塔克拉玛干地区春季沙尘演变及气候因素分析

Analysis of spring sand dust storm evolution and climatic factors of sand dust originating areas of Taklimakan dry area

利用塔克拉玛干地区18个气象台站的观测资料，分析了该地区1961—2005年春季沙尘暴发生和演变规律，并分析了降水、温度、风速、起沙风（≥5m／s）日数等气象条件的变化特征及其对沙尘暴发生的影响．结果表明，塔克拉玛干地区除轮台、巴楚、塔什库尔干外。其余15个台站的沙尘日数呈现出明显的逐年递减趋势，其中11个台站减少显著．该地区冬季、春季降水和温度呈增加趋势，而春季平均风速则不断减小，起沙风日数也呈现出显著的减小趋势．沙尘源区的平均风速和起沙风日数与沙尘日数的相关系数分别达到0．662和0．674，呈显著的正相关（P〈0．01），表明大风是引起沙尘暴的直接原因．沙尘日数与春季和冬季降水相关系数分别为-0．589和-0．274，与春季降水呈显著的负相关（P〈0．01），而与冬季降水的相关性不显著，说明春季降水对该地区的沙尘暴有直接的抑制作用，而冬季降水对春季沙尘暴的影响不大；春季和冬季平均平均气温与沙尘日数呈不显著负相关，表明冬、春季节的气温变化对春季沙尘暴的影响有限．

Utilizing the observing data of 18 meteorological stations in Taklimakan dry area, the occurrence and evolution of sand dust storm from 1961 to 2005 in this area was analyzed, and the changing character of climatic conditions of precipitation, temperature, wind speed and sand wind （≥5m/s） day number were analyzed. In Taklimakan dry area, except Luntai, Bachu, and Takmagan, in the remaining 15 stations, the numbers of sand dust days appeared obvious decrease trend each year, in which 11 stations decrease markedly, in this area, the winter and spring precipitation and temperature appeared increasing trends, while the average wind speed in spring decreased constantly and the number of days of sand wind also appeared markedly decreasing trends. The average wind speed and the number of days of mean wind speed ≥5m/s have markedly positive correlation with the number of dust storm days（P〈0.01）, the correlations coefficients is 0.662 and 0.674, respectively. Indicating great wind was the direct cause inducing the sand dust storm. The spring and the winter precipitation and sand dust day number correlation factor was -0.589 and -0.274, respectively, appearing markedly negative correlation with spring precipitation （P〈0.01）, while the correlatively with winter precipitation was not markedly, indicating spring precipitation had direct restrain action on sand dust occurrence, in this area, while the influence of winter precipitation on spring sand dust occurrence was not great. The spring and winter average air temperature appeared not marked negative correlation with dust days, indicating the influence of winter and spring air temperature changing on spring sand dust occurrence was limited.