Convection and shear flow in TC development and intensification

The paper presents some preliminary results from the Tropical cyclone structure -2008 (TCS08) field experiments. We study the vorticity/convection initiation processes in the storm environment. The impact of strain effect on the cloud system development is emphasized. TCS08 made it possible to directly compute filamentation time at the convection scale in typhoons, allowing investigation into the effect of filamentation around eyewall regions. A Rapid Filamentation Zone (RFZ, filamentation time < 30 min) is found during the re-intensification stage of Typhoon Sinlaku between 12 - 35 km radius that extends outward with height. In the 2-4 km layer of RFZ, we found that (1) dBZ shows a larger variability; (2) weak updraft is diminished; and (3) smaller dBZ occurs more frequently. These results suggest that some deep convection immediately outside the Typhoon Sinlaku eyewall is weakened by the filamentation dynamics. Refined Eldora data and 3-dimensional winds analysis will be used to study the thermodynamics at various stages of the TC development.