Sep 30, 2005

Precipitation Shifts over Western North America as a Result of Declining Arctic Sea Ice Cover: The Coupled System Response

Jacob O. Sewall
American Meteorological Society
  • States that Arctic sea ice cover have the potential to impact midlatitude climate
  • Validates and explores the robustness of climate impacts due to reduced Arctic sea ice cover by:
  1. Repeating a previous sensitivity study utilizing the National Center for Atmospheric Research’s (NCAR) atmospheric general circulation model using an updated model
  2. Investigating the climate response to dynamically reduced Arctic sea ice cover (driven by a quadrupling of atmospheric CO2) in the updated climate model
  3. Analyzing similar results from six other coupled climate system models
  • Results validate the original study with declining Arctic sea ice cover driving up to 25% less mean annual precipitation (MAP) over southwestern North America and up to an 8% increase in MAP over northwestern North America
  • Results represent a significant shift in the precipitation pattern over western North America and support the findings of the original sensitivity study in suggesting that, as future reductions in Arctic sea ice cover take place, there will be a substantial impact on water resources in western North America