MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
2.2 Enhancement of PQ metrics and standardization 
of their operational production 
During the first phase of the Copernicus Marine Service 
2015-2018), the product quality cross-cutting coordination 
ansured that metrics, individually defined and exploited by 
producers since MyOcean Project, were identified using a 
common naming system. This was necessary for individual 
verification procedures and constituted also a major 
step toward homogenization and standardization of PQ 
procedures. Likewise, basic sets of metrics were defined 
as baseline, especially for modelled product validation. 
Following the GODAE standards, four classes of metrics 
are defined for model products in order to check: 
1) Synoptic and large-scale behaviour of modelled 
:elds (Class 1: eyeball validation), 
2) Model timeseries and vertical sections at higher 
“requencies (Class 2: statistics at specific mooring 
‚ocations and sections), 
3) Integrated quantities against previous estimates in 
literature (Class 3: applied to transport, heat content, 
etc.), 
4) Last but not least, evaluation of model performance 
against contemporaneous collocated observations 
‘Class 4: skill scores, residual, pointwise and spatially 
averaged model-observation metrics). 
During the second phase of the Copernicus Marine Service 
(2018-2021), validation documents and PQ processes in 
place were reviewed, and their evolution was scheduled in 
order to meet some of the main users’ feedback which were: 
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-to produce user friendly quality scores and synthetic 
overviews of product quality. 
- to provide the number of valid observation avallability, 
more information on quality flags and quality checks, 
as well as why some model products may be less 
validated (usually due to lack of observational data to 
be used as reference). 
to provide higher-resolution error estimates (and 
error estimates as an extra product dataset). 
While it was possible to start addressing the first two 
voints before 2021, the last one is linked to the continuous 
improvement of the catalogue, and progress toward this 
2bjective shall be made during Copernicus 2 (see Section 4) 
Product quality experts have implemented new metrics 
in their respective validation procedures and validated 
new variables all along 2015-2021 period, including wave 
variables (new in the catalogue at the end of phase 1) 
and biogeochemical variables. Quality improvement of 
products themselves was also quantified (see Copernicus 
Marine Service element description articles, this issue). 
Meanwhile, the number of metrics monitored centrally 
almost tripled in 3 years (as illustrated in Figure 4). The 
significant increase between 2020 and 2021 is due to: 
- the addition of Class 2 metrics in monthly deliveries of 
producers for the central validation website (example 
of Class 2 metric in the PQ-Dashboard shown in the 
lower panel of Figure 4), and 
the homogenization effort done as part of the new 
website development. 
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Jigure k&: Temporal evolution in the number of PQ monitoring metrics generated/delivered for physical ocean (blue), biogeochemical (green) 
Nave (orange) and sea-ice (cyan) products, managed through the CMEMS central cal/val website (upper panel). Snapshot of the PAQ-Dashboard 
interactive display of Estimated Accuracy Numbers (EAN) for each product on predefined areas, together with visualization of model and in- 
situ observed timeseries at mooring locations (lower panel).