基于实地观测的库姆塔格沙漠风场时空变化特征研究

Spatial and Temporal Variation of Wind Field in the Kumtagh Desert

库姆塔格沙漠分布在新疆东部,罗布泊洼地以南,阿尔金山以北,向东可延伸至甘肃敦煌的西部,总面积2.29万km2,是我国第6大沙漠。该沙漠内部气候极为干旱,植被稀疏,是我国最后一个开展全面考察的沙漠。通过对建在库姆塔格沙漠内东部和西部的两个自动测风站和南北的两个自动气象观测站在2007年10月至2008年9月的观测资料,结合相应时段MICAPS通过VSAT接收到的地面风场格点资料,对沙漠内部风场的日变化、季节变化以及起沙风的特征进行了分析,结果表明:①由于受南面阿尔金山高大山体的阻挡作用,库姆塔格沙漠的风场存在明显的日变化,表现出类似山谷风的风向转换规律,白天以上山的偏北风为主,夜晚以下山的偏南风为主,不同的季节山谷风的转化时间相应地不同。②冬季沙漠整体以偏南风为主,夏季偏北风占主导,而春秋季沙漠北部仍以偏北风为主,而沙漠东部和南部出现偏南风,沙漠西部为偏东风。③起沙风速的特征表现为:沙漠整体以偏北风为主,沙漠北部和西部以偏东北风为主,南部和东部以偏西北风为主,风向在沙漠中部从北向南由东北转为北,到了沙漠南部转为偏西北风向东南方向流去,风向的转变与库姆塔格沙漠沙丘走向最后转向东南是一致的。

The Kumtagh Desert is known as the sixth largest desert in China.The desert is extremely arid with sparse vegetation,and it＇s the last desert to be comprehensively studied in China.The daily change and seasonal change of wind field in the desert and the character of the sand-blowing wind in the desert were analyzed by use of the data of October 2007 to September 2008 from 2 automatic wind observation stations established in west and east Kumtagh Desert,and 2 automatic climatic stations located in north and south Kumtagh Desert.The analyzed data also included grid point data of wind field of MICAPS during the corresponding period received from VSAT.The results are as follows.（1） There＇s a daily change of wind field,like the shift of mountain and valley wind,in the Kumtagh Desert because of the uplift effect of the Altyn Tagh Mountains,and the predominant wind is in northern direction in day time and in southern direction in the night.The transition time of wind direction is different in different seasons.（2） Southern wind is predominant in winter and northern wind is predominant in summer.In spring or autumn,northern wind controls the north part of the desert,southern wind controls the eastern and southern parts,and eastern wind controls the western part.（3） Sand-blowing wind is principally the northern one,and the northeastern wind controls the western and the northern Kumtagh Desert,northwestern wind controls the eastern and the southern Kumtagh Desert.In the middle of the Kumtagh Desert,from the northern part to the southern part,the wind direction is from northeastern wind to northern wind and last to northwestern wind.The change of wind direction is as same as rotating of dune orientation in the Kumtagh Desert.