MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
Chlorophyll concentration (Chl-a), the Primary Production 
(PP), and the Phytoplankton Functional Types. Whereas 
OPTICS refers to other variables retrieved from ocean 
zolour sensors, and includes: 
- inherent Optical Properties (IOPs), such as absorption 
and scattering coefficients, 
the diffuse attenuation coefficient of light at 490 nm 
(Kd490), 
secchi depth (transparency of water), 
spectral Remote Sensing Reflectance (Rrs), 
- photosynthetically available radiation (PAR), 
coloured Dissolved Organic Matter (CDOM), and 
the Suspended Particulate Matter (SPM). 
1.1 Processing levels and timeliness 
updated, hindcast, ancillary information such as precision 
orbital data and meteorological fields used for atmospheric 
correction (Le Traon et al., 2015). 
Generally, once a year, the full data timeseries undergoes 
reprocessing to ensure the most recent findings to be 
consistently applied and back-propagated to all data. 
These MY timeseries are produced with a consolidated anc 
consistent input dataset and processing software version, 
resulting in a dataset suitable for long-term analyses and 
climate studies (Von Schuckman et al, 2017, 
Sathyendranath et al., 2017 and references therein). Since 
June 2020, REP timeseries are extended automatically 
every six months and superseded NRT datasets for those 
months are removed from the catalogue. 
1.2 The OCTAC catalogue evolution 2015-2021 
The CMEMS data are produced in near-real time (NRT), 
delayed time (DT) and as reprocessed (REP) or Multi-Year 
'MY) data. These are delivered as daily and monthly 
datasets (Level 3, L3) and as “gap-free” products (Level 4, 
L4) to overcome cloud cover in subsequent oceanographic 
analyses (Le Traon et al., 2017; Le Traon et al., 2019). 
Within OCTAC, NRT products are operationally produced 
every day to provide the best estimate of ocean colour 
variables at the time. These products are generated using 
available satellite data as well as climatological ancillary 
data (meteorological and ozone data for atmospheric 
correction, and predicted attitude and ephemerides for 
data geolocation). Improved DT products are also produced 
operationally by reprocessing OC upstream data using 
In 2015, the OCTAC catalogue was composed of 30 OC 
Products (184 datasets) covering the Global Ocean and 
European Regional Seas (Table 1). In NRT, all regional 
products were based on single-sensors (MODIS and VIIRS} 
and only the global product was based on sensor merging. 
For the REP, the consistent re-processed multi-sensor 
timeseries from 1997 to 2012 were based on the ESA OC- 
SCI v2 including SeaWIFS, MODIS and MERIS 
“Sathyendranath et al., 2019). The L4 “gap-free” products 
were available only for a few products (GLO, MED and BS) 
and they were based on Optimal Interpolation and variants 
5f the DINEOF procedure (Beckers and Rixen, 2003). 
CT: 
lie: 
TEN 
ID 
Glohal Ocean 
Multi (MODIS+VIIRS) 
3SM (Maritorena, et al., 
2010} 
Multi 
{MODIS+VIIRS) 
Multi (0C-CCI 4km): 
SeaWIFS+MODIS+MERIS 
ChlO0C5, ChlOC4 
Multi (0C-CCI 1km) 
SeaWIFS+MODIS+MERIS 
0C488 (Taberner et al., 2014) 
Multi (0C-CCI 1km) 
SeaWIFS+MODIS+MERIS 
0C488 (Taberner et al., 2014) 
Multi (0C-CCI 4km) 
SeaWIFS+MODIS+MERIS 
(Pitarch et al 21 A} 
Arctic 0cean 
single MODIS & VIIRS 
IC488 (Taberner et al, 
2014) 
single MODIS & VIIRS 
3C488 (Taberner et al., 
2014) 
Atlantic Ocean 
Multi (MODIS+VIRS) 
Ol scheme 
Baltic Sea 
single MODIS HZG 
Mediterranean Sea 
single MODIS & VIIRS 
Med0OC4 (Volpe et al., 2007) 
single ) Multi (0C-CCI 4km) 
MODIS & VIIRS SeaWIFS+MODIS+MERIS 
DINEOF scheme Med0OC4 (Volpe et al., 2007) 
single MODIS & VIIRS Multi (0C-CCI 4km) | Based on L3 Multi 
DINEOF scheme SeaWIFS+MODIS+MERIS DINEOF scheme 
Black Sea | 
Single MODIS & VIIRS 
{Kopelevich et al.. 20123) 
Euronean Sea 
an 
Sinale (MODIS) 
A 
— a 
[au 12 Summary of the upstream and processing chains in the OCTAC cataloaue at the start of Copernicus 1.