Long-term shoreline response of a nontidal, barred coast

Abstract

Long-term variations of shoreline positions along the southern Baltic coast were investigated using multichannel singular spectrum analysis (MSSA) to determine the most dominant long-term response patterns. The investigated beach is located at Lubiatowo on the Polish Coast and is mildly sloping with multiple bars. Data on coastal morphology have been collected at Lubiatowo including (1) bathymetric surveys since 1987 twice a year, and (2) beach topography surveys since 1983 every 4 weeks on the average, extending from the shoreline to the dune foot. Furthermore, several dedicated field campaigns have been carried out at Lubiatowo, as well as measurements of deep-water wave properties since 1998. MSSA was employed to the whole data set of shoreline position from all survey lines. In summary, three patterns emerged reproducing alongshore standing waves with different periods 7 to 8, 20+ and several decades. They represent long-term shoreline response, such that at some locations the longest wave is most predominant, at other locations the medium cycle predominates, whereas the shortest is the most prominent at yet other locations. However, all three can be detected at every location monitored, eliminating the confusion resulting from ordinary singular spectrum analysis (SSA) analysis, done previously for the same data set.