Systematic variation in evapotranspiration trends and drivers across the Northeastern United States

Hydrological Processes
By: , and 

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Abstract

The direction and magnitude of responses of evapotranspiration (ET) to climate change are important to understand, as ET represents a major water and energy flux from terrestrial ecosystems, with consequences that feed back to the climate system. We inferred multidecadal trends in water balance in 11 river basins (1940–2012) and eight smaller watersheds (with records ranging from 18 to 61 years in length) in the Northeastern United States. Trends in river basin actual ET (AET) varied across the region, with an apparent latitudinal pattern: AET increased in the cooler northern part of the region (Maine) but decreased in some warmer regions to the southwest (Pennsylvania–Ohio). Of the four small watersheds with records longer than 45 years, two fit this geographic pattern in AET trends. The differential effects of the warming climate on AET across the region may indicate different mechanisms of change in more‐ vs. less‐energy‐limited watersheds, even though annual precipitation greatly exceeds potential ET across the entire region. Correlations between AET and time series of temperature and precipitation also indicate differences in limiting factors for AET across the Northeastern U.S. climate gradient. At many sites across the climate gradient, water‐year AET correlated with summer precipitation, implying that water limitation is at least transiently important in some years, whereas correlations with temperature indices were more prominent in northern than southern sites within the region.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Systematic variation in evapotranspiration trends and drivers across the Northeastern United States
Series title Hydrological Processes
DOI 10.1002/hyp.13278
Volume 32
Issue 23
Year Published 2018
Language English
Publisher Wiley
Contributing office(s) New York Water Science Center
Description 14 p.
First page 3547
Last page 3560
Country United States