关键词: 降水时空演变, Mann-Kendall趋势检验, 周期, 突变, 长江源区

Abstract: 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.

Key words: temporal and spatial evolution of precipitation, Mann-Kendall trend test, period, abrupt change, headwaters of the Yangtze River