Atmosphere 2022, 13, 1634 
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The lowest LW ever measured at Cuxhaven was found in 1987, for St. Pauli it was 
in 2018. The two corresponding values in Figure 2 are marked by red circles. The latter 
is analysed in more depth below (Section 3.2) and subject of a sensitivity study shown in 
Section 3.5.2. 
3.2. Case Study 2018 
In March 2018, an ELW chain event occurred in Cuxhaven. Figure 3 shows a period of 
high wind velocity (>15 m/s) and a wind direction of 70-90 degrees, measured by Hamburg 
Port Authority (HPA) [29] in Scharhörn— a small Island located in the mouth of the Elbe 
and close to Cuxhaven— and a concurrent drop of the water level at Cuxhaven measured 
by WSA (Waterways and Shipping Agency) Elbe-North Sea [29]. The five consecutive LW 
levels, which can be categorized as ELWs according to our definition are marked by red 
circles, the lowest ELW of this period is marked by a star. The same LW at St. Pauli occurred 
to be 55 cm lower than in Cuxhaven and led to the lowest LW ever measured at St. Pauli. 
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De 15. 
10. 
RR 
Wa 
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p K 
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Ps WS 
270.0: 
180.0 -' 
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13.03.2018 14.03.2018 15.03.2018 16.03.2016 17.03.2018 18.03.2018 19.03.2018 20.03.2018 21.03.2018 
00:00:00 00:00:00 00:00:00 00:00:00 00:00:00 00:00:00 00:00:00 00:00:00 00:00:00 
Figure 3. Observed water level relative to NHN at Cuxhaven and wind velocity and direction in 10 m 
height at Scharhörn between 13 March and 21 March 2018. The five consecutive LW levels, which can 
be categorized as ELWs according to our definition are marked by red circles, the lowest ELW of this 
period is marked by a red star. 
Figure 4 shows the synoptic situation leading to this ELW. On 14 March 2018, a high 
pressure zone extends from Scandinavia to Southern Germany, complemented by lows in 
the east and west resembling an anticyclonic (A) LWT over the North Sea. On 15 March, 
the LWT changes to South-East (SE) and a trough of low pressure enters the North Sea 
arca while the high-pressure system is pushed towards Scandinavia. As a result, the 
German Bight is directly impacted by flow from the Southeast, from 15 March to 17 March 
reaching gale strength (SE/G) on all of these days. From 19 March onwards this situation 
changes again in favour of an anticyclonic LWT over the North Sea and significantly 
weakened winds. 
This case study serves as a prototype for the kind of weather type evolution that is 
favourable for producing ELWSs in the Elbe estuary. It fits the common understanding 
that a strong south-easterly flow over the North Sea essentially means offshore winds 
over the German Bight which is to be associated with a certain risk of producing 
an ELW.