HESS Hydrology and Earth System Sciences HESS Hydrol. Earth Syst. Sci. 1607-7938 Copernicus Publications Göttingen, Germany 10.5194/hess-15-75-2011 A dynamic approach for evaluating coarse scale satellite soil moisture products Loew A. 1 Schlenz F. 2 Max-Planck-Institute for Meteorology, KlimaCampus, Hamburg, Germany Department of Geography, University of Munich, Munich, Germany 11 01 2011 15 1 75 90 Copyright: © 2011 A. Loew 2011 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://hess.copernicus.org/articles/15/75/2011/hess-15-75-2011.html The full text article is available as a PDF file from https://hess.copernicus.org/articles/15/75/2011/hess-15-75-2011.pdf

Validating coarse scale remote sensing soil moisture products requires a comparison of gridded data to point-like ground measurements. The necessary aggregation of in situ measurements to the footprint scale of a satellite sensor (>100 km<sup>2</sup>) introduces uncertainties in the validation of the satellite soil moisture product. Observed differences between the satellite product and in situ data are therefore partly attributable to these aggregation uncertainties. The present paper investigates different approaches to disentangle the error of the satellite product from the uncertainties associated to the up-scaling of the reference data. A novel approach is proposed, which allows for the quantification of the remote sensing soil moisture error using a temporally adaptive technique. It is shown that the point-to-area sampling error can be estimated within 0.0084 [m<sup>3</sup>/m<sup>3</sup>].

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