Air-Sea Interactions and Deep Convection in the Labrador Sea

Deep convection in the oceans, particularly at high latitudes, plays an important role in the climate systems of the world's oceans and atmosphere. This study was conducted to examine atmospheric forcing effects on deep convection in the Labrador Sea. The Naval Postgraduate School one dimensional ocean mixed layer model was applied to the Labrador Sea from February 12 to March 10, 1997. The model was initialized and forced with oceanographic and atmospheric data collected onboard the RN Knorr during the first field program of the Labrador Sea Deep Convection Experiment. An ocean mixed layer depth close to 1300 m was predicted and verified using the observed data. A sensitivity study was conducted using deviations from observations as input to determine how variations in atmospheric forcing could lead to the observed and even deepened ocean mixed layer. Observed Conductivity, temperature and depth (CTD) data were used to verify the model's spatial and temporal predictions of mixed layer temperature, salinity and depth. Model predicted mixed layer depths were usually slightly deeper than those observed. The final model output predicted temperature rather accurately, but model predicted salinity values were consistently low. A variety of sensitivity studies gave new insight to the individual influences of surface fluxes, momentum stresses, precipitation, salinity and individual storm variations to the mixed layer temperature, salinity and depth of the Labrador Sea.