Springer book Coastline Changes of the Baltic Sea from South to East edited by Harff, J., Furmanczyk, K., and Von Storch, H., in which HZG colleagues have contributed to.
The importance of sea-level and coastline changes increases for the population living along the edge of the world’s oceans and seas. This holds in particular where eustatic sea-level rise is superimposed on isostatic subsidence and storm induced coastal erosion. This is the case on the southern and eastern Baltic Sea coast. In the South, glacio-isostatic subsidence enhances the effect of climate induced sea-level rise and strong storm effects cause a continuous retreat of the coast. On the eastern coast the glacio-isostatic uplift compensates eustatic sea-level rise, but storm induced waves cause permanent morphodynamic changes of the coastline. Concepts for protection, defense but also for the economic use of the coastal zone adjusted to their different environments are required increasingly. The elaboration of these management concepts can be facilitated through models generating future projection of coastal developments in front of the modern climate change. The anthology comprises results of a research project “Coastline Changes of the southern Baltic Sea – Past and future projection (CoPaF)” which was run by a team of Estonian, German, and Polish geoscientists and coastal engineers from 2010 to 2013. In the first part, the chapters are devoted to the explanation of conceptual and dynamical models to describe morphodynamic changes along the Baltic Sea southern coasts consisting of Pleistocene and Holocene sediments. In the second part, regional studies are published ranging from the Mecklenburgian Bay to the Gulf of Finland. Here, not only local and regional effects of coastal dynamics are considered, but also methodological aspects, such as the use of historical maps for the parameterization of morphodynamic models. As the southern and eastern Baltic serves as a natural laboratory for the investigation of coastal processes – the achievements of the project will contribute not only to the solution of regional problems in Baltic coastal research and engineering, but, will also contribute to general problems in the description, modelling and parameterization of coastal processes and morphodynamics.
Harff, J., J. Deng, J. Durzinska-Nowak, P. Fröhle, A. Groh, B. Hünicke, T. Soomere, and W. Zhang (2017): Chapter 2: What determines the change of coastlines in the Baltic Sea? In: Harff J., Furmanczyk K., von Storch H. (eds) Coastline changes of the Baltic Sea from south to east – past and future projection. Coastal research library, vol 19. Springer, Cham, Switzerland. DOI:10.1007/978-3-319-49894-2
The change of coastline positions of the Baltic Sea is mainly determined by both the eustatic sea-level change and the glacio-isostatic adjustment (GIA). For changes on the Holocene time scale, the relative sea-level change can be reconstructed from paleo-coastline positions and correspondingly dated sediments and organic remains. On the decadal scale, tide gauge data are available. Both data sets display the relative value of sea-level change resulting from the superposition of climatically and meteorologically induced factors, vertical crustal displacement, and related gravitational forces. The isolation of the GIA signal from the compound relative sea-level change data plays a critical role for future projections of coastline changes within the frame of coastal zone management. To separate different components of sea-level data sets, statistical methods for the exploration of empirical water level, meteorological, and GPS data are combined with analytical methods to solve the sea-level equation. In the result, the pattern of vertical crustal movement can be displayed as maps covering the uplifting Fennoscandian Shield and its subsiding belt. Whereas along the uplifting coasts morphodynamic processes play a subordinated role, in the subsiding Southeast and South, Quaternary sediments are permanently exposed to coastal erosion, sediment transport, and re-deposition. This mainly wave-driven sediment dynamics together with aeolian processes depend on meteorological forcing of the in general west-east directed air-flow from the northern Atlantic Ocean to Eurasia. Regional coastal morphogenesis can generally be described by alongshore sediment transport pattern deduced from the integration of subregional to local models of transport capacities. For future projection, coastlines and the morphology of the adjacent zones have to be regarded a function of its position related to the vertical displacement of the Earth’s crust, the regional climatic and meteorological conditions, and the geological setting. Results of climate modelling, the Earth’s visco-elastic response to the deglaciation, geological data and regional sediment transport capacities have to be interpreted comprehensively.
Hünicke, B., E. Zorita, and H. von Storch (2017): Chapter 3: The Challenge of Baltic Sea Level Change.
Baltic Sea level variability is caused by different climatic and geological factors that render their understanding more difficult than for other areas of the Earth. Yet this understanding is crucial to predict with reliability the sea-level rise in the Baltic Sea that will be brought about by anthropogenic climate change. We illustrate this complexity by a few, in our opinion, important questions that ultimately are related to the estimation of long-term trends in the presence of land crust movements, to the heterogeneity of the Baltic sea-level response to atmospheric forcing, and the difficulty of identifying a sea-level rise acceleration in the observed records.
Deng, J., J. Harff, W. Zhang, R. Schneider, J. Durzinska-Nowak, A. Giza, P. Terefenko, and K. Furmanczyk (2017): Chapter 5: The Dynamic Equilibrium Shore Model for the Reconstruction and Future Projection of Coastal Morphodynamics.
Sea level and coastline change are becoming increasingly important topics to the population living along the edge of the world’s oceans and seas. This is the case at the southern Baltic Sea coast where climate change and glacio-isostatic response cause a relative sea-level rise of up to 2 mm/y and where storms events lead to continuous coastal retreat. There is an increasing need of numerical models applicable for reconstruction and future projection of coastal morphogenesis within the frame of coastal zone management and planning. By adopting a concept of dynamic equilibrium changes of coastal profiles and three dimensional generalization of the generalized Bruun concept, a quantitative model Dynamic Equilibrium Shore Model (DESM) is elaborated to study coastal morphogenesis including the reconstruction of the geological past and projection to future on the decadal to centennial time scale. The DESM model requires data of historical coastline configuration derived from maps, a high-resolution modern Digital Elevation Model (DEM), relative sea-level change data, and modelling data of long-shore sediment transport capacity. This model is applied in the study to three research areas of the southern Baltic Sea (Swina Gate, Łeba coast and Hel Peninsula). Their developments represent distinct examples of morphodynamics at wave dominated coast: formation of barrier islands, development of open coasts and processes at sandy spits. This study concentrates on areas in particular vulnerable to erosion and destruction due to their geological build-up, the glacio-isostatic subsidence and an exposure to the westerly and northern wind and storm tracks.
Zhang W., R. Schneider, J. Harff, B. Hünicke, and P. Fröhle (2017): Chapter 6: Modelling of Medium-Term (Decadal) Coastal Foredune Morphodynamics-Historical Hindcast and Future Scenarios of the Świna Gate Barrier Coast (Southern Baltic Sea).
Coastal foredunes are developed as a result of interplay among multi-scale land-sea processes. Natural foredune ridges along the Świna Gate barrier coast (southern Baltic Sea) developed since 6000 cal. year BP provide an excellent laboratory to study the land-sea interaction under a medium- to long-term climatic control. In this paper we investigate several basic driving mechanisms of coastal foredune morphodynamics as well as natural environmental factors involved in shaping the foredune geometry by a numerical model. The model couples a process-based module for subaqueous sediment transport and a probabilistic-type module for subaerial aeolian sand transport and vegetation growth. After an evaluation of the model performance for a 61-year (1951–2012 AD) historical hindcast of the foredune development along a 1 km-long section of the Świna Gate barrier coast, the model is applied for a future projection of the same area to 2050 AD based on three different climate change scenarios. The climate change scenarios represent three different impact levels with regard to their capacity to shape the coastal morphology. Simulation results demonstrate a remarkable variability in foredune development even along a small (1 km) coast section, implying that the medium-term land-sea interaction and foredune morphodynamics is quite sensitive to boundary conditions and various processes acting on multi-temporal and spatial scales. Foredune morphodynamics such as migration, bifurcation, destruction and separation are determined by different combinations of storm frequency, onshore sediment supply rate and relative sea-level change. In contrast to a low rate of relative sea-level rise during the last few decades, an accelerated sea level-rise over the twenty-first century predicted by existing literature, would result in a dramatic and non-linear response from the foredune development according to our simulations.