Global retrieval of phytoplankton functional types based on empirical orthogonal functions using CMEMS GlobColour merged products and further extension to OLCI data
Global retrieval of phytoplankton functional types based on empirical orthogonal functions using CMEMS GlobColour merged products and further extension to OLCI data
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DOI：
10.1016/j.rse.2020.111704
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发表时间：
2020-04
影响因子：
13.5
通讯作者：
H. Xi;S. Losa;A. Mangin;M. A. Soppa;P. Garnesson;J. Demaria;Yangyang Liu;O. F. d'Andon;A. Bracher
中科院分区：
文献类型：
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作者：
H. Xi;S. Losa;A. Mangin;M. A. Soppa;P. Garnesson;J. Demaria;Yangyang Liu;O. F. d'Andon;A. Bracher
本文提出了一种在哥白尼海洋环境监测服务（CMEMS）框架下，从多传感器合并海洋颜色（OC）产品或Sentinel-3A （S3）海洋和陆地颜色仪器（OLCI）数据中全球检索浮游植物功能类型（PFTs）叶绿素（Chl-a）浓度的算法。检索到的PFTs包括硅藻、海藻、鞭毛藻、绿藻和原核浮游植物。本文研究了先前提出的基于经验正交函数（EOF）检索各种浮游植物色素的方法，并利用广泛的全球原位色素测量数据集和卫星OC产品比对，对该方法进行了改进，以检索多种浮游植物色素的Chl-a浓度。基于eof的方法的性能进行了评估和交叉验证统计。将检索到的PFTs与基于原位色素测量的诊断色素分析（DPA）得出的PFTs进行比较。结果表明，该方法可以很好地预测上述大多数PFTs的氯离子浓度。然而，对于原核生物，该方法的准确性较低，可能是由于它们的一般低变异性和较小的浓度范围导致从反射率数据和相应的EOF模式中提取的信号较弱。为了验证该方法的应用，将基于9个波段卫星反射率产品的eofs拟合模型应用于glocolour月度合并产品。通过与其他现有的浮游植物组成卫星衍生产品（浮游植物大小类别（phytoplankton size class， PSC）、SynSenPFT、OC-PFT和PHYSAT）的相互比较，还基于10年合并产品（2002 - 2012）评估了pft的气候特征。相互比较表明，除了原核生物在低纬度地区显示出更高的chl浓度外，我们的研究检索到的大多数PFT/PSC产品与先前相应的PFT/PSC产品一致。从我们的产品中获得的PFT优势通常与PHYSAT产品相一致。使用11个OLCI波段的检索算法的初步实验应用于每月OLCI产品，显示与合并产品的PFT分布相当，尽管OLCI匹配数据在数量和覆盖范围上都是有限的。本研究的最终目标是提供长期连续观测的卫星全球PFT产品，并与即将发布的OC数据进行及时更新，从而全面了解全球或区域尺度上浮游植物组成结构的变化。
This study presents an algorithm for globally retrieving chlorophylla(Chl-a) concentrations of phytoplankton functional types (PFTs) from multi-sensor merged ocean color (OC) products or Sentinel-3A (S3) Ocean and Land Color Instrument (OLCI) data from the GlobColour archive in the frame of the Copernicus Marine Environmental Monitoring Service (CMEMS). The retrieved PFTs include diatoms, haptophytes, dinoflagellates, green algae and prokaryotic phytoplankton. A previously proposed method to retrieve various phytoplankton pigments, based on empirical orthogonal functions (EOF), is investigated and adapted to retrieve Chl-a concentrations of multiple PFTs using extensive global data sets of in situ pigment measurements and matchups with satellite OC products. The performance of the EOF-based approach is assessed and cross-validated statistically. The retrieved PFTs are compared with those derived from diagnostic pigment analysis (DPA) based on in situ pigment measurements. Results show that the approach predicts well Chl-aconcentrations of most of the mentioned PFTs. The performance of the approach is, however, less accurate for prokaryotes, possibly due to their general low variability and small concentration range resulting in a weak signal which is extracted from the reflectance data and corresponding EOF modes. As a demonstration of the approach utilization, the EOF-based fitted models based on satellite reflectance products at nine bands are applied to the monthly GlobColour merged products. Climatological characteristics of the PFTs are also evaluated based on ten years of merged products (2002−2012) through inter-comparisons with other existing satellite derived products on phytoplankton composition including phytoplankton size class (PSC), SynSenPFT, OC-PFT and PHYSAT. Inter-comparisons indicate that most PFTs retrieved by our study agree well with previous corresponding PFT/PSC products, except that prokaryotes show higher Chl-aconcentration in low latitudes. PFT dominance derived from our products is in general well consistent with the PHYSAT product. A preliminary experiment of the retrieval algorithm using eleven OLCI bands is applied to monthly OLCI products, showing comparable PFT distributions with those from the merged products, though the matchup data for OLCI are limited both in number and coverage. This study is to ultimately deliver satellite global PFT products for long-term continuous observation, which will be updated timely with upcoming OC data, for a comprehensive understanding of the variability of phytoplankton composition structure at a global or regional scale.