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triangulation of pressure readings (Schmidt and von 
Storch 1993; Alexandersson et al. 1998, 2000), or storm 
surge records from tide gauge measurements (von 
Storch and Reichardt 1997; Zhang et al. 2000). 
The North Atlantic European sector is probably the 
most intensively studied and discussed region for that 
topic. From analyzing annual geostrophic wind statistics 
back to 1876, Schmidt and von Storch (1993) found pro 
nounced decadal variability in the southern North Sea 
but no evidence for a significant long-term trend. These 
results were confirmed for the larger North Atlantic- 
European region—for example, by Alexandersson et al. 
(1998, 2000) and Matulla et al. (2008)—with the com 
mon finding that storminess was high at the end of the 
nineteenth century and subsequently declined until 
about 1960, followed by a strong upward trend until the 
mid-1990s. Since then, up until now, a return to average 
conditions is evident. 
In contrast to annual storm statistics, Wang et al. 
(2009) pointed to differences in seasonal 99th geo 
strophic wind percentiles linking the high values at the 
end of the nineteenth century to a summer maximum 
and the high values in the 1990s to increasing storminess 
during winter. Apart from these seasonal differences 
over the northeast Atlantic and North Sea region, Wang 
et al. (2009) confirmed the absence of any robust long 
term trend for high annual percentiles of geostrophic 
wind speeds since 1874. The study showed in addition 
that the periods of high storm activity furthermore co 
incided with positive decadal trends in the North At 
lantic Oscillation (NAO) index (Hurrell 1995). A similar 
NAO link and strong decadal trends are also visible in 
extreme sea levels in the southeastern North Sea 
(Dangendorf et al. 2013a; Mudersbach et al. 2013). 
Using data from the Twentieth-Century Reanalysis 
(20CRv2; Compo et al. 2011), Donat et al. (2011b) 
detected—contrary to observational analyses—significant 
upward long-term trends in the occurrence of extreme 
storms based on daily wind speeds since 1871 over 
Europe and suggested that the increase could (at least 
partly) be a response to enhanced greenhouse gas emis 
sions during the past decades. Bronnimann et al. (2012) 
showed that the variance of the 20CRv2 ensemble in 
creases back in time, leading to a better representa 
tion of trends after 1950 than before. Krueger et al. 
(2013b) highlighted that the upward trends detected by 
Donat et al. (2011b) are inconsistent with observations and 
suggested this being mainly an artifact of assimilating less 
surface pressure data into 20CRv2 back in time, leading to 
larger inconsistencies before 1940. This finding is currently 
controversially discussed (Krueger et al. 2013a; Wang et al. 
2014) partly because of the usage of different storminess 
measures but also inhomogeneous observations, which 
were still present in the Krueger et al. (2013a,b) study. By 
removing some potential inhomogeneities in the pressure 
records, Wang et al. (2014) were able to bring the storm 
indices from 20CRv2 and from observations closer to 
gether but fail to remove the major inconsistencies in 
dicating that there still might be severe homogeneity issues 
in the early years of the (i) 20CRv2, (ii) observations, or 
(iii) both. 
In the light of these competing results, the aim of the 
present study is to analyze an independent and homo 
geneous storm surge record from the tide gauge of 
Cuxhaven located in the southeastern North Sea, cov 
ering the period from 1843 to 2012. Since storm surges 
are generated by low atmospheric pressure and intense 
winds over the ocean, surges generally exhibit a com 
prehensive, independent, and more homogeneous archive 
(Zhang et al. 2000) of information about storminess. 
Although some tide gauge records reach back into the 
seventeenth and eighteenth centuries, storm surge re 
cords have been surprisingly rarely analyzed in the last 
decades and earlier assessments in the North Sea region 
just focused on the twentieth century (Ullmann and 
Monbaliu 2010). This is mainly attributed to the limited 
availability of continuous hourly measurements, which 
are required for a harmonic analysis in order to remove 
the deterministic tidal water level components from the 
tide gauge data (Pawlowicz et al. 2002). In this study, we 
use a method first introduced by Horn (1948,1960) that 
allows us to reconstruct a homogeneous storm surge 
record based on tidal high and low water levels only 
instead of hourly data, which are just available after 
1918. This enables us to extend the storm surge record in 
Cuxhaven back to 1843, enhancing information about 
storminess of conventional proxies in that region 
(Schmidt and von Storch 1993) by more than 30 yr. The 
method is globally applicable and will open potential for 
the assessment of storminess. Here, we introduce, to our 
knowledge, the longest contemporary storm surge re 
cord in the world and (i) analyze long-term trends in the 
upper percentiles of storm surges, (ii) investigate the 
relationship between storm surges and large-scale at 
mospheric patterns, and (iii) use the empirical relation 
ship between local winds and sea level pressure (SLP) to 
compare observations with the 20CRv2 data. 
2. Data and methods 
Tide gauges are well suited for the assessment of 
storminess as they measure, beside tides and longer- 
term MSL changes, the direct response of the ocean to 
the atmosphere. Especially in the North Atlantic region, 
some gauges have measured sea level for hundreds of 
years (Amsterdam, the longest record, starts in 1682;