中国西北地区东部沙尘暴区划研究

利用西北地区东部98个气象站的沙尘暴日数、持续时间资料,采用经验正交分解(EOF、REOF)、滑动t检验、Mann-Kendall突变检验及小波变换,对其时空分布规律进行了诊断分析。结果表明:整个区域沙尘暴日数大致呈北多南少型分布;受大尺度气候异常的影响,全区一致的沙尘暴异常是该区域最主要的表现形式。西北地区东部沙尘暴日数空间异常可分为4个沙尘暴气候区:河西走廊—阿拉善区、鄂尔多斯—乌兰布和区、柴达木—茶卡寒旱区、陕甘宁黄土高原区。河西走廊—阿拉善区沙尘暴频次最高,陕甘宁黄土高原区频次最少;近40多年来西北地区东部沙尘暴日数呈减少的态势;沙尘暴日数在20世纪80年代中期到末期发生气候突变,突变起源于沙漠及相邻地区,并由外围沙漠区向中间地带传播。沙尘暴持续时间最长的不是高频区河西走廊—阿拉善区,而是鄂尔多斯—乌兰布和区,最短的也不在频次最低的陕甘宁黄土高原区,而在柴达木—茶卡寒旱区;沙尘暴高发的河西走廊—阿拉善区、鄂尔多斯—乌兰布和区,持续时间没有发生明显的突变,这两个区域20世纪80年代中期以后沙尘暴持续时间变率增大;90年代以后沙尘暴持续时间有增长的趋势。

Study on Sandstorm Climatic Regionalization in Eastern Part of Northwest China

In this paper, we used data of the days and duration time of sandstorms and 98 weather stations of eastern part of Northwest China together with the methods such as EOF, REOF, t-test, Mann-Kendall and wavelet analysis to analyze the spatio-temporal distribution and evolution law and the cyclical characteristics of each climate area on the days and duration time of sandstorms. The result indicated: the sandstorm days were more in the north and less in the south of the eastern part of Northwest China. Being influenced by macro-scale weather system, the main manifestation of the sandstorm days was abnormal in the entire area, but there was regional difference. The sandstorm days in eastern part of Northwest China could be divided into four climate areas. They were Hexi Corridor-Alashan area, Ordos-Ulan Buh area, Qaidam-Chaka cold area and Shaanxi-Gansu-Ningxia Loess Plateau area. The number of sandstorm days in eastern part of Northwest China was reducing in recent a 40 years. There was a 4-year cycle in all climate areas. The jump of sandstorm days took place in the mid to the late of 1980s. The source area of the jump of sandstorm days was in desert areas and their correlative areas, and the jump spread from these areas to the remaining areas. There were different distribution characteristics between duration time and sandstorm days . The longest (shortest) duration time of sandstorm was not in the areas where the sandstorm days were the most (least). The duration time has different change characteristic in different climate areas. The difference existed in the time of jump between duration time and sandstorm days. The jump of duration time of sandstorm did not take place in the Hexi Corridor-Alashan area and Ordos-Ulan Buh area where the sandstorm days were more. And the change rate of duration time of sandstorm increased after the mid 1980s. There was the tendency of the duration time of sandstorm changing longer after the 1990s.