Global land-surface evaporation estimated from satellite-based observations
Global land-surface evaporation estimated from satellite-based observations
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DOI：
10.5194/hess-15-453-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Dolman, A. J.
中科院分区：
文献类型：
--
作者：
Miralles, D. G.;Holmes, T. R. H.;Dolman, A. J.
本文概述了一种新的战略，从卫星观测获得蒸发。该方法使用各种卫星传感器产品，以0.25度的空间分辨率估算全球范围内的日蒸发量。这种方法的核心是使用Priestley和Taylor（PT）蒸发模型。最小的PT方程结合了少量的输入，其中大部分可以从太空中检测到。这减少了需要建模的变量的数量。该方法的主要特点是使用微波导出的土壤湿度、地表温度和植被密度，以及对降雨截留损失的详细估计。模拟蒸发验证一年的涡度相关测量43站。估算的年总蒸发量与各站的年累积蒸发量相关性较好（R = 0.80，N = 43），平均偏差较小（-5%）。对每个站的每日时间序列的验证表明，在所有植被类型和气候条件下，模型性能良好，平均相关系数为（R）/bar = 0.83，仍低于对月时间序列验证中发现的（R）/bar = 0.90。通过这种方法开发的第一个全球年蒸发量图也被提出。
This paper outlines a new strategy to derive evaporation from satellite observations. The approach uses a variety of satellite-sensor products to estimate daily evaporation at a global scale and 0.25 degree spatial resolution. Central to this methodology is the use of the Priestley and Taylor (PT) evaporation model. The minimalistic PT equation combines a small number of inputs, the majority of which can be detected from space. This reduces the number of variables that need to be modelled. Key distinguishing features of the approach are the use of microwave-derived soil moisture, land surface temperature and vegetation density, as well as the detailed estimation of rainfall interception loss. The modelled evaporation is validated against one year of eddy covariance measurements from 43 stations. The estimated annual totals correlate well with the stations' annual cumulative evaporation (R = 0.80, N = 43) and present a low average bias (-5%). The validation of the daily time series at each individual station shows good model performance in all vegetation types and climate conditions with an average correlation coefficient of (R) over bar = 0.83, still lower than the (R) over bar = 0.90 found in the validation of the monthly time series. The first global map of annual evaporation developed through this methodology is also presented.