24 November 2015

Impact of the Dynamical Core on the Direct Simulation of Tropical Cyclones in a High-Resolution Global Model


Reed et al. (2015) examines the impact of the choice of CAM5's dynamical core on tropical cyclone frequency, distribution and intensity in a pair of 26-year AMIP simulations. The dynamical core, the central fluid flow component of any general circulation model, is often overlooked in the analysis of a model's ability to simulate tropical cyclones compared to the impact of more commonly documented components (e.g., physical parameterizations).  It is shown that the selection of a dynamical core can have a significant impact on tropical cyclone intensity and frequency even in the presence of similar climatology and large-scale environments. CAM5-SE is demonstrated to produce stronger cyclones, and therefore more hurricanes and major hurricanes per year, than CAM5-FV. These differences cannot be traced back straightforwardly to differences in the large-scale features of the simulated climate state. The exact causes for these differences in the simulation of tropical cyclones due to the dynamical core will be an area of continued work.