MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
A new version of both MY and NRT processing chains was 
released in April 2019 to include new SSS upstream 
satellite product from SMOS and internal climatological 
fields as background. The last improvement was 
implemented in December 2020 to include SST upstream 
data changes with the exploitation of Copernicus Marine 
Service OSTIA SST. The MY timeseries covers now the 
1993-2019 period and is extended by the NRT. 
1.2 ARMOR3D 
Main achievements of the last 6 years are the continuous 
improvement of the product with: 
-the addition of information to answer user needs 
(mixed-layer depth variable, monthly mean field, 
increase in vertical resolution), 
the use of new or updated upstream (first guess 
climatology, MULTIOBS SSS, OSTIA SST, DUACS18 L4 
altimeter sea level anomaly, CNES-CLS18 MDT), 
the improvement of the method (correction of non- 
steric signal in altimeter measurements, updated 
and denoised covarilances used to project vertically 
downwards the information provided by surface 
fields), 
- the provision of fully consistent MY and NRTtimeseries. 
ARMOR3D contributes directly to two OMlIs for ocean 
Narming. The first one is the Global Ocean Heat Content 
‘production under GLO-MFC responsibility). The second 
ane, online since September 2019, is the Global Cumulative 
Trend of zonal mean Subsurface Temperature (production 
under MULTIOBS TAC responsibility) and was published in 
'ssues 1 and 2 of Copernicus marine Service Ocean State 
Report (Guinehut et al., 2017, Mulet et al., 2018). Both are 
zomputed from a multi-product approach using fields from 
ARMOR3D, 4 global reanalyses (GREP) and the in situ 
gridded field CORA. Estimation of the robustness of both 
indicators is provided from the multi-product approach. 
From ARMOR3D solution, confirmed by all solutions, the 
warming appears to be significant in almost all parts of the 
5cean and at depths of up to 800 m depth (Figure 1) 
During MyOcean projects (MyOcean1l, MyOcean2 and 
MyOcean-FO), CLS developed a global 3D physical ocean 
state product (namely ARMOR3D). ARMOR3D provides on a 
1/4° horizontal grid at weekly sampling (monthly averaged 
fields are also available) 3D global fields of temperature, 
salinity, geopotential heights and geostrophic currents 
down to the bottom. This L4 product is avallable as a MY 
timeseries since 1993 and in NRT. It is obtained by 
combining satellite (SLA, geostrophic currents, SST, SSS) 
and in situ (T/S profiles) observations through statistical 
methods (Guinehut et al., 2012; Mulet et al., 2012). 
ARMOR3D has a major role in MULTIOBS TAC ocean state- 
estimates as it uses MULTIOBS SSS product (see previous 
section) as input and as it is used by almost all other 
products (OMEGA3D, Copernicus-Globcurrent, surface 
carbon, 3D POC/Chla: see following sections). 
#1.2 
0.9 
0.6 
0.3 
00 U 
-0.3” 
—0.6 
—0.9 
+-1.2 
100 
LO 
m 6001 
8004 
a 
1000 
200 
1400 
= 
v 
Latitude 
20 
igure 1: ARMOR3D Depth/Latitude global mean temperature cumulative trend aver 1993-2019 (in °C).