High-Resolution Modeling to Assess Tropical Cyclone Activity in Future Climate Regimes. Final Report.

摘要

Work supported by this project included (i) assessment of general circulation model output (Aiyyer and Talgo), (ii) novel methods for downscaling (Xie, Liu, Peng, and Semazzi), and (iii) the impact of climate change on tropical cyclone intensity and frequency (Lackmann, Hill, and Gentry/Mallard). The project supported 1 MS student and 2 PhD students; all of these students are now employed professionally in closely related fields of study. A total of 9 full-length, peerreviewed journal articles were supported by this project, along with at least 15 conference and invited workshop/symposium presentations. Central to the problem of future tropical cyclone activity is the ability of GCMs to consistently represent vertical wind shear in the main tropical cyclone development regions. To this end, Dr. Anantha Aiyyer, working with graduate student Kevin Talgo, undertook a detailed analysis of the 20th century output from the IPCC AR4 GCMs to assess the consistency between observational analyses and the models. First, it was found that projected increases in Atlantic basin shear are much less robust when statistical significance of the shear increase is taken into account, contrary to some previous publications. Analysis of the ENSO-shear and Sahel-shear relations for the Atlantic basin reveal that some of the models are in reasonable agreement with the NCAR/NCEP reanalysis, but many others are not. GCM representation of the African monsoon system also accounts for substantial variability in projections of Atlantic shear. These results are presented in Talgo (2009), and a journal publication based on this thesis will be forthcoming.