The approach of iisPACS involves several scientific disciplines. We explain the question and our methods in the topics above.

 

 

 

The roll of sea ice in the climate system

The important role sea ice plays in the global climate system has long been recognized. Sea ice provides at least three important feedbacks to the rest of the climate system.


  • First, sea ice changes the surface albedo of the ocean by making the ocean surface whiter and more reflective of the solar radiation. This is a positive feedback mechanism – growth in sea ice extent → increase albedo → decrease solar absorption → decrease temperature →increase sea ice extent.

  • Second, sea ice insulates the ocean water from the atmosphere. This not only makes the atmosphere temperature above the ocean colder, but also blocks heat exchange between the ocean and atmosphere. This effect is also a positive feedback mechanism for climate change – growth in sea ice extent → decrease in ocean-atmosphere change → cooling of the atmosphere → more sea ice.

  • Third, sea ice inhibits evaporation of the sea surface, and thus reduces precipitation in the Arctic region. This sea-ice to evaporation/precipitation link is again a negative feedback mechanism in the climate system → growth in sea ice extent → decrease in evaporation → decrease in precipitation → increase in albedo (from snow precipitation) → more absorption of solar radiation → decrease in sea ice extent.
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    Among these three feedback mechanisms, the third one is the most difficult to measure and quantify. It is the goal of iisPacs to quantitatively study the link between sea ice and precipitation. The question is to what degree can Arctic precipitation increases be attributed to sea ice variation across numerous Arctic locations, differing storms, changing seasons, passing years, and into the long-term (decades, centuries, or even between glacial in interglacial times).






sea ice
Sea ice photographed during the SHEBA project.

(Don Perovich, CRREL)