TY  - JOUR
A1  - Müller Schmied, Hannes
A1  - Adam, Linda
A1  - Eisner, Stephanie
A1  - Fink, Gabriel
A1  - Flörke, Martina
A1  - Kim, Hyungjun
A1  - Oki, Taikan
A1  - Portmann, Felix Theodor
A1  - Reinecke, Robert
A1  - Riedel, Claudia
A1  - Song, Qi
A1  - Zhang, Jing
A1  - Döll, Petra
T1  - Variations of global and continental water balance components as impacted by climate forcing uncertainty and human water use
T2  - Hydrology and earth system sciences discussions
N2  - When assessing global water resources with hydrological models, it is essential to know the methodological uncertainties in the water resources estimates. The study presented here quantifies effects of the uncertainty in the spatial and temporal patterns of meteorological variables on water balance components at the global, continental and grid cell scale by forcing the global hydrological model WaterGAP 2.2 (ISI-MIP 2.1) with five state-of-the-art climate forcing input data-sets. While global precipitation over land during 1971–2000 varies between 103 500 and 111 000 km3 yr−1, global river discharge varies between 39 200 and 42 200 km3 yr−1. Temporal trends of global wa- ter balance components are strongly affected by the uncertainty in the climate forcing (except human water abstractions), and there is a need for temporal homogenization of climate forcings (in particular WFD/WFDEI). On about 10–20 % of the global land area, change of river discharge between two consecutive 30 year periods was driven more strongly by changes of human water use including dam construction than by changes in precipitation. This number increases towards the end of the 20th century due to intensified human water use and dam construction. The calibration approach of WaterGAP against observed long-term average river discharge reduces the impact of climate forcing uncertainty on estimated river discharge significantly. Different homgeneous climate forcings lead to a variation of Q of only 1.6 % for the 54 % of global land area that are constrained by discharge observations, while estimated renewable water resources in the remaining uncalibrated regions vary by 18.5 %. Uncertainties are especially high in Southeast Asia where Global Runoff Data Centre (GRDC) data availability is very sparse. By sharing already available discharge data, or installing new streamflow gauging stations in such regions, water balance uncertainties could be reduced which would lead to an improved assessment of the world’s water resources.
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/43822
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-438220
SN  - 1812-2116
N1  - © Author(s) 2016. CC-BY 3.0 License.
VL  - 2016
SP  - 1
EP  - 41
PB  - Soc.
CY  - Katlenburg-Lindau
ER  -