Characteristics of intra-, inter-annual and decadal sea-level variability and the role of meteorological forcing: the long record of Cuxhaven Sönke Dangendorf & Christoph Mudersbach & Thomas Wahl & Jürgen Jensen Received: 24 August 2012 / Accepted: 15 January 2013 / Published online: 2 February 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract This paper addresses the role of meteorological forcing on mean sea level (MSL) variability at the tide gauge of Cuxhaven over a period from 1871 to 2008. It is found that seasonal sea level differs significantly from annual means in both variability and trends. The causes for the observed differ- ences are investigated by comparing to changes in wind stress, sea level pressure and precipitation. Stepwise regression is used to estimate the contribution of the different forcing factors to sea level variability. The model validation and sensitivity analyses showed that a robust and timely indepen- dent estimation of regression coefficients becomes possible if at least 60 to 80 years of data are available. Depending on the season, the models are able to explain between 54 % (spring, April to June) and 90 % (winter, January to March) of the observed variability. Most parts of the observed variability are attributed to changes in zonal wind stress, whereby the con- tribution of sea level pressure, precipitation and meridional wind stress is rather small but still significant. On decadal timescales, the explanatory power of local meteorological forcing is considerable weaker, suggesting that the remaining variability is attributed to remote forcing over the North Atlantic. Although meteorological forcing contributes to line- ar trends in some sub-periods of seasonal time series, the annual long-term trend is less affected. However, the uncer- tainties of trend estimation can be considerably reduced, when removing the meteorological influences. A standard error smaller than 0.5 mm/year requires 55 years of data when using observed MSL at Cuxhaven tide gauge. In contrast, a similar standard error in the meteorologically corrected residuals is reached after 32 years. Keywords Mean sea level variability . German Bight . Meteorological forcing . Sea level rise 1 Introduction In the last few decades, there has been a great effort to under- stand the characteristics of long-term global sea level rise (SLR) (Douglas 1991; Woodworth 1990; Church and White 2006; Church and White 2011). The importance of such studies is rooted in the high impacts, which are related to possible future sea level rise. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC 2007) suggested a global mean sea level (MSL) rise of up to 60 cm by 2100 as a result of global ocean warming, glacier melting and the balance between melting, snowfall and the regular outflow from glaciers from ice sheets (potential accelerated ice-sheet melting, which could add another 20 cm of SLR, is not included in these projections). Such an increase would have considerable consequences for the flood risk in coastal areas, as the MSL is the reference frame for storm surges. However, studies dealing with future SLR base on the knowledge of the physics behind past sea level changes. Hence, a detailed un- derstanding of observed sea level in the past is a fundamental step before doing studies focusing on future SLR. Responsible Editor: Birgit Andrea Klein S. Dangendorf (*) : C. Mudersbach : T. Wahl : J. Jensen Research Institute for Water and Environment (fwu), University of Siegen, Paul-Bonatz-Str. 9-11, 57076 Siegen, Germany e-mail: soenke.dangendorf@uni-siegen.de URL: http://www.uni-siegen.de/fb10/fwu/ T. Wahl Institute of Advanced Studies, Research Group of Civil Security, University of Siegen, Unteres Schloss 2, 57072 Siegen, Germany Ocean Dynamics (2013) 63:209–224 DOI 10.1007/s10236-013-0598-0