An Analysis of Hydrological Model Uncertainty at the
Local Stage of a Climate Change Impact Assessment in the Suir
Masters thesis, National University of Ireland Maynooth.
This thesis presents an analysis of uncertainty at the local stage of a climate impact
assessment. Impact model structural uncertainty and uncertainty due to equifinality of
parameter sets are evaluated, in addition to uncertainty due to GCMs and emissions
scenarios. The Suir catchment is employed as a case study area to analyse the changes in
catchment hydrology and in future flood magnitude and frequency relationships due to
climate change. Two lumped conceptual rainfall-runoff models of different degrees of
complexity are forced with the output of three GCMs and two emissions scenarios (A2 and
B2) downscaled to synoptic station level by empirical statistical downscaling (Fealy and
Sweeney, 2007). In the analysis of changes to catchment hydrology for the 2050s and the
2080s, GCM uncertainty is the greatest source of uncertainty. However, by the 2080s,
uncertainty due to equifinality of parameter sets and model structure is also a significant
source of uncertainty, with increases in streamflow being most extreme in February.
Furthermore, results suggest that flood magnitude and frequency relationships will intensify
under climate change. A robust finding is the notable agreement in new return period
values in the 2080s with both models suggesting that the 10, 25 and 50 year flood events
simulated in the control period will become 3.2, 5.4 and 9 year flood events. However, the
magnitudes of the flood events differ for each model. These results suggest that model
structural uncertainty is a significant source of uncertainty and should be taken into account
by employing a suite of hydrological models at the local stage of climate change impact
analyses that inform anticipatory flood adaptation decisions or policy frameworks.
||This research was funded by an Irish Research Council for Science
Engineering and Technology Embark Initiative scholarship.
||Hydrological Model Uncertainty; Climate Change Impact Assessment; Suir Catchment; Climate Change; Ireland;
||Faculty of Social Sciences > Geography
||17 Nov 2010 15:11
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