Sunlight and the Arctic System
Collaborative Research on Sunlight and the Arctic Atmosphere-Ice-Ocean System
- Don Perovich, Cold Regions Research and Engineering Laboratory
- Bonnie Light, Polar Science Center, University of Washington
- Hajo Eicken, Geophysical Institute, University of Alaska Fairbanks
The distinct annual cycle of solar radiation is a key defining feature of the Arctic system. The lack of sunlight in winter and the long daylight hours in summer structure both terrestrial and marine ecosystems, drive the seasonal build-up and sequestration of carbon and control the annual cycle of the surface heat budget. Recent research has also demonstrated that the seasonal photochemistry of snow over sea ice plays a major role in the cycling of major atmospheric constituents. One of the most important aspects of the disposition of solar radiation within the Arctic system is the reflection, absorption and transmission of sunlight by the atmosphere-sea ice-ocean system (AIOS). In large part, the disproportionate importance of the Arctic in the global climate system derives from the response of the sea-ice cover to atmospheric warming and the resulting impacts on the surface radiation balance through ice-albedo feedback. General circulation models (GCMs) consistently predict a substantial amplification of global climate warming in the Arctic.
- To enhance our understanding of the present role that solar radiation plays in the Arctic atmosphere-sea ice-ocean system.
- To improve our ability to predict the future role of solar radiation in the Arctic atmosphere-sea ice-ocean system.
- Determine the spatial and temporal variability of the input and partitioning of solar energy.
- Understand how climate change (sea ice retreat, changes in snow cover and cloudiness) will affect the solar radiation partitioning in the Arctic, and the resulting impacts.
- Assess the cumulative impact of seasonal, interannual, and decadal variability on the distribution of absorbed sunlight in the Arctic AIOS.
- Establish if the spatio-temporal variability of solar heating is commensurate with the dominant modes of large-scale variability (e.g. Arctic Oscillation).
- Evaluate the treatment of solar energy in Arctic atmosphere, ocean, and sea ice models and assess their impact on biases in simulations of the Arctic climate system.
- Are ice-albedo feedback processes currently operative on regional or pan-Arctic scale?
- Are the mechanisms that produce polar amplification of global climate warming in GCMs commensurate with observations?
- Has the AIOS approached a “tipping point” as suggested by recent model simulations?
- What is the role of the atmosphere (through cloud cover and precipitation) in modifying the response of the cryosphere to variations in external forcing?
- What is the role of the ocean (through the mixed layer) in transporting and sequestering solar energy on seasonal to interannual time scales?