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Titel |
Estimating root zone soil moisture using near-surface observations from SMOS |
VerfasserIn |
T. W. Ford, E. Harris, S. M. Quiring |
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 ; 18, no. 1 ; Nr. 18, no. 1 (2014-01-13), S.139-154 |
Datensatznummer |
250120249
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Publikation (Nr.) |
copernicus.org/hess-18-139-2014.pdf |
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Zusammenfassung |
Satellite-derived soil moisture provides more spatially and temporally
extensive data than in situ observations. However, satellites can only measure
water in the top few centimeters of the soil. Root zone soil moisture is
more important, particularly in vegetated regions. Therefore estimates of
root zone soil moisture must be inferred from near-surface soil moisture
retrievals. The accuracy of this inference is contingent on the relationship
between soil moisture in the near-surface and the soil moisture at greater
depths. This study uses cross correlation analysis to quantify the
association between near-surface and root zone soil moisture using in situ data
from the United States Great Plains. Our analysis demonstrates that there is
generally a strong relationship between near-surface (5–10 cm) and root
zone (25–60 cm) soil moisture. An exponential decay filter is used to
estimate root zone soil moisture using near-surface soil moisture derived
from the Soil Moisture and Ocean Salinity (SMOS) satellite. Root zone soil
moisture derived from SMOS surface retrievals is compared to in situ soil moisture
observations in the United States Great Plains. The SMOS-based root zone
soil moisture had a mean R2 of 0.57 and a mean Nash–Sutcliffe score of
0.61 based on 33 stations in Oklahoma. In Nebraska, the SMOS-based root zone
soil moisture had a mean R2 of 0.24 and a mean Nash–Sutcliffe score of
0.22 based on 22 stations. Although the performance of the exponential
filter method varies over space and time, we conclude that it is a useful
approach for estimating root zone soil moisture from SMOS surface
retrievals. |
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