How many independent quantities can be extracted from ocean color?
How many independent quantities can be extracted from ocean color?
复制标题
DOI：
10.1002/lol2.10319
复制
发表时间：
2023-03-14
影响因子：
7.8
通讯作者：
Erickson, Zachary K.
中科院分区：
文献类型：
--
作者：
Cael, B. B.;Bisson, Kelsey;Erickson, Zachary K.
从遥感反射率（R-rs（λ））得出的产品，例如叶绿素、浮游植物碳、真光层深度或颗粒大小，广泛用于海洋学。有问题的是，R-rs（lambda）的自由度（DoF）可能比测得的波段或衍生产品少。在这里，我们表明，全球海面高光谱R-rs（lambda）数据集的DoF = 4。类似MODIS的多光谱等效原位数据也有DoF = 4，而其SeaWiFS等效数据的DoF = 3。这两个多光谱等效数据集在标称不确定性内预测单个高光谱波长的R-rs（lambda）。遥感气候学多光谱R-rs（lambda）的DoF = 2，因为大气校正、转移到更大的时空尺度和/或更多的公海测量会丢失信息，但R-rs（lambda）衍生产品的DoF = 1。这些结果表明，遥感产品的基础上，现有的卫星的R-rs（λ）是不独立的，不应该被视为这样，现有的R-rs（λ）测量保持未利用的信息，未来的多或特别是超光谱算法必须严格考虑R-rs（λ）波段之间的相关性。
Products derived from remote sensing reflectances (R-rs(lambda)), for example, chlorophyll, phytoplankton carbon, euphotic depth, or particle size, are widely used in oceanography. Problematically, R-rs(lambda) may have fewer degrees of freedom (DoF) than measured wavebands or derived products. Here, we show that a global sea surface hyperspectral R-rs(lambda) dataset has DoF = 4. MODIS-like multispectral equivalent in situ data also have DoF = 4, while their SeaWiFS equivalent has DoF = 3. Both multispectral-equivalent datasets predict individual hyperspectral wavelengths' R-rs(lambda) within nominal uncertainties. Remotely sensed climatological multispectral R-rs(lambda) have DoF = 2, as information is lost by atmospheric correction, shifting to larger spatiotemporal scales, and/or more open-ocean measurements, but suites of R-rs(lambda )-derived products have DoF = 1. These results suggest that remote sensing products based on existing satellites' R-rs(lambda ) are not independent and should not be treated as such, that existing R-rs(lambda) measurements hold unutilized information, and that future multi-or especially hyper-spectral algorithms must rigorously consider correlations between R-rs(lambda ) wavebands.