淖毛湖区域沙尘暴气候特征分析

对1961—2010年淖毛湖气象站沙尘暴资料的分析表明，沙尘暴主要出现在3—5月，4月份最多；沙尘暴天气主要集中在白天，占总次数的83%，夜间相对较少，只占17%。50年内淖毛湖出现沙尘暴天气过程804次，以西方和西北方冷空气入侵为主，集中发生在3—5月；50年来淖毛湖沙尘暴日数呈减少趋势，按线性拟合其减少率为0.711 d/10 a。20世纪60年代中期到70年代沙尘暴日数呈现急剧增加趋势，1974年沙尘暴日数多达54 d，20世纪80年代后沙尘暴日数呈现急剧下降趋势，年日数减少到1 d，甚至个别年份未出现沙尘暴天气，该时期大风日数减少、风力强度减弱是主要原因外，生态环境改善，局地植被增加也是重要因素。

Sandstorm Characteristics in Naomao Lake Area

Through analyzing sand-storm data of Naomao Lake Weather Sta-tion from 1961 to 2010, sandstorm main-ly occurred from March to May, especial-ly in April;sandstorm mainly occurred in the daytime （accounting for 83% of the total）, and less at night （only 17% of the total）. Within the half century, 804 sand-storms occurred in the region of the Naomao Lake, especially cold air invad-ed from west and northwest from March to May;the sandstorm days in this region reduce, and the reduction rate of the lin-ear fitting was 0.711 d/10 a. From the middle 1960s to the 1970s, sandstorm days increased drastically, achieved 54 days in 1974; sandstorm days reduced sharply since the 1980s, by 1 day annu-ally, even no sandstorm occurred in some years, because heavy wind days and wind strength reduced, ecological environment improved, and regional veg-etation increased.