Evaluation of remotely sensed and modelled soil moisture products using global ground-based in situ observations
Evaluation of remotely sensed and modelled soil moisture products using global ground-based in situ observations
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DOI：
10.1016/j.rse.2011.11.017
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发表时间：
2012-03-15
影响因子：
13.5
通讯作者：
Wagner, Wolfgang
中科院分区：
文献类型：
--
作者：
Albergel, Clement;de Rosnay, Patricia;Wagner, Wolfgang
利用来自非洲、澳大利亚、欧洲和美国的200多个站点的现场土壤湿度数据，确定了三种土壤湿度产品的可靠性，其中一种来自欧洲中期天气预报中心数值天气预报系统(SM-DAS-2)，另两种是遥感土壤湿度产品，即高级散射仪(ASCAT)和土壤湿度海洋盐度(SMOS)。SM-DAS-2是在欧洲气象局离线生产的，依靠先进的地面数据同化系统(扩展卡尔曼滤波)，以最佳方式将常规观测与卫星测量结合起来。ASCAT遥感地表土壤湿度由欧洲气象卫星组织近乎实时地提供。在ECMWF，ASCAT也被用于SM-DAS-2中的土壤水分分析。最后，使用了CESBIO开发的SMOS遥感土壤水分数据二级产品。对时间序列和距平值的评价表明，这三种产品对表层土壤水分的年周期和短期变化都有较好的捕捉效果。与现场数据的相关性非常令人满意，大多数调查地点位于不同的生物群和气候条件下，SM-DAS-2的平均值为0.70，ASCAT的平均值为0.53，SMOS的平均值为0.54。尽管无线电频率干扰干扰了SMOS在世界各地观测到的地球自然微波辐射，从而恢复了土壤水分，但SMOS在澳大利亚的表现非常令人鼓舞。(C)2011 Elsevier Inc.保留所有权利。
In situ soil moisture data from more than 200 stations located in Africa, Australia, Europe and the United States are used to determine the reliability of three soil moisture products, one analysis from the ECMWF (European Centre for Medium-Range Weather Forecasts) numerical weather prediction system (SM-DAS-2) and two remotely sensed soil moisture products, namely ASCAT (Advanced scatterometer) and SMOS (Soil Moisture Ocean Salinity). SM-DAS-2 is produced offline at ECMWF and relies on an advanced surface data assimilation system (Extended Kalman Filter) used to optimally combine conventional observations with satellite measurements. ASCAT remotely sensed surface soil moisture is provided in near real time by EUMETSAT. At ECMWF, ASCAT is used for soil moisture analyses in SM-DAS-2, also. Finally the SMOS remotely sensed soil moisture data level two product developed at CESBIO is used. Evaluation of the times series as well as of the anomaly values, shows good performances of the three products to capture surface soil moisture annual cycle and short term variability. Correlations with in situ data are very satisfactory over most of the investigated sites located in contrasted biomes and climate conditions with averaged values of 0.70 for SM-DAS-2, 0.53 for ASCAT and 0.54 for SMOS. Although radio frequency interference disturbs the natural microwave emission of the Earth observed by SMOS in several parts of the world, hence the soil moisture retrieval, performances of SMOS over Australia are very encouraging. (C) 2011 Elsevier Inc. All rights reserved.