Development of new type videosonde system for the study of torrential rain

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Whole knowledge of precipitation particle distribution in cloud in the prerequisite to increase our understanding of precipitation mechanisms of torrential rain producing clouds. Two types of videosonde systems were developed. One type aims to measure precipitation particles larger than 500mum in diameter. When precipitation particle interrupts the infra-red light running across the sight of camera, flash is triggered. The images are pictured by videocamera and sent to the ground by 1680 MHz. This videosonde system is also able to monitor both electric charge of precipitation particles, and temperature, humidity and pressure.The other type of videosonde, cloud particle videosonde measures cloud droplets. The unique feature of this system is to take a picture of cloud particles on the film as it runs. Flash is used to make stational images of cloud droplets. Both videosonde systems were launched during the MCTEX project which was conducted at Melville Is., Australia. This was the first to elucidate the precipitation particles in the Hector clouds. Videosonde observation showed many frozen particles as large as 7 mm in diameter and abundant ice crystals, sometimes reaching to ten per cm^3. Analysis shows the very active ice phase process which may explain the most frequent lightning frequencies.