Sep 1, 2016

Recent amplification of the North American winter temperature dipole

by
Singh, Deepti, Swain, Daniel L., Mankin, Justin S., Horton, Daniel E., Thomas, Leif N., Rajaratnam, Bala, Diffenbaugh, Noah S.
,
Journal of Geophysical Research: Atmospheres
  • Investigates the occurrence of concurrent “warm-West/cool-East” surface temperature anomalies, called the “North American winter temperature dipole”
  • Finds that, historically, warm-West/cool-East dipole conditions have been associated with anomalous mid-tropospheric ridging over western North America and downstream troughing over eastern North America
  • Finds that the occurrence and severity of warm-West/cool-East events have increased significantly between 1980 and 2015, driven largely by an increase in the frequency with which high-amplitude “ridge-trough” wave patterns result in simultaneous severe temperature conditions in both the West and East
  • Shows that the observed positive trend in the warm-West/cool-East events is attributable to historical anthropogenic emissions including greenhouse gases, but that the co-occurrence of extreme western warmth and eastern cold will likely decrease in the future as winter temperatures warm dramatically across the continent, thereby reducing the occurrence of severely cold conditions in the East
  • States the analysis framework is generally transferable to the physical conditions shaping different types of extreme events around the globe