塔里木盆地沙尘天气的气候特征

利用塔里木盆地周边28个气象站1961-2003年逐日地面观测资料,分析了沙尘天气的空间分布特征和时间演变规律,在构建多元线性回归影响因子模型的基础上,探讨了气温、地温日较差、气压、平均风速、降水量5个气候因子对沙尘天气的影响程度,建立了沙尘指数.塔里木盆地沙尘天气有着明显的地域分布特征和季节变化,春季是高发期,沙尘日数与气候因子季节变化的关系非常密切.沙尘日数年际变化呈明显的减少趋势,具有6～9 a的振荡周期.3-9月盆地沙尘天气的主要影响因子依次是平均风速、降水量和地温日较差.春季降水量占主导地位,6-9月平均风速占主导地位.选取各月对沙尘天气影响有意义的气候因子建立了沙尘指数,它在时间序列上对沙尘天气有很好的反映,可用来做沙尘天气出现日数的气候预测.

Climatological Characteristics of Dust Weathers in the Tarim Basin

The authors study the temporal and spatial distributions of dust weathers and the trends in occurring days of dust weathers using data from 28 observational stations in the Tarim Basin during the period of 1961-2003. Five meteorological factors, which affect dust weathers, are analyzed, including air temperature, daily range of ground temperature, air pressure, average wind speed and precipitation on dust weathers with the method of linear multi-regression. Based on the analyses, the indices of dust weathers are constructed. The results show that the regions where dust weathers occur most frequently are in the Taklimakan Desert and its southern marginal zone. The temporal and spatial distributions of dust weathers are different in these regions. Dust weathers occur most frequently in spring. The days of dust weathers are closely related to daily variations of the meteorological factors. Dust- weather days have a tendency toward decrease, lnterannual variations of dust-weather days have a period of about 6-9 years. According to their importance in affecting the occurrence of dust weathers, the factors are in an order of average wind speed, precipitation and daily range of ground temperature over March-September. In spring, the dominant factor is precipitation. The dominant factor is average wind speed over June-September. Indices of dust weathers are constructed to demonstrate the temporal series of dust weathers and to predict the occurrence of dust weathers.