关键词: 水量平衡, NLDAS, MODIS MOD16, 蒸散发, 蓄量变化, 美国

Abstract: In order to understand the spatio-temporal variation of water balance and the impact of climate, vegetation, topography, human activities and other factors on the water storage change(WSC) in different spatial scales, based on the water balance formula, this paper calculates the spatio-temporal variation characteristics of WSC in the mainland of United States by using different combinations of remote sensing evapotranspiration data, remote sensing and ground observation precipitation data, re-analysis precipitation data, model simulation of evapotranspiration and runoff data, and site measured runoff data. The results show that the spatio-temporal distributions of the WSC from different data sources are greatly different and all have significant deviations. WSC in the western coastal areas and the mountainous areas have significant seasonal fluctuations, while that in the eastern areas are relatively stable. Precipitation has the greatest influence on WSC. The causes of the significant deviation of the calculated WSC based on different data sources include: ① lack of understanding and measurement of basin water cycle composition structure; ② uncertainty of precipitation, runoff and evapotranspiration data sets;③ time and space scales.

Key words: water balance, NLDAS, MODIS MOD16, evaporation, water storage variation, United State;