Tropical cyclone environmental vertical wind shear analysis using a microwave sounder

The area averaged vertical wind shear imposed on a tropical cyclone circulation is an important influence on intensity changes. Numerical model analyses and model fields that optimize satellite motion wind vector data have been used to quantify and measure the vertical wind shear forcing. This presentation introduces an alternate method of tropical cyclone vertical shear analyis using the Advanced Microwave Sounder Unit (AMSU) on the NOAA polar orbiting satellites. The AMSU radiances are used to retrieve the mass field, which in turn is used to retrieve the three-dimensional wind field using the nonlinear balance equation. A tropical cyclone centered circle is then used to area average the winds for environmental vertical shear computations. Preliminary results will be presented with several Atlantic hurricanes along with comparisons with model derived vertical shear.