1961-2015年陕西省不同等级降水事件变化特征

利用19612015年陕西省70个气象观测站的逐日降水资料，采用线性倾向估计、趋势分析及Mann Kendall等方法，分析了陕西省不同等级降水量、降水日数及降水强度的气候变化特征。结果表明：无论是降水量、降水日数，还是降水强度，均呈现出南多北少的分布特征，且随着降水级别的逐级增加，地区分布差异逐渐增大；整体上降水量和降水日数呈现出减少趋势，其中降水日数的下降趋势均非常显著，全省年均降水日数的气候倾向率达到了-3.83天·10a-1，通过了0.01的显著性检验，降水强度的增加趋势通过了0.05的显著性检验，每10 a全省年均降水强度增加0.15 mm·d-1；陕西降水量及降水日数的减少主要体现在春秋两季小雨及中雨的减少上，小雨降水强度在夏、秋两季的气候倾向率分别为0.05和0.04 mm·d-1·10a-1，其上升趋势分别通过了0.01和0.1的显著性检验，这是年均降水强度上升的主要原因；陕西年均降水量及降水日数自1984年出现了突变性下降，而降水强度的突变则出现在2004年，之后一直呈现持续的上升趋势。

Variation Characteristics of Precipitation Events in Different Levels in Shaanxi Province from 1961 to 2015

Based on daily precipitation data of 70 meteorological stations of Shaanxi province from 1961 to 2015, climate variation characteristics of amount, days and intensity of precipitation at different levels are analyzed using methods of linear trend estimate, trend analysis, Mann Kendall and so on. The results show that: the amount, days and intensity of precipitation all decrease from south to north.With precipitation levels increasing, the regional difference gradually increases. The precipitation amount and days are in a decreasing trend in general, and the decreasing trend of precipitation days is very significant. The climate tendency rate of the provincial annual average precipitation days reaches -3.83 d·10 a-1, through the significance test of 0.01. The increasing trend of precipitation intensity through the significance test of 0.05, the annual average precipitation intensity increases 0.15 mm·d-1 in every 10 years. The reducing of the precipitation amount and days in Shaanxi is mainly reflected in the decline of light and moderate rains in spring and autumn. The climate tendency rates of precipitation intensity of light rain in summer and autumn are 0.05 and 0.04 mm·d-1·10a-1, and the increasing trend through the significance test of 0.01 and 0.1 respectively, which is the main reason for the increasing of annual average precipitation intensity. The annual average precipitation amount and days in Shaanxi has a sudden drop since 1984, and the mutation of precipitation intensity appears in 2004, after that it has been showing a continuous upward trend.