Summaries - Research
Back Collaborative Research: Dynamic and Thermodynamic Control of Tropical Intensity in Sheared Environments
|Division||Graduate School of Engineering & Applied Science|
|Investigator(s)||Montgomery, Michael T.|
|Sponsor||National Science Foundation (NSF)|
We propose to undertake a comprehensive investigation of the physics of the interaction between tropical cyclones and sheared flow in which they are embedded, focusing on the mutual operation of dynamic and thermodynamic processes. We hypothesize that tropical cyclones are weakened by the injection of low-entropy, middle level air into the vortex core by vortex Rossby waves excited by the interaction between the vortex and environmental shear flow. Our emphasis on the mutual importance of dynamical and thermodynamical processes departs from most previous investigations, which have focused almost exclusively on direct dynamical effects. We present evidence from an operational tropical cyclone intensity prediction model that dry air injection is indeed an important factor in tropical cyclone intensity change. The research proposed here would have a direct path to improved prediction of tropical cyclones through the improvement of this operational model.
The starting point of our proposed research will be two key theoretical developments that have matured over the previous decade: the quantitative theory of thermodynamic control of hurricane intensity, and the theory governing the generation, behavior and wave/mean flow interaction of vortex Rossby waves. From these points, we will develop an extended theory for the generation and maintenance of vortex Rossby waves as a consequence of the interaction between vortices and ambient shear flow, addressing as well the rate at which these waves flux passive tracers in and out of the vortex core region. We will use this as guidance in modifying the thermodynamic cycle to account for dry air injection at middle levels by the vortex Rossby waves. Having developed this theoretical framework, we will test it using a suite of models, focusing on fully three dimensional simulations at high resolution using a nonhydrostatic model. We expect to modify the theory based on the results of these tests. Finally, we will use this theory to develop a parameterization of Rossby wave-induced fluxes of low entropy air, for use in axisymmetric models, including the aforementioned operational forecast model.
|Publications||Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal|
|Data||Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal|