Estimating Tropical Cyclone Intensity at Low Wind Speeds

At very low (e.g., 20-35 kt) wind speeds, current methods of estimating the intensity of weak tropical cyclones (TCs) leave much to be desired. Moreover, existing best track database of observed TC intensities lack validation at low wind speeds due to limited resources. Therefore, we utilize the WRF model to create our own database of wind speeds that we then correlate to the Deviation Angle Variance technique (DAV).

The DAV uses brightness temperatures of a developing storm to determine a value that represents how symmetric the storm is. By utilizing the DAV and WRF simulation data, a quantification of the symmetry of a developing storm's wind speeds provides an additional measurement of the early stages of tropical cyclone intensity. Thus, the focus of this study is to investigate the dependence of a storm's symmetry (or asymmetry) on its observed intensity. In this presentation, we will show the results of the technique.