Climate Dynamics

, Volume 22, Issue 6, pp 591-595

First online:

Actual and insolation-weighted Northern Hemisphere snow cover and sea-ice between 1973–2002

  • R. A. PielkeSr.Affiliated withDepartment of Atmospheric Science, Colorado State University Email author 
  • , G. E. ListonAffiliated withDepartment of Atmospheric Science, Colorado State University
  • , W. L. ChapmanAffiliated withDepartment of Atmospheric Sciences, University of Illinois at Urbana-Champaign
  • , D. A. RobinsonAffiliated withDepartment of Geography, Rutgers University

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Actual and insolation-weighted Northern Hemisphere snow cover and sea ice are binned by latitude bands for the years 1973–2002. Antarctic sea-ice is also analyzed for the years 1980–2002. The use of insolation weighting provides an improved estimate of the radiative feedbacks of snow cover and sea-ice into the atmosphere. One conclusion of our assessment is that while a decrease in both areal and insolation-weighted values have occurred, the data does not show a monotonic decrease of either Arctic sea-ice or Northern Hemisphere snow cover. If Arctic perennial sea-ice is decreasing since the total reduction in areal coverage is relatively small, a large portion of it is being replenished each year such that its radiative feedback to the atmosphere is muted. Antarctic sea-ice areal cover shows no significant long-term trend, while there is a slight decrease in the insolation-weighted values for the period 1980–2002. From the early 1990s to 2001, there was a slight increase in both values. The comparison of general circulation model simulations of changes over the last several decades to observed changes in insolation-weighted sea-ice and snow cover should be a priority research topic.