The seasonal cycle of the Arctic Ocean under climate change

The seasonal cycle of Arctic Ocean temperature is weak due to the insulating and light‐scattering effects of sea ice cover and the moderating influence of the seasonal storage and release of heat through ice melting and freezing. The retreat of sea ice and other changes in recent decades is already warming surface air temperatures in winter. These meteorological changes raise the question of how the seasonal cycle of the ocean may change. Here we present results from coupled climate model simulations showing that the loss of sea ice will dramatically increase the amplitude of the seasonal cycle of sea surface temperature in the Arctic Ocean. Depending on the rate of growth of atmospheric greenhouse gases, the seasonal range in Arctic sea surface temperature may exceed 10°C by year 2300, greatly increasing the stratification of the summer mixed layer. Key Points The temperature seasonal cycle is weak due to the presence of sea ice Future loss of sea ice could increase the Arctic seasonal cycle 5 times The increase is due to increased heat flux but mostly to loss of melting/freezing