Meresa, Hadush and Murphy, Conor and Fealy, Rowan and Golian, Saeed (2021) Uncertainties and their interaction in flood hazard assessment with climate change. Hydrology and Earth System Sciences, 25 (9). pp. 5237-5257. ISSN 1607-7938

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Abstract

The assessment of future impacts of climate change is associated with a cascade of uncertainty linked to the modelling chain employed in assessing local-scale changes. Understanding and quantifying this cascade is essential for developing effective adaptation actions. We evaluate and quantify uncertainties in future flood quantiles associated with climate change for four catchments, incorporating within our modelling chain uncertainties associated with 12 global climate models contained in the Coupled Model Intercomparison Project Phase 6, five different bias correction approaches, hydrological model parameter uncertainty and the use of three different extreme value distributions for flood frequency analysis. Results indicate increased flood hazard in all catchments for different Shared Socioeconomic Pathways (SSPs), with changes in flooding consistent with changes in annual maximum precipitation. We use additive chains and analysis of variance (ANOVA) to quantify and decompose uncertainties and their interactions in estimating selected flood quantiles for each catchment. We find that not only do the contributions of different sources of uncertainty vary by catchment, but that the dominant sources of uncertainty can be very different on a catchment-by-catchment basis. While uncertainties in future projections are widely assumed to be dominated by the ensemble of climate models used, we find that in one of our catchments uncertainties associated with bias correction methods dominate, while in another the uncertainty associated with the use of different extreme value distributions outweighs the uncertainty associated with the ensemble of climate models. These findings highlight the inability to generalise a priori about the importance of different components of the cascade of uncertainty in future flood hazard at the catchment scale. Moreover, we find that the interaction of components of the modelling chain employed are substantial ( 20 % of overall uncertainty in two catchments). While our sample is small, there is evidence that the dominant components of the cascade of uncertainty may be linked to catchment characteristics and rainfall-runoff processes. Future work that seeks to further explore the characteristics of the uncertainty cascade as they relate to catchment characteristics may provide insight into a priori identifying the key components of modelling chains to be targeted in climate change impact assessments.

Item Type:	Article
Additional Information:	Cite as: Meresa, H., Murphy, C., Fealy, R. and Golian, S. (2021) 'Uncertainties and their interaction in flood hazard assessment with climate change', Hydrology and Earth System Sciences, 25(9), 5237, available: https://link.gale.com/apps/doc/A676874800/AONE?u=nuim&sid=summon&xid=bfcf20cf [accessed 14 Apr 2022].
Keywords:	climate change; global climate models; Shared Socioeconomic Pathways;
Academic Unit:	Faculty of Social Sciences > Geography Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	15848
Identification Number:	https://doi.org/10.5194/hess-25-5237-2021
Depositing User:	Conor Murphy
Date Deposited:	14 Apr 2022 11:29
Journal or Publication Title:	Hydrology and Earth System Sciences
Publisher:	Open Global Trusted
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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