利用1961—2019年宁夏20个气象站逐日气象资料以及农业用水量和耗水量等资料,采用数理统计方法,从降水量的时空差异、潜在蒸散量和降水量差值、持续“湿”和“干”过程时长、关键等雨量线、不同等级降水日数和降水强度及其对降水量的贡献、农业用水量和耗水量等方面,从1961—1982年、1983—2010年、2011—2019年3个时段分析了宁夏降水资源在西北暖湿化背景下的演变特征。结果表明:（1） 年降水量总体呈减少趋势,阶段性特征明显、区域性和季节性差异大,各地、各季节在2011年以来降水量增多,且超过1961—1982年和1983—2010年。（2） 区域间降水量增加幅度差异增大及年际间的不同步,尤其中雨量和大雨量的变化差异使得区域间降水之差越来越大,南北“暖湿”和“暖干”现象同时出现的几率增大;（3） 潜在蒸散量增加,降水量减少,两者之差增加,中北部春季、南部山区秋季增加最多;（4） 引黄灌区持续“干”时长增长,春、夏旱或春夏连旱仍然频繁发生,农业耗水量占用水量比例仍然较大,中南部持续“干”时长缩短,持续“湿”时长增长;（5） 总体上,200 mm等雨量线有南移趋势,400 mm等雨量线的西侧有南移趋势,2010年以来随着降水量增加有所北移;（6） 降水总日数减少,降水强度增强;小雨日数均为减少趋势,大部分量级降水强度呈增强趋势;春季中雨量和大雨量、夏季大雨量和暴雨量、秋季小雨量和中雨量的变化对总雨量的变化作用突出。总体上,2011年以来降水增多有利于生态环境恢复,然而也会使得极端降水及无雨日数增加,增加了城市内涝、山洪泥石流等次生灾害的风险,同时,南北差异增大,增加了防灾减灾难度。

Ningxia is in the east of Northwest China,and although it is only more than 400 kilometers from north to south,its climate is quite different. In this paper,the characteristics of the precipitation resources pattern evolution in Ningxia under the background of warm-humid in northwest are analyzed,including the precipitation, the difference between potential evapotranspiration and precipitation,the length of continuous “wet” and “dry” processes,the key isohyets of 200 mm and 400 mm,and precipitation intensity and days of different grades and their contribution to precipitation,the relationship between precipitation and water consumption. The results show that: (1) The annual precipitation decreased on the whole,but the stages characteristics and the regional and seasonal difference were higher. Only the precipitation in spring increased around the year of warm-humid in northwest (1983), but which in all regions and seasons increased since 2011 and was more than that of 1961-1982 and 1983-2010. (2) The higher regional difference of precipitation increasing-range and the regional annual unsynchronism,especially the variation difference between medium and large rainfall made the difference of precipitation between regions more and more big and the probability of “warm-wet” and “warm-dry” phenomenon occur at the same time between the north and the South increases. (3) The potential evapotranspiration increasing and the precipitation decreasing made the difference between evapotranspiration and precipitation increase,which in spring and in autumn separately in the Middle North region and in southern mountains was the most. (4) In the Yellow River Diversion Irrigation Area,the continuous drought process increased,but there was no increase trend of the continuous rainy month,and drought in spring,summer or even in spring and summer was still frequent,so the proportion of agricultural water consumption was still large. While the continuous drought process was shortened and the continuous rainy months increased in the south central part. (5) The 200 mm isoline had a southward trend,and the west side of the 400 mm isoline had a southward trend, and which moved northward with the increase of precipitation. (6) The total days of precipitation decreased and the intensity of precipitation increased. The number of light rainy days in all regions and seasons decreased,and most of the precipitation intensity increased. The contribution rate changed remarkably of moderate and heavy rainfall in spring,all of the four magnitudes rainfall in summer and light and heavy rainfall in autumn. Then the changes of moderate and heavy rainfall in spring, heavy and rainstorm rainfall in summer, light and moderate rainfall in autumn played an important role in the change of total rainfall. The precipitation resources pattern evolution in Ningxia had both advantages and disadvantages,and on the whole, the precipitation increase since 2011 was conducive to the restoration of ecological environment,but it would also increase the extreme precipitation and rainless days also,and the risk of urban waterlogging, mountain flood and debris flow. At the same time,the precipitation difference increasing between the north and the South made the difficulty of disaster prevention and mitigation increase.