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

全面了解降水粒子在云中的分布，是加深我们对暴雨产生云的降水机制的认识的前提。开发了两种类型的视频探空仪。一种是测量直径大于500微米的降水颗粒。当降水粒子干扰穿过相机视线的红外光时，闪光灯被触发。这些图像由摄像机拍摄下来，并以1680 MHz的频率发送到地面。这种视频探空仪还能够监测降水粒子的电荷，以及温度、湿度和气压。另一种类型的视频探空仪，云粒子视频探空仪测量云滴。这个系统的独特之处在于，它可以在运行时拍摄胶片上的云粒照片。闪光灯被用来拍摄云滴的静态图像。这两个视频探空仪系统都是在澳大利亚梅尔维尔进行的MCTEX项目期间发射的。这是首次阐明赫克托星云中的降水粒子。视频探空仪观测到许多直径达7毫米的冰冻颗粒和丰富的冰晶，有时高达每厘米10个。分析表明，非常活跃的冰相过程可能解释了最频繁的闪电频率。

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.