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Decadal variability of the North Pacific Polar Front: Subsurface warming versus surface cooling
Author(s) -
Belkin Igor,
Krishfield Richard,
Honjo Susumu
Publication year - 2002
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 - 10.1029/2001gl013806
Subject(s) - front (military) , stratification (seeds) , subarctic climate , hydrography , polar front , climatology , geology , cold front , oceanography , convection , environmental science , meteorology , geography , seed dormancy , botany , germination , dormancy , biology
Over 200 hydrographic sections are used to trace the Polar Front defined as the southern boundary of the “pure” subarctic stratification with a pronounced, extremely cold, subsurface temperature minimum underlain by a temperature maximum. The front extends from 40°N off Japan to 57°N in the Gulf of Alaska where it retroflects and continues WSW with the Alaskan Stream. The front's decadal variability from 1977–1999 is examined along 150°E, 170°E, 175.5°E, and 180°E. At these longitudes the front is relatively stable, except for 170°E, where it shifts north‐south by 400 km every 6 years. Most time series reveal a subsurface warming of ∼1°C per decade, and a surface cooling, of the front. Since the subsurface temperature minimum is a remnant of winter convection, the subsurface warming signals an amelioration of the winter climate, whereas the summer climate becomes colder.