Determination of Cloud Radiative Properties from Satellite Observations

根据卫星观测确定云辐射特性

• 批准号: 8912669
• 负责人: James Coakley
• 金额: $ 20.91万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-12-01 至 1992-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8912669&HistoricalAwards=false
• 关键词: Determination; Cloud; Radiative; Properties; Satellite

The treatment of satellite fields-of-view in the International Satellite Cloud Climatology Project (ISCCP) permits only two descriptive categories: either free of or contaminated by clouds. For the cloud-contaminated cases, a single-layer "effective" cloud model is then used to derive the radiative properties of the cloud, which is presumed to be spatially homogeneous plane-parallel with fixed scattering properties. An ability to distinguish either broken or uniform clouds has profound consequences for computing radiative fluxes at the surface and top of the atmosphere. The "spatial coherence method" (Coakley and Bretherton, 1982) is designed to address this problem by taking advantage of the "structure" amongst the pixels to retrieve percentage cloud cover. Using the 4 km AVHRR data, Dr. Coakley will derive empirical estimates of cloud cover and radiative properties for the Pacific and Atlantic Ocean basins from 50 degrees South to 50 degrees North. He will determine the effect of cloud geometry on its reflectivity, and assess the opacity of clouds at IR wavelengths and possible bias of the spatial coherence method. Dr. Coakley will also collaborate with ISCCP scientists to compare and contrast the results from two different approaches.

国际卫星云气候学项目（ISCCP）对卫星视场的处理只允许两种描述类别：无云或被云污染。对于云污染的情况，然后使用单层“有效”云模型来推导云的辐射特性，假定云在空间上是均匀的平面平行的，具有固定的散射特性。区分破碎云和均匀云的能力对计算大气表面和顶部的辐射通量具有深远的影响。“空间相干方法”（Coakley和Bretherton， 1982）旨在通过利用像素之间的“结构”来检索百分比云覆盖来解决这个问题。利用4公里AVHRR数据，Coakley博士将得出从南纬50度到北纬50度的太平洋和大西洋盆地的云量和辐射特性的经验估计。他将确定云的几何形状对其反射率的影响，并评估云在红外波长的不透明度和空间相干方法的可能偏差。Coakley博士还将与ISCCP的科学家合作，比较和对比两种不同方法的结果。