Zhao, F., Lange, S., Goswami, B., & Frieler, K. (2024). Frequency Bias Causes Overestimation of Climate Change Impacts on Global Flood Occurrence. Geophysical Research Letters 51 (16) e2024GL108855. 10.1029/2024GL108855.
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Geophysical Research Letters - 2024 - Zhao - Frequency Bias Causes Overestimation of Climate Change Impacts on Global Flood.pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (2MB) | Preview |
Abstract
The frequency change of 100-year flood events is often determined by fitting extreme value distributions to annual maximum discharge from a historical base period. This study demonstrates that this approach may significantly bias the computed flood frequency change. An idealized experiment shows frequency bias exceeding 100% for a 50-year base period. Further analyses using Monte Carlo simulations, mathematical derivations, and hydrological model outputs reveal that bias magnitude inversely relates to base period length and is weakly influenced by the generalized extreme value distribution's shape parameter. The bias, persisting across different estimation methods, implies floods may exceed local defenses designed based on short historical records more often than expected, even without climate change. We introduce a frequency bias adjustment method, which significantly reduces the projected rise in global flood occurrence. This suggests a substantial part of the earlier projected increase in flood occurrence and impacts is not attributable to climate change.
Item Type: | Article |
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Research Programs: | Biodiversity and Natural Resources (BNR) Biodiversity and Natural Resources (BNR) > Water Security (WAT) |
Depositing User: | Luke Kirwan |
Date Deposited: | 26 Aug 2024 06:55 |
Last Modified: | 09 Sep 2024 13:00 |
URI: | https://pure.iiasa.ac.at/19959 |
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