John Marshall

Cecil and Ida Green Professor of Oceanography, MIT

Partitioning of poleward heat transport between the atmosphere and ocean

Partitioning of poleward heat transport between the atmosphere and ocean.

(Czaja, A and Marshall, J), JOURNAL OF THE ATMOSPHERIC SCIENCES, vol. 63, no. 5, pp. pages, 2006.

Abstract

Observations of the poleward heat transport of the earth (H) suggest that the atmosphere is the primary transporting agent poleward of 30 degrees, that oceanic (H-O) and atmospheric (H-A) contributions are comparable in the tropical belt, and that ocean transport dominates in the deep Tropics. To study the partition we express the ratio H-A/H-O as the ratio of mass transports in the two fluids multiplied by the ratio of change in energy across the circulation defined by the overturning circulation psi. It is argued here that the observed partitioning of heat transport between the atmosphere and ocean is a robust feature of the earth’s climate and reflects two limits: (i) dominance of atmospheric mass transport in mid-to-high latitudes (psi(A) >> psi(O) with C-A Delta theta(A) similar to C-O Delta theta(O) and hence H-A/H-O >> 1) and (ii) dominance of oceanic energy contrast in the Tropics (C-O Delta theta(O) > C-A Delta theta(O) >> with psi(A) similar to psi(O) and hence H-A/H-O << 1). Motivated by simple dynamical arguments, these ideas are illustrated through diagnosis of atmospheric reanalyses, long simulations of an ocean model, and a coupled atmosphere-ocean model of intermediate complexity.

doi = 10.1175/JAS3695.1