1 Application of a Tropical Cyclone Index to Climate Modeling Downscaling 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 Research Program to Secure Energy for America, and NSF EASM Grant Greg Holland and Cindy Bruyere Holland WRF Workshop 0612
2 Summary Preamble o A Regional Climate Group o The Hybrid Statistical/Dynamical Approach The Cyclone Genesis Index o History o Climatological Components that do (do not) work o CGI o How to apply Climate Applications Reference Bruyere et al (2012) J. Climate
Goes back to Palmen 1948 Gray 1968, 1970 derived first Index All use some combination of moisture, SST and Stability (MPI), and vertical windshear e.g. Emanuel and Nolan (2004): Holland WRF Workshop Genesis Index History
Holland WRF Workshop Components that Do/Do not Work Vorticity V. Shear PI RH Observed
Holland WRF Workshop Why were RH and Vorticity Included?
Holland WRF Workshop The Cyclone Genesis Index
Holland WRF Workshop Applying Indices Raw GP
Holland WRF Workshop Application to Intense Hurricane Frequency
Holland WRF Workshop Climate Applications
Holland WRF Workshop Summary Hybrid Statistical/Dynamical Approach is an important (essential) component of regional climate prediction Example: The Cyclone Genesis Index o Can accurately reproduce tropical cyclone and intense hurricane annual frequency variations from coarse reanalyses o Care needs to be taken with content and application method For Climate, when used in combination with high- resolution time-slice simulations the CGI can fill in the gaps and provide a poor-person’s ensemble CGI can provide a quality check on historical archives.