Atmosphere 2022, 13, 1634 
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volumes [59]. These changes seem to have outweighed the effect of sea level rise at St. Pauli 
in the past. 
4.2. Favouring Meteorological Conditions 
Our results show, that there is a strong connection between the general direction of 
the atmospheric circulation and a potential for an ELW. Some studies already showed that 
the remote winds play an important role in more exposed locations [4,7]. Analysis based 
on an objective weather classification scheme showed that the SE weather type and an 
effective wind direction of 142° both mark situations where the wind is blowing offshore, 
literally pushing the water out of the Elbe estuary. Most (>85%) of the ELWs coincide with 
a SE weather type which is a frequency that is significantly higher than expected from 
climatology (10.5%; p < 0.001). In addition, the wind magnitude, in our case represented by 
distinct gale classes, was considered. Over half (>55%) of the events were preceded by a 
wind field classified as a storm for the North Sea area, again significantly more frequent 
than expected from climatology (9.1%, p < 0.001). The effective wind is combining the 
direction and the strength of the flow and with >90% of the events with prevailing effective 
wind above 10 m/s. This is a strongly favouring condition for ELWs in the Elbe estuary. 
The small p-values found for these differences from climatology indicate that the 
statistical likelihood of the findings resulting from chance is very low. However, the specific 
numbers are of course subject to a few uncertainties. These are mainly based on the dataset 
used and the employed weather type classification scheme. Usage of other pressure data 
and/or a different classification scheme will yield slightly differing numbers. To our 
knowledge, there is no previous research done on ELWs in the German bight and the Elbe 
estuary. However, the results confirm what would be expected for the location of the Elbe 
estuary: Considering the overall geographic situation and coastline of the German Bight 
as well as the well-known fact that north-westerly winds are associated with (positive) 
storm tides on the German North Sea coast (see, e.g., [45]) it was expected that a contrasting 
south-easterly wind would lead to ELWs. 
The meteorological analysis in this study is solely based on large-scale conditions 
that are derived from SLP data. Further analysis of gridded wind fields or direct wind 
measurements before and during ELWs could possibly extend the knowledge of the effect 
of local wind on these extreme water levels. 
4.3. Possible Future Changes in Favouring Meteorological Conditions 
For the investigation of possible future changes, SMHI-LENS—a large ensemble of the 
GCM EC-Earth3—was used. While the exploitation of this large ensemble of 50 members 
significantly reduces the uncertainty of climate change signal estimates, the problem of 
model uncertainty prevails. The results presented here show a clear signal that conditions 
leading to ELWs will become significantly less frequent, especially when considering 
scenarios of strong global warming. However, similar investigations with different GCMs 
may yield differing outcomes. A profound multi-model analysis would yield a more robust 
assessment in this respect. 
4.4. Effect of Future Sea Level Rise on ELWs 
To estimate the effect of future SLR on ELWs, the ELW chain event from March 2018 
was simulated with a hydrodynamic-numerical model, applying different SLR scenarios. A 
comparison shows that the observed water level during the ELW chain event 2018 is well 
reproduced by the model. The results show an increase of the lowest LW at Cuxhaven and 
St. Pauli between 88 and 98% relative to the SLR scenarios of 10, 30, 50, 80 and 110 cm. 
The weaker increase of ELW at St. Pauli compared to Cuxhaven results from the stronger 
increase of tidal range due to SLR at St. Pauli. A detailed study on the influence of SLR 
on tidal amplification in the Elbe estuary is currently in process. To our knowledge, there 
are no previous studies on the influence of SLR on ELWSs in the Elbe estuary. However, 
studies on the effect of SLR on mean tides [19] and (positive) storm surges [18] in the