REMOTE SENSING OF MICROPHYSICAL AND RADIATIVE PROPERTIES OF ICE CLOUDS

本研究的主要目的是发展一种结合地基主动和被动遥感的冰云微物理和辐射特性的协同观测技术，并验证其对计划中的星载云雷达和激光雷达从空间测量冰云的有效性。本文发展了有冰云的多云大气短波（太阳）和长波（红外）辐射的传输计算方案。利用该计算方案，模拟了混合相云和中纬度卷层云的观测辐射特性，并研究了含冰粒子云的微物理特性与辐射特性之间的关系。一项敏感性研究表明，混合相云的微物理特性可以通过使用云雷达与双频在35-GHz和95-GHz的检索。此外，我们还发展了一个三维的准解析解， ...更多信息 非均匀大气的辐射传输方程初步计算表明，云的均匀性对辐射场，特别是透射辐射场有显著的影响;本文提出了一种新的正演算法，利用95 °的太阳辐射率反演冰云的有效尺度和冰水含量。GHz云雷达与0.532 μm光学激光雷达配置。该算法使我们能够估计冰云微物理特性的垂直廓线。我们已经测试了算法的性能，通过数值模拟的潜在来源，如冰晶的方向，尺寸分布的形状，激光雷达信号的多重散射效应，在雷达和激光雷达信号的观测偏差。我们将该算法应用于卷云的地面和船上观测数据，发现冰晶的有效尺寸和下降速度之间存在密切的相关性。本研究的结果将有助于改进气候模式中的冰云遥感和云辐射方案。少

The major purpose of the present study is to develop a synergy observational technique to retrieve microphysical and radiative properties of ice clouds by combining the ground-based active and passive remote sensing, and to validate its effectiveness for the planed satellite-borne cloud radar and lidar for measuring ice clouds from space. We have developed the transfer computation scheme of shortwave (solar) and longwave (infrared) radiation for cloudy atmospheres with ice clouds. By using the computation scheme, we have simulated the observed radiative properties for mixed-phase clouds and mid-latitude cirrostratus clouds and studied the relationship between the microphysical properties and radiative properties of the clouds containing ice particles. A sensitivity study suggested that microphysical properties of mixed-phase clouds can be retrieved by using cloud radars with dual frequencies at 35-GHz and 95-GHz. Further, we have developed a quasi-analytic solution of the three-dimensi … More onal radiative transfer equation for inhomogeneous atmospheres. The preliminary computation showed cloud in homogeneity substantially affects the radiation fields, especially, of the transmitted radiances ; this suggests that remote sensing of cloud properties from the transmitted solar radiance measurements is not-practical.We have developed a new forward algorithm for the retrieval of effective size and ice water content of ice clouds by using a 95-GHz cloud radar collocated with an optical lidar of wavelength at 0.532 μm. The algorithm enables us to estimate vertical profiles of the ice cloud microphysical properties. We have tested the performance of the algorithm through numerical simulations for potential sources of such errors as ice crystal orientation, shapes of size distribution, multiple scattering effects to lidar signals, and observational biases in the radar and lidar signals. We applied the retrieval algorithm to the ground-based and shipboard observation data for cirrus clouds, and found a close correlation between effective size and fall velocity of ice crystals. The results from the present study will be useful for improving ice cloud remote sensing and cloud-radiation schemes in climate models. Less