Research On Change Characteristics Of Wind Speed At Hotan Region

The study of climate change has always been a hot issue for experts and scholars at home and abroad.As an important meteorological factor for characterizing climate change and the formation of atmospheric movement,wind speed has brought many influences on human production and life.In recent years,changes in wind speed have attracted widespread attention from experts at home and abroad.The Hetian area is a typical mid-temperate continental arid and semi-arid climate.It is a northwestern border area with four distinct seasons.The temperature rises rapidly and is unstable in spring,which leads to windy and dry seasons,often plagued by wind and sand weather.Agricultural production and the lives of local residents have had an adverse impact.Moreover,frequent human activities cause damage to the ecological environment.As a clean renewable energy source,wind energy has received much attention.Therefore,it is particularly important to study the characteristics of wind speed change and its influencing factors in Hetian area.In this paper,the Hetian area is used as a research area,and the average wind speed time and spatial variation characteristics of the four meteorological stations in the region in 1960 and 2016 are analyzed.The time changes mainly include the following contents:annual average wind speed variation characteristics,seasonal variation characteristics,mutation test and Morlet wavelet cycle analysis for long-term sequences;and possible influence on near-surface average wind speed from topographical terrain,climate change and human activities Factors are analyzed.The results show that:?1?In the 57-year long-term scale of Hetian area,the annual average wind speed generallyshowsadownwardtrend,andthechangetrendis increase-decrease-increase-decrease.The maximum annual mean wind speed appeared in 1969 with a value of 2.22 ms^-1,the minimum value appeared in 1992,the value was 1.09 ms^-1,and the range between the maximum and minimum values was1.13 m/s.The rate is-0.0063.?10a?and passed the significance level test.The average wind speed averaged 1.63 m.s^-1,and the trend showed a slight increase-fluctuation drop-a sharp rise-again decline.The annual average wind speed in the region has two peaks around 1970 and around 2002,and a trough in 1993.The average wind speed in spring is the highest in the four seasons,the mean is 2.03ms^-1,the average wind speed in summer is 1.82ms^-1,and the average values in autumn and winter are 1.35ms^-11 and1.33ms^-1,respectively.The average wind speed is the smallest.The wind speed in the four seasons has a relatively significant weakening trend,especially in the spring.The average rate of change of wind speed in the four seasons was-0.011 m.s^-1/10a,-0.004m.s^-1/10a,-0.005 m.s^-1/10a,-0.002 m.s^-1/10a,respectively.That is,the spring has the largest change,followed by the fall,and the summer and winter are the smallest.?2?The average speed-speed mutation test and wavelet analysis show that the average annual wind speed in Hetian area was mutated in 1981 and 2000 respectively.On the whole,the average annual wind speed in the Hotan area is dominated by fluctuations,with obvious stages.In the four seasons,the sudden change of the average wind speed in spring occurred in 1982,and the mutation points were the same in summer,autumn and winter,and mutations occurred in 1982 and 1996 respectively.The cumulative anomalies of the four seasons in the region generally showed a decreasing trend.From the perspective of the reduction,the four seasons did not differ much.In addition to the positive anomaly values in spring,the positive and negative values of the cumulative anomalies in summer,autumn and winter fluctuate.The annual mean wind speed Morlet wavelet transform has obvious oscillation period on the time scale of 5-10 years,mainly in short period,short period and short period,and Morrow continuous wavelet transform variance of average wind speed continues to increase at 33a.The periodicity of the low-frequency oscillations of seasonal wind speed evolution in this area is not obvious,and the seasonal scale change period corresponding to high-frequency oscillation is significant.The short period of 5-10years in the four seasons always exists,and it exists in 10-15 years but the shock is not obvious.?3?Analysis of the spatial variation characteristics of average wind speed.The results show that the area has the characteristics of decreasing toward the two sides with the Hetian site as the center.The difference between the east and the west is more significant,and the difference between the south and the north is smaller.The average wind of the four stations is between 2.1m/s and 1.55m/s,which is roughly decreasing from west to east.The wind speeds of the Pishan and Hetian stations are greater than those of the Yutian and Minfeng stations.Overall,the average wind speed in the entire region of Hotan is decreasing from west to east.Among them,the Hetian site has the highest wind speed.?4?The main factors affecting wind speed change are three kinds:the average wind speed in Hetian area is affected by topography and terrain,and the average wind speed at the low-altitude stations Pishan and Hetian stations is higher than that of the high-altitude stations Minfeng and Yutian;thaverage temperature in climate change Meteorological elements such as precipitation have an effect on the average wind speed;the decrease of wind speed may be closely related to the degree of urban development,especially the increase of buildings,and urban expansion has a weakening effect on wind speed.