AUTRET, E.', Bud 
‚GIORNO NARDELLI, B.?, GOOD, S.A.?, HOYER, J.“, PAYET, J.M.5, 
PIOLLE, J.F.', PISANO, A.?, SAUX-PICART, E.> 
Ifremer, France - *°CNR, Italy - *MetOffice, United Kingdom - *DMI, Denmark - MeteoFrance, France 
OVERVIEW 
A continuous effort was dedicated to the inclusion of all 
relevant new sources of data in the processing systems as 
they became available. The main developments were: 
-the ingestion of Sea and Land Surface Temperature 
Radiometer (SLSTR) data acquired by ESA Sentinel- 
3A and Sentinel-3B missions, 
- the release of more homogeneous and accurate REP 
products and information on the ocean state with 
respect to phase 1, by integrating the upstream high 
Juality climatic records by the ESA CCI/C3S initiatives 
in all multi-year (MY) processing chains. 
"hese major evolutions are summarized in the following 
subsectlions. 
Since the beginning of Copernicus Marine Service phase 
2, in 2018, the Sea Surface Temperature Thematic Assembly 
Centre (SST-TAC) has been in charge of the near real-time 
\NRT) and delayed mode (REP) processing of SST products 
based (primarily) on satellite observations. During the first 
ohase (2015-2018), this service was operated as the Ocean 
and Sea Ice Thematic Assembly Centre (0S| TAC). The SST- 
TAC has produced both single and multi-sensor merged 
data (L3C/L3S) and interpolated data (L4), delivered as 
global and regional products. The regional products have 
been specifically designed for European seas. Ocean 
Monitoring Indicators (OMIs), needed to provide consistent 
descriptions of the ocean state over the past decades, have 
also been developed. The SST-TAC activities have been 
carried out in close relationship with main satellite data 
and product providers: EUMETSAT, the 0SI SAF, NOAA, 
REMSS and ESA. Additionally, strong links have been 
developed with specific programs and initiatives such as: 
the ESA Climate Change Initiative (CCI), the Copernicus 
Climate Change Service (C3S), and the Group for High 
Resolution Sea Surface Temperature (GHRSST), which has 
provided international coordination among the institutions 
and agencies involved in satellite SST data production. 
1.1 Ocean products (GLOB) 
The SST-TAC produced a number of global L4 products to 
serve different user needs. Those produced in NRT were: 
-a daily foundation SST product (commonly known 
as the Operational Sea Surface Temperature and Ice 
Analysis: OSTIA; Donlon et al., 2012; Good et al., 2020), 
- an hourly diurnal skin SST product (While et al., 2017), 
-an ensemble of SST analyses produced around the 
world (Martin et al., 2012). 
Complementing the NRT foundation SST product is a MY 
Jjataset. In addition, CMEMS disseminated a L4 climate 
data record representing daily average SST at 20 cm depth 
from ESA CCI (Merchant et al., 2014; Merchant et al., 2019) 
and its extension produced by C3S. 
The NRT foundation SST production system was the 
subject of particularly significant changes over the course 
of CMEMS phase 2. In early 2018, the production system 
transitioned to use the NEMOVAR data assimilation 
scheme (Mogenson et al., 2009). The benefit emerged from 
ability to adapt background error covariance length scales 
in the region of high SST gradients (Fiedler et al., 2019) 
these define for the analysis system how errors in the 
1 
aATM ACHIEVEMENTS 
The SST-TAC product portfolio has been continuously 
evolving during the service through: 
the update of existing products, 
-the development of new products and datasets, 
the removal of products which exhibited degraded 
performances and/or were superseded.