Northwest Atlantic per-pixel spring bloom metrics derived from OC-CCI POLY4 satellite Chlorophyll-a, 1998-present

NWA OCCCI spring bloom metrics 2024

cdm_data_type = Grid
VARIABLES (all of which use the dimensions [time][latitude][longitude]):
t_start (Day of year of the start of the spring phytoplankton bloom)
t_duration (Duration of the spring phytoplankton bloom, days)
amplitude_real (Maximum concentration during the spring phytoplankton bloom period, mg/m3)
magnitude_real (Total chlorophyll-a produced during the spring phytoplankton bloom period, days*mg/m3)
annual_mean (Average chlorophyll-a over the year, mg/m3)
NRMSE_bloom (Root mean square error between the fitted Gaussian and real chl-a values during the bloom period, normalized to amplitude_real, mg/m3)
percent_dineof (Percentage of days with pixel values estimated using DINEOF)


POLY4 Chlorophyll-a MODIS-Aqua Data in the Northwest Atlantic, 2002-2023

NWA Moderate Resolution Imaging Spectroradiometer (MODIS)-AQUA CHL_POLY4

cdm_data_type = Grid
VARIABLES (all of which use the dimensions [time][latitude][longitude]):
chlor_a (Chlorophyll-a Concentration (POLY4v2 model with coefficients optimized to MODIS-AQUA and Northwest Atlantic), mg m-3)


POLY4 Chlorophyll-a OC-CCI Data in the Northwest Atlantic, 1997-Present

Chlorophyll-a concentration (Chl-a) is used as a proxy for phytoplankton biomass to track blooms and monitor the state of the ecosystem. This dataset contains daily satellite Chl-a since Sep 1997. The data is at a 4.64x4.64 km spatial resolution covering an area of the Northwest Atlantic from 39-82°N, 42-95°W. Regionally-tuned coefficients for POLY4 Chl-a (Clay et al., 2019, see resources) were obtained by matching level-3 gridded 1km-resolution satellite pixels to in situ HPLC (High Performance Liquid Chromatography) Chl-a samples within the region of interest. POLY4 Chl-a was then optimized by forcing the linear regression of POLY4 against HPLC to the 1:1 line to reduce the negative bias observed in higher concentrations in the default global Chl-a models. Daily Chl-a images were generated by applying the optimized POLY4 algorithm on level-3 binned remote sensing reflectance (Rrs) data from the OC-CCI multisensor product generated by the Plymouth Marine Laboratory (PML) as part of the European Space Agency (ESA) climate change initiative. The Chl-a data were then projected onto an Equidistant Cylindrical grid (4.64x4.64 km per pixel) using a nearest neighbour method.  This model and the Northwest Atlantic coefficients are available in the R package oceancolouR (https://github.com/BIO-RSG/oceancolouR).

cdm_data_type = Grid
VARIABLES (all of which use the dimensions [time][latitude][longitude]):
chlor_a (Chlorophyll-a Concentration (POLY4v1 model with coefficients optimized to OC-CCI multisensor product in the Northwest Atlantic), mg m-3)