Time series of major phytoplankton functional types serving as an Ocean Monitoring Indicator (OMI) for Copernicus Marine Service

In the framework of Copernicus Marine Service Evolution Program, our project GLOPHYTS aims at establishing a complete and systematic approach for a consistent long-term monitoring of surface ocean phytoplankton function types (PFTs) on global scale. The current global PFT products available on CMEMS are generated based on remote sensing reflectance from multi-sensor merged and Sentinel-3 OLCI data and OSTIA sea surface temperature product, using a set of empirical-orthogonal-function based PFT algorithms that were previously developed and recently updated within GLOPHYTS. These products provide global chlorophyll a data with per-pixel uncertainty for five PFTs spanning from 2002 until today. A correction and merging scheme has been applied to these PFT data sets of different sensors to generate long-term consistent satellite PFT products, which are expected to act as potentially important ocean monitoring indicators (OMI). In providing inter-annual variation and trend analyses of the surface phytoplankton community structure, the OMI is likely to help in the assessment of the ocean health. In the context of this study, we present the PFT time series on global scale and for some key regions, e.g.  the Arctic Ocean. For the latter, we will also show the perspective of improving PFT estimations using machine learning techniques. The proposed improved Arctic PFT products can supplement the current ocean colour data sets for the Arctic Ocean in the Copernicus Marine Service.