MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
Model log,o(chlorophyll a) rmse vs ARGO in the Nordic Seas 
40 WU U a 
25 = 30m 
30-40m 
= 40-100m 
30 444 
Fr 
_ 2.5 uf 
T 2.0 4 
ao 
5 15- 
5 
AHREEEEEBEN HERREN n 
una] 0 
& 
au 200 0 
S 
. DD * 
2018.0 2018.53 2019%4.0 
7. 
2.0 - 
2015.00 2015.5 2016.00 2016.5 
2017.00 20175 
figure 3: Comparison of Chlorophyll profiles to BGC-Argo buoys (panel a). Note the inclusion of surface Chlorophyll from satellite in January 
2017 and the loaarithmic scale for concentratian« 
1.5 Physical data assimilation 
The Arctic MFC started assimilating sea ice thickness 
aroducts with the thin ice product from SMOS in both 
eanalysis and forecast products using the EnKF in 2017. 
The merged product from CryoSAT-2 and SMOS was then 
assimilated, first in reanalysis, then in near-real time in 
\ovember 2020. The resulting improvement of sea ice 
“hickness persists a few months through the summer 
when satellite products are unavallable. 
The physical reanalysis product was updated with the 
“ollowing: 
doubling of HYCOM ocean model vertical resolution, 
°eplacement of time-mean model by CNES/CLS 
Mean SSH Rio2018 reference to assimilate sea level 
anomalies, 
ınclusion of freshwater discharge related to the 
5reenland mass loss, 
mprovement of salinity profiles assimilation. 
Systematic assimilation of ESA CCI products throughout 
he whole reanalysis period, removing discontinuities In 
*he previous physical reanalysis (Xie et al., 2017). The new 
eanalysis product should therefore be better suited for 
climate studies. 
The validation of wave parameters uses satellite altimeter 
data (Bohlinger et al., 2019) for both forecast and multiyear 
products. Compared to the validation with wave buoys, 
results are now much more representative of the Arctic. 
1.7 Ocean Monitoring Indicators 
The Nordic Seas is an area for key climatic processes in 
the North Atlantic. The ARC MFC has therefore established 
two sets of Ocean Monitoring Indicators that monitor North 
Atlantic - Arctic Ocean exchanges through the Nordic Seas. 
The first is the exchange of water across the straits that 
separate the two basins. Moorings are available there 
for validation. Then, the sea ice export from the central 
Arctic to the south was later included since it makes up an 
important part of sea ice budget in the Arctic. 
Ocean monitoring indicators thus make highly valuable 
data accessible to a large number of users interested in 
the Arctic, without the need to download discouraging 
amounts of data. 
1.6 Enhanced validation 
Objective forecast evaluation metrics are provided monthly 
*o Copernicus Marine Service for dissemination. In 
addition, products are monitored on a weekly basis by our 
.eam. Due to its relevance for operations in the Arctic, ice 
edge position Is particularly scrutinized using two metrics: 
ntegrated ice edge error (IlEE) and fractions skill score 
{FSS). Melsom et al.. (2019) have reviewed these metrics.