Geolocation of Indian Ocean tropical cyclones using 85 GHz observations from TRMM Microwave Imager

High resolution observations from 85 GHz channel of TRMM microwave imager have been used for the determination of the centre of tropical cyclones over the Indian Ocean. Upwelling microwave radiation at higher frequencies (e.g. 85 GHz) is highly sensitive to the scattering due to ice and snow particles that are generally associated with the deep convection in the inner core and convective bands of a tropical cyclone. Moreover, the microwave radiation is not affected by the presence of cirrus clouds that often obscure the view of the central features of cyclone in visible and infrared observations. We used three characteristic features in microwave observations to determine the centre of the Indian Ocean cyclones and compared the results with the operational analysis. The comparison indicates that the differences between the above two positions of cyclone centres are significant, considering the impact of initial position error on the forecast of the future position of cyclones.