塔里木盆地南缘风动力环境研究

Study of Dynamical Environments Over Southern Margin of the Tarim Basin

风动力是沙尘天气发生并产生大量沙尘气溶胶的最重要因素之一,是评估某个区域风沙活动强度和沙尘气溶胶潜在释放能力的依据。文章以和田地区为研究区,利用和田市、皮山县、墨玉县、洛浦县、策勒县、于田县及民丰县气象台站观测的1991-2011年的小时风速风向资料,计算了研究区各观测站点的风动力,并分析了其时空变化特征。初步结论如下:(1)研究区年平均风速小于2.0m/s,呈现东西两侧大,中间小的空间分布特征;风速月变化呈现单峰分布态势,风速的高值出现在5-8月份;研究区起沙风风向主要集中在偏W方向,其中以SSW、SW、WSW、W、WNW、NW六个方位为主,合计占到全部起沙风风向的89.9%。(2)研究区输沙势高值中心东侧的民丰县,年均输沙势达173.1VU,合成输沙势为153.2VU,最小值出现在洛浦站,年均输沙势仅有3.2VU,合成输沙势为2.2VU;研究区各站月平均输沙势的高值区也集中在5-8月;输沙势的年际变化呈现较大的波动性,2001年达到最高值,为102.8VU;研究区合成输沙方向主要集中在ENE方向。

The dynamical environment was one of the most important factors causing dust weather and production of dust aerosol,and was also basis for assessment of regional sand movement intensity and potential dust emission. In this study,the dynamical environments were calculated and its spatial and temporal distributions were analyzed based the data of wind speed and wind direction over Hotan area including Hotan,Pishan,Moyu,Luopu,Cele,Yutian and Minfeng seven meteorological stations during 1991 to 2011. Some preliminary conclusions as follows：（1）In study area,the annual average wind speeds were lower than 2.0 m/s with the spatial distribution characters of higher wind speed in the east and the west,and lower wind speed in the center of study area. The monthly wind speed followed unimodal distribution,and higher wind speed appeared during May to August. The wind directions of sand-driving wind were dominated by SSW、SW、WSW、W、WNW、NW,and the occurring frequency was as high as89.9%.（2）The highest value of the sand drift potential appeared in Minfeng and the lowest value appeared in Luopu locating at the east and the center of the study area,respectively. The annual average sand drift sand potential and resultant sand drift potential were 173.1 VU and 153.2 VU in Minfeng,and 3.2 VU and 2.2 VU in Luopu. And higher monthly the drift sand potential also appeared during May to August. The interannual variation of sand drift potential varied fluctuant,and the highest value appeared in 2001 with the value of 102.8 VU.