我国西北干旱区区域性沙尘暴特征及成因研究

Characteristics and Cause of Regional Sand-dust Storm Process in Northwest China

利用1954—2001年131个国家基本基准气象站的逐日观测资料,运用小波分析等统计方法分析了中国西北地区区域性沙尘暴天气过程特征及变化趋势,并对其成因进行了初步探讨。结果表明:1954—2001年,中国西北地区共出现了1974次区域沙尘暴天气过程,平均每年42次,共出现了247次强沙尘暴天气过程,平均每年5次。沙尘暴和强沙尘暴天气过程的地理分布比较一致,有两个高发区:一个位于南疆盆地;另一个位于西北地区东部。沙尘暴天气过程主要发生在3～7月,强沙尘暴天气过程集中发生在3～5月。近48a来区域沙尘暴和强沙尘暴天气过程都呈波动下降趋势,且强沙尘暴天气过程比沙尘暴天气过程下降趋势更为剧烈。1956—1987年是沙尘暴和强沙尘暴天气过程的多发时期,1988年后无论沙尘暴或强沙尘暴天气过程均大幅减少。2月的北极涛动指数对当年沙尘暴天气过程的发生多少具有预报意义。

Based on the available original sand-dust storm data observed at 131 meteorological stations from 1954 to 2001 in arid regions of Northwest China, the characteristics and cause of regional sand-dust storm process happened within 48 years was analyzed with statistics methods such as Mexican Hat Wavelet. It is shown that 1975 regional sand-dust storm processes and 247 regional strong sand-dust storm processes have been confirmed from 1954 to 2001 in arid regions of Northwest China. The spatial distribution of regional sand-dust storm process and regional strong sand-dust storm process is coincident. Tarim Basin and the eastern part of Northwest China are two frequently occurred areas of sand-dust storms. The regional sand-dust storm processes concentrate in March to July, while strong sand-dust storm processes in March to May. Whether regional sand-dust storm processes or strong sand-dust storm processes all have reduced fluctuantly from 1954 to 2001, during which time from 1956 to 1987 was the most frequently occurred period, and since 1988 all reduced obviously. The Atlantic Oscillation index in February has forecasting significance for the number of regional sand-dust storm process in the same year.