De-noising of passive and active microwave satellite soil moisture time series

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...

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Bibliographic Details
Published in:Geophysical research letters 2013-07, Vol.40 (14), p.3624-3630
Main Authors: Su, Chun-Hsu, Ryu, Dongryeol, Western, Andrew W., Wagner, Wolfgang
Format: Article
Language:English
Subjects:
de-noising
Design engineering
digital signal processing
Earth sciences
Earth, ocean, space
Exact sciences and technology
Filters
In situ measurement
Mathematical models
Meteorological satellites
Microwaves
Retrieval
Satellite soil moisture
Satellites
Soil moisture
Soil surfaces
Spectra
spectral analysis
Stochasticity
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Summary: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. Key Points Systematic periodic and stochastic errors exist in satellite soil moisture Semi‐empirical model of active and passive satellite retrievals was proposed Designs of Wiener and bandstop filters were proposed for de‐noising
ISSN:0094-8276
1944-8007
DOI:10.1002/grl.50695