4A.6
Signatures of Thunderstorm and Heavy Rain, their Accurate Locations From AMSU-B Data onboard NOAA Satellite
Abolhassan Gheiby, University of Pune, Pune, Maharshtra, India; and P. N. Sen, D. M. Puranik, and R. N. Karekar
Abstract.
The aim of present study is to bring out the microwave signatures and determine the vertical distribution along with accurate location of Thunderstorm and heavy rain. For this purpose we use the microwave data provided by the Advanced Microwave Sounding Unit-B (AMSU-B) onboard NOAA 15 and 16 satellites. The AMSU-B measures brightness temperature TB in five frequencies, 89, 150, 176.3, 180.3 and 182.3 GHz with 16 km nadir resolution.
Since moisture and small cloud droplet are partially transparent in microwave, the multi-band microwave instruments (like AMSU-B) appears to be useful tool for distinguishing and accurate location of Mesoscale meteorological phenomena like thunderstorm with possibility tracking. Simulations of upwelling microwave radiation at top of the atmosphere for AMSU-B frequencies have been reported in literature. These results are used for image interpretation and distinguish of thunderstorm /heavy rain. It is found that the intensity features that can be seen in all five AMSU-B frequencies (all level in the troposphere) are related to thunderstorm. The vertical extension of thunderstorm in frequencies above 176.3GHz (176.3, 180.3 and 182.3 GHz) gives accurate vertical distribution and horizontal extent of thunderstorm, and its whiteness roughly indicates the rain rate.
In the present analysis, the location of heavy rain and thunderstorm area are defined by the location of image area with the maximum brightness in the proper frequency (level). For thunderstorm maximum brightness is in 150 GHz frequency, which is thus located in the other AMSU-B frequencies as well. The rain intensity is roughly estimated by the grey tones in the images.
We have shown the meteorological phenomena can be better distinguished in AMSU-B images as compared to IR, WV and the other microwave instruments. The validation has been done with ground observations and available radiosonde observations.
Session 4A, Phenomenological Forecasting I
Tuesday, 13 August 2002, 1:30 PM-3:00 PM
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