Error characterisation of global active and passive microwave soil moisture datasets
Dorigo, Wouter A. and Scipal, Klaus and Parinussa, Robert M. and Liu, Y.Y. and Wagner, Wolfgang and De Jeu, Richard A M and Naeimi, Vahid (2010) Error characterisation of global active and passive microwave soil moisture datasets. Hydrology and Earth System Sciences, 14 (12), pp. 2605-2616. Copernicus publicatios. DOI: 10.5194/hess-14-2605-2010. ISSN 10275606.
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Understanding the error structures of remotely sensed soil moisture observations is essential for correctly interpreting observed variations and trends in the data or assimilating them in hydrological or numerical weather prediction models. Nevertheless, a spatially coherent assessment of the quality of the various globally available datasets is often hampered by the limited availability over space and time of reliable in-situ measurements. As an alternative, this study explores the triple collocation error estimation technique for assessing the relative quality of several globally available soil moisture products from active (ASCAT) and passive (AMSR-E and SSM/I) microwave sensors. The triple collocation is a powerful statistical tool to estimate the root mean square error while simultaneously solving for systematic differences in the climatologies of a set of three linearly related data sources with independent error structures. Prerequisite for this technique is the availability of a sufficiently large number of timely corresponding observations. In addition to the active and passive satellite-based datasets, we used the ERA-Interim and GLDAS-NOAH reanalysis soil moisture datasets as a third, independent reference. The prime objective is to reveal trends in uncertainty related to different observation principles (passive versus active), the use of different frequencies (C-, X-, and Ku-band) for passive microwave observations, and the choice of the independent reference dataset (ERA-Interim versus GLDAS-NOAH). The results suggest that the triple collocation method provides realistic error estimates. Observed spatial trends agree well with the existing theory and studies on the performance of different observation principles and frequencies with respect to land cover and vegetation density. In addition, if all theoretical prerequisites are fulfilled (e.g. a sufficiently large number of common observations is available and errors of the different datasets are uncorrelated) the errors estimated for the remote sensing products are hardly influenced by the choice of the third independent dataset. The results obtained in this study can help us in developing adequate strategies for the combined use of various scatterometer and radiometer-based soil moisture datasets, e.g. for improved flood forecast modelling or the generation of superior multi-mission long-term soil moisture datasets.
|Title:||Error characterisation of global active and passive microwave soil moisture datasets|
|Journal or Publication Title:||Hydrology and Earth System Sciences|
|In Open Access:||Yes|
|In ISI Web of Science:||Yes|
|Page Range:||pp. 2605-2616|
|Series Name:||Earth observation and water cycle science|
|Keywords:||Error estimations; Active and Passive microwaves; Remotely sensed soil moistur|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Raumfahrt|
|HGF - Program Themes:||R EO - Erdbeobachtung|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R EO - Erdbeobachtung|
|DLR - Research theme (Project):||R - Vorhaben Fernerkundung der Landoberfläche|
|Institutes and Institutions:||German Remote Sensing Data Center > Land Surface|
|Deposited By:||Dr.techn. Vahid Naeimi|
|Deposited On:||06 Nov 2012 11:23|
|Last Modified:||07 Feb 2013 20:18|
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