1960～2010年漓江流域降水变化特征研究

Characteristics of Precipitation in Lijiang River Basin during 1960～2010

利用漓江流域及周边地区25个降水观测点50年的监测数据,通过Mapgis 6.7计算流域年降水量和月降水量.在此基础上,采用变差系数法、5年滑动平均法和Mann-Kendall检验法,分析漓江流域1960～2010年降水变化规律.结果表明：（1）1960～2010年,漓江流域降水年际动态为波动增加,年降水量每10a增加23.1mm;其中1970～2010年间,漓江流域年降水变化表现为波动减少,年降水量每10a减少14.6mm;但增减趋势都没有通过显著性检验;（2）漓江流域年内降水具有典型的雨季和旱季交替特征,雨季降水占全年降水的76.26％;（3）漓江流域月降水量随时间变化具有规律性的增减,其中1月和6月降水量随着时间推移增加,4月降水量随着时间推移而减少,1、4、6月的这种增减趋势通过99％的显著性检验;（4）漓江流域降水年内变化幅度比年际明显,年降水量变差系数小于0.18,月降水量变差系数大于0.61.

The annual and monthly precipitation were calculated with Mapgis 6.7 based on the 50-year precipitation data at the 25 stations in the Lijiang River Basin and surrounding areas, on which the change of the precipitation during the period of 1960-2010 was analyzed using coefficient of variation method,five-year moving average method and Mann-Kendall test. The results show that （1） The annual precipitation in the Lijiang River had an increasing trend with fluctuation and increased by 23.1 mndl0a from 1960 to 2010, during which the annual precipitation was decreased by14.6 mm/10a from 1970 to 2010. But both of the trends were not significant. （2） The annual precipitation in the Lijiang River Basin has the typical characteristics with rainy season and dry season. The precipitation in rainy season account for 76.26% of the total. （3） The precipitation in January and June show an increasing trend, while the trend in April show a sign of decreasing. （4） There are obvious differences between annual variations and monthly variations and the variation coefficient is less than 0.18 and more than 0.61, respectively.