CHARACTERISTICS OF BASIN AVERAGE PRECIPITATION ESTIMATED FROM WATER BUDGET

Abstract

 Rain gages have problems that they don’t observe precipitation at mountain area because they are sparse there, and they can’t capture snowfall enough. Therefore, the basin average precipitation from them may not be suitable to evaluate it in climate models and so on for basin scale or more. Aiming to evaluate precipitation without influenced by these problems, this study estimates basin average precipitation from water budget using observed runoff, evapotranspiration, soil moisture and snow water equivalent ; the last three values are calculated by the land surface model SiBUC. And then, the bias in d4PDF was evaluated using both precipitation estimated from water budget and the precipitation grid data APHRODITE. It reveals that the former is better to evaluate basin average d4PDF precipitation than the latter.