Oct 19, 2012

Anatomy of an Extreme Event

Martin Hoerling, Arun Kumar, Randall Dole, John W. Nielsen-Gammon, Jon Eischeid, Judith Perlwitz, Xiao-Wei Quan, Tao Zhang, Philip Pegion, and Mingyue Chen
Journal of Climate
  • Examines observational data and climate model simulations to identify physical processes, underlying causes, and predictability of the record-setting 2011 Texas drought/heat wave
  • States that events of similar or larger magnitude appear in preindustrial control runs of climate models
  • Results show that the principal factor contributing to the heat wave magnitude was a severe rainfall deficit related to anomalous sea surface temperatures (SSTs) that included a La Niña event
  • Results show that virtually all the precipitation deficits appear to be due to natural variability
  • Finds that observed SST conditions increased the frequency of severe rainfall deficit events from 9% to 34% relative to 1981–2010, while anthropogenic forcing did not appreciably alter their frequency
  • Finds that human-induced climate change increased the probability of a new temperature record from 3% during the 1981–2010 reference period to 6% in 2011, while the 2011 SSTs increased the probability from 4% to 23%