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| Titel |
Impact of ASAR soil moisture data on the MM5 precipitation forecast for the Tanaro flood event of April 2009 |
| VerfasserIn |
G. Panegrossi, R. Ferretti, L. Pulvirenti, N. Pierdicca |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 11, no. 12 ; Nr. 11, no. 12 (2011-12-05), S.3135-3149 |
| Datensatznummer |
250009821
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| Publikation (Nr.) |
 copernicus.org/nhess-11-3135-2011.pdf |
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| Zusammenfassung |
| The representation of land-atmosphere interactions in weather forecast
models has a strong impact on the Planetary Boundary Layer (PBL) and, in
turn, on the forecast. Soil moisture is one of the key variables in land
surface modelling, and an inadequate initial soil moisture field can introduce
major biases in the surface heat and moisture fluxes and have a
long-lasting effect on the model behaviour. Detecting the variability of
soil characteristics at small scales is particularly important in mesoscale
models because of the continued increase of their spatial resolution. In this
paper, the high resolution soil moisture field derived from
ENVISAT/ASAR
observations is used to derive the soil moisture initial condition for the
MM5 simulation of the Tanaro flood event of April 2009. The ASAR-derived
soil moisture field shows significantly drier conditions compared to the
ECMWF analysis. The impact of soil moisture on the forecast has been
evaluated in terms of predicted precipitation and rain gauge data
available for this event have been used as ground truth. The use of the
drier, highly resolved soil moisture content (SMC) shows a significant
impact on the precipitation forecast, particularly evident during the early
phase of the event. The timing of the onset of the precipitation, as well as
the intensity of rainfall and the location of rain/no rain areas, are better
predicted. The overall accuracy of the forecast using ASAR SMC data is
significantly increased during the first 30 h of simulation. The impact
of initial SMC on the precipitation has been related to the change in the
water vapour field in the PBL prior to the onset of the precipitation, due
to surface evaporation. This study represents a first attempt to establish
whether high resolution SAR-based SMC data might be useful for operational
use, in anticipation of the launch of the Sentinel-1 satellite. |
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