Uncertainties in Projected Runoff over the Central United States

Thursday, 18 December 2014
Ignazio Giuntoli1,2, Gabriele Villarini3, Christel Prudhomme2 and David M Hannah1, (1)University of Birmingham, Birmingham, United Kingdom, (2)Centre for Ecology and Hydrology, Wallingford, United Kingdom, (3)University of Iowa, Civil and Environmental Engineering, Iowa City, IA, United States
Global multi-model ensemble experiments provide a valuable basis for the examination of potential future changes in runoff. However, these projections suffer from uncertainties that originate from different sources at different levels in the modelling chain. This study aims to partition the uncertainty in projections of annual maximum, median and low flows over the Central United States into four distinct sources. More specifically, we quantify the relative contribution of the uncertainties arising from internal variability, global impact models (GIMs), global climate models (GCMs), and representative concentration pathways (RCPs). We use a set of eight state-of-the-art GIMs driven by five GCMs under four RCPs from the ISI-MIP multi-model ensemble.

Results will be presented at both annual and decadal time scales, and we will examine the temporal changes in the relative contribution of each source of uncertainty over the course of the 21st century. This work will provide basic information towards the potential reduction of uncertainties in runoff projections.