MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
2. STATUS AT THE END OF COPERNICUS 1 
By the end of the Copernicus 1 contract, the Baltic 
production system is based on: 
the ocean model code NEMOv4.0 (released 2019). 
The model configuration and set up has been heavily 
zalibrated to the Baltic Sea (see the Nemo-Nordic v2.0 
description in Kärnä et al., 2021), 
-the Biogeochemical model code ERGOM, with both 
carbon and iron cycles included and online coupled 
with the NEMOv4.0, 
the wave sea state model code, WAMv4.6.2, offline 
coupled with NEMOv4.0. 
For the data assimilation, the LESTKF scheme from the 
PDAF system is applied in both forecast and reanalysis 
oroduction. 
The coupling between the Baltic model sub-system 
has evolved during the Copernicus 1 contract, from 
two separate standalone systems for the wave and the 
coupled 3D ocean-biogeochemical system, respectively, 
to a coupled and harmonized production system. This also 
included harmonizing the weather forcing dataset. The 
goal in 2021 is to have all six Baltic Sea model products 
in the Copernicus Marine Service data catalogue produced 
ay this coupled system. The purpose Is to ensure seamless 
products from a user point of view when investigating the 
Baltic Sea conditions for the whole product period from 
year 1993 and up to the latest forecast for the next 6 days 
The Baltic MFC ocean forecast product is furthermore 
included in a multi-model-ensemble product approach 
together with other available forecast products for the Baltic 
Sea produced by the national institutes. See the dedicated 
website under the Baltic Operational Oceanographic 
System and Golbeck et al., 2015 for further details 
3. POST 2021 PERSPECTIVES 
The Baltic MFC consortium plans to continue the coupling 
activities, toenhance the number of processes and variables 
that are exchanged between models and to move toward a 
fully coupled system. Improving products in coastal areas 
will also be a field of study. These activities will be plannec 
in interaction with the national agencies. In the Blue ocean 
system special focus will be on improving the important 
inflow events to the Baltic Sea with saline and oxygenated 
water. This will include implementation of new bathymetry 
data, increased vertical resolution in the computational 
Jrid, as well as introduction of 2-ways nesting grids in 
areas with narrow passage and complicated coastline. 
Focus will also be on surface layer dynamics by increasing 
the wave-current interaction. 
Developments in the Green ocean will focus on the optical 
parameters, improve the forecast capability of algae 
blooms, hypoxia and eutrophication processes. Further 
Jjevelopment in data assimilation techniques would 
ıower products biases and improve our quantitative 
understanding of the processes (see for instance 
Raudsepp et al., 2019 and Köuts et al., 2021). Additionally 
new observation types and dataset will, when available, be 
tested and included in the data assimilation (e.g., future 
Sentinels and SWOT missions)