Recent Warming in the Western North Pacific in Relation to Rapid Changes in the Atmospheric Circulation of the Siberian High and Aleutian Low Systems*

• DOI: 10.1175/2011jcli4142.1
• Publication Date: 2011-10-10T19:02:36Z
• Authors: Young-Hyang Park; Jong-Hwan Yoon; Yong-Hoon Youn; Frédéric Vivier
• Keywords: Siberian High; Atmospheric Circulation; Teleconnection; Middle latitudes

Abstract On the basis of a new East Asian winter monsoon (EAWM) index and by analyzing relationship between sea surface temperature (SST) anomalies different atmospheric oceanic factors in winter, this study investigates causes recent unusual warming western North Pacific Ocean. Analyses presented here emphasize dual contribution from atmosphere ocean to local SST variability, with relative importance each contributor varying period place. During 1970–89, EAWM, controlled mostly Siberian high, is predominantly responsible for variability most Pacific, whereas 1990–2005 dynamics become increasingly important places or even dominant Kuroshio–Oyasio Extension (KOE) region. The delayed response KOE basinwide wind stress curl forcing via Rossby waves epoch dependent significant at lags 1, 3, 4 yr before 1990 but only 1 afterward. This dependency impact related locations centers action midlatitude two epochs. In addition, mean advection EAWM-driven anomalous southern China Sea, which can be transported into region about year Kuroshio, likely affects lagged yr. strongest positive trend observed results combined effects abrupt weakening EAWM due unprecedented decline high increasing role ocean. latter best evidenced 1-yr gyre circulation adjustment decadal-scale change associated northward shift strengthened Aleutian low.