MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
managing Various orbit changes that occurred for some 
missions which required an adaptation of the SL-TAC 
system. In that way, the Jason-2 interleaved and long- 
repeat orbits phases were respectively implemented in 
2016 and 2018 before the definitive deactivation of the 
altimeter in 2019; AltiKa drifting phase was implemented 
in 2016; Cryosat-2 new orbit was implemented in 2020, 
- Managing various Iincidents and anomalies observed 
on different missions. Different algorithms have 
been improved to better take into account the quality 
evolution of different measurements (e.g., specific 
data selection applied on AltiKa to avoid residual 
errors during important miss-pointing anomalies). 
Other missions were temporally disactivated from 
the NRT system during specific events (e.g., long safe 
hold mode events observed on Jason-2 during year 
2019). After several serious incidents affecting HY-2A 
measurements quality, the satellite was deactivated 
from the SL-TAC NRT system in 2015. 
7) 
MEAN_DFS_SUR_SOMME _J0 - GLOBAL product 
"From 2017-01-01 to 2020-72-74 
MG 
09% 
A 
2 30% 1 
Z 
E 
[3% 
EN 
nd 
Jason-3 
Sentinel 3A 
Sentinel 3B 
Jeson-2 
lason-2 Tandem 
kosorn-2 LRO 
Altika 
Altika Drift 
— Cryosat-2 
== Cryosat:2N 
— Halyang-z2B 
Pf 
igure 1: Temporal evolution of the fraction of multi-mission merged product (L4) coming from each sensor: Degrees of Freedom of Signal (DFS). 
S0°N 
D°S 
50°S5 
VAR (5sat Serie-Hv2A)-Var(3sat Serie -Hy2A) (cm2) 
1 
KEN 
Blue: Less 
hi a! 
erfor with: 
gr 
Bat 
En 
SE“ mr — a3——— a 
150°W 100°W 50°W 0°W 50°E 100°E 150°E 
30 
24 
18 
2 
} 
J 
-6 
=-12 
-18 
-24 
=20 
ure 2: Error reduction thanks to Sentinel-3 constellation (OSE studies)