Mesoscale eddy effects on the wintertime vertical mixing in the formation region of the North Pacific Subtropical Mode Water PAN Aijun

摘要

Mesoscaie eddy effects OB the wintertime vertical mixing in the formation region of the North Pacific Subtropical Mode Water (NPSTMW) are studied using hydro-graphic from Argo profiling floats deployed in the Ku-roshio recirculation region in February and March of 2001. Anticyclonic (warm) eddy enhances the wintertime vertical results in the deep mixed layer and the deep thenaodine. Consequently, a large volumetric water with low potential vorticity corresponding to the prototype of NPSTMW tends to be formed. By contrast, cyclonic (cold) eddy is unfavorable for the vertical mixing process and halts the deepening of the mixed layer and thus the formation of mode water. Farther analysis shows that cyclonic eddies prevail in the late-1990s in the formation region of NPSTMW, which to significant suppression of the wintertime vertical mixing (96-98) and thus are unfavorable for the.formation of NPSTMW; while the situation is completely reversed in the early 1990s (93-95).