Estimation of Tropical Cyclone Intensity from the Satellite Infrared Images of Its Spiral Cloud Bands

B. S. Yurchak

The spiral signatures of infrared satellite images of the tropical cyclone Phanfone observed in the Northwest Pacific in August 2002 are analyzed using the hyperbolic-logarithmic model of a streamline in the Rankine vortex. Maximum wind speed Vmax and some other physical characteristics of the cyclone are estimated by identifying hyperbolic-logarithmic spirals (HLS) which “fit” into the geometric boundaries of the signatures. The comparison of temporal variations in Vmax with the data of meteorological services of the USA (JTWC) and Japan (RSMC) revealed satisfactory agreement of the time course of tropical cyclone intensity from the HLS estimates and JTWC data. The absolute estimates of intensity were within an interval between the corresponding JTWC and RSMC data. It seems that if the presented approach is enhanced, the HLS estimation may be a useful contribution to the empirical methods of tropical cyclone intensity determination by remote sensing means.