Axisymmetric Hurricane in a Dry Atmosphere: Theoretical Framework and Numerical Experiments

Abstract

his paper discusses the possible existence of hurricanes in an atmosphere without water vapor and analyzes the dynamic and thermodynamic structures of simulated hurricane-like storms in moist and dry environments. It is first shown that the ?potential intensity? theory for axisymmetric hurricanes is directly applicable to the maintenance of a balanced vortex sustained by a combination of surface energy and momentum flux, even in the absence of water vapor. This theoretical insight is confirmed by simulations with a high-resolution numerical model. The same model is then used to compare dry and moist hurricanes. While it is found that both types of storms exhibit many similarities and fit well within the theoretical framework, there are several differences, most notably in the storm inflow and in the relationship between hurricane size and intensity. Such differences indicate that while water vapor is not necessary for the maintenance of hurricane-like vortices, moist processes directly affect the structure of these storms.