Measurements of the Size, Shape, Scattering Phase Function and Extinction Coefficient of Ice Crystals at South Pole Station

9909593 Lawson该项目是一项为期三年的南极站卷云辐射特性和大气中冰晶光散射特性研究，使用高分辨率数字云粒子成像仪自动将云粒子按大小和形状分类。 一些理论和实验研究表明，粒子的大小和形状强烈影响云粒子的辐射效应，特别是冰晶，两个云粒子成像仪将与正在进行的辐射传输计划合作在南极洲运行，实地工作将在2000-01年和2001-02年南半球夏季进行。 将在现场处理颗粒图像、浓度和粒度分布，并进行初步分析以确保数据质量。 目前的软件功能的系统允许拒绝的文物，各种尺寸和形状参数的计算，散射特性，冰/水分数。 单独的观察，以及集体的统计数据将显着增加几个并发的实验，有关雪的排放特性，在大气中的冰晶，和近地表的温室气体。 这些数据，加上对云底高度、温度和湿度结构等环境条件的测量，将有助于发展云和云粒子特性的气候学，以及新的算法，以大大改善辐射过程在大气环流模型中的表现。

9909593LawsonThis project is a three-year study of the radiative characteristics of cirrus clouds and the light-scattering properties of ice crystals in the atmosphere at South Pole Station, using a high-resolution digital cloud particle imager to automatically classify cloud particles by size and shape. A number of theoretical and experimental studies have demonstrated that particle size and shape strongly affect the radiative effects of cloud particles, and specifically ice crystals.Two cloud particle imagers will be operated in Antarctica in cooperation with an ongoing radiation transfer program, with field work to be carried out in the 2000-01 and 2001-02 austral summer seasons. Particle images, concentrations, and size distributions will be processed on site and preliminary analyses will be conducted to assure data quality. Current software capabilities of the system allow the rejection of artifacts, the computation of various size and shape parameters, of scattering characteristics, and of ice/water fraction. The individual observations, as well as the collective statistics will significantly add to several concurrent experiments concerning the emission characteristics of snow, of ice crystals in the atmosphere, and of greenhouse gases near the surface. This data, together with measurements of environmental conditions such as cloud base altitude, temperature, and humidity structure, will allow the development of a climatology of cloud and cloud particle properties, and of new algorithms to substantially improve representations of radiation processes in general circulation models.***