Spatial and temporal precipitation variability in the source region of the Yellow River

摘要

Spatial patterns of annual and seasonal precipitation over the source region of the Yellow River and the corresponding long-term trends for the period 1960-2013 are investigated using the meteorological station data. The spatial precipitation variability analysis shows an increasing gradient of precipitation from northeast to southwest in the study area. Annual, spring, summer, and winter precipitation present increasing trend, but autumn precipitation shows a decreasing trend in the last 50 years. It is also noted that the distribution of the intra-annual precipitation is very uneven, precipitation in rainy season (May-October) accounts for about 90 % of the total annual rain. Meanwhile, this research analyzes the spatial precipitation characteristic of the rainy season in 2013 (mainly from June to September). Based on the observed precipitation data and the meteorological station data, the rainy season precipitation that varies according to different topographic conditions is analyzed, and the regression model between recorded precipitation and geographical factors is built up too. The spatial distribution graph of the rainy season precipitation is generated on GIS platform by regression model and graphical features. This distribution shows a general northeast-southwest gradient of increasing rainy season precipitation in the study area and has detailed spatial precipitation characteristic along with altitude.