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| Titel |
A groundwater drought index for Germany |
| VerfasserIn |
Jude Lubega Musuuza, Rohini Kumar, Luis Samaniego, Roland Barthel, Sabine Attinger |
| 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 |
250094556
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| Publikation (Nr.) |
 EGU/EGU2014-9972.pdf |
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| Zusammenfassung |
| Droughts occur when storage in the surface-water bodies, soil and the ground falls below
long-term climatological mean values. Surface-water storage reacts immediately to
precipitation events and can result in meteorological droughts. Soil moisture however needs
longer reaction times than surface water and is only influenced by longer-term precipitation
deficits, causing agricultural droughts. Groundwater storage responds very slowly in
comparison to surface-water and soil moisture and is usually only affected by very persistent
deficits in precipitation and soil moisture, resulting in hydrological droughts. The
groundwater response lags behind those in surface water and soil moisture. A systematic
investigation of the lag times could give valuable insights into the temporal relationships
between the meteorological, agricultural and hydrological droughts. The specific questions
are whether a system can recover from meteorological and agricultural droughts before
the onset of a hydrological drought; if it is possible for a system to to be under
hydrological drought conditions after surface and soil moisture storages have been
replenished and the severity of meteorological and agricultural droughts required to
trigger a hydrological drought. Such knowledge would be useful in the agricultural
regions of Germany and for planning sustainable use of groundwater. Measured
water-table positions are direct representations of groundwater storage with increased
draw-downs indicating depletion. Due to lack of reliable long-term water-table
measurements over the entire country, we first correlate the modelled groundwater
storage anomaly derived from a hydrological model mHM (Samaniego et al. 2010),
with the limited groundwater measurements at locations in the Southern region of
Germany. After this model verification process, we extend our analysis to develop a
groundwater drought index GWI similar to the soil moisture index SMI (see e.g.,
Samaniego et al. 2012). The latter index is used to characterise soil moisture deficit in
agricultural drought monitoring and forecasting systems while the proposed GWI
characterises the groundwater deficit. Based on GWI, we investigate different statistics
(severity, area and duration) of individual groundwater drought events. Furthermore, the
regional relationships between different drought indices will be investigated in this
study.
1. Luis Samaniego, Rohini Kumar and Sabine Attinger. Multiscale parameter
regionalisation of a grid-based hydrologic model at the mesoscale. Water Resour. Res.,
46(W05523), 2010. doi:10.1029/2008WR007327.
2. Luis Samaniego, Rohini Kumar and Matthias Zink. Implications of parameter
uncertainity on soil moisture drought analysis in Germany. J. Hydrometeor. pp. 47-68, 2012.
doi:10.1175/JHM-D-12-075-1. |
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