Oct 18, 2012

On the Measurement of Heat Waves

S. E. Perkins and L. V. Alexander
American Meteorological Society
  • Employs a set of three heat wave definitions, derived from surveying heat-related indices in the climate science literature
  • Includes the following three definitions for heat waves: three or more consecutive days above one of the following: the 90th percentile for maximum temperature, the 90th percentile for minimum temperature, and positive extreme heat factor (EHF) conditions
  • Studies each index using a multi-aspect framework measuring heat wave number, duration, participating days, and the peak and mean magnitudes
  • Presents observed climatologies and trends for the Australian continent for two time periods (1951–2008 and 1971–2008)
  • Finds that trends in all aspects and definitions are smaller in magnitude but more significant for 1951–2008 than for 1971–2008
  • Finds that considerable similarities exist in trends of the yearly number of days participating in a heat wave and yearly heat wave frequency, suggesting that the number of available heat wave days drives the number of events
  • Finds that larger trends in the hottest part of a heat wave suggest that heat wave intensity is increasing faster than the mean magnitude