Surface Heat Budget of the Arctic Ocean

The Surface Heat Budget of the Arctic Ocean (SHEBA) study was a National Science Foundation-funded research project designed to quantify the heat transfer processes that occur between the ocean and the atmosphere over the course of a year in the Arctic Ocean, where the sun is above the horizon from spring through summer and below the horizon the rest of the time. The study was designed to provide data for use in global climate models, which scientists use to study global climate change. Ice reflects sunlight more readily than open water. Snow-covered sea ice reflects about 80% of the incident sunlight. Seasonal changes in the Arctic result in clear skies and radiational cooling from snow-covered sea ice in the constantly dark arctic winter. In spring, with the return of sunlight, melt pools begin to form and increase the rate of heat absorption from the sun. In the summer, during constant daylight, clouds form which reflect light to the sky, but impede heat flow from the ocean. In order to quantify these effects over a large portion of earth's area—the Arctic Ocean—required a large-scale scientific data-gathering and analysis effort over the span of a year. Consequently, the National Science Foundation, together with other sponsors, funded a study to better quantify these processes. The scientific party traveled aboard the Canadian Coast Guard Ship Des Groseilliers to the Arctic Ocean. It arrived at a location on 2 October 1997 where the plan was to allow the ship to become frozen in the pack ice and be the base for scientific observations. Those observations included measurements of the oceanic and atmospheric processes from the water beneath the ice, near the ship, to the top of the atmosphere. Measurements included: Radiative fluxes: longwave and shortwave Heat flux: turbulent fluxes of latent and sensible heat Cloud height, thickness and other properties Processes of energy exchange in the boundary layers of the atmosphere and ocean Snow depth and ice thickness Ocean salinity, temperature, and currents The ship remained stationary with respect to the ice for one year, leaving on 11 October 1998.