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Step increase in eastern U.S. precipitation linked to Indian Ocean warming

August 21, 2020

A step increase in annual precipitation over the eastern U.S. in the early 1970’s commenced five decades of invigorated hydroclimate, with ongoing impacts on streamflow and water resources. Despite its far-reaching impacts, the dynamical origin of this change is unknown. Here, analyses of a century of atmospheric and oceanic data trace the dynamics to changes in the Indian Ocean. Spring and fall precipitation explain more than half the annual eastern-U.S. precipitation variance over the century, and changes in fall are predominantly responsible for the step increase. The driving mechanism is emergence of a pan-Pacific atmospheric wave emanating from deep convection over the warming Indian Ocean. Documentation of this fall teleconnection draws attention to projected anthropogenic increases in tropical oceanic heat content, and their potential impacts on hydroclimate of the midlatitudes.

Publication Year 2021
Title Step increase in eastern U.S. precipitation linked to Indian Ocean warming
DOI 10.1029/2020GL088911
Authors Courtenay Strong, Gregory J. McCabe, Alexander Weech
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70217915
Record Source USGS Publications Warehouse
USGS Organization WMA - Integrated Modeling and Prediction Division