Open AccessCharacterizing ENSO Coupled Variability and Its Impact on North American Seasonal Precipitation and Temperature*
Author(s) -
Michelle L’Heureux,
Michael K. Tippett,
Anthony G. Barnston
Publication year - 2015
Publication title -
journal of climate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.315
H-Index - 287
eISSN - 1520-0442
pISSN - 0894-8755
DOI - 10.1175/jcli-d-14-00508.1
Subject(s) - outgoing longwave radiation , climatology , environmental science , el niño southern oscillation , precipitation , empirical orthogonal functions , sea surface temperature , context (archaeology) , multivariate enso index , la niña , atmospheric sciences , geography , meteorology , geology , convection , archaeology
Two questions are addressed in this paper: whether ENSO can be adequately characterized by simple, seasonally invariant indices and whether the time series of a single component—SST or OLR—provides a sufficiently complete representation of ENSO for the purpose of quantifying U.S. climate impacts. Here, ENSO is defined as the leading mode of seasonally varying canonical correlation analysis (CCA) between anomalies of tropical Pacific SST and outgoing longwave radiation (OLR). The CCA reveals that the strongest regions of coupling are mostly invariant as a function of season and correspond to an OLR region located in the central Pacific Ocean (CP-OLR) and an SST region in the eastern Pacific that coincides with the Niño-3 region. In a linear context, the authors explore whether the use of a combined index of these SST and OLR regions explains additional variance of North American temperature and precipitation anomalies beyond that described by using a single index alone. Certain seasons and regions benefit from the use of a combined index. In particular, a combined index describes more variability in winter/spring precipitation and summer temperature.