Climate driven trends in historical extreme low streamflows on four continents

Hodgkins, Glenn A.; Renard, Benjamin; Whitfield, Paul H.; Laaha, Gregor; Stahl, Kerstin; Hannaford, Jamie ORCID: https://orcid.org/0000-0002-5256-3310; Burn, Donald H.; Westra, Seth; Fleig, Anne K.; Araújo Lopes, Walszon Terllizzie; Murphy, Conor; Mediero, Luis; Hanel, Martin. 2024 Climate driven trends in historical extreme low streamflows on four continents. Water Resources Research, 60 (6), e2022WR034326. 25, pp. 10.1029/2022WR034326

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Abstract/Summary

Understanding temporal trends in low streamflows is important for water management and ecosystems. This work focuses on trends in the occurrence rate of extreme low-flow events (5- to 100-year return periods) for pooled groups of stations. We use data from 1,184 minimally altered catchments in Europe, North and South America, and Australia to discern historical climate-driven trends in extreme low flows (1976–2015 and 1946–2015). The understanding of low streamflows is complicated by different hydrological regimes in cold, transitional, and warm regions. We use a novel classification to define low-flow regimes using air temperature and monthly low-flow frequency. Trends in the annual occurrence rate of extreme low-flow events (proportion of pooled stations each year) were assessed for each regime. Most regimes on multiple continents did not have significant (p < 0.05) trends in the occurrence rate of extreme low streamflows from 1976 to 2015; however, occurrence rates for the cold-season low-flow regime in North America were found to be significantly decreasing for low return-period events. In contrast, there were statistically significant increases for this period in warm regions of NA which were associated with the variation in the Pacific Decadal Oscillation. Significant decreases in extreme low-flow occurrence rates were dominant from 1946 to 2015 in Europe and NA for both cold- and warm-season low-flow regimes; there were also some non-significant trends. The difference in the results between the shorter (40-year) and longer (70-year) records and between low-flow regimes highlights the complexities of low-flow response to changing climatic conditions.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2022WR034326
UKCEH and CEH Sections/Science Areas:	Water Resources (Science Area 2017-)
ISSN:	0043-1397
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
NORA Subject Terms:	Hydrology Meteorology and Climatology
Related URLs:	Other
Date made live:	18 Jun 2024 09:16 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/537592

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