Ocean surface heat flux variability in the Barents Sea

Abstract

A 40 year (1958–1997) hindcast simulation from the regional coupled ice–ocean model HAMSOM is used to study climate relevant processes in the Barents Sea and their interannual to decadal variability. Compared to observations the model captures the variability in temperature and ice extent in a satisfying manner. The heat input through the Barents Sea Opening (BSO) is effectively lost through intense atmosphere–ocean heat exchange within the Barents Sea. Correlation analysis suggests that heat transport through the BSO leads the Barents Sea heat content by 1–10 months, while the heat content leads the air–sea heat fluxes with 1–5 months. Averaged over the period the advected heat input is 32 TW, augmented by 79 TW of shortwave radiation and reduced by 113 TW through longwave radiation and latent and sensible heat loss. Including the sensible heat loss at the ice–ocean boundary yields an oceanic heat loss in the Barents Sea of 40 TW. Cooling of Atlantic Water is very efficient just east of the BSO, and contributes to 50% of the total heat loss. Significant positive trends in both heat transport through the BSO and solar radiation, combined with a reduction in seasonal ice cover cause increased oceanic heat loss. Excess heat still enters the Barents Sea and a significant warming is observed in the northern areas. Sea-ice acts as an effective insulator against oceanic heat loss resulting in 4 TW of net heat input at the sea-ice surface. This heat flux balances the ice–ocean heat budget and the corresponding ice melt compensates for net ice production at the ice–ocean interface and ice advection into the Barents Sea.