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| Titel |
ASCAT data assimilation at ECMWF |
| VerfasserIn |
P. de Rosnay, C. Albergel, G. Balsamo, J. Muñoz Sabater |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063386
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| Zusammenfassung |
| Soil moisture initialisation is crucial for Numerical Weather
Prediction (NWP). New generation of satellites, such as ASCAT
(Advanced Scatterometer) and SMOS (Soil Moisture and Ocean Salinity)
provide highly suitable data from active and passive microwave sensors
for surface soil moisture remote sensing. For NWP applications,
satellite data monitoring provides a continuous evaluation of
observations and first guess departures (observation minus model)
values at global and regional scales.
The EUMETSAT operational ASCAT surface soil moisture product is used
at ECMWF for soil moisture analysis developments as well as for the
H-SAF ( Satellite Application Facility on support to operational
hydrology and water management) activities. Within the H-SAF project
ECMWF developed a retrieval algorithm of root zone soil moisture
profile based on ASCAT data assimilation in the ECMWF Land Data
Assimilation System. The derived soil moisture product, the so-called
SM-DAS-2 product, is a level-4 type soil moisture product, providing
soil moisture in the root zone (0-3m) with a global daily
coverage. ASCAT surface soil moisture data assimilation relies on a
simplified Extended Kalman Filter approach. A Cumulative Distribution
Function (CDF) matching is used a bias correction to rescale, for each
model grid point, the scatterometer surface soil moisture index to fit
the model surface soil moisture climatology. The ASCAT CDF matching
was recently revised, allowing to account for a seasonal correction,
improving thereby the efficiency of ASCAT data assimilation in both
the root zone retrieval algorithm and for NWP applications.
In this presentation ASCAT data assimilation activities at ECMWF are
presented. First monitoring and data assimilation in the ECMWF NWP
system are presented and the impact of ASCAT data assimilation on NWP
performance is addressed. Second, the separate root zone retrieval
data assimilation system is described and the SM-DAS-2 product is
presented. |
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