Requirements of a global near-surface soil moisture satellite mission: accuracy, repeat time, and spatial resolution

被引:110
作者
Walker, JP [1 ]
Houser, PR
机构
[1] Univ Melbourne, Dept Civil & Environm Engn, Parkville, Vic 3010, Australia
[2] NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Greenbelt, MD 20771 USA
基金
美国国家航空航天局;
关键词
soil moisture; remote sensing; mission requirements; data assimilation; modelling;
D O I
10.1016/j.advwatres.2004.05.006
中图分类号
TV21 [水资源调查与水利规划];
学科分类号
081501 ;
摘要
Soil moisture satellite mission accuracy, repeat time and spatial resolution requirements are addressed through a numerical twill data assimilation study. Simulated soil moisture profile retrievals were made by assimilating near-surface soil moisture observations with various accuracy (0, 1 2, 3 4, 5 and 10%v/v standard deviation) repeat time (1, 2, 3, 5, 10, 15, 20 and 30 days), and spatial resolution (0.5, 6, 12 18, 30, 60 and 120 arc-min). This study found that near-surface soil moisture observation error must be less than the model forecast error required for a specific application when used as data assimilation input, else slight model forecast degradation may result. It also found that near-surface soil moisture observations must have all accuracy better than 5%v/v to positively impact soil moisture forecasts, and that daily near-surface soil moisture observations achieved the best soil moisture and evapotranspiration forecasts for the repeat times assessed, with 1-5 day repeat times having the greatest impact. Near-surface soil moisture observations with a spatial resolution finer than the land surface model resolution (similar to30 arc-min) produced the best results, with spatial resolutions coarser than the model resolution yielding only a slight degradation. Observations at half the land surface model spatial resolution were found to be appropriate for our application. Moreover, it was found that satisfying the spatial resolution and accuracy requirements was much more important than repeat time. Published by Elsevier Ltd.
引用
收藏
页码:785 / 801
页数:17
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