MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
Another important achievement for the SL-TAC was the 
vefinement of products’ errors description. The different 
validation diagnostics and procedures were refined in 
öarder to: 
quantify errors of different products at different 
physical scale, from climate to meso-scale. This 
estimation involved different diagnostics for 
different variables and implied different independent 
measurement (in situ and altimeter) a/o intermediate 
altimeter products. The error budget was fully 
estimated and documented after each significant 
change in the production (i.e update of the QUID 
for different products). Scientific peer-reviewed 
publications also completed the quality information 
after each full reprocessing activities (Pujol et al., 
2016; Juza et al., 2016; Taburet et al., 2019). Specific 
diagnostics were implemented in order to quantify 
abserving capability of gridded products at regional 
scale. This diagnostic was presented by Ballarotta et 
al. (2019) and is illustrated by Figure 2, 
assess the quality of Sentinel-3 measurements. A 
methodology of comparison of the along-track products 
with Iin-situ tide gauge measurements available in 
the Copernicus Marine Service catalogue has been 
’mplemented. Results obtained with Sentinel-3A and 
Jason-3 measurements were compared over the 
European coast. They revealed the improved capability 
af the Sentinel-3A to capture the signal near the coast, 
with a RMSD reduction of about 13% compared to the 
jason-3 capabilities (Sänchez-Romän et al., 2020). 
assess the quality of different corrections applied on 
along-track products. The comparison with in-situ 
tide gauge was also used to quantify the impact of the 
Long Wavelength Error. It showed that this correction 
reduced errors in altimetry enhancing the consistency 
between altimeter and in-situ datasets (reduction of 
the errors up to 10%) (Sänchez-Romaän et al., 2020). 
Finally, the SL-TAC also contributed to the cross-cutting 
activities, and more specifically the Ocean State Report 
(0SR) and associated OMI production. 
- The SL-TAC leaded a/o contributed to different 
sections of 0SRs from 2015 to 2019. 
The sea level trend OMI was introduced in the OM 
catalogue, first for the global ocean in 2018, then for 
regional seas in 2019, in coordination with the C3S 
production. Data processing and corrections developed 
with R&D activities (e.g., ESA CCI) were also taken into 
account to improve the OMI pertinence and precision. In 
“hat way, a specific correction for the Topex-A Altimeter 
Instrumental Anomaly and drift was implemented in 
the Sea level trend global OMI in 2020 as illustrated 
on Figure 3. This issue was also described in the 2019 
ISR. 
The North Pacific Gyre oscillation index (Di Lorenzo et 
al., 2008) was introduced in the OSR for year 2018 and 
in the OMIs catalogue in 2019. 
The Kuroshio extension phase index (Qiu and Chen, 
2005) was introduced in the OMlIs catalogue in 2020.