The annual cycle of oceanic heat storage and oceanic meridional heat transport



The global climatology of monthly heat storage and heat transport are presented using data from the Master Oceanographic Observations Data Set for the period 1949–1980. Heat storage and the rate of heat storage change are calculated for the Pacific, Atlantic and Indian Oceans. Heat transports on a monthly basis are calculated using surface energy flux data from a previous study together with the computed heat storage change. There is a large annual cycle in heat storage change at almost all latitudes with the largest amplitude in latitudes where the western boundary currents dominate. There is also a considerable annual cycle in the heat transport estimates. The heat transport in the Atlantic is northward most of the year except in January when there is significant southward transport. The largest northward transport is found at 5°N during March with a magnitude of about 2.0PW (1 PW =1015W). In the Pacific Ocean, northward transport dominates north of 20°N with a maximum of about 1.5PW at 25°N in July-September. South of 20°N, there is significant southward transport in July through September with a maximum of 1.5PW at 10°S in August. Overall, the largest northward transport in the Pacific is about 2.1 PW in March at 10°N. Heat transport in the Indian Ocean is mostly southward with a maximum of about 2.5 PW in May at 20°S except for a small northward transport in January-February north of 5°S. Although the uncertainties involved with the transport estimates are large, the transport values presented here compare rather well with direct estimates and with model results.