Idealized tropical cyclones in atmospheric general circulation models: sensitivity to convective parameterizations

The paper discusses the design of idealized tropical cyclone experiments in Atmospheric General Circulation Models (GCMs). The development of an idealized, initially weak warm-core vortex into a tropical cyclone is investigated in a high-resolution GCM. In particular, an ocean-covered aqua-planet configuration of NCAR's Community Atmosphere Model CAM 3.1 is utilized. The prescribed sea surface temperatures of 29°C and moist initial conditions guarantee favorable conditions for cyclogenesis. The evolution of the vortex is an ideal candidate to study the impact of convective parameterizations on the cyclogenesis processes and structure of the tropical cyclone. A group of sensitivity tests is presented. The convective parameterizations include numerous schemes implemented in GCMs used in conjuncture with a simple physics suite that only incorporates surface fluxes, turbulence, and large-scale precipitation as the driving mechanisms. Such a process study reveals the impact of different convection schemes on the development and structure of the vortex and sheds light on the relative importance of the physics parameterizations. The realism of the tropical cyclone simulations in CAM 3.1 is assessed.