Time variations of the regional evapotranspiration rate from Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry
Time variations of the regional evapotranspiration rate from Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry
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DOI：
10.1029/2005wr004331
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发表时间：
2006-10
影响因子：
5.4
通讯作者：
G. Ramillien;F. Frappart;A. Güntner;T. Ngo‐Duc;Anny Cazenave;K. Laval
中科院分区：
文献类型：
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作者：
G. Ramillien;F. Frappart;A. Güntner;T. Ngo‐Duc;Anny Cazenave;K. Laval
重力恢复和气候实验（GRACE）使命自2002年3月发射以来，一直在测量地球重力场的全球时间变化，目前的分辨率为1500公里。特别是在大陆上，这些测量代表了完整的陆地水团，包括地表沃茨（湖泊、湿地和河流）、土壤水分、地下水和积雪。在这项研究中，我们使用由Ramillien等人（2005 a）通过迭代反演2002年4月至2004年5月的月大地水准面计算的GRACE陆地水溶液来估计流域尺度区域蒸散率的时间序列和相关的不确定性。蒸散量是通过对水质量平衡方程进行积分和求解来确定的，该方程涉及陆地水储存（来自GRACE）、降水数据（来自全球降水气候学中心）、径流（来自全球陆地表面模型）和蒸散量（未知）。我们进一步研究的敏感性计算时，使用不同的模型径流。蒸散的结果进行了比较，四个不同的全球陆面模型的输出。GRACE导出的蒸散量与基于模型的蒸散量之间总体上令人满意的一致性证明了GRACE提供该参数的现实估计的能力。
Since its launch in March 2002, the Gravity Recovery and Climate Experiment (GRACE) mission has been measuring the global time variations of the Earth's gravity field with a current resolution of ∼500 km. Especially over the continents, these measurements represent the integrated land water mass, including surface waters (lakes, wetlands and rivers), soil moisture, groundwater, and snow cover. In this study, we use the GRACE land water solutions computed by Ramillien et al. (2005a) through an iterative inversion of monthly geoids from April 2002 to May 2004 to estimate time series of basin‐scale regional evapotranspiration rate and associated uncertainties. Evapotranspiration is determined by integrating and solving the water mass balance equation, which relates land water storage (from GRACE), precipitation data (from the Global Precipitation Climatology Centre), runoff (from a global land surface model), and evapotranspiration (the unknown). We further examine the sensibility of the computation when using different model runoff. Evapotranspiration results are compared to outputs of four different global land surface models. The overall satisfactory agreement between GRACE‐derived and model‐based evapotranspiration prove the ability of GRACE to provide realistic estimates of this parameter.