Remote sensing of phytoplankton pigments: A comparison of empirical and theoretical approaches
Remote sensing of phytoplankton pigments: A comparison of empirical and theoretical approaches
复制标题
DOI：
10.1080/014311601449925
复制
发表时间：
2001-01
影响因子：
3.4
通讯作者：
S. Sathyendranath;G. Cota;V. Stuart;H. Maass;T. Platt
中科院分区：
文献类型：
--
作者：
S. Sathyendranath;G. Cota;V. Stuart;H. Maass;T. Platt
根据海岸带颜色扫描仪、海洋观测宽视场传感器和海洋颜色和温度扫描仪等卫星传感器提供的海洋颜色数据，常规用于遥感浮游植物色素叶绿素a的算法都是经验性的。然而，存在着一些理论模型，可以将海洋颜色表示为海水固有光学特性的函数，如吸收系数和后向散射系数。这些特性又可以表示为叶绿素a的函数，至少对于所谓的情况1沃茨水域，其中浮游植物可以被认为是负责海洋光学特性中的大多数变化的单一独立变量。在这里，我们使用这样的理论方法来模拟海洋颜色的变化作为叶绿素浓度的函数，并将结果与常规使用的一些经验模型进行比较。海洋颜色模型的实施所需的浮游植物吸收的参数来自我们的数据库中的700多个观测浮游植物吸收光谱和浮游植物色素的HPLC（高效液相色谱）技术的并发测量。由于文献中有报道称，与低纬度地区相比，极地地区的算法性能存在显着差异，因此该模型首先使用在纬度小于50的地区进行的观测来实现。然后将其应用于拉布拉多海，一个高纬度的环境。我们的研究结果表明，在高纬度地区的算法的性能确实存在差异，这些差异可能是由于浮游植物的光学特性的变化，伴随着其组合的分类组成的变化。模型的敏感性的假设有色溶解有机物（或黄色物质）的吸收和颗粒的后向散射进行检查。研究了拉曼散射对海洋颜色的重要性及其对算法的影响。
Algorithms that have been used on a routine basis for remote sensing of the phytoplankton pigment, chlorophyll- a, from ocean colour data from satellite sensors such as the CZCS (Coastal Zone Color Scanner), SeaWiFS (Sea Viewing Wide Field-of-View Sensor) and OCTS (Ocean Colour and Temperature Scanner) are all of an empirical nature. However, there exist theoretical models that allow ocean colour to be expressed as a function of the inherent optical properties of seawater, such as the absorption coefficient and the backscattering coefficient. These properties can in turn be expressed as functions of chlorophyll- a, at least for the so-called Case 1 waters in which phytoplankton may be considered to be the single, independent variable responsible for most of the variations in the marine optical properties. Here, we use such a theoretical approach to model variations in ocean colour as a function of chlorophyll- a concentration, and compare the results with some empirical models in routine use. The parameters of phytoplankton absorption necessary for the implementation of the ocean colour model are derived from our database of over 700 observations of phytoplankton absorption spectra and concurrent measurements of phytoplankton pigments by HPLC (High Performance Liquid Chromatography) techniques. Since there are reports in the literature that significant differences exist in the performance of the algorithms in polar regions compared with lower latitudes, the model is first implemented using observations made at latitudes less than 50. It is then applied to the Labrador Sea, a high-latitude environment. Our results show that there are indeed differences in the performance of the algorithm at high latitudes, and that these differences may be attributed to changes in the optical characteristics of phytoplankton that accompany changes in the taxonomic composition of their assemblages. The sensitivities of the model to assumptions made regarding absorption by coloured dissolved organic matter (or yellow substances) and backscattering by particles are examined. The importance of Raman scattering on ocean colour and its influence on the algorithms are also investigated.