TY - JOUR

T1 - Daily vs. hourly simulation for estimating future flood peaks in mesoscale catchments

AU - Beylich, Marcus

AU - Haberlandt, Uwe

AU - Reinstorf, Frido

N1 - Funding Information: The authors thank the Lower Saxony Water Management, Coastal Defence and Nature Conservation Agency (Niedersäch-sischer Landesbetrieb für Wasserwirtschaft, Küsten-und Naturschutz, NLWKN) for providing and preparing the ensemble data within the KliBiW project. The authors also thank an anonymous reviewer for the helpful comments and Hannes Müller-Thomy for providing the MRC model. The publication of this article was funded by the Open Access Fund of the Leibniz Universität Hannover.

PY - 2021/8/1

Y1 - 2021/8/1

N2 - Daily hydrological models are commonly used to study changes in flood peaks due to climate change. Although they often lead to an underestimation of absolute floods, it is assumed that future flood peaks in smaller mesoscale catchments are less underestimated when examining the relative change signal of floods. In this study, the applicability of this hypothesis is investigated by comparing the results of a daily hydrological model set, calibrated on runoff hydrographs, with an hourly model set calibrated on flood peak distributions. For analysis, a daily RCP8.5 climate model ensemble is disaggregated to hourly values and the runoff is simulated on a daily and hourly basis for six mesoscale catchments in Central Germany. Absolute floods and relative flood changes are compared between both model sets. The results show significant differences between the absolute floods of both model sets, in most cases caused by underestimations due to the daily modeling process. In contrast, the differences between the two model sets are not significant for the relative change signal of the floods, especially for higher return periods. To improve results in climate studies with coarse modeling time step, the use of relative change signal of floods instead of absolute values is recommended.

AB - Daily hydrological models are commonly used to study changes in flood peaks due to climate change. Although they often lead to an underestimation of absolute floods, it is assumed that future flood peaks in smaller mesoscale catchments are less underestimated when examining the relative change signal of floods. In this study, the applicability of this hypothesis is investigated by comparing the results of a daily hydrological model set, calibrated on runoff hydrographs, with an hourly model set calibrated on flood peak distributions. For analysis, a daily RCP8.5 climate model ensemble is disaggregated to hourly values and the runoff is simulated on a daily and hourly basis for six mesoscale catchments in Central Germany. Absolute floods and relative flood changes are compared between both model sets. The results show significant differences between the absolute floods of both model sets, in most cases caused by underestimations due to the daily modeling process. In contrast, the differences between the two model sets are not significant for the relative change signal of the floods, especially for higher return periods. To improve results in climate studies with coarse modeling time step, the use of relative change signal of floods instead of absolute values is recommended.

KW - Climate change

KW - Disaggregation

KW - Flood modeling

KW - Mesoscale

KW - Modeling time step

UR - http://www.scopus.com/inward/record.url?scp=85113528759&partnerID=8YFLogxK

U2 - 10.2166/nh.2021.152

DO - 10.2166/nh.2021.152

M3 - Article

AN - SCOPUS:85113528759

VL - 52

SP - 821

EP - 833

JO - Hydrology Research

JF - Hydrology Research

SN - 1998-9563

IS - 4

ER -