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Warming and oxygen decrease of intermediate water in the northwestern North Pacific, originating from the Sea of Okhotsk, 1955–2004
Author(s) -
Nakanowatari Takuya,
Ohshima Kay I.,
Wakatsuchi Masaaki
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028243
Subject(s) - subarctic climate , oceanography , global warming , ocean gyre , water mass , current (fluid) , environmental science , climatology , geology , climate change , fishery , subtropics , biology
On the basis of all available data, it is found that intermediate water temperature on the 26.8–27.4 σ θ isopycnals in the northwestern North Pacific has significantly increased during the past 50 years. The largest warming area exists in the western part of the Sea of Okhotsk with a 0.68°C/50‐yr temperature increase observed at 27.0 σ θ . The warming in the Pacific is found over the Oyashio and Subarctic Current regions, where the Okhotsk water extends along the subarctic gyre. This suggests that the warming originates from the Sea of Okhotsk. The warming trend is also accompanied by the significant decreasing trend of dissolved oxygen content, suggesting the weakening of overturning in the northwestern North Pacific. We propose that these trends of the water mass property are caused by a decrease in dense shelf water production in the northwestern shelf of the Sea of Okhotsk, which is a sensitive area to the current global warming.