Role of the Gulf Stream and Kuroshio–Oyashio Systems in Large-Scale Atmosphere–Ocean Interaction A Review

• Published in: Journal of climate Vol. 23; no. 12; pp. 3249 - 3281
• Main Authors: Kwon, Young-Oh, Alexander, Michael A., Bond, Nicholas A., Frankignoul, Claude, Nakamura, Hisashi, Qiu, Bo, Thompson, LuAnne
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 15.06.2010
• Subjects: Atmosphere; Atmospheric boundary layer; Atmospheric circulation; Atmospheric models; Atmospherics; Boundary layers; Climate change; Climate models; Climate variability; Earth Sciences; Earth, ocean, space; Eddies; Exact sciences and technology; External geophysics; General circulation models; Geophysics; Global climate models; Gyres; Latitude; Marine; Meteorology; Observational studies; Ocean circulation; Ocean currents; Ocean-atmosphere interaction; Oceanic climates; Oceans; Physics; Sciences of the Universe; SPECIAL U.S. CLIVAR Western Boundary Currents COLLECTION; Oyashio Current; West Pacific; Atlantic Ocean; Kuroshio; North Atlantic; Pacific Ocean; Gulf Stream; North Pacific; INW, Pacific, Oyashio Current; ASW, Equatorial Atlantic, Deep Western Boundary Current; AN, North Atlantic, Gulf Stream; INW, Pacific, Kuroshio Current; A, Atlantic, Gulf Stream; ocean currents; tropical zone; climate variability; Wind effect; Review; Oceanic front; Sea surface temperature; ocean-atmosphere interaction; anomalies; Variance; Dynamical climatology; Deep ocean current; Rossby wave; Mesoscale; Winter; Northern Hemisphere; Atmospheric boundary layer; Forcing; atmospheric circulation; Vortex; Western boundary current; ocean waves; heat transfer
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/2010JCLI3343.1

Ocean–atmosphere interaction over the Northern Hemisphere western boundary current (WBC) regions (i.e., the Gulf Stream, Kuroshio, Oyashio, and their extensions) is reviewed with an emphasis on their role in basin-scale climate variability. SST anomalies exhibit considerable variance on interannual to decadal time scales in these regions. Low-frequency SST variability is primarily driven by basin-scale wind stress curl variability via the oceanic Rossby wave adjustment of the gyre-scale circulation that modulates the latitude and strength of the WBC-related oceanic fronts. Rectification of the variability by mesoscale eddies, reemergence of the anomalies from the preceding winter, and tropical remote forcing also play important roles in driving and maintaining the low-frequency variability in these regions. In the Gulf Stream region, interaction with the deep western boundary current also likely influences the low-frequency variability. Surface heat fluxes damp the low-frequency SST anomalies over the WBC regions; thus, heat fluxes originate with heat anomalies in the ocean and have the potential to drive the overlying atmospheric circulation. While recent observational studies demonstrate a local atmospheric boundary layer response to WBC changes, the latter’s influence on the large-scale atmospheric circulation is still unclear. Nevertheless, heat and moisture fluxes from the WBCs into the atmosphere influence the mean state of the atmospheric circulation, including anchoring the latitude of the storm tracks to the WBCs. Furthermore, many climate models suggest that the large-scale atmospheric response to SST anomalies driven by ocean dynamics in WBCregions can be important in generating decadal climate variability. As a step toward bridging climate model results and observations, the degree of realism of the WBC in current climate model simulations is assessed. Finally, outstanding issues concerning ocean–atmosphere interaction in WBC regions and its impact on climate variability are discussed.