MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
1.2.3 Sea Level 
Sealevel is an important variable to monitor the ocean and 
coastal sea levels measured by tide gauges are a key 
source of information to assess sea level related hazards 
along the coast. By 2015, coastal sea level data was 
delivered in In Situ TAC NRT products, even when sea level 
was not yet included in the catalogue. In 2016, In Situ TAC 
started a fruitful collaboration with the EuroGOOS Tide 
gauges Task Team (TGTT) to agree on best practices and 
basic metadata about sea level data. This TGTT group 
published on May 2017 (updated October 2017) a document, 
in collaboration with Global Sea level Observing System 
(GLOSS) and In Situ TAC representatives. By 2019, In Situ 
TAC distributed, by github, a software for NRT quality 
control of tide gauge data based on GLOSS standards. The 
software has been implemented in IBI and MED regions; it 
is run every 15-min and includes spike detection and 
flagging, stability test, resampling and interpolation of 
short gaps and computation of filtered hourly values. By- 
products of this procedure include flagged original 
sampling data (as provided by national centres, typically 
5-15 min) and filtered hourly values. Procedures and 
methods applied follow the best practices described in the 
last IO0C Manual No. 83 and represent an important step to 
leverage tide gauge data in operational oceanography. In 
2020, a new collaboration line has been opened with 
EuroGO0S TGTT, GLOSS and OceanOPS to work on new 
unique platform identifiers and mandatory metadata. This 
will improve interoperability and reliable gaps analysis 
that should be performed between existing tide gauge data 
portals. 
Agreat effort has been made by the In Situ TAC to integrate 
the European sea level measuring stations going from 383 
in 2017 to 870 in 2021 operational tide gauges. However, in 
2021, only NRT sea level data from European providers Is 
distributed in NRT products. Finally, strong needs are 
‚dentified such as a REP product of sea level and the 
ıntegration of international networks at global level. Those 
are priorities for Copernicus 2. 
1.2.4 Wave 
In 2015, the In Situ TAC started the preparation of Wave 
products. Waves inclusion in the CMEMS catalogue was 
carried out not only by the In Situ TAC but also by MFCs. 
Then, the CMEMS WAVE Working Group, led by Mercator, was 
created to work on homogenized products at CMEMS level 
and the In Situ TAC was collaborating actively with this group 
to adopt standards from bodies such as IODE (International 
Oceanographic Data and Information Exchange) and CF 
(Climate and Forecast) international Conventions 
Additionally, an Intense work was done to develop common 
automatic quality control procedures for NRT data. This 
work led to the Copernicus In Situ TAC, Real Time Quality 
Control for WAVES manual, published in 2016 and reviewed 
and updated in 2020. These quality control procedures 
were implemented in 2016 and are based on range levels 
and spikes and stuck values detection. Applying these 
procedures in NRT, users benefit from data with an 
associated quality flag. In April 2017, the NRT product was 
ıaunched with more than 400 wave platforms. During 2018, 
an important improvement was performed with networks 
integration at global level of two new sources: the Global 
Telecommunication System and the NDBC/USA. Also, a 
Jreat effort was conducted to integrate coastal stations 
and to complete historical timeseries since 1980. The 
same year, the REP WAVE product was published in 
»perations at global level with data validated and visualized, 
and flagged accordingly, by wave experts. In 2019, In Situ 
TAC started to work on wave spectra inclusion as requestec 
by users, MFCs and WAVE satellite TAC. It was carried out 
on the March 2020 release for regional and global NRT 
products and on the December 2020 release for the WAVE 
REP product. The Real Time Quality Control for Waves 
manual was updated to include wave spectra and new 
tools were developed to visualize spectral information. At 
the end of Copernicus 1, figures demonstrate an evolution 
of integration efforts with more than 1500 platforms 
providing wave integrated parameters and wave spectra 
avallable in more than 150 platforms 
1.2.5 Oxygen, Chlorophyll and Nutrients 
"he In Situ TAC REP biogeochemical product offers high 
Juality data on Chlorophyll, oxygen, and nutrients (nitrate. 
silicate and phosphate) collected across the globe fror 
"993 and up to present date. Measurements include both 
discrete bottle data and sensor data coming from CTD, 
ferryboxes, moorings, BGC Argo and gliders. 
Nevertheless, the quality control applied on data may be 
ınconsistent between providers and sometimes also 
unknown to In Situ TAC partners that channel the data up 
to Copernicus Marine. To make sure that data of high or low 
Juality are flagged accordingly, Copernicus partners 
Jeveloped new automated quality control procedures for 
REP biogeochemical data to Identify questionable data 
before visual inspection. These procedures greatly 
anhanced the team's delayed-mode quality controı 
zapabilities and could also be used to improve the NRT QC. 
ihe automated QC is parameter-dependent and based on 
statistical testing. Moreover, tests were applied when 
possible to check the data against physical constraints 
For Chlorophyll a purely statistical approach has been 
chosen. The world ocean is divided into coastal and pelagic 
regions and each region is divided into upper and deeper 
ocean. Then, the 99th percentile for Chlorophyll 
zoncentration is computed for each region individually and 
used as upper boundary for accepting data, l.e., any data 
point outside the 99th percentile of any given region Is 
visually checked before being flagged as either ‘1 - good’ 
or ‘4 — bad’