Robust warming pattern of global subtropical oceans and its mechanism

TitleRobust warming pattern of global subtropical oceans and its mechanism
Publication TypeJournal Article
Year of Publication2015
AuthorsWang G.H, Xie SP, Huang R.X, Chen C.L
JournalJournal of Climate
Date Published2015/11
Type of ArticleArticle
ISBN Number0894-8755
Accession NumberWOS:000363766200016
Keywordscirculation; climate change; Climatology; dynamics; gyre; indo-pacific; Kuroshio Extension; model; Ocean circulation; Physical Meteorology and; sea-level rise; variability

The subsurface ocean response to anthropogenic climate forcing remains poorly characterized. From the Coupled Model Intercomparison Project (CMIP), a robust response of the lower thermocline is identified, where the warming is considerably weaker in the subtropics than in the tropics and high latitudes. The lower thermocline change is inversely proportional to the thermocline depth in the present climatology. Ocean general circulation model (OGCM) experiments show that sea surface warming is the dominant forcing for the subtropical gyre change in contrast to natural variability for which wind dominates, and the ocean response is insensitive to the spatial pattern of surface warming. An analysis based on a ventilated thermocline model shows that the pattern of the lower thermocline change can be interpreted in terms of the dynamic response to the strengthened stratification and downward heat mixing. Consequently, the subtropical gyres become intensified at the surface but weakened in the lower thermcline, consistent with results from CMIP experiments.

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