LONG-TERM VARIABILITY OF SEA-AIR HEAT-TRANSFER IN THE NORTH-ATLANTIC OCEAN

There is evidence that climatological variations of the ocean-atmosphere fixes in the North Atlantic are significant with respect to long-term climate changes. To study year-to-year changes of ocean-atmosphere interaction processes in the North Atlantic Ocean, two meteorological data sets were used: the Comprehensive Ocean-Atmosphere Data Set (GOADS) and the Soviet National Meteorological Centre (SNMC) data set for the period from 1957 to 1990. Data sets were compared with each other in order to find out set-to-set variations of ocean-atmosphere interaction parameters. The next step was to calculate sea-air interaction characteristics on the basis of one data set, but with the use of different schemes for the parameterization of fluxes. Both set-to-set and scheme-to-scheme variations are significant, but at the same time annual and interannual changes in radiation and heat fluxes indicate that variability patterns are dose to each other. Differences obtained in the parameters of variability were taken to determine the confidence level for future consideration of climatological variability. Long-term changes in net air-sea heat fluxes were explored for the period from 1950 to 1990. Results demonstrate the different character of variations in the tropics, mid-latitudes and high latitudes. Meridional heat transport for different climatological periods has been calculated in order to discuss the variations obtained in terms of ocean circulation. Two significantly different regimes of meridional heat transport were obtained. The first regime is characterized by high values in the tropics and a sharp decrease in mid-latitudes. The second regime is connected with relatively high values of heat transport in mid-latitudes.