Observations on the nature of clouds and their glaciation

云对降水形成、辐射能量传输等大气过程有重要影响。云的降水效率和光学性质与云的性质和状态密切相关，要阐明云对大气过程的影响，必须了解云的性质及其冰化作用。因此，本研究对云的性质及其冰川作用进行了观测。本文介绍了云的性质及其冰化作用的三个研究成果：(1)云粒视频测量探头的研制为了直接测量云粒的种类、大小和浓度，研制了一种便携式云粒视频测量探头。采用撞击法采集载玻片上的云粒，经放大后由一台CCD相机拍摄。(2)云微结构的飞机观测利用美国PMS云滴光谱仪(美国的PMS，FSSP-100型)和安装在飞机上的视频测量探头(塞斯纳404)观测了名古屋和海美岛附近云的云粒尺寸分布和云水含量。这些观测结果表明，水云的冰化作用可以改变云滴的大小和云中的水分含量。(3)在滋贺高地用沉降法和撞击法观测了冬季云中冰晶的数量和状态。从GMS的红外图像中推断出滋贺高地上空的云顶温度。如果报道的冰核数据是正确的，从观测中可以推断，许多冰晶可能是由于日本上空云层中的一些冰增强而形成的。

Clouds have a significant effect on atmospheric processes such as formation of precipitation and radiative energy transfer. The precipitation efficiency and optical properties of clouds are related closely to nature and state of clouds.Knowledge on nature of clouds and their glaciation is indispensable for elucidation of the effects of clouds on atmospheric processes. Therefore, observations on nature of clouds and their glaciation were made in this study. This report presents the three results of a study on nature of clouds and their glaciation.(1) Development of video measuring probe of cloud particles In order to measure species, size and concentration of cloud particles directly, a handy video measuring probe of cloud particles was developed. Cloud particles collected on slide glass by means of impaction method are photographed by a CCD camera after magnification. Cloud particles larger than about three microns in diameter are detected by this probe.(2) Aircraft observation on microstructure of clouds The size distribution of cloud particles and cloud water content for clouds near Nagoya and Amami Island were observed with the cloud droplet spectrometer (PMS in USA, Model FSSP-100) and video measuring probe mounted on an aircraft (Cessna 404). It was suggested from these observations that size of cloud droplets and cloud water content may be modified by glaciation of water clouds.(3) Observations of nature and state of ice clouds Number concentration of ice crystals in wintertime clouds were observed with sedimentation and impaction method at Shiga Heights. Top temperature of clouds over Shiga Heights were inferred from IR images of GMS. It is inferred from the observation that many ice crystals are possibly formed by some ice enhancement in clouds over Japan, if reported data on ice nuclei are correct.