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| Titel |
The world in 5 minutes - new features of the large scale hydrological model WaterGAP |
| VerfasserIn |
Frank Voß, Stephanie Eisner, Kerstin Verzano, Martina Flörke, Tim Aus der Beek, Anja Voss, Christof Schneider, Martina Weiß, Ilona Bärlund, Joseph Alcamo |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056254
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| Zusammenfassung |
| We present the first high-resolution global hydrological model, WaterGAP3, operating on a 5
arc minutes spatial grid (approx. 6 x 9 km in Europe) covering the global land area with the
exception of Antarctica.
The WaterGAP model (Water - Global Assessment and Prognosis) has been developed at the
Center for Environmental Systems Research (CESR) with the aim of providing a basis both
for an assessment of the current state of water resources and water use, and for gaining an
integrated perspective of impacts of global change on the water sector. WaterGAP consists of
two main components: a global water use model and a global hydrology model. The water
use model takes into account basic socio-economic factors such as population and
GDP on a national level, to estimate water withdrawals and consumptive water
uses for the domestic, industry, irrigation, and livestock sectors. The aim of the
hydrological model is to simulate the characteristic macro-scale behavior of the
terrestrial water cycle in order to estimate water availability. Based on the time series of
climatic data, the hydrological model calculates the daily water balance for each grid
cell, taking into account physiographic characteristics of drainage basins (e.g. soil,
vegetation, slope and aquifer type), the inflow from upstream cells, the extent and
hydrological influence of lakes, reservoirs, dams, and wetlands, as well as the reduction
of river discharge by human water consumption (as computed by the water use
model).
For the current version, WaterGAP3, the spatial resolution has been enhanced, from 0.5° by
0.5° (longitude and latitude) to 5 by 5 arc minutes gridded scale, for two main reasons: First,
most model input data for both the hydrological model and the water use model now feature a
distinctively higher resolution. Secondly, the WaterGAP framework has recently been
extended by a large scale water quality sub-model (WorldQual) in order to determine
chemical fluxes in different pathways which allows the combination of water quantity with
water quality analysis but requires a considerably higher resolution of the stream
network.
Partially enabled by the enhanced spatial resolution, the process representations of
runoff formation and runoff concentration in the hydrological model have been
substantially improved: (1) the snow routine has been revised by modeling snow dynamics
on sub-grid scale (~0.4 x 0.4 km); (2) a module has been added for a dynamic
representation of permafrost occurrence, which directly influences groundwater
recharge; (3) in order to distinguish between mountainous rivers with steep river
bed slopes and rivers in lower regions a variable flow velocity algorithm has been
implemented; (4) the river length has been enhanced by applying an individual meandering
factor for each grid cell derived from a high-resolution drainage direction map;
(5) an approach has been developed which utilizes Köppen regions to estimate
potential evapotranspiration and groundwater recharge. As a last point, dams from
the Global Reservoir and Dam Database (GRanD) have been implemented into
WaterGAP3 in order to consider anthropogenic flow regulation. Thereby, all dams
with a storage capacity higher than 0.1 km3 have been taken into account and a
management scheme according to the algorithm of Hanasaki et al. (2006) has been
applied.
We will demonstrate how the aforementioned model revisions affect the simulation of certain
components of the hydrological cycle on the basis of selected case studies.
Corresponding author: Stephanie Eisner, eisner@usf.uni-kassel.de |
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