Quantification of the interannual variability of sea ice extent and cold bottom water in the Bering Sea and how this affects marine phytoplankton.
The Cold Pool is important for ecosystem functioning in the Bering Sea and has a very large range of variability. RASM forecasts show potential for prediction of the winter sea ice cover and the subsequent summer Cold Pool area in the Bering Sea.
The Bering Sea experiences a seasonal sea ice cover, which is important to the biophysical environment found there. A pool of cold bottom water (<2 ̊C) is formed on the shelf each winter as a result of cooling and vertical mixing due to brine rejection sea ice growth. The extent and distribution of this Cold Pool (CP) are largely controlled by the winter extent of sea ice in the Bering Sea. We use the fully-coupled Regional Arctic System Model (RASM) to examine the variability of the extent and distribution of the CP and sea ice cover in the Bering Sea during the period 1980–2018. RASM results confirm the direct correlation between the extent of sea ice and the CP and show a smaller CP as a consequence of realistically simulated recent declines of the sea ice cover in the Bering Sea. In addition, we also find that a low ice year is followed by a later diatom bloom, while a heavy ice year is followed by an early diatom bloom. Finally, the RASM probabilistic intra-annual forecast capability is reviewed for its potential use for prediction of the winter sea ice cover and the subsequent summer CP area in the Bering Sea.