Design and Testing of a Fiber Optic Radiometer to Study the Horizontal Convergence of Solar Fluxes in Clouds

用于研究云中太阳通量水平会聚的光纤辐射计的设计和测试

• 批准号: 9901063
• 负责人: Stephen Cox
• 金额: $ 23.05万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9901063&HistoricalAwards=false
• 关键词: Design; Testing; Fiber; Optic; Radiometer

Observations of solar radiation entering clouds at the top and exiting at the bottom indicate that more energy is absorbed than predicted from the optical properties of the drops and gases of which the clouds are composed. Several hypotheses have been proposed to explain this so-called "anomalous absorption" but none is generally accepted. Part of the difficulty in resolving the apparent discrepancy is that the measurements available to now only tell part of the story. At best, what is measured is the total downwards flux of energy (the irradiance) at cloud top and the same quantity simultaneously at cloud base. The difference in irradiance is accounted for not only by the absorption and scattering of radiation along the line in the direction of the sun but also by the extinction of scattered radiation flowing in all other directions. Information on the directional dependence of the radiant energy, or the radiance, is needed to get at the heart of the problem of anomalous cloud absorption. This grant supports the development and testing of a radiometer of novel design to measure the radiance in approximately 50 different directions in the upwards or downwards hemisphere. Recent developments in fiber optics and CCD technology will be employed. Evaluation of the instrument will include comparisons with standard measurements of solar irradiance. The ultimate application of the instrument will be the airborne measurement of radiances in clouds.

太阳辐射进入顶部并在底部退出的观察结果表明，比从云层和气体的光学特性中所预测的能量更多的能量所吸收的能量更多。 已经提出了几种假设来解释这种所谓的“异常吸收”，但没有一个普遍接受。 解决明显差异的一部分困难是，现在可用的测量仅讲述了故事的一部分。 充其量是，所测量的是云顶部的总能量（辐照度）和云基库同时量相同的数量。 辐照度的差异不仅是由于沿太阳方向沿线的吸收和散射，而且还通过在所有其他方向上流动的散射辐射的灭绝。 需要有关辐射能量或辐射的方向依赖性的信息，以达到异常云吸收问题的核心。 该赠款支持新型设计辐射计的开发和测试，以在向上或向下的半球中大约50个不同方向上测量辐射。 光纤和CCD技术的最新发展将采用。 该仪器的评估将包括与太阳辐照度标准测量值的比较。 该仪器的最终应用将是对云中的辐射的空中测量。