Modeling the Energy Budget of the Arctic Ocean

The annual energy budget of the Arctic Ocean is characterized by a net heat loss at the air-sea interface which is balanced by oceanic heat transport into the Arctic . The energy loss at the air-sea interface is due to the combined effects of radiative and sensible and latent heat fluxes. The inflow of heat by the ocean can be divided into two components, one due to the exchange of water masses of different temperatures between the Arctic and the Atlantic and Pacific oceans and one due to the export of sea ice, primarily through Fram Strait. Two pairs of 150-year simulations of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. Relative to the controls, the last 50-year periods of the GHG experiments indicate that even though the net incident solar radiation hitting the surface decreases by 4.6 W/m^2(because of greater cloud cover), the absorbed solar radiation increases by 2.9 W/m^2 (because of less sea ice). The net radiation into the ocean increases by about 4.8 W/m^2 due to the combined effects of increased absorption of short wave radiation and increased downward long wave radiation. The increased radiative flux into the ocean, however, is compensated for by larger increases in both sensible and latent heat fluxes out of the ocean so that the net loss from the ocean surface increases by 1.5 W/m^2. Feedbacks between the energy budget and the Arctic hydrologic cycle are also examined.