河西地区近40a来气候变化与风沙活动

利用1951- 1990年14站的年平均气温、降水和大风日数资料,对近40 a来河西地区气候特征作了初步分析。结果表明, 50年代最暖, 60年代最冷, 70年代后气温开始回升但低于50年代的水平。河西地区40 a来是变冷的,全区年平均温度40 a下降了0.21℃,西部下降了0.27℃,东部下降了0.13℃。全区50年代雨量较多, 60年代是近40 a来的最干旱期, 70年代为最湿润期, 80年代又趋于干旱,总体上降水略有增加。最干旱期与最冷期对应,最多雨期并非最高温期,在温度开始回升时降水量最大,雨量与温度的变化并不同步,降水滞后于温度。40 a来河西西部大风日数是增加的,东部是减少的。高温少雨大风日数少,低温少雨大风日数较多,温度开始回升降水达到最大时,大风日数最多。春季大风日数最多,夏季次之,秋冬相差不大。

Studies on Climate Change and Sand-drift Activity in Hexi Region of China in Recent 40 Years

Based on the data of yearly mean air temperature, precipitation and strong wind days from 14 stations in 1951-1990, the climate change and its characteristics in Hexi Area of China in recent 40 years have been analyzed and studied preliminarily. The results show that, during the 40 years in Hexi Area, 1950s were the warmest period, 1960s the coldest decade and 1970s the warmer period but lower than 1950s. The temperature showed a decreasing trend in general. The yearly mean air temperature drop 0.21℃ in the entire region, in details, 0.27℃ in the west part and 0.13℃ in the east part. Precipitation in Hexi Area showed a slightly rising trend during the 40 years. Temporally, 1950s had more precipitation, 1960s were the driest periods, 1970s the rainiest ones and 1980s returned to aridrization. During the last 40 years in Hexi Area the driest periods were in accordance with the coldest periods, while the warmest periods didn't keep pace with the rainiest periods but earlier than the later. Strong wind days above 8 grades were increasing from 1950s on, in 1970s reached the biggest and in 1980s indicated a dropping trend. The strong wind days were the most when temperature started rising. In spring the strong wind days were the most, the summer followed and in autumn and winter were almost equal.