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De‐noising of passive and active microwave satellite soil moisture time series
Author(s) -
Su ChunHsu,
Ryu Dongryeol,
Western Andrew W.,
Wagner Wolfgang
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50695
Subject(s) - satellite , microwave , remote sensing , series (stratigraphy) , environmental science , spectral density , water content , time series , frequency domain , meteorology , geology , mathematics , computer science , physics , statistics , mathematical analysis , telecommunications , paleontology , geotechnical engineering , astronomy
Satellite microwave retrievals and in situ measurements of surface soil moisture are usually compared in the time domain. This paper examines their differences in the conjugate frequency domain to develop a spectral description of the satellite data, suggesting the presence of stochastic random and systematic periodic errors. Based on a semiempirical model of the observed power spectral density, we describe systematic designs of causal and noncausal filters to remove these erroneous signals. The filters are applied to the retrievals from active and passive satellite sensors and evaluated against field data from the Murrumbidgee Basin, southeast Australia, to show substantive increase in linear correlations.