1. 1 Severe Weather Response to Climate Change: A Transient Increase then Saturation? Regional Climate Research Section NCAR Earth System Laboratory NCAR is Sponsored by NSF and this work is partially supported by the Willis Research Network, the DOE Research Program to Secure Energy for America and NSF EASM Grants 1048841 and 1048829 Greg Holland Collaboration with Cindy Bruyere and Mari Jones Holland WRF Workshop 2013

2. Working Hypothesis: o Absolute extremes are capped by available energy Thus, for Climate Change The PDF becomes bimodal or skewed with climate variability and change These changes may saturate after an initial rapid response Definition of Climate Change Hurricane response Temperature Response. Holland WRF Workshop 2013 2 Summary

3. a The Anthropogenic Climate Change Index ACCI Holland WRF Workshop 2013 3 Meehl et al 2004, IPCC AR4 CMIP3 Ensemble

4. The Anthropogenic Climate Change Index ACCI Holland WRF Workshop 2013 4 a b

5. 5 Global Intense Hurricane Response (Holland and Webster 2007) (Elsner et al 2009) (Holland and Bruyere 2013) SH Cyclones are in year season commenced All Cyclones no Change Saffir-Simpson Categories used. Cat 4-5 Change/ o C = 40%

6. Holland WRF Workshop 2013 6 Sensitivity of Extremes (IPCC SREX 2012)

7. Holland WRF Workshop 2013 7 Character of the Observed Tropical Cyclone Changes (Holland and Bruyere 2013) Proportion is relative to all hurricanes

8. Nested Regional Climate Model 36 km plus embedded WRF Hurricane Model 4 km. Base is 2012 North Atlantic Hurricane Season. Holland WRF Workshop 2013 8 Model Assessment

9. Holland WRF Workshop 2013 9 Temperatures? Evap Cond Mix (Advection) Diurnal Timescale Downwelling Radiation IR Radiational Cooling αT 4

10. Holland WRF Workshop 2013 10 MODIS Skin vs Air Temperature (Mildrexler et al 2011)

11. Holland WRF Workshop 2013 11 Temperature Stations Giles Norfolk Sydney Melbourne Work in progress Alice Springs Adelaide

12. Holland MMM 0513 12 Seasonal: Desert In Situ Temperatures Extremes bumping up against the maximum possible Skewed distribution develops

13. Holland WRF Workshop 2013 13 Giles Maxima

14. Holland WRF Workshop 2013 14 Climate Change: In Situ Temperatures Variable, but marked increase in hot days and no change in extremes.

15. Holland WRF Workshop 2013 15 Climate Change: In Situ and Advective Temperatures AdvectiveIn Situ

16. Holland WRF Workshop 2013 16 Summary: Trend 1970-2011 >35 o C Maximum Temperature (Bureau of Meteorology 2013) In Situ Advective

17. Holland WRF Workshop 2013 17 Summary Working Hypothesis: Absolute extremes are capped by available energy Thus, for Climate Change The PDF becomes bimodal or skewed with climate variability and change These changes may saturate, after an initial rapid response.