近50年半干旱典型草原区域不同时间尺度上的降水、径流研究

以内蒙古锡林河流域典型草原区域为研究区，采用1963—2015年气温、相对湿度、降水量、风速、日照时数、蒸发量、径流日数据，应用统计分析、趋势检验和Spearman相关分析等方法对研究区区域7项水文气象要素的平均最高值、平均值、平均最低值突变前后变化及突变后停滞特征进行了分析，结果表明；（1）内蒙古锡林河流域典型草原区域的降水量最大月（7月）与径流量最大月（4月）不同，降水天数明显小于径流天数，且降水量远大于径流深，多年丰水季降水总量近似于枯水季的3倍，而多年枯水季径流总量是丰水季的2倍；（2）径流量多年来呈现显著减少的趋势，而降水的整体变化趋势不太明显，存在1998—2011年处于由丰变枯阶段，2011年后有由枯转丰的迹象；（3）年、丰水季、枯水季径流发生突变年份均为2004，同一时期发生突变，年、枯水季径流天数发生突变年份为2007年、2004年，丰水季在此期间未发生突变；（4）该区年径流天数枯水季所占比例居多，径流量年、丰、枯水季突变年限一致，造成突变的驱动因数接近，枯水季径流天数相对于年径流天数突变年份较早，枯水季对引起突变的驱动因数更为敏感；（5）影响该区降水大小的主要气象因素依次为日照时数 > 相对湿度 > 平均风速 > 平均气温 > 降水量=蒸发，影响该区径流大小的主要气象因素依次为蒸发 > 相对湿度 > 平均风速 > 平均气温=降水量 > 日照时数。

Study on Precipitation and Runoff at Different Time Scales in Semi-Arid Grassland Basin over the Past 50 Years

The Xilin River basin in Inner Mongolia steppe area was selected as the study area. Based on the daily data of air temperature, relative humidity, rainfall, wind speed, sunshine time, evaporation, and runoff from 1963 to 2015, the maximums, minimums and averages before and after the abrupt points and the stagnation characteristics after this time point were analyzed by using the statistical method, the M-K inspection method, and the Spearman method. The results showed that: (1) the maxima of precipitation and runoff aroused in different months, the maximum precipitation occurred in July and maximum runoff occurred in April; the number of precipitation day was much less than that of runoff day. The days of precipitation were more than those of the runoff; the amount of precipitation in wet seasons was 3 times of that in the dry season, but the volume of runoff in dry season was 2 times of that in the wet season; (2) the runoff presented the significant decreasing trend over the past years, while the trend of precipitation change was not significant; the precipitation pattern changed from abundance to scarcity between 1998 and 2011, while it changed from scarcity to abundance after 2011; (3) the abrupt year, wet season and dry season of runoff occurred in 2004, the abrupt change of runoff days in a year and dry season occurred in 2007 and 2004, and the change of runoff days in wet season was not found during the period; (4) the number of runoff days in the dry season was majority proportion in whole year; there were the same abrupt years of annual runoff and runoff in wet season and dry season, and their driving factors were similar; (5) the orders of meteorological factors influencing the precipitation followed the sequence: sunshine time, relative humidity, average wind speed, average temperature, precipitation and evaporation; The orders influencing the runoff followed the sequence: evaporation, relative humidity, average wind speed, average temperature, precipitation and sunshine time.