近50a来民勤绿洲-荒漠过渡带气候变化及沙尘天气特征

Climate Changes and Dust Events in Minqin Oasis-Desert Transitional Zone in the Past 50 Years

根据近50a民勤绿洲-荒漠过渡带气象和风沙观测资料,对过渡带温度、降水、蒸发量、相对湿度、风沙活动等气候要素进行了系统的分析。结果表明,近50a过渡带平均增温率为0.009℃.a-1,20世纪80年代后增温显著,增温率高达0.025℃.a-1,增温主要发生于冬、春两季;降水呈波动上升趋势且年际稳定性增强,近8a与60年代相比,增加幅度达27.45%,增加主要发生于春、秋两季;蒸发量减少,相对湿度线性增加;受气候变化,沙尘暴在近50a持续减少,而扬沙和浮尘天气与人为干扰关系密切,存在波动和反弹;气候变化对过渡带退化植被的恢复与重建以及沙漠化的逆转将起到正面作用。

Based on meteorological data and dust events data during the past 50 years,the authors systematically analyzed the changes of temperature,precipitation,evaporation capacity,dust events and some other climate factors of oasis-desert transitional zone in Minqin,Gansu,China.The results indicated that the mean warming rate in this transitional zone was 0.009 ℃·a-1 during the past 50 years;the temperature increase was relatively significant after 1980s and the warming rate reached up to 0.025 ℃·a-1;the temperature increase occurred mainly in winter and spring.The precipitation increased in a fluctuating way and the stability was strengthened.Compared to that of 1960s,the precipitation increased by 27.45% in 2000s,and the increase mainly occurred in spring and autumn.Evaporation capacity decreased and relative humidity presented a linear increase.Influenced by the climatic changes,the sandstorm days decreased constantly in recent 50 years,but the sand blowing and dust floating presented fluctuation and rebound because they had close relation with the human interference.Climate change will be benefit to the recovery and rebuilt of vegetation as well as reversion of desertified lands.