Radiative Transfer Applications to the Remote Sensing of Ice Clouds: Theory and Experiment

辐射传输在冰云遥感中的应用：理论与实验

• 批准号: 0331550
• 负责人: Kuo-Nan Liou
• 金额: $ 105.3万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-11-15 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0331550&HistoricalAwards=false
• 关键词: Radiative; Transfer; Applications; Remote; Sensing

This project is a continuation of the Principal Investigator's ongoing research on radiative transfer in ice clouds, with specific applications to remote sensing in both cirrus cloudy atmospheres and a laboratory cloud chamber. The Principal Investigator and his graduate students have developed a method to infer ice crystal size and shape from airborne and satellite polarization and reflectance observations at visible and near-infrared wavelengths. They also employ a new theoretical approach using the reflected line spectrum in the 1.38 micrometer band to determine the vertical profile of ice crystal size in cirrus clouds. Laboratory activities include construction of a cloud chamber used to generate ice crystals of various shapes and sizes and equipped with a special radiation sensing platform. The observational apparatus measures the reflected light and polarization simultaneously at several scattering angles and at specific wavelengths in the visible and near-infrared by using imaging grating spectrometers, in a way that reproduces the bidirectional reflection geometry observed by satellite and aircraft. The reflected spectrum in the 1.38 micrometer region is measured by a Fourier Transform Infrared Spectrometer for application to vertical profiling. The broader impacts of the research include advancing the understanding of radiative transfer in ice clouds containing nonspherical crystals of intricate shape, size, and orientation. The combined theoretical and experimental approach provides the physical foundation and validation data for the development of new methods of remote sensing to infer cirrus cloud composition from satellites and space-borne radar and lidar in support of weather and climate research. It also supplies the correct light scattering and radiative properties of ice clouds for their parameterization in climate models, which information is critical for understanding the effect of widespread cirrus clouds on the reflection of sunlight and the trapping of thermal infrared radiation associated with greenhouse warming and climate feedback processes.

该项目是首席调查员正在进行的关于冰云中辐射传输的研究的继续，具体应用于卷云多云大气和实验室云室的遥感。首席研究员和他的研究生们开发了一种方法，可以从可见光和近红外波长的机载和卫星偏振和反射观测中推断冰晶的大小和形状。他们还使用了一种新的理论方法，使用1.38微米波段的反射线光谱来确定卷云中冰晶尺寸的垂直轮廓。实验室活动包括建造一个云室，用于产生各种形状和大小的冰晶，并配备一个特殊的辐射传感平台。该观测仪器使用成像光栅光谱仪，以再现卫星和飞机观测到的双向反射几何图形的方式，同时测量可见光和近红外中几个散射角和特定波长的反射光和偏振。利用傅里叶变换红外光谱仪测量了1.38微米区域的反射光谱，并将其应用于垂直剖面测量。这项研究的更广泛影响包括促进对含有复杂形状、大小和取向的非球形晶体的冰云中辐射传输的理解。理论和实验相结合的方法为开发新的遥感方法提供了物理基础和验证数据，以从卫星和星载雷达和激光雷达推断卷云组成，以支持天气和气候研究。它还为冰云在气候模式中的参数化提供了正确的光散射和辐射特性，这些信息对于理解广泛的卷云对阳光反射的影响以及与温室变暖和气候反馈过程有关的热红外辐射的捕获是至关重要的。