Horizontal Transition of Turbulent Cascade in the Near-surface Layer of Tropical Cyclones

Wednesday, 17 December 2014
Jie Tang, Shanghai Typhoon Institute, Shanghai, China, Jun Zhang, NOAA/AOML, Key Biscayne, FL, United States, David Byrne, ETH Zurich, Department of Environmental, Zurich, Switzerland and Yuan Wang, Nanjing University, DEPARTMENT OF ATMOSPHERIC SCIENCE, Nanjing, China
Tropical cyclones (TC) consist of a large range of interaction scales from hundreds of kilometers to only a few meters and a change in how energy is transferred amongst theses scales i.e. from smaller to larger scales (upscale) or vice versa (downscale), can have profound impacts on TC energy dynamics due to the associated changes in available energy sources and sinks. Here we sh1ow, from multi-layer tower measurements in the boundary layer of several landing typhoons at the coast of southeast China, that there are two distinct regions where the energy flux changes from upscale to downscale as a function of radius and that the boundary between these two regions is approximately the radius of maximum wind. Combing previous observations and our results, we propose a general concept model in TCBL including an inverse cascade region (ICR) and a direct cascade region (DCR), where each region depends on height and radius.