5B.8 Assessing climate variability and change impact on heat extremes

Holland, Greg, C. Bruyere, and M. Jones, National Center for Atmospheric Research

The impact of past climate change on current heat extremes and the potential for future changes are investigated using a combination of station data and WRF 1D running in both current and future climate mode. First it is shown that temperature PDFs may be broken down into a combination of in situ and advection components, each of which changes in a quite different manner. Useful information on both types can be obtained through examination of in-situ changes alone. These are primarily driven by local radiative and surface effects so local changes are assessed directly, but advection requires an additional step to assess the source region for the hot air.

Evidence will be provided that the most extreme temperatures may be limited in their response to climate variability and change and that this results in a steepening of the PDF as temperatures in upper deciles increase without there being a concomitant change in the extreme.