关键词: 时空分布, 祁连山地区, TRMM降水, 最大降水高度带, 时空分布, 祁连山地区

Abstract:

Atmospheric precipitation is the most important link in the process of global water vapor cycle and energy conversion, and it is the material basis for the global ecosystem to maintain stability. Therefore, it is increasingly important to monitor and forecast precipitation for regional climate analysis, water resources evaluation and hydrological process simulation. As an important ecological barrier, the Qilian Mountains plays a critical role in maintaining the natural environment and social development in Northwest China. Thus, it is of great significance to examine the distribution and variation of precipitation in the Qilian Mountains. However, there are relatively few studies on precipitation in mountainous areas due to some factors, such as insufficient measured data, complicated precipitation environment and so on, which limits the further study to some extent. In recent years, with the development of satellite inversion technology, the application of satellite to precipitation retrieval is becoming more and more mature, which provides data support for the study of precipitation in mountainous areas. Therefore, this paper uses the data of TRMM monthly precipitation and ground meteorological station precipitation, combined with the error evaluation and other mathematical statistics and Kriging interpolation method, to calibrate TRMM precipitation, so as to examine the spatiotemporal variations of the zone of the maximum precipitation in the study area. The results show that: (1) The overall performance of TRMM precipitation is good in the Qilian Mountains. The measured annual precipitation of 31 meteorological stations has a high correlation (0.94) with the TRMM data, and the correlation coefficients of the seasonal average precipitation are 0.87 (spring), 0.89 (summer), 0.88 (autumn) and 0.7 (winter). (2) The errors of some stations are large and the low values are overestimated and the high values are underestimated. (3) Annual average precipitation shows a decreasing trend from east to west in the region, and zones of the maximum precipitation in the eastern, central and western parts appear at 4100 m, 4500 m and 4700 m, respectively. The vertical variation rates of the average annual precipitation are 16.6 mm/100 m, 10.8 mm/100 m, 9.8 mm/100 m, respectively. (4) The precipitation fluctuated and increased in the eastern, central and western parts of the study area from 1998 to 2016. The zone of the maximum precipitation also shows a fluctuating upward trend. The maximum precipitation height in each season decreases in the order of summer, spring, autumn and winter.

Key words: TRMM precipitation, maximum precipitation height zone, spatial and temporal distribution, Qilian Mountains area, TRMM precipitation, maximum precipitation height zone, spatial and temporal distribution, Qilian Mountains area