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Step Increase in Eastern U.S. Precipitation Linked to Indian Ocean Warming
Author(s) -
Strong Courtenay,
McCabe Gregory J.,
Weech Alexander
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl088911
Subject(s) - teleconnection , climatology , precipitation , environmental science , atmospheric circulation , middle latitudes , global warming , ocean heat content , streamflow , oceanography , deep convection , climate change , geology , convection , ocean current , geography , el niño southern oscillation , meteorology , drainage basin , cartography
Abstract A step increase in annual precipitation over the eastern United States in the early 1970s 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. Increases in fall precipitation contribute most strongly to the step increase, and the associated 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.