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| Titel |
Estimation of surface soil moisture and roughness from multi-angular ASAR imagery in the Watershed Allied Telemetry Experimental Research (WATER) |
| VerfasserIn |
S. G. Wang, X. Li, X. J. Han, R. Jin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 5 ; Nr. 15, no. 5 (2011-05-06), S.1415-1426 |
| Datensatznummer |
250012778
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| Publikation (Nr.) |
 copernicus.org/hess-15-1415-2011.pdf |
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| Zusammenfassung |
| Radar remote sensing has demonstrated its applicability to the retrieval of
basin-scale soil moisture. The mechanism of radar backscattering from soils
is complicated and strongly influenced by surface roughness. Additionally,
retrieval of soil moisture using AIEM (advanced integrated equation
model)-like models is a classic example of underdetermined problem due to a
lack of credible known soil roughness distributions at a regional scale.
Characterization of this roughness is therefore crucial for an accurate
derivation of soil moisture based on backscattering models. This study aims
to simultaneously obtain surface roughness parameters (standard deviation of
surface height σ and correlation length cl) along with soil moisture
from multi-angular ASAR images by using a two-step retrieval scheme based on
the AIEM. The method firstly used a semi-empirical relationship that relates
the roughness slope, Zs (Zs = σ2/cl) and the difference in
backscattering coefficient (Δσ) from two ASAR images acquired
with different incidence angles. Meanwhile, by using an experimental
statistical relationship between σ and cl, both these parameters can
be estimated. Then, the deduced roughness parameters were used for the
retrieval of soil moisture in association with the AIEM. An evaluation of
the proposed method was performed in an experimental area in the middle
stream of the Heihe River Basin, where the Watershed Allied Telemetry
Experimental Research (WATER) was taken place. It is demonstrated that the
proposed method is feasible to achieve reliable estimation of soil water
content. The key challenge is the presence of vegetation cover, which
significantly impacts the estimates of surface roughness and soil moisture. |
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