Ocean-atmosphere interaction effects on tropical cyclone inner-core convective bursts

Tropical cyclones draw energy from warm ocean waters, but also cool the ocean surface directly beneath the storm by mixing up cold, deep water. This interaction significantly influences tropical cyclone structure and intensity, however the mechanisms of these ocean-tropical cyclone feedback effects remain largely unexplained mostly due to a lack of oceanographic and atmospheric boundary layer observations within the inner core region.

The deep moist convection of the tropical cyclone inner-core region links the surface layer below the storm to the upper troposphere and is, thus, at the heart of the tropical cyclone thermodynamic cycle. The primary goal of this research is to examine the the ocean's role in triggering and sustaining mesoscale inner-core convective burst events, and the feedback of the extreme convection on the storm-scale thermodynamic and kinematic fields.

The rich datasets collected by the NOAA and NASA research aircraft, and satellite data during NASA's Tropical Cloud Systems and Processes experiment (2005) are used to investigate the structure, evolution and thermodynamics of extreme eyewall convective burst events in Hurricane Dennis, Hurricane Emily and Tropical Storm Gert. In addition, a multivariate Lagrangian time series of the inner-core SST, the inner-core-wake SST, the ahead-of-storm SST, and measures of spatial variability of these variables for these three storms was constructed using an objectively interpolated SST tropical cyclone cold-wake climatology. Latent and sensible heat flux estimates and a measure of upper-ocean energy utilization were calculated for the inner-core (<.5° radius) and the near-core (.5° - 1° radius). The cooperating interactions between the oceanic energy flux and the upward mass flux in the convective burst events is analyzed in an attempt to ascertain whether convective bursts correspond to changes in the upper-ocean in distinct and obvious ways.