甘肃农牧交错带1971—2019年降水量变化研究

为了探索甘肃农牧交错带影响农牧业生产的关键因素——降水的变化规律，本研究利用1971-2019年甘肃农牧交错带30个气象站点的降水量时间序列，研究了区域49 a来降水的年、季、月变化趋势和空间分布特征，并运用Mann-Kendall突变检验法和小波分析法分析了区域降水量变化的突变特征和周期特征。结果表明：近49 a来，研究区年平均降水量为442.24 mm，以5.39 mm·（10a）^-1的速率增加，并分别于1973，1980，1984和2018年发生了突变；就季节而言，夏季降水量最多，但呈微弱减少趋势，秋季降水量增加最明显，冬季降水量最少但呈微弱增加趋势，4季降水量均发生了突变；年内各月降水量变化不一致，3月和8月的降水量呈减少趋势，其他月份的降水量均呈增加趋势，其中5月降水量增加最为明显；从空间分布来看，研究区年降水量南多北少，自南向北逐步递减；而年降水量变化速率自南向北逐步递增。

Study on the Change of Precipitation in Agro-Pastoral Ecotone of Gansu Province from 1971 to 2019

In order to explore the change law of precipitation,which was the key factor affecting the production of agriculture and animal husbandry in Agro-Pastoral Ecotone of Gansu Province,this paper used precipitation time series of 30 meteorological stations in Agro-Pastoral Ecotone of Gansu Province from 1971 to 2019 to study the annual,seasonal and monthly variation trends and spatial distribution characteristics of regional precipitation,and used the Mann-Kendall mutation test and wavelet analysis to analyze the mutation and periodic characteristics of regional precipitation. The results showed that:in the past 49 years,the average annual precipitation in the study area was 442.24 mm,which increased at the rate of 5.39 mm·(10a)^-1,and mutated in 1973,1980,1984 and 2018,respectively. As far as season was concerned,the precipitation in summer was the most,but it showed a slight decreasing trend,the increase of precipitation in autumn was the most obvious,the precipitation in winter was the least,but showed a slight increasing trend,the precipitation in all four seasons had abrupt changes. The precipitation in March and August showed a decreasing trend,while the precipitation in other months showed an increasing trend,with the most precipitation increase in May. From the spatial distribution,the annual precipitation in the study area was more in the south than that in the north and decreased gradually from south to north,but the precipitation tendency rate increased gradually from south to north.