Energy Transports by Ocean and Atmosphere Based on an Entropy Extremum Principle. Part 1: Zonal Averaged Transports

Abstract

Required global energy transports determined from Nimbus-7 satellite net radiation measurements have been separated into atmospheric and oceanic components by applying a maximum entropy production principle to the atmospheric system. Strong poleward fluxes by the oceans in the Northern Hemisphere exhibit a maximum of 2.4 1015W at 18°N, whereas maximum atmospheric transports are found at 37°N with a magnitude of 4.5 1015W. These results are in good agreement with other published results. In the Southern Hemisphere, atmospheric transports are found to be considerably stronger than oceanic transports, and this finding corroborates findings based on other published direct estimates. Maximum atmospheric energy transports are found at 37°S with a magnitude of 4.7 ? 1015 W; two local oceanic transport maxima are shown at 1 8°S and 45°S with magnitudes of 1.3 ? 1O15 W and 1.1 ? 1015 W, respectively. There is also evidence of net cross-equatorial) transport in which the Southern Hemisphere oceans give rise to a net transfer of beat northward across the equator that exceeds a net transfer from Northern to Southern Hemisphere by the atmosphere. Since Southern Hemisphere results in this study should have the same degree of accuracy as in the Northern Hemisphere, these findings suggest that Southern Ocean transports are weaker than previously reported. A main implication of the study is that a maximum entropy production principle can serve as a governing rule on macroscale global climate, and in conjunction with conventional satellite measurements of the net radiation balance, provides a means to decompose atmosphere and ocean transports from the total transport field. Furthermore, the modeling methodology provides a possible means to partition the transports in a two-dimensional framework; this approach is tested on the separate ocean basins with qualified success.