Physics of Clouds and Precipitation

该项目是对云和降水物理学某些方面的理论和观测研究的继续。 主要包括以下几个方面的研究：1.层状雨的蒸发。 蒸发的数值计算将与多普勒雷达、剖面仪、无线电探空仪以及地面和空中测量的液滴大小分布的观测结果进行比较。2.由成核、凝结和聚结引起的液滴尺寸分布的演变。 特别强调的是液滴大小的范围内，占主导地位的增长过程的变化，从冷凝到聚结。一团不断增长的水滴中的过饱和场。 这将通过求解具有连续分布的蒸汽源和多个汇的介质中的扩散方程来分析，使用数值和近似分析方法。雨中的微波衰减。 同时观测两个雷达工作在衰减波长将被用来估计领域的衰减。 还将对希氏-博丹衰减校正方法进行理论分析。小积云的混合过程。 关于水滴大小分布、含水量、温度和雷达反射率的实验数据将用于研究多云空气和环境之间发生的小尺度混合。冰晶习性的起源。 将研究最近关于树枝状晶体形式成因的物理原理的工作，以便可能应用于解释冰晶形式和这些形式对温度和湿度的依赖性的云物理问题，这些研究有助于从根本上了解降水的发展和应用，如用雷达遥测降水。

This project is a continuation of theoretical and observational investigations of certain aspects of cloud and precipitation physics. It comprises the following studies:1. Evaporation of stratiform rain. Numerical calculations of evaporation will be compared with observations by Doppler radar, profiler, radiosondes, and ground-based and airborne measurements of the drop-size distribution. 2. Evolution of drop-size distribution by nucleation, condensation, and coalescence. Special emphasis is on the range of drop sizes where the dominant growth process changes from condensation to coalescence.3. The field of supersaturation in a cloud of growing drops. This will be analyzed by solving the diffusion equation in a medium with a continuously distributed source of vapor and multiple sinks using numerical and approximate analytical methods.4. Microwave attenuation in rain. Simultaneous observations with two radars operating at attenuating wavelengths will be used to estimate the field of attenuation. A theoretical analysis of the Hitschfeld-Bordan approach to attenuation correction will also be carried out.5. Mixing processes in small cumulus clouds. Experimental data on drop-size distributions, water content, temperature, and radar reflectivity will be used to study the small-scale mixing that takes place between cloudy air and the environment.6. The genesis of ice crystal habit. Recent work on the physical principles underlying the genesis of dendritic crystal forms will be studied for possible application to the cloud physical problem of explaining the forms of ice crystals and the dependence of these forms on temperature and humidity.These studies contribute to the fundamental understanding of precipitation development and to applications such as the remote measurement of rainfall by radar.