Tropical Cyclone Intensity Estimation and Formation Detection using the Deviation Angle Variance Technique

Results using the Deviation-angle variance technique (DAV-T) to objectively determine: 1) the current intensity of existing tropical cyclones; and 2) determine which pre-genesis cloud clusters will go on to develop into tropical cyclones, are presented for the North Atlantic, western North Pacific, and eastern North Pacific basins.

The DAV-T is a method that objectively characterizes the level of axisymmetry of a cloud cluster using infrared brightness temperatures. To estimate intensity, the axisymmetry parameter is calculated for a set of training data in each basin and fitted to best-track wind speed intensity to produce a curve used to estimate intensity for an independent set of tropical cyclones. The DAV-T is slightly modified for genesis prediction to take into account the lack of a center location. Instead, a map of variances is calculated for the entire satellite infrared scene in each basin and minimum values of the DAV-T parameter are archived when they meet statistically-based threshold values for development. In the presentation we will describe the technique and show performance statistics for all three basins.