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Springtime ENSO phase evolution and its relation to rainfall in the continental U.S.
Author(s) -
Lee SangKi,
Mapes Brian E.,
Wang Chunzai,
Enfield David B.,
Weaver Scott J.
Publication year - 2014
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 - 10.1002/2013gl059137
Subject(s) - climatology , spring (device) , storm , boreal , jet stream , geology , el niño southern oscillation , anomaly (physics) , oceanography , environmental science , atmospheric sciences , jet (fluid) , mechanical engineering , paleontology , physics , condensed matter physics , engineering , thermodynamics
Springtime El Niño–Southern Oscillation (ENSO) phase evolution and associated U.S. rainfall variability are explored by performing composite analysis of observational data. Although the tropical Pacific ENSO sea surface temperature anomalies are weaker and less coherent in boreal spring compared to those in winter, there are unique and significant patterns of U.S. rainfall anomalies frequently appearing during the onset and decay phases of ENSO. In early spring of a decaying El Niño, the atmospheric jet stream and associated storm track shift southward, causing more frequent wet conditions across the southern U.S. and dry conditions in a belt south and east of the Ohio River. In late spring of a developing El Niño, the synoptic activity over the U.S. reduces overall and the southwesterly low‐level winds that carry moist air from the Gulf of Mexico to the U.S. shift westward, causing a similar dipole of rainfall anomalies between the southern U.S. and the Ohio Valley.