乌海市沙尘暴日数变化特征及相关因素分析

Variation Characteristics and Related Factors of Sandstorm Days in Wuhai City

使用乌海市国家一般气象站1961—2019年沙尘暴日数、降水量、气温等气象要素数据以及土壤水分、绿化覆盖率数据,分析了乌海市沙尘暴变化特征和影响因素。结果表明:(1)乌海地区沙尘暴日数呈减少趋势,以5.6 d/10 a的速度下降。(2)沙尘暴日数具有明显的月季变化,主要集中在3—7月,表现为“春夏多,秋冬少”的特征。(3)内蒙古荒漠化和沙化面积的减少,乌海地区绿化覆盖率的增加,为沙尘暴日数的减少提供了基础条件。(4)10~50 cm土壤相对湿度与春季沙尘暴日数的相关性较小或相关不显著;前一年年平均气温、平均水汽压与春季沙尘暴日数呈负相关;前一年平均风速、夏季大风日数、当年春季大风日数与春季沙尘暴日数呈正相关。

Using the data of weather elements such as precipitation,temperature and sandstorm from 1961 to 2019,as well as the data of soil moisture and green coverage from the National General Weather Station of Wuhai City,the characteristics and influencing factors of sand storms in Wuhai City are analyzed.The results show that:(1)The number of sandstorm days in Wuhai area shows a decreasing trend,with a rate of 5.6 d/10a.(2)There are obvious changes in the rose season,mainly concentrated in March to July,showing the characteristics of“more in spring and summer,less in autumn and winter”.(3)The reduction of desertification in Inner Mongolia and the increase of green coverage in Wuhai area provide the basic conditions for the reduction of sandstorms.(4)The correlation between 10-50cm soil relative humidity and the number of spring dust storm days is small or not significant.The previous year’s annual average temperature and average water vapor pressure are negatively correlated with spring dust storms.The average wind speed of the previous year,the number of gale days in summer and the number of gale days in spring were positively correlated with the sandstorm in spring.