A high-resolution global runoff estimate based on GIS and an empirical runoff coefficient

Abstract

This paper reviews 110 years of global runoff estimation. By employing the method of ordinary least square regression on a sample region's runoff coefficient, an empirical formula of a runoff coefficient is calculated for China. Based on this empirical formula applied with a high-resolution grid of precipitation, runoff is calculated resulting in an equally high-resolution map of global runoff using a geographic information system (GIS). The main results are (1) the global total runoff volume is 47,884 km3, (2) the average runoff depth is 359 mm, (3) the interior drainage region's runoff volume is 1,663 km3, and (4) the average runoff depth is 58.4 mm. The results are compared with the results of the existing literature on global runoff. This study emphasizes the importance of runoff and groundwater recharge in arid and semi-arid regions where the estimation value of runoff depth is significantly increased. HIGHLIGHTS By employing the method of ordinary least square regression on the sample region's runoff coefficient, the empirical formula of the runoff coefficient is calculated.; Based on the empirical formula and high-resolution grid of precipitation, the high-resolution field of global runoff is calculated.; Main results are that the global total runoff volume is 47,884 km3 and the average runoff depth is 359 mm.; The interior drainage region's runoff volume is 1,663 km3 and the average runoff depth is 58.4 mm.; This study emphasizes the importance of runoff and groundwater recharge in arid and semi-arid regions where the estimation value of runoff depth is significantly increased.;

Keywords

• geographic information system
• global runoff
• high-resolution
• interior drainage
• runoff coefficient