Ventilation time and anthropogenic CO2 in the Bering Sea and the Arctic Ocean based on carbon tetrachloride measurements

Abstract

The Arctic Ocean is connected to the Pacific by the Bering Sea and the Bering Strait. During the 4th Chinese National Arctic Research Expedition, measurements of carbon tetrachloride (CCl4) were used to estimate ventilation time-scales and anthropogenic CO2 (Cant) concentrations in the Arctic Ocean and Bering Sea based on the transit time distribution method. The profile distribution showed that there was a high-CCl4 tongue entering through the Canada Basin in the intermediate layer (27.6 < σθ < 28), at latitudes between 78 and 85°N, which may be related to the inflow of Atlantic water. Between stations B09 and B10, upwelling appeared to occur near the continental slope in the Bering Sea. The ventilation time scales (mean ages) for deep and bottom water in the Arctic Ocean (~ 230–380 years) were shorter than in the Bering Sea (~ 430–970 years). Higher mean ages show that ventilation processes are weaker in the intermediate water of the Bering Sea than in the Arctic Ocean. The mean Cant column inventory in the upper 4000 m was higher (60–82 mol m−2) in the Arctic Ocean compared to the Bering Sea (35–48 mol m−2).