THE ROLE OF AIR-SEA HEAT FLUXES IN ANNUAL AND INTERANNUAL OCEAN TEMPERATURE VARIABILITY ON THE EASTERN NEWFOUNDLAND SHELF

Monthly-mean fluxes computed from the Comprehensive Ocean-Atmosphere D ata Set (GOADS) are used to describe the variability in air-sea heat e xchange over the eastern Newfoundland Shelf and examine its role in oc ean temperature variability. Attention is focussed on the climatologic al annual variation and interannual (monthly) anomalies of fluxes and ocean temperature during 1951-1988 in two areas: Station 27 on the inn er shelf and the central Grand Bank. A vertical diffusion model is use d to quantify the contribution of the fluxes to ocean temperature vari ability, and examine the temporal and vertical structure of the vertic al eddy diffusivity. For the climatological annual temperature variati on, the model indicates that local air-sea fluxes can account for 89% and 77% of the variance for Sta. 27 and the central Grand Bank, respec tively, although there are also influences from ocean advection. Stron g seasonal and vertical variations in the diffusivity are suggested by the model, with values generally in the range (0.5 - 20) x 10(-4) m(2 ) s(-1). For interannual ocean temperature variability, the model and flux estimates indicate that local air-sea fluxes can account for only a small fraction of the observed variability, although there is a str ong suggestion of coupled atmosphere-ocean temperature variability, pa rticularly at low frequencies. Ocean advection, sea ice influences and flux inaccuracies are discussed as possible factors in the interannua l variability results. Collectively, the study results indicate that o cean temperature variability on the eastern Newfoundland Shelf is part of an atmosphere-ice-ocean interconnection involving both regional an d large-scale processes.