Variability and trends of sea ice production in the Arctic polynyas from the Regional Arctic System Model

The Arctic Ocean has been experiencing an accelerated sea ice loss and an amplified warming in response to ongoing climate change occurring anywhere on the globe. One of the major changes taking place within the Arctic sea-ice pack has been the relative expansion of younger and thinner sea ice cover at an expense of the unprecedented decline of the multi-year and thicker sea ice. Given such fundamental changes in the marine cryosphere, it is anticipated that greater fracturing and more lead and polynya opening become prevalent in the Arctic Ocean. As a potential example of what to expect in the near-term future, two consecutive large open water polynyas were recently observed in the winter and summer of 2018 off the coast of northern Greenland, where sea ice is supposed to be thickest and oldest in the Arctic. Since the occurrence, formation, size of and energy exchange in polynyas and leads play a crucial role at the interface between the atmosphere and the ocean, an accurate assessment of winter sea ice production in the Arctic under warming climate is essential to understanding the Arctic system as a whole. We use the Regional Arctic System Model (RASM) to investigate variability of sea ice production along the Arctic coasts, where most of high ice production is confined to, focusing on long-term changes and possible impacts on and feedbacks to other Arctic environments. RASM is a fully coupled regional climate system model, consisting of the atmosphere, ocean, sea-ice, land hydrology, and streamflow routing components, coupled through a mass and energy conserving flux coupler. The ocean and sea-ice components in RASM share the same domain configured at the spatial resolution of 1/12 degree (or ~9km), and the atmosphere and land hydrology components are configured on a 50-km horizontal grid. This modeling study provides insights on spatial patterns as well as interannual variability and trends of sea ice production in major polynyas over the entire Arctic Ocean from 1980 to 2018.