FY 1996

Regional variations of moist static energy flux into the Arctic

Overland, J.E., P. Turet, and A.H. Oort

J. Climate, 9(1), 54–65 (1996)

The authors investigate the climatological heating of the Arctic by the atmospheric moist static energy (MSE) flux from lower latitudes based on 25 years (November 1964-1989) of the GFDL dataset. During the five month winter period (NDJFM) the transport of sensible heat by transient eddies is the largest component (50%) at 70°N, followed by the transport of sensible heat by standing eddies (25%), and the moist static energy flux by the mean meridional circulation (25%). The mean meridional circulation (MMC) changes from a Ferrel cell to a thermally direct circulation near 60°N; maximum horizontal velocities in the thermally direct circulation peak near 70°N. North of 60°N the sensible heat flux by the MMC is southward and opposes the greater northward transport of geopotential energy. The transport of energy is not uniform. Major pathways are the northward transport of positive anomalies through the Greenland and Barents Seas into the eastern Arctic and the southward transport of negative anomalies to the east of the Siberian high. The Atlantic pathway in winter relates to transport by transient eddies while the western Siberian flux relates to the standing eddy pattern. Interannual variability of northward MSE is concentrated in these two regions. The western Arctic Ocean from about 30°W to 60°W receives about 50 W m^–2 less energy flux convergence than the eastern Arctic. This result compares well with the observed minimum January surface air temperatures in the Canadian Basin of the western Arctic and implies that the greater observed ice thickness in this region may have a thermodynamic as well as a dynamic origin.