MONITORING TROPICAL CYCLONE INTENSITY IN THE AUSTRALIAN REGION USING NOAA TOVS DATA

From the late 1980s the Bureau of Meteorology has been able to monitor tropical cyclone intensity using NOAA (National Oceanographic and Atm ospheric Administration) TOVS (TIROS Operational Vertical Sounder) obs ervations received at satellite groundstations in Darwin, Melbourne an d Perth. These observations provide near-continuous coverage of the tr opical oceans surrounding mainland Australia. Tropical cyclones in bot h the Indian Ocean and Coral Sea basins have been analysed using the B ureau's operational TOVS processing system. Both MSU (microwave soundi ng unit) and stratospheric HIRS (high resolution infrared sounder) obs ervations have been employed to estimate the upper-level temperature f ields around the tropical cyclones. This note shows that the TOVS retr ieval system can define upper-level tropospheric temperature anomaly f ields, which then can be related to storm central pressure and maximum wind speed. The ground-truth data used in this study generally consis ted of operational estimates of storm intensity. Based on these data, temperature anomaly and storm intensity were related in a way that res ults in regression curves which may be used for operational purposes. This note also briefly examines the capacity of the next generation op erational polar-orbiting NOAA sounder, the advanced TOVS (ATOVS), whic h includes the advanced microwave sounding unit (AMSU) to monitor trop ical cyclones. It appears that this sounder has the potential to provi de an improved capacity for analysis of these temperature anomalies an d hence tropical cyclone intensity.