基于长江源区1956—2016年8个测站的逐日降水数据,采用集中度、集中期、Mann-Kendall趋势检验和滑动T检验法等统计方法,分析了长江源区近60 a来降水量序列的空间分布特征、年际和年内变化趋势、突变和周期变化特征等。结果表明:① 长江源区降水量呈现明显的增加趋势并通过显著性检验,增加速率10.2 mm/(10 a),多年平均降水量为344.8 mm;②长江源区的降水量在时间维度上存在显著的不均匀现象,多数聚集于为6—9月份,约占全年降水量的81.1%;③长江源区的降水量序列在1997年发生显著性突变,降水量变化存在25 a左右的第一主周期,第二、第三周期分别为3 a和10 a;④长江源区内各站点年降水量增加趋势空间变异性较大,总体呈现通天河上游降水量增加速率大于下游。研究结果可为长江流域水资源可持续利用和生态安全提供重要的科学依据。

Based on the daily statistical data of eight stations in the source area of the Yangtze River from 1956 to 2016, we examined the spatial distribution, intra-annual and inter-annual trends, abrupt change and periods of precipitation in the headwaters of the Yangtze River in the last six decades by using precipitation concentration degree, precipitation concentration period, Mann-Kendall trend test and moving-T test. Results revealed that: 1) the precipitation in the headwaters of the Yangtze River presented an evident increasing trend, passing the significance test with the growth rate amounting to 10.2 mm/10 a and the multi-year average precipitation reaching 344.8 mm. 2) Precipitation in the headwaters of the Yangtze River was significantly uneven in time dimension, most concentrated between June and September, accounting for 81.1% of the whole year. 3) Precipitation changed abruptly in 1997, with the first principal period of 25 years, the second and the third principal period of 3 years and 10 years, respectively. 4) The annual precipitation growth varied largely in spatial scale among different stations, i.e., the growth rate of precipitation in the upstream of Tongtian River was larger than that in the downstream. The research findings offer support for sustainable water resources utilization and ecological security in the Yangtze River basin.