The annual heat balance of the surface 100 meters of the northwest Gulf of Alaska shelf

Abstract

Oceanographic and meteorologic data collected from 1970 to 1978 on the northern Gulf of Alaska shelf are used to compute monthly heat budgets within the surface 100 m for a composite year. During months of net heat gain, radiation is the primary source. Latent and sensible heat transfer dominate during months of net heat loss. Persistent downwelling is the second most important route for heat loss. During winter, alongshore advection is the principal contributor of heat to this region. Cross-shelf advection and diffusion of heat are of minor importance throughout the year and generally counter each other. The prevalence of onshore Ekman transport explains the cross-shelf variation in the annual amplitude of heat content and the differential propagation rates of surface temperature anomalies to greater depths. No significant linear relationships were determined between anomalies of surface heat transfer and sea surface temperature. Several hypotheses are presented to explain this result.