Climatology and decadal variations in multicore structure of the North Pacific subtropical mode water

TitleClimatology and decadal variations in multicore structure of the North Pacific subtropical mode water
Publication TypeJournal Article
Year of Publication2017
AuthorsLiu C., Xie SP, Li P.L, Xu LX, Gao W.D
JournalJournal of Geophysical Research-Oceans
Date Published2017/09
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000413167200030
KeywordsArgo; calibration; decadal; impact; Kuroshio Extension; kuroshio-extension system; layer; Mesoscale eddies; multicore structure; observations; ocean; subduction; subtropical mode water; theta-s climatology; variability; variations

The pycnostad of the North Pacific subtropical mode water (STMW) often displays multiple vertical minima in the potential vorticity profile. Argo profile data from 2004 to 2015 are used to investigate interannual to decadal variations of the multicore structure. Climatologically, about 24% pycostads of STMW have multicore structure, and most of them distribute in the region west of 150 degrees E. STMW cores are classified into three submodes-the cold, middle, and warm ones with potential temperatures of 16.0-17 degrees C, 17-18 degrees C, and 18-19.5 degrees C, respectively. The Kuroshio Extension (KE) varies between stable and unstable states. The unstable KE with large meanders increases the subsurface stratification and shoals the winter mixed layer east of 150 degrees E with warmer temperatures. There, the dominant STMW type varies from the cold single type in stable KE years (making up 72% of the profiles with STMW) to the middle single one (53%) in unstable years. The variation of the dominant STMW type in the region east of 150 degrees E subsequently affects the multicore structure of STMW west of 150 degrees E. In a broad region between 130 degrees E and 180 degrees E, profiles with STMW are fewer in unstable years but the proportion of multicore profiles increases among STMW profiles. This might be due to the split recirculation gyre with a chaotic KE.

Short TitleJ Geophys Res-Oceans
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