Annual Reviews OnlineSearch Annual ReviewsAnnual Review of Marine ScienceOnlineMost Downloaded Marine ScienceReviewsMost Cited Marine ScienceReviewsAnnual Review of Marine ScienceErrataView Current Editorial CommitteeAll Articles in the Annual Review of Marine Science, Vol. 2Paleophysical Oceanography with an Emphasis on Transport RatesAdvances in Estuarine PhysicsThe Effect of Submarine Groundwater Discharge on the OceanMarine EcomechanicsSea Surface Temperature Variability: Patterns and MechanismsContemporary Sea Level RiseEstimation of Anthropogenic CO2 Inventories in the OceanOcean Deoxygenation in a WarmingWorldArchaeology Meets Marine Ecology: The Antiquity of Maritime Cultures and Human Impacts on Marine Fisheries and EcosystemsThe Ecology of Seamounts: Structure, Function, and Human ImpactsMicrobial Provinces in the SubseafloorProchlorococcus: Advantages and Limits of MinimalismOceanographic and Biogeochemical Insights from Diatom GenomesGenetic Perspectives on Marine Biological InvasionsBiocomplexity in Mangrove EcosystemsWhat Can Ecology Contribute to Ecosystem-Based Management?Bioluminescence in the SeaANRV399-MA02-05 ARI 13 November 2009 17:19Sea Surface TemperatureVariability: Patternsand MechanismsClara Deser,1Michael A. Alexander,2Shang-Ping Xie,3and Adam S. Phillips11Climate Analysis Section, Climate and Global Dynamics Division, National Center forAtmospheric Research, Boulder, Colorado 80305; email: [email protected], [email protected] System Research Laboratory, National Oceanic and Atmospheric Association, Boulder,Colorado 80305; email: [email protected] Pacific Research Center, School of Ocean and Earth Science and Technology,University of Hawaii, Honolulu, Hawaii 96822; email: [email protected]. Rev. Mar. Sci. 2010. 2:115–43First published online as a Review in Advance onSeptember 15, 2009The Annual Review of Marine Science is online atmarine.annualreviews.orgThis article’s doi:10.1146/annurev-marine-120408-151453Copyrightc 2010 by Annual Reviews.All rights reserved1941-1405/10/0115-0115$20.00Key Wordsocean-atmosphere interaction, El Ni˜no, Pacific Decadal Oscillation,Atlantic Multidecadal Oscillation, climate variabilityAbstractPatterns of sea surface temperature (SST) variability on interannual andlonger timescales result from a combination of atmospheric and oceanicprocesses. These SST anomaly patterns may be due to intrinsic modes ofatmospheric circulation variability that imprint themselves upon the SSTfield mainly via surface energy fluxes. Examples include SST fluctuations inthe Southern Ocean associated with the Southern Annular Mode, a tripolarpattern of SST anomalies in the North Atlantic associated with the NorthAtlantic Oscillation, and a pan-Pacific mode known as the Pacific DecadalOscillation (with additional contributions from oceanic processes). Theymay also result from coupled ocean-atmosphere interactions, such as the ElNi˜no-Southern Oscillation phenomenon in the tropical Indo-Pacific, thetropical Atlantic Ni˜no, and the cross-equatorial meridional modes in thetropical Pacific and Atlantic. Finally, patterns of SST variability may arisefrom intrinsic oceanic modes, notably the Atlantic Multidecadal Oscillation.115Annu. Rev. Marine. Sci. 2010.2:115-143. Downloaded from arjournals.annualreviews.orgby David A. Siegel on 03/29/10. For personal use only.Click here for quick links to Annual Reviews content online, including:• Other articles in this volume• Top cited articles• Top downloaded articles• Our comprehensive searchFurtherANNUALREVIEWSANRV399-MA02-05 ARI 13 November 2009 17:191. INTRODUCTIONThe oceans play an important role in the climate system owing in part to their large heat-storagecapacity: Approximately 3.5 m of water contains as much energy as an entire atmospheric column.The oceans’ thermal inertia is communicated to the atmosphere via turbulent and radiative energyexchange at the sea surface. These energy fluxes in turn depend on a single oceanic quantity, thesea surface temperature (SST), as well as several atmospheric parameters including wind speed,air temperature, humidity, and cloudiness. SSTs thus play a key role in regulating climate and itsvariability. In particular, slow variations in SST provide a source of potential predictability forclimate fluctuations on timescales of seasons and longer. In this review, we describe the dominantspatial and temporal patterns of nonseasonal SST variability observed over the past ∼150 yearsand discuss the current state of knowledge regarding their underlying physical mechanisms andclimate impacts.The rest of the paper is outlined as follows: Section 2 provides some background on the physicalprocesses governing SST variability, including the role of atmospheric circulation forcing. TheNorth Atlantic SST tripole mode is used to illustrate the latter. Section 3 introduces the SST datasets commonly used for climate studies, with an emphasis on issues related to spatial and tem-poral coverage. Section 4 discusses the geographical distribution of nonseasonal SST variabilityand provides a brief introduction to Empirical Orthogonal Function analysis, a commonly usedtechnique for identifying patterns of variability. Section 5 presents the primary modes of nonsea-sonal SST variability in each ocean basin. These include the following (in addition to the NorthAtlantic SST tripole): (a) the El Ni˜no-Southern Oscillation (ENSO) phenomenon in the tropicalPacific, with teleconnections to the other ocean basins; (b) the tropical Indian Ocean dipole mode;(c) the tropical Atlantic Ni˜no and meridional modes; (d ) Southern Ocean variability; (e) the PacificDecadal Oscillation; and ( f ) the Atlantic Multidecadal Oscillation. Summary Points and FutureIssues sections conclude this article.2. PHYSICAL BACKGROUND2.1. Heat Budget of the Upper-Ocean Mixed LayerSSTs are governed by both atmospheric and oceanic processes. On the atmospheric side, windspeed, air temperature, cloudiness, and humidity are the dominant factors regulating the exchangeof energy at the sea surface. On the oceanic side, heat transport by currents, vertical mixing, andboundary layer depth influence SST. Mathematically, the heat budget for the upper-ocean mixedlayer may be written as∂T/∂t = Qnet/(ρCpH) + (Ugeo+Uek) ·∇T + (We+ Wek)(T − Tb)/H, (1)where ρ is the density of seawater, Cp is the specific heat of seawater, H is the mixed layer depth,T is the