Global modes of climate variability

• Published in: Geophysical Research Letters
• Main Authors: de Viron, O., Dickey, J.O., Ghil, M.
• Other Authors: Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), Institute of Geophysics and Planetary Physics Los Angeles (IGPP), University of California Los Angeles (UCLA), University of California (UC)-University of California (UC), Department of Atmospheric and Oceanic Sciences Los Angeles (AOS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Pacific; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-01092296; https://hal.science/hal-01092296v1/document; https://hal.science/hal-01092296v1/file/grl.50386.pdf; https://doi.org/10.1002/grl.50386

International audience The atmosphere, hydrosphere, and cryosphere form a fully coupled climate system. This system exhibits a number of large-scale phenomena, such as the El Niño-Southern Oscillation, the Asian Monsoon, the North Atlantic Oscillation, and the Madden-Julian Oscillation. While these modes of variability are not exactly periodic, they are oscillatory in character, and their state is monitored using so-called climate indices. Each of these scalar indices is a combination of several climate variables. Here we use a comprehensive set of 25 climate indices for time intervals that range between 1948 and 2011 and estimate an optimal set of lags between these indices to maximize their correlation. We show that most of the index pairs drawn from this set present a significant correlation on interannual time scales. It is also shown that on average, about two thirds of the total variability in each index can be described by using only the four leading principal components of the entire set of lagged indices. Our index set's leading orthogonal modes exhibit several interannual frequencies and capture separately variability associated with the North Atlantic and the North Pacific. These modes are associated, in turn, with large-scale variations of sea surface temperatures. Key PointsMost of the climate indices are cross-correlated significantlyMost of their variability can be captured with only four principal componentsThose components are associated with global signatures in the SST ©2013. American Geophysical Union. All Rights Reserved.