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The Greenland Sea Jet: A mechanism for wind‐driven sea ice export through Fram Strait
Author(s) -
van Angelen J. H.,
van den Broeke M. R.,
Kwok R.
Publication year - 2011
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 - 10.1029/2011gl047837
Subject(s) - sea ice , climatology , arctic ice pack , katabatic wind , drift ice , geology , antarctic sea ice , forcing (mathematics) , arctic sea ice decline , cryosphere , arctic , environmental science , oceanography , atmospheric sciences
We present a mechanism for wind‐driven sea ice export from the Arctic Ocean through Fram Strait for the period 1979–2007, using the output of a high‐resolution regional atmospheric climate model. By explicitly calculating the components of the atmospheric momentum budget, we show that not large scale synoptic forcing (LSC), but mainly thermal wind forcing (THW) causes the persistent northerly jet (the Greenland Sea Jet) over Fram Strait. The jet results from horizontal temperature gradients in the atmospheric boundary layer (ABL), set up between cold ABL‐air over the sea ice covered western Greenland Sea and the relatively warmer ABL over the ice‐free eastern Greenland Sea. From 1993 onwards we find a negative trend in THW, due to a stronger response to climate warming of the ABL over the sea ice covered ocean, compared to that over the ice free ocean. Although on average LSC is smaller than THW, year to year variations in LSC explain most of the interannual variability in the sea ice area flux through Fram Strait (R = 0.81). A small positive trend is found for LSC, partly compensating the decrease in THW in recent years.