Synergistic Exploitation of Hyper- and Multi-Spectral Precursor Sentinel Measurements to Determine Phytoplankton Functional Types (SynSenPFT)

Svetlana N. Losa , Mariana A. Soppa , Tilman Dinter , Aleksandra Wolanin , Robert J. W. Brewin (1) , Annick Bricaud (2) , Julia Oelker , Ilka Peeken (3) , Bernard Gentili (2) , Vladimir Rozanov , Astrid Bracher (4)

1 PML - Plymouth Marine Laboratory
2 LOV - Laboratoire d'océanographie de Villefranche
3 AWI - Alfred Wegener Institute for Polar and Marine Research
4 AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine

We derive the chlorophyll a concentration (Chia) for three main phytoplankton functional types (PFTs) - diatoms, coccolithophores and cyanobacteria - by combining satellite multispectral-based information, being of a high spatial and temporal resolution, with retrievals based on high resolution of PI-I absorption properties derived from hyperspectral satellite measurements. The multispectral-based PI-I Chla retrievals are based on a revised version of the empirical OC-PFT algorithm applied to the Ocean Color Climate Change Initiative (OC-CCI) total Chla product. The PhytoDOAS analytical algorithm is used with some modifications to derive PI-I Chla from SCIAMACHY hyperspectral measurements. To combine synergistically these two PFT products (OC-P1-I and PhytoDOAS), an optimal interpolation is performed for each PI-I in every OC-P1-I sub-pixel within a PhytoDOAS pixel, given its Chla and its a priori error statistics. The synergistic product (SynSenPFT) is presented for the period of August 2002 March 2012 and evaluated against PFT Chla data obtained from in situ marker pigment data and the NASA Ocean Biogeochemical Model simulations and satellite information on phytoplankton size. The most challenging aspects of the SynSenPFT algorithm implementation are discussed. Perspectives on SynSenPFT product improvements and prolongation of the time series over the next decades by adaptation to Sentinel multi-and hyperspectral instruments are highlighted.

Domaines: Océanographie

Svetlana N. Losa, Mariana A. Soppa, Tilman Dinter, Aleksandra Wolanin, Robert J. W. Brewin, et al.. Synergistic Exploitation of Hyper- and Multi-Spectral Precursor Sentinel Measurements to Determine Phytoplankton Functional Types (SynSenPFT). Frontiers in Marine Science, 2017, 4, ⟨10.3389/fmars.2017.00203⟩. ⟨hal-03502968⟩