美国本土地区蓄量时空变化特性及其影响因素研究

为了解美国本土地区水量平衡的时空变化规律以及气候、植被、地形、人类活动等影响因子对不同空间尺度蓄量变化的影响,基于水量平衡公式,利用遥感观测蒸散发数据、遥感与地面观测融合降水数据、再分析降水数据、模型模拟蒸散发与径流数据、站点实测径流数据的不同组合计算蓄量变化,分析美国本土地区的蓄量变化时空变化特征。结果发现:不同来源数据计算的蓄量变化时空分布差异较大并且均存在显著偏差,其中西部沿海与山区的蓄量变化有显著季节性波动,而东部地区较稳定;众多因子中降水对蓄量变化的影响最大。根据不同来源数据计算得到的蓄量变化有显著偏差,其原因包括:①对流域水循环结构组成的认识不足且缺乏测量;②降水、径流与蒸散发数据存在不确定性;③时空尺度问题。

Study on temporal and spatial variation and influencing factors of water balance in mainland of United State

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.