Satellite analysis of tropical cyclones using NOAA-16 AMSU measurements over Indian region

Abstract

  The first Advanced Microwave Sounding Unit (AMSU) was launched aboard NOAA-15 satellite on 13 May 1998.  AMSU measurements are now also available from NOAA-16 and NOAA-17 satellites.  The AMSU is well suited for the observation of tropical cyclones because the ice clouds that cover tropical cyclones do not significantly affect its measurements.  In this paper the intensity of three tropical cyclones formed over Bay of Bengal and Arabian Sea in the month of October 1999, May and September 2001 were studied using AMSU measurements.  The upper tropospheric warm core thermal anomalies over the tropical cyclone areas were computed from temperature profiles using the NOAA-15 and NOAA-16 AMSU-A measurements. It has been observed that the magnitude of the warm core temperature anomaly at about 250 hPa was an indicator of the intensity of tropical cyclones in all three cases. The order of the temperature anomaly was about 6^oC in case of super tropical cyclone, 1999 while in other two cases the order of the temperature anomaly were of about 3^oC for moderate tropical cyclones, 2001. Therefore, it may be stated that the AMSU data appeared to offer substantial opportunities for improvements in tropical cyclone analysis and forecasting.