Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 14, 1247-1258, 2010
© Author(s) 2010. This work is distributed under
the Creative Commons Attribution 3.0 License.
15 Jul 2010
Uncertainties in climate change projections and regional downscaling in the tropical Andes: implications for water resources management
W. Buytaert1, M. Vuille2, A. Dewulf3, R. Urrutia4, A. Karmalkar5, and R. Célleri6 1Imperial College London, Civil and Environmental Engineering, London, UK
2Univ. at Albany, State Univ. of New York, Dept. of Atmospheric and Environmental Sciences, Albany, USA
3Wageningen Univ., Public Administration and Policy Group, Wageningen, The Netherlands
4Univ. Austral de Chile, Laboratorio de dendrocronología, Valdivia, Chile
5Univ. of Massachusetts Amherst, Climate System Research Center, Amherst, USA
6Univ. de Cuenca, Centro para el Análisis de Sistemas Naturales, Cuenca, Ecuador
Abstract. Climate change is expected to have a large impact on water resources worldwide. A major problem in assessing the potential impact of a changing climate on these resources is the difference in spatial scale between available climate change projections and water resources management. Regional climate models (RCMs) are often used for the spatial disaggregation of the outputs of global circulation models. However, RCMs are time-intensive to run and typically only a small number of model runs is available for a certain region of interest. This paper investigates the value of the improved representation of local climate processes by a regional climate model for water resources management in the tropical Andes of Ecuador. This region has a complex hydrology and its water resources are under pressure. Compared to the IPCC AR4 model ensemble, the regional climate model PRECIS does indeed capture local gradients better than global models, but locally the model is prone to large discrepancies between observed and modelled precipitation. It is concluded that a further increase in resolution is necessary to represent local gradients properly. Furthermore, to assess the uncertainty in downscaling, an ensemble of regional climate models should be implemented. Finally, translating the climate variables to streamflow using a hydrological model constitutes a smaller but not negligible source of uncertainty.

Citation: Buytaert, W., Vuille, M., Dewulf, A., Urrutia, R., Karmalkar, A., and Célleri, R.: Uncertainties in climate change projections and regional downscaling in the tropical Andes: implications for water resources management, Hydrol. Earth Syst. Sci., 14, 1247-1258,, 2010.
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