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Monthly river temperature trends across the US confound annual changes

Environmental Research Letters
By: , and 

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Abstract

Climate variations and human modifications of the water cycle continue to alter the Earth's surface water and energy exchanges. It is therefore critical to ascertain how these changes impact water quality and aquatic ecosystem habitat metrics such as river temperatures. Though river temperature trend analyses exist in the literature, studies on seasonal trends in river temperatures across large spatial extents, e.g. the contiguous United States (US), are limited. As we show through both annual and monthly trend analyses for 20 year (n = 138 sites) and 40 year (n = 40 sites) periods, annual temperature trends across the US mask extensive monthly variability. While most sites exhibited annual warming trends, these annual trends obscured sub-annual cooling trends at many sites. Monthly trend anomalies were spatially organized, with persistent regional patterns at both reference and human-impacted sites. The largest warming and cooling anomalies happened at human impacted sites and during summer months. Though our analysis points to coherence in trends as well as the overall impact of human activity in driving these patterns, we did not investigate the impact of river temperature observation accuracy on reported trends, an area needed for future work. Overall, these patterns emphasize the need to consider sub-annual behavior when managing the ecological impacts of river temperature throughout lotic networks.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Monthly river temperature trends across the US confound annual changes
Series title Environmental Research Letters
DOI 10.1088/1748-9326/ac2289
Volume 16
Year Published 2021
Language English
Publisher IOP Science
Contributing office(s) WMA - Integrated Modeling and Prediction Division
Description 104006, 10 p.
Country United States
Google Analytic Metrics Metrics page
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