Barents Sea hydrographic variability (1975-1991)

Abstract

Barents Sea temperature and salinity anomalies and their connection to the Arctic Oscillation (AO) are analyzed using a 16-year time-series of hydrographic data (1975-1991). Seasonal and inter-annual variations are investigated along two sections spanning the meridional and zonal length of the Barents Sea over two depth layers, 0 to 50m and 50 to 200m. Depending on location, mean seasonal differences in the deeper layer are as large as 3°C in temperature and 0.2 in salinity, whereas the upper layer differences are 6°C and 1.4. Inter-annual anomalies are 0.6°C and 0.07 in the deeper layer and 0.8⁰C and 1.2 in the upper layer. Temperature and salinity anomalies' leading EOFs explain 49% and 34% of the total variance, and are in-phase from 1975-1985 but out-of-phase for 1985-1991. Examination of the surface heat-flux suggests the temperature anomaly is advective before 1985 and locally formed after 1985. This is supported by the temperature anomaly's changing propagation pattern through the Barents Sea after 1985. The salinity anomaly's source appears to be advective throughout the period. The AO correlates with the temperature EOF suggesting the AO's influence on the temperature anomaly is stronger over the Norwegian Sea before 1985 and stronger over the Barents Sea after 1985.