近52年来磴口地区扬沙天气变化特征

分析了磴口近52年(1954—2005)逐月扬沙天气。结果表明:(1)该区扬沙天气一年四季均出现,但主要发生在春季,其次为冬季;一年中扬沙天气高峰出现在4月,低谷出现在8-9月。(2)年及春季、冬季、夏季扬沙日数各年代际变化规律一致,均为逐年代递减。秋季与其他三季扬沙日数变化略有不同。(3)年及四季扬沙日数均为线性下降,线性方程均通过了置信度0.001的显著性检验,下降率为年>春季>冬季>夏季>秋季,20世纪80年代为转折期,体现为"先多后少"的特点。年扬沙日数与春季扬沙日数滑动序列的波动趋势比较接近。

Variation Characteristics of Sand-Blowing Weather in Dengkou Region in Recent 52 Years

Sand-blowing weather in Dengkou county over the months during 1954 to 2005 were analyzed. Result shows that： （1） sand-blowing weather occur in the entire year, but mainly during spring and secondly winter;the peak time appear in April, and the low ebb appear from August to September in a year; （2） the interdecadal change rule of the annual , spring, summer and winter sand-blowing days are fit, showing decreasing trend. However, change of sand-blowing days during autumn is different from other three seasons; （3） annual ＆ 4 seasons＇ sand-blowing days appear a linear decline; the significance inspection for the linear equation shows the confidence degree of equation is 0. 001 ;the order of declining rate is annual〉spring〉winter〉summer〉 autumn. 1980＇ s is the turning point, showing the feature of ＂majority to minority＂. The fluctuation trend of sliding sequence for annual number of sand-blowing days has a close accordance with that in springs.