Spatial and temporal pattern difference of blue-green water flows in typical reference years in the Heihe River Basin, northwestern China.

In order to better understand the spatial and temporal pattern difference of blue-green water in typical reference years (dry years, wet years, and normal years) on a watershed scale, we chose the inland river (Heihe River Basin) in northwestern China to analyze the spatial and temporal distribution pattern difference of blugreen water in climate influence. We obtained the typical reference years by using two indicators firstly, namely standardized precipitation index ( SPI) and precipitation anomaly index (M). The results showed: 1) the blue-green water of Heihe River Basin had a decreasing trend from upstream to downstream; 2) the blue-green water quantities in typical wet year (1998,25.272 billion m3 ) were more than in typical dry year ( 1978, 16.773 billion m3 ); 3 ) the green water coefficient, i. e. the percent of evapotranspiration in total water, was greater in typical dry years (90. 30% ) than in typical wet year (85.41% ). Meanwhile, the percent of green water in total water resource was greater in typical dry year or dry region (downstream) than in typical wet year or wet region (upstream). The study carried out a comprehensive analysis of temporal and spatial difference of blue- green water in Heihe River Basin of northwestern China in typical years, and it can provide references for improving the management of inland river water resources in China.