Jun 1, 2010

Climate change, atmospheric rivers, and floods in California - a multimodel analysis of storm frequency and magnitude changes

M. Dettinger
Journal of the American Water Resources Association
  • States that recent studies have documented the important role that ‘‘atmospheric rivers’’ (ARs) of concentrated near-surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington
  • Evaluates the occurrence of atmospheric river storms in historical observations and in a 7-model ensemble of historical-climate and projected future climate simulations
  • Finds that under an A2 greenhouse-gas emissions scenario (with emissions accelerating throughout the 21st Century), average AR statistics do not change much in most climate models; however, extremes change notably
  • Finds that years with many AR episodes increase, ARs with higher-than-historical water-vapor transport rates increase, and AR storm-temperatures increase
  • Finds that the peak season within which most ARs occur is commonly projected to lengthen, extending the flood-hazard season
  • States that all of these tendencies could increase opportunities for both more frequent and more severe floods in California under projected climate changes