 |
| Titel |
A bare ground evaporation revision in the ECMWF land-surface scheme: evaluation of its impact using ground soil moisture and satellite microwave data |
| VerfasserIn |
C. Albergel, G. Balsamo, P. Rosnay, J. Muñoz-Sabater, S. Boussetta |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 10 ; Nr. 16, no. 10 (2012-10-16), S.3607-3620 |
| Datensatznummer |
250013516
|
| Publikation (Nr.) |
 copernicus.org/hess-16-3607-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| In situ soil moisture data from 122 stations
across the United States are used to evaluate the impact of a new bare
ground evaporation formulation at ECMWF. In November 2010, the bare
ground evaporation used in ECMWF's operational Integrated Forecasting System
(IFS) was enhanced by adopting a lower stress threshold than for the
vegetation, allowing a higher evaporation. It results in more realistic soil
moisture values when compared to in situ data, particularly over dry areas.
Use was made of the operational IFS and offline experiments for the
evaluation. The latter are based on a fixed version of the IFS and make it
possible to assess the impact of a single modification, while the operational
analysis is based on a continuous effort to improve the analysis and
modelling systems, resulting in frequent updates (a few times a year).
Considering the field sites with a fraction of bare ground greater than 0.2,
the root mean square difference (RMSD) of soil moisture is shown to decrease
from 0.118 m3 m−3 to 0.087 m3 m−3 when using the new formulation in offline
experiments, and from 0.110 m3 m−3 to 0.088 m3 m−3 in operations. It also improves
correlations. Additionally, the impact of the new formulation on the
terrestrial microwave emission at a global scale is investigated. Realistic
and dynamically consistent fields of brightness temperature as a function of
the land surface conditions are required for the assimilation of the SMOS
data. Brightness temperature simulated from surface fields from two offline
experiments with the Community Microwave Emission Modelling (CMEM) platform
present monthly mean differences up to 7 K. Offline experiments with the new
formulation present drier soil moisture, hence simulated brightness
temperature with its surface fields are larger. They are also closer to SMOS
remotely sensed brightness temperature. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|