1980—2019年青藏高原降水时空变化特征分析

Analysis on the Characteristics of Spatiotemporal Changes of Precipitation on the Tibetan Plateau from 1980 to 2019

利用青藏高原79个站点的降水观测资料和ERA-Interim再分析资料,分析了青藏高原1980—2019年全年和4个季节降水的气候特征,并通过滑动平均、Mann-Kendall突变检验等方法分析高原降水的时空变化特征。结果表明:(1)高原全年降水量为西北—东南向的均匀带状分布,降水量自东南部向西北部逐步递减;4个季节中,夏季平均降水量最多、冬季最少,春秋两季次之。(2)近40年来,高原年降雨量呈较为迅速的上升趋势,在20世纪80年代降水量为增多的趋势,20世纪90年代初期开始略有减少,1998年以后又表现为波动式的增多;4个季节的降水量变化趋势均趋向增多,其中上升变率较快的为春季降水量,冬季降水的上升速率则较为缓慢。(3)夏季降水偏多年的风场与散度场一致反映出低层的异常辐合、高层的异常辐散;水汽输送也是影响降水的重要因素。

Used precipitation observation data from 79 stations on the Tibetan Plateau and ERA-Interim reanalysis data, the climatic characteristics of precipitation throughout the year and four seasons on the Tibetan Plateau from 1980 to 2019 were analyzed. Further methods such as moving average, MannKendall test method, synthetic analysis are used to analyze the spatiotemporal characteristics of precipitation in the plateau.The main results are as the follows:(1) The annual precipitation of the plateau is uniformly distributed in a northwest-southeast direction,and the precipitation gradually decreases from the southeast to the northwest. Among the four seasons, the average precipitation in summer is the most, and the least in winter, followed by spring and autumn. The annual precipitation is mainly concentrated in summer.(2) The annual precipitation on the plateau showed an upward trend. In the 1980s, the precipitation began to decrease, and the precipitation began to decrease in the early 1990s. After 1998,the precipitation increased in a fluctuating manner. The precipitation in the four seasons all showed an increasing trend, of which the rising rate of precipitation in spring was faster and that in winter was slower.(3) The precipitation in summer has been more than for many years, the lower tropospheric air currents converge, and the upper divergence.