Ruddick K G, Gons H J, Rijkeboer M, Tilstone G
Appl Opt. 2001 Jul 20;40(21):3575-85. doi: 10.1364/ao.40.003575.
Two-band algorithms that use the ratio of reflectances at 672 and 704 nm have already proved successful for chlorophyll a retrieval in a range of coastal and inland waters. An analysis of the effect of reflectance measurement errors on such algorithms is made. It provides important indications of the range of validity of these algorithms and motivates the development of an entirely new type of adaptive two-band algorithm for hyperspectral data, whereby the higher wavelength is chosen for each input spectrum individually. When one selects the wavelength at which reflectance is equal to the reflectance at the red chlorophyll a absorption peak, chlorophyll a retrieval becomes entirely insensitive to spectrally flat reflectance errors, which are typical of imperfect atmospheric correction, and is totally uncoupled from the retrieval or an estimation of backscatter. This new algorithm has been tested for Dutch inland and Belgian coastal waters.
利用672纳米和704纳米处反射率比值的双波段算法，已被证明在一系列沿海和内陆水域中用于叶绿素a反演是成功的。本文对反射率测量误差对此类算法的影响进行了分析。这为这些算法的有效范围提供了重要指示，并推动了一种全新的用于高光谱数据的自适应双波段算法的开发，即针对每个输入光谱单独选择较高波长。当选择反射率等于叶绿素a红色吸收峰处反射率的波长时，叶绿素a反演对光谱平坦的反射率误差（这是不完美大气校正的典型特征）完全不敏感，并且与后向散射的反演或估计完全解耦。这种新算法已在荷兰内陆水域和比利时沿海水域进行了测试。
