field Measurement ◽  
Bridge Site ◽  
Design Code ◽  
Average Wind Speed ◽  
Average Wind ◽  
Mean Wind Speed ◽  
The Mean ◽  
Fluctuating Wind

It is seriously different about characteristics of the mean wind speed between a deep gorge and plains, because of the deck of Aizhai bride to deep gorge bottom up to 335m. Characteristics of the mean wind speed in the deep gorge at the Aizhai bridge site are investigated based on field measurement using three 2D anemometers. The plan of field measurement was induced, and the wind speed, fluctuating wind speed and the 10min average wind speed with 10 days as a unit was analyzed. It if found that wind direction is basically consistent with the gorge toward. Based on the Wind-Resistant Design code, the surface roughness coefficients was fitted about 0.29, and very close to D class of the wind code.

scholarly journals Temporal variation of wind speed and wind direction and interrelationship between air temperature and wind speed for different climatic seasons Northern State, Sudan

2021 ◽  
Vol 6 (4) ◽  
pp. 164-173
Author(s):  
Mohammed Ahmed Haj Alzubair ◽  
Motasim Hyder Abdelwahab
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Wind Direction ◽  
Climatic Data ◽  
Prevailing Wind Direction ◽  
Prevailing Direction ◽  
Simple Regression Analysis ◽  
The Mean ◽  
Northern State ◽  
Temperature Correlations

The research aims to study the temporal variability of wind speed and direction and their correlation with air temperature in different climatic seasons in Northern State, to produce broad data base on winds variability and interrelationship between air temperature and wind speed for different climatic seasons. Mean monthly and daily climatic data dating back to 2001(first season) and 2011(second season) were obtained from Karima meteorological station representing three different climatic seasons namely: April for summer, August for autumn and December for winter. Data were subjected to simple regression analysis, statistical analysis and computations were done by “Excel 2000”. The results showed that the wind speed varied widely during each month and day even within the same climatic season. In two seasons, the diurnal variation for different climatic seasons Apr., Aug. and Dec. was much lower than the monthly; due to the higher monthly variability of wind speed. The results also revealed that the prevailing direction of winds was generally northwards. The results of April in the first season are presented as an example; the mean daily wind speed (Va) ranged from 0.6 to 17m/s, with a mean of 7.2m/s, a STD of 4.3 and a CV of 60%. The daily mean data ranged from 5.4 (3hrs) to 8.2 (24hrs), with a mean of 7.2m/s, a STD of 1.1 and a CV of 15.3%.The prevailing wind direction decreases in the following order: N>NE=NNE>NNW. The monthly variability of the air temperature in the two seasons decreased in the following order: winter> summer> autumn. Significant, inversely proportional and cubic wind speed-temperature correlations in the two seasons for Aug. and Dec. were (P<0.05, r=0.362); (P<0.01, r= 0.488); (P<0.001, R=585) and (P<0.001, r= 0.679), respectively.

Measuring Sub-second Wind Velocity Changes for Agricultural Drift One Meter Above the Ground

2019 ◽  
Vol 35 (5) ◽  
pp. 697-704
Author(s):  
Matthew W. Schramm ◽  
H Mark Hanna ◽  
Matt J. Darr ◽  
Steven J. Hoff ◽  
Brian L. Steward
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Wind Velocity ◽  
Wind Direction ◽  
Weather Conditions ◽  
Spray Drift ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind ◽  
Velocity Changes

Abstract. Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, 1 m above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what conditions wind may be most likely to have a significant direction or speed change which affects droplet trajectory. For two individual datasets in which the average wind speed was 3.6 and 1.5 m/s (8.0 and 3.4 mi/h), there exists little linear correlation of wind speed or wind direction between an upwind and downwind anemometer separated by 30.5 m (100 ft). The highest observed correlation, resulting from a 12-s lag between the upwind and downwind datasets, was 0.29 when the average wind speed was 3.6 m/s (8.0 mi/h). Correlations greater than 0.1 were only found for wind speeds exceeding 3 m/s. Using this lag time, it was observed that the wind direction 30 s into the future had a 30% chance to be different by more than 20° from current conditions. A wind speed difference of more than 1 m/s (2.2 mi/h) from current conditions [mean wind speed was 3.6 m/s (8.0 mi/h)] was observed about 50% of the time. Analyzing 36 days of the 2014 and 2015 spray season wind velocity data showed that the most variability in wind direction occurred with wind speeds below 2 m/s (4.5 mi/h). Greater wind direction variability occurred in the mid-afternoon with higher solar radiation. Keywords: Sprayers, Spray drift, Spray droplets, Turbulence, Wind effects.

scholarly journals Prevailing Surface Wind Direction during Air–Sea Heat Exchange

2019 ◽  
Vol 32 (17) ◽  
pp. 5601-5617 ◽  
Author(s):  
Fumiaki Ogawa ◽  
Thomas Spengler
Keyword(s):  
Heat Exchange ◽  
Time Scales ◽  
Wind Direction ◽  
Surface Wind ◽  
Reanalysis Data ◽  
Heat Fluxes ◽  
Prevailing Wind ◽  
Prevailing Wind Direction ◽  
Mean Wind Speed ◽  
Time Averages

AbstractWhile the climatological-mean sensible and latent heat fluxes are remarkably well described using climatological-mean fields in the bulk flux formulas, this study shows that a significant fraction of the climatological-mean wind speed in the midlatitudes is associated with wind variations on synoptic time scales. Hence, the prevailing wind direction associated with the most intense air–sea heat exchange can differ from the mean wind direction. To pinpoint these striking differences between the climatological and synoptic viewpoint, this study presents a global climatology of the prevailing surface wind direction during air–sea heat exchanges calculated for instantaneous and time-averaged reanalysis data. The interpretation of the fluxes in the lower latitudes is basically unaffected by the different time averages, highlighting the time-mean nature of the circulation in the lower latitudes. In the midlatitudes, however, the prevailing wind direction features a significant equatorward component for subweekly time averages and reverts to pure westerlies for longer time averages. These findings pinpoint the necessity to consider subweekly time scales, in particular along the midlatitude SST fronts, to describe the air–sea heat exchange in a physically consistent way.

The effect of row orientation on below-canopy turbulence characteristics in a wine-vineyard

2020 ◽  
Author(s):  
Nurit Agam ◽  
Yasmin Levi ◽  
Joe Alfieri ◽  
John Prueger
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Momentum Flux ◽  
Power Spectra ◽  
Prevailing Wind ◽  
High Momentum ◽  
Turbulence Characteristics ◽  
Grape Quality ◽  
Sonic Anemometers ◽  
Prevailing Wind Direction

&lt;p&gt;The momentum flux affects the energy exchange processes and thus may indirectly affect the water balance of agricultural fields. In wine vineyards, a high momentum flux between the vine rows may augment the evaporation and transpiration fluxes, and therefore decrease the water use efficiency. On the other hand, at night, high momentum fluxes may reduce (or even prevent) the formation of dew on the vine canopy, thus decrease the potential development of fungi and related diseases. We hypothesized that the wind direction relative to the row orientation in largely-spaced narrow hedge-rows characterizing wine vineyards greatly affects the turbulent structure and the momentum flux. This, in turn affects the vineyard microclimate, and ultimately, the grape quality. The objective of our research was to explore the effect of wine-vineyard row orientation on wind and temperature profiles below (and slightly above) the canopy and on the turbulence characteristics and eddy size.&amp;#160;&amp;#160;The research was conducted in two adjacent vineyards in the Judean foothills in Israel (31&amp;#176;48'38.6&quot;N 34&amp;#176;50'43.6&quot;E and 31&amp;#176;48'37.1&quot;N 34&amp;#176;50'24.0&quot;E) having row orientations of NE-SW and SE-NW, respectively. With a NW prevailing wind direction, the wind is typically flowing perpendicularly to the former and in parallel to the latter. In each vineyard, 10 self-made type-T fine-wire thermocouples (0.08 mm diameter) were set on a pole places in the middle of the inter row, at heights above the ground of 5, 10, 20, 40, 80, 140, 220, 250, 300, and 400 cm. In addition, 4 fast-response 2D sonic anemometers were set at 10, 40, 140, and 250 cm above the ground. The measurements were conducted at 20 Hz.&amp;#160;&amp;#160;Below canopy wind regime differed with orientation, mostly at heights lower than 2.5m. Higher wind speed below the canopy and smaller wind speed gradients were observed at the vineyard parallel to the prevailing wind direction.&amp;#160; Temperature gradients were mostly larger in the vineyard perpendicular to the prevailing wind direction.&amp;#160; Nevertheless, the power spectra were generally more uniform in height at the perpendicular vineyard. &amp;#160;&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document