MERCATOR OCEAN JOURNA: 
SEPTEMBER 2021 
comprehensive tuning and validation was performed for 
this set up called Nemo-Nordic 1.0. New bathymetry data, 
including a new coastline was implemented; the boundary 
data was updated to use the Copernicus Marine Service 
NWS MFC near real time product. However, results showed 
that the sea level forecast in the transition water between 
the North Sea - Baltic Sea, the salinity inflow and sea ice 
forecast had lower quality than compared with the existing 
Copernicus Marine Service HBM based product, and an 
ntercomparison study was performed with the newly 
released NEMOv4.0 code version. Improved results were 
achieved by: 
- tuning the bathymetry data and bottom roughness, 
- changing the Galpering parameter in the turbulence 
model, 
using more accurate numerics, 
- adding the Stokes drift from the wave model WAM. 
Frederikshavn 
Soteborg Torshamnen 
Grena 
Skagen 
5mogen | 
Dragor — 
;redericia —x— © 
Fynshav - x" ©- 
Hornbaek “— 
Kobenhavn - —> 
Korsor — > 
Slipshavn he S— 
Travemuende — 49 | m 
Viken M—O— — 
Barhoeft - XD 
Koserow * 
Landsort Norra Mi — 
Marviken > 
Rodvig '— — Le 
Skanor 
Jaugavgriva 
Kronstadt 
Lehtma 
Parnu 
5illamae E 
Degerby 
Forsmark 
Kalix 
Kaskinen - 
D)jetarsaari 
Ratan 
5kagsudde 
Spikarna — 
Aarhus —>x-—© 
Bagenkop —*x © 
Ballen L I 
Furuogrund — 
Gedser - 
Helsinki 
Kemi 
Kiel Holtenau 
Kungsholmsfort 
AT 
Ringhals 
Rodby 
Sassnitz 
St Petersburg 
Tallinr 
Tejn \- 
visby | Hd 
WäarnemuenNdE —- + N ost] —— &— — 
-0.2 0 0.2 0.4 0.05 0.1 0 20 40 60 80 100 
Bias [m] CRMSD [m] Correlation 
Missing observations [%] 
SEN A 
Tg missing observations © V201804 X V202012 
Aigure 1: Sea level validation statistics from the HBM (V201804) and the NEMO (V202012) systems based on observations from Baltic Sez 
coastal tide gauges for a two year validation period. The bias, centered root mean sauare difference, correlation and number of missing 
ıbservations are shown (from left to right).