Pan-Arctic Climate and Ecosystem Response to Historical and Projected Changes in the Seasonality of Sea Ice Melt and Growth

The primary goal of this work is to explore the causes and effects of ongoing seasonal changes in the annual cycle of sea ice. This includes a quantitative assessment of the drivers and effects of the seasonal timing of sea ice melt onset, freezing initiation, and snowfall within the observational record and coupled climate model simulations of historical and future climate. We are examining this from both energy budget and ecosystem perspectives and are explicitly considering feedbacks to the Arctic and global systems. In particular, we are investigating the interactions between seasonal changes in the surface marine state and shortwave radiation and assessing the implications of those interactions for changes in climate and marine ecosystem behavior. In turn, we plan to assess and ultimately improve the capabilities of GCMs by improving the physics associated with the parameterization of solar radiation incident on ice covered seas. Within this primary goal, three focused questions will be used to direct the specific course of research.

1. How do variations in the timing of seasonal triggers, including melt onset, melt pond evolution, freeze-up initiation, and snow accumulation affect the timing and partitioning of solar energy over the historical record?

2. How do relationships among seasonal triggers and solar energy partitioning evolve in a warming climate with a transition to seasonal ice cover? What are the consequent implications for sea ice mass budgets, amplified Arctic warming, and marine ecosystem behavior?

3. How well do climate models simulate the relationships between seasonal triggers and the partitioning of solar radiation? What processes are missing or inadequately represented in terms of these relationships?