562
Observations Mohrholz (20156
V. Maurer et al.: Evaluation of coupled and uncoupled simulations
ROAM-NBS
NEMO-NBS
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15. Practical salinity along the Baltic thalweg for NEMO-NBS, ROAM-NBS and observational data (Mohrholz, 2016) at three time
instances around the MBI 2014: 11 November 2014 (top panels), 7 February 2015 (middle panels) and 22 March 2015 (bottom panels).
2015) and caused much damage and a severe storm surge
in the North Sea. Storm ELON passed on 9 January and dissolved
afterwards. For 10 January 2015, 12:00 UTC, the center
of storm FELIX with a minimum pressure of less than
960hPa is simulated by ROAM-NBS directly to the west
of the Norwegian coast (Fig. 16a). The location and minimum
pressure agree well with the one reported by the DWD
surface analysis (Haeseler, 2015). Accordingly, ROAM-NBS
simulates strong westerly winds (due to surface friction,
near-surface winds are rotated towards the low pressure cen-(er
compared to the geostrophic wind) on 10 January with a
maximum of up to 24m s7! (about 86 km h7!) to the northwest
of Helgoland (Fig. 16b). Observed winds on Helgoland
show maxima of up to 20ms”! on 9 and 10 January and
slightly weaker maxima on 8 and 11 January (Fig. 16c), indicating
that storm conditions prevailed over several days.
The near-surface wind speed is not as well matched with the
Geosci. Model Dev... 19. 543578, 2026
observations by ROAM-NBS as by ERAS (Fig. 16c), but the
maximum on 10 January is well reproduced by both.
The storm events in January occur shortly after the Major
Baltic inflow event in December 2014. The non-detided
SSH results are compared against GESLAv3.0 observational
data described in Haigh et al. (2023). Stations in the German
Bight (Helgoland), Skagerrak (Helgeroa), and Baltic
Sea (Travemünde) are chosen to discuss the model’s instant
behavior exemplarily. Associated time series of the sea level
minus the yearly mean sea level are presented in Figs. 16d
and A8. At the station Helgoland, the warning level of 2.5 m
for a severe storm surge in the North Sea is exceeded on
11 January in the early morning hours. A small time shift
can be observed compared to the wind speed maximum on
10 January. The maximum sea level on 11 January is slightly
better represented by the coupled model than NEMO-NBS,
although wind speed maxima are comparable in ROAMhttps://doi.ore/10.5194/esmd-19-543-2026
