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| Titel |
Water balance estimation for large scale basins from regional atmospheric moisture budgets and comparison to GRACE |
| VerfasserIn |
Benjamin Fersch, Harald Kunstmann |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039526
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| Zusammenfassung |
| Besides energy fluxes and temperature properties, atmospheric downscaling models
also describe the vertical water fluxes and exchange processes between soil and
atmosphere. The analysis of long term impacts of land use and climate variations with
hydrometeorological models requires a proper description of the energy and water
interplay.
In our study, we investigate how well the mesoscale Weather Research and Forecasting
modeling system WRF (WRF-ARW) is able to reproduce the 2003-2006 water balance of
continental scale river catchments and basins without discharge, based on the analysis of
atmospheric moisture budgets. The divergence of the vertically integrated moisture flux is
used as a proxy for precipitation minus evapotranspiration (P-E). Therefore, at
basins where discharge measurements are available or outflow equals zero, the
water budget can be determined also for the basin storage change. Global boundary
conditions from ECMWF ERA-INTERIM and the NCAR/NCEP Reanalysis are
used for the driving of WRF. Water budgets are analyzed for the river basins of
Amazon, Yenisei, and Lena, and also for the Sahara and the central arid region of
Australia.
The results show that for cold and winterly conditions, WRF reproduces the basin
water budget quite well. For warm and moist conditions, net water input (P-E) is
mostly overestimated. Different model driving with ECMWF and NCEP boundary
conditions has small effects for the Siberian tundra. The Amazonian, Saharan and
Australian domains show stronger deviances. The evaluation of the derived storage
changes with their global counterparts and with the Gravity Recovery And Climate
Experiment GRACE suggests that for moist and warm environments, the regional
atmospheric model has substantial problems in describing the vertical water fluxes,
whereas for cold conditions downscaling is likely to decrease overall uncertainty. |
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