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| Titel |
Impact of meteorological forcing datasets on regional scale water fluxes and drought characteristics over Germany |
| VerfasserIn |
Rohini Kumar, Luis Samaniego, Ben Livneh, Matthias Zink, David Schäfer |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250088741
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| Publikation (Nr.) |
 EGU/EGU2014-2885.pdf |
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| Zusammenfassung |
| Accurate representation of regional-scale water fluxes is crucial for hydrological assessments
of societally relevant events such as droughts. Hydrologic models are now commonly used to
derive gridded estimates of land surface water budgets, i.e. soil moisture, runoff, in the
absence of long-term observations. Consequently, the skill of such models depends on
the quality of their driving data, particularly the choice of meteorological forcing
data.
In this study, we provide a comprehensive assessment of regional-scale water fluxes and
states over Germany since 1950 using a well-established mesoscale hydrologic model
(mHM). The goal is to analyze uncertainties in the representation of hydrologic fluxes and
large-scale drought characteristics based on the choice of meteorological forcing data. A
long-term (1950-2012) country wide hydrological simulation of the land surface water
budgets at a 0.25° spatial resolution was carried out with mHM using (a) the publicly free
E-OBS data set (v8.0) from the European Climate Assessment & Dataset project and (b) the
gridded product based on the relatively dense station network (over 5500 rainfall
gauges and 1100 weather stations) operated by the German Weather Service (DWD).
These simulations serve to characterize historical agricultural and hydrological
drought events based on soil moisture (SMI), and surface runoff (SRI) indices,
respectively.
Simulated water fluxes and states (e.g., runoff, evapotranspiration, soil moisture) with
different meteorological data sets generally showed a high degree of correspondence to each
other at annual and seasonal time scales. However, substantial regional differences emerged
in the northeast part of Germany (in the Elbe river basin), where the E-OBS-based
simulations produced drier conditions than those of the DWD based simulation. Despite
similar covariances between both data sets for major historical drought events (1953-54,
1959-60, 1962-65, 1972-74, 1975-78, 1991-93, 1995-97, 2003-05), other drought statistics
such as the severity, duration, areal extend, persistence varied substantially, with more
severe, persistent E-OBS derived droughts than those using the DWD product. For
some interior regions of Germany, differences in drought indices were so great that
they failed to identify a common drought event roughly 40 to 60% of the time,
with poor agreement (r2 = 0.4-0.8) in drought severity classification. These results
emphasize the importance of meteorological uncertainty in drought monitoring. |
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