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| Titel |
Estimating spatial mean root-zone soil moisture from point-scale observations |
| VerfasserIn |
A. J. Teuling, R. Uijlenhoet, F. Hupet, E. E. Loon, P. A. Troch |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2006-10-17), S.755-767 |
| Datensatznummer |
250008199
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| Publikation (Nr.) |
 copernicus.org/hess-10-755-2006.pdf |
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| Zusammenfassung |
| Root zone soil moisture is a key variable in many land surface hydrology
models. Often, however, there is a mismatch in the spatial scales at which
models simulate soil moisture and at which soil moisture is observed. This
complicates model validation. The increased availability of detailed datasets
on space-time variability of
root-zone soil moisture allows for a posteriori analysis of the uncertainties
in the relation between point-scale observations and the spatial mean. In
this paper we analyze three comprehensive datasets from three different
regions. We identify different strategies to select observation sites. For
instance, sites can be located randomly or according to the rank stability
concept. For each strategy, we present methods to quantify the uncertainty
that is associated with this strategy. In general there is a large
correspondence between the different datasets with respect to the relative
uncertainties for the different
strategies. For all datasets, the uncertainty can be strongly reduced if some
information is available that relates soil moisture content at that site to the
spatial mean. However this works best if the space-time dynamics of the soil
moisture field are known. Selection of the site closest to the spatial mean
on a single random date only leads to minor reduction of the uncertainty with
respect to the spatial mean over seasonal timescales. Since soil moisture
variability is the result of a complex interaction between soil, vegetation,
and landscape characteristics, the soil moisture field will be correlated
with some of these characteristics. Using available information, we show that
the correlation with leaf area index or a wetness coefficient alone is
insufficient to predict if a site is representative for the spatial mean soil
moisture content. |
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