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| Titel |
Spatial variability and its scale dependency of observed and modeled soil moisture over different climate regions |
| VerfasserIn |
B. Li, M. Rodell |
| 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 ; 17, no. 3 ; Nr. 17, no. 3 (2013-03-19), S.1177-1188 |
| Datensatznummer |
250018831
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| Publikation (Nr.) |
 copernicus.org/hess-17-1177-2013.pdf |
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| Zusammenfassung |
| Past studies on soil moisture spatial variability have been mainly conducted
at catchment scales where soil moisture is often sampled over a short time
period; as a result, the observed soil moisture often exhibited smaller
dynamic ranges, which prevented the complete revelation of soil moisture
spatial variability as a function of mean soil moisture. In this study,
spatial statistics (mean, spatial variability and skewness) of in situ soil
moisture, modeled and satellite-retrieved soil moisture obtained in a warm
season (198 days) were examined over three large climate regions in the US.
The study found that spatial moments of in situ measurements strongly depend
on climates, with distinct mean, spatial variability and skewness observed
in each climate zone. In addition, an upward convex shape, which was
revealed in several smaller scale studies, was observed for the relationship
between spatial variability of in situ soil moisture and its spatial mean
when statistics from dry, intermediate, and wet climates were combined. This
upward convex shape was vaguely or partially observable in modeled and
satellite-retrieved soil moisture estimates due to their smaller dynamic
ranges. Despite different environmental controls on large-scale soil
moisture spatial variability, the correlation between spatial variability
and mean soil moisture remained similar to that observed at small scales,
which is attributed to the boundedness of soil moisture. From the smaller
support (effective area or volume represented by a measurement or estimate)
to larger ones, soil moisture spatial variability decreased in each climate
region. The scale dependency of spatial variability all followed the power
law, but data with large supports showed stronger scale dependency than
those with smaller supports. The scale dependency of soil moisture
variability also varied with climates, which may be linked to the
scale dependency of precipitation spatial variability. Influences of
environmental controls on soil moisture spatial variability at large scales
are discussed. The results of this study should be useful for diagnosing
large scale soil moisture estimates and for improving the estimation of land
surface processes. |
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