泸水河中上游流域近55年降水时空分布特征

Analysis on the spatiotemporal distribution of precipitation in upper and middle reaches of the Lushui river during the past 55 years

通过kendall秩次相关检验法分析泸水河中上游流域近55年(1959~2013年)降水序列变化趋势,并用专业制图软件做出区域降水量及降水倾斜度值等值线图,研究该区域降水的时空分布特征.结果表明:时间上,泸水河中上游流域降水总体上以年均1.720 mm/a的幅度增加,其中灌溉期和枯水期降水呈增加趋势,汛期降水总体呈减少趋势.此外,研究范围内降水年内、年际分布不均,年际降水最大值与最小值极值比为1.96,年内降水主要集中在主汛期(4~6月),占全年降水总量的44.2%.空间上,对于年序列而言,总体上游降水高于下游,上游在章庄附近形成高值区,由中心向周边不断减少,在东谷附近出现低值中心;对于各降水时间段降水序列而言,汛期降水高值出现在章庄附近,而增幅最大为洋溪站(1.099 mm/a),降幅最大为东谷站(-1.189 mm/a),灌溉期降水高值与增幅高值均出现在章庄附近;枯水期降水增幅高值出现在洋溪附近.

On the basis of precipitation database in upper and middle reaches of the Lushui river during the period from 1959 to 2013 ,the long - term trend of precipitation in upper and middle reaches of the Lushui river was analyzed by using the Kendall rank correlation test, and the isopleth maps of the series of precipitation were made by professional mapping software, the spatiotemporal distribution of the long - term trend of precipitation in upper and middle reaches,,of the Lushui fiver was analyzed. The study results are as follows：firstly, the mean annual precipitation was in an increase trend and its gradient was 1. 720 mm / a, the irrigation period and the withered water period showed an increasing trend, and the flood season showed a decreasing trend. In addition, the precipitation of flood season occupied 44.2% of the annual precipitation. Secondly, spatially, upstream annual precipitation is higher than downstream, the maximum value of annual precipitation oc- curred in the Zhangzhuang station, and the maximum value occurred in the Donggu station. In all periods except the flood; season, the precipitation showed an increasing trend all over the studied area, the maximum value of the gradient in irriga- tion period occurred in the Zhangzhuang station, and the maximum value of the gradient in withered water period occurred in the Yangxi station. The values of gradient in flood season were ty, the reduction gradient of Donggu station was the largest, that station was the laraest, that was 1. 099 mm/a. both negative and positive showing the change complexi- was -1. 189mm/a, and the increment gradient of Yangxi