Light absorption measurements of aquatic particles: status and prospects
Light absorption measurements of aquatic particles: status and prospects
复制标题
DOI：
10.1109/igarss.1997.615269
复制
发表时间：
1997-08
期刊：
影响因子：
--
通讯作者：
S. Tassan;B. Mitchell;D. Stramski;A. Bricaud
中科院分区：
文献类型：
--
作者：
S. Tassan;B. Mitchell;D. Stramski;A. Bricaud
支持使用遥感器进行环境或地球化学研究的光学模型需要精确描述上层水层所含各种物质的个别贡献。这意味着需要精确测量光学特性，例如悬浮在水生环境中的颗粒物质的光吸收系数，其中包括浮游植物、有机和无机碎屑。海洋学家使用两种基本方法来测量海洋颗粒的吸收。首先，现场仪器，如来自WetLabs，Inc.的ac-9，如果使用和不使用微粒过滤器，则提供在几个离散波长处的微粒吸收的估计值，作为测量的总吸收与测量的可溶性材料的吸收之间的差。这种方法几年前才出现。第二种方法涉及过滤器上的颗粒浓度，随后在实验室中使用标准的双光束实验室比重计进行吸收测量。作者的注意力只集中在后一种方法上。虽然近年来已经取得了相当大的进展，但尚未就测量颗粒吸收的最有效方法达成普遍共识。鉴于这一专题的重要性，美国航天局SeaWiFS项目办公室于1996年12月在斯克里普斯海洋学研究所主办了一个讲习班，讨论方法问题。讲习班的目的是比较各实验室采用的测量协议，从准确性、易用性和实用性的角度评估和分析不同的方法，并提出改进测量的建议。本文简要回顾了测量水中颗粒物光吸收的一些方法学问题。
Optical models in support of environmental or biogeochemistry studies using remote sensors require precise description of the individual contributions of the various substances contained in the upper water layers. This implies a demand for accurate measurements of optical properties, such as the light absorption coefficient of particulate matter suspended in aquatic environments, which includes phytoplankton, organic and inorganic detritus. Oceanographers use two basic approaches to measure absorption by marine particles. First, in situ instruments such as the ac-9 from WetLabs, Inc., if deployed with and without a particle filter, provide estimates of particulate absorption at several discrete wavelengths as a difference between the measured total absorption and the measured absorption by soluble materials. This approach became available only a few years ago. The second approach involves the concentration of particles on filters with subsequent absorption measurements in the laboratory using standard dual-beam laboratory spectrophotometers. The authors' attention is focused solely on the latter approach. Although in recent years considerable progress has been achieved, a general consensus on the most effective methodology for measuring particulate absorption has not been reached. In view of the importance of the topic, the NASA SeaWiFS Project Office sponsored a workshop, held at the Scripps Institution of Oceanography in December 1996, to address methodological issues. The goal of the workshop was to compare measurement protocols adopted by various laboratories, to assess and analyze different methodologies from the point of view of accuracy, ease of use, and practicality, and to provide recommendations for improving the measurements. The present paper briefly reviews some of the methodological issues for measuring light absorption by aquatic particles.