Southern Ocean Phytoplankton Functional Types and Size-Class Diversity Matchup Data

This dataset contains both CSV and NetCDF (NC) files: CSV files include eight pigment variables from the SeaBASS database and the Hayward et al., (2024) dataset for the period 1998–2024. These data are limited to surface observations (0–20 m) in the Southern Ocean, within the latitude range from south to 40°S and longitude range 180°W–180°E. NetCDF (NC) files contain gridded monthly phytoplankton size classes (PSCs) and phytoplankton functional types (PFTs) for the period 1998–2024, covering the austral spring–summer season from September to February. These data are derived using an empirical approach applied to the CSV dataset, combined with Ocean Colour Climate Change Initiative (OC-CCI) satellite products. NC file DescriptionThis dataset provides gridded estimates of the PFTs/PSCs expressed as both percentage contribution and concentration (mg m⁻³), derived from satellite ocean-colour observations spanning 1998–2024. The product is designed to support analyses of long-term phytoplankton community structure, size-class variability, and ecosystem change. PFT/PSC estimates are generated using a fourth-degree polynomial diagnostic approach applied to log₁₀-transformed chlorophyll. The resulting fractional contribution is constrained to the 0–100% range and subsequently converted to concentration by scaling it by the total chlorophyll. This approach is consistent with abundance-based phytoplankton size-class reconstruction methods commonly used in satellite biogeochemical studies. The dataset is provided in NC format, following CF-conventions where applicable, and includes spatial and temporal coordinates suitable for regional, basin-scale, and climatological analyses. Spatial Coverage Latitude: 1176 grid points (degrees north) Longitude: 8640 grid points (degrees east) Global ocean coverage at high spatial resolution Temporal Coverage Time dimension: 162 monthly time steps Reference time: days since 1998-01-01 00:00:00 Calendar: proleptic Gregorian Aggregated for the September–February seasonal window over 1998–2024 Variables 1. Latitude Units: degrees_north Description: Latitude coordinate Axis: Y 2. Longitude Units: degrees_east Description: Longitude coordinate Axis: X 3. Time Units: days since 1998-01-01 00:00:00 Description: Time coordinate Axis: T 4. PFT/PSC_pct Units: % Description: Percentage contribution of PFT/PSC to total chlorophyll Method: Derived from a 4th-degree polynomial applied to log₁₀(CHL), clipped to [0, 100] Scale factor: 0.01 Fill value: −32767 5. PFT/PSC_conc Units: mg m⁻³ Description: PFT/PSC concentration Calculation: (PFT/PSC_pct / 100) × total chlorophyll Scale factor: 0.001 Fill value: −32767