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| Titel |
A variational data assimilation system for soil–atmosphere flux estimates for the Community Land Model (CLM3.5) |
| VerfasserIn |
C. M. Hoppe, H. Elbern, J. Schwinger |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 7, no. 3 ; Nr. 7, no. 3 (2014-05-28), S.1025-1036 |
| Datensatznummer |
250115627
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| Publikation (Nr.) |
 copernicus.org/gmd-7-1025-2014.pdf |
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| Zusammenfassung |
| This paper presents the development and implementation of
a spatio-temporal variational data assimilation system (4D-var)
for the soil–vegetation–atmosphere transfer model "Community Land
Model" (CLM3.5), along with the development of the adjoint code for
the core soil–atmosphere transfer scheme of energy and soil
moisture. The purpose of this work is to obtain an improved
estimation technique for the energy fluxes (sensible and latent heat
fluxes) between the soil and the atmosphere. Optimal assessments of
these fluxes are neither available from model simulations nor
measurements alone, while a 4D-var data assimilation has the
potential to combine both information sources by a Best Linear
Unbiased Estimate (BLUE). The 4D-var method requires the
development of the adjoint model of the CLM which is established in
this work. The new data assimilation algorithm is able to assimilate
soil temperature and soil moisture measurements for one-dimensional
columns of the model grid. Numerical experiments were first used to
test the algorithm under idealised conditions. It was found that the
analysis delivers improved results whenever there is a dependence
between the initial values and the assimilated quantity.
Furthermore, soil temperature and soil moisture from in situ field
measurements were assimilated. These calculations demonstrate the
improved performance of flux estimates, whenever soil property
parameters are available of sufficient quality. Misspecifications
could also be identified by the performance of the variational
scheme. |
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