Publications
Following publications have been announced by our Institute of Coastal Systems – Analysis and Modeling. For further information please contact the marked authors of the publications:
Porz, L., Zhang, W., & Schrum, C. (2022): Natural and anthropogenic influences on the development of mud depocenters in the southwestern Baltic Sea. Oceanologia, doi:10.1016/j.oceano.2022.03.005
Abstract:
The morphological evolution of two mud depocenters in the southwestern Baltic Sea is investigated by comparison of numerical model results to geological and oceanographic data. The pathways of dense currents during episodic dense-water inflows from the North Sea are shown to correspond to current pathways inferred from contouritic depositional geometries in the flow-confining channels within the study area. A favorable comparison of model results to published current speed observations shows that the mesoscale dynamics of individual inflow events are reproduced by the model, indicating that external forcing and basin geometry rather than internal dynamics control the mesoscale dynamics of inflow events. The bottom current directions during inflows show high stability in the flow-confining channels and explain the contouritic depositional geometries. Asymmetric depositional features in the channels are qualitatively reproduced in the model. Bottom currents are less stable in areas without contouritic features, possibly resulting in an overall diffusive effect on sediment distribution in those areas. In a simulation of resuspension by bottom-contacting fishing gear, inter-basin sediment transport is increased by 4–30%, depending on the area, compared to the case of natural hydrodynamic resuspension. The model predicts an increased winnowing of the finest sediment fraction due to bottom trawling, leading to an overall coarsening-to-fining trend in the direction of net sediment transport. The results show that rather than hemi-pelagic background sedimentation, episodic events with high bottom current velocities as well as bottom-trawling induced resuspension are responsible for the present-day and future morphological configuration of the mud depocenters in the southwestern Baltic Sea.
Kjellström, E., Hansen, F., & Belušić, D. (2022): Contributions from Changing Large-Scale Atmospheric Conditions to Changes in Scandinavian Temperature and Precipitation Between Two Climate Normals. Tellus A: Dynamic Meteorology and Oceanography, 74, pp 204–221, doi:10.16993/tellusa.49
Abstract:
Multidecadal changes in regional climate can occur as a forced response to changing greenhouse gases and aerosols, as a result of natural internal climate variability, or due to their combination. Internal climate variability is frequently associated with regional changes in large-scale circulation. We investigate how changes in Scandinavian temperature and precipitation conditions during 1961–2020 can be linked to changes in the atmospheric large-scale circulation. The study is based on data from the ERA5 reanalysis and on Swedish average conditions based on observations from the Swedish Meteorological and Hydrological Institute. In general, it is shown that all seasons have become warmer and there is a predominance for more precipitation in the last 30 years. The results also show a clear decrease in daily temperature variability for winter and an increase in summer while there is no similar systematic change for precipitation. Further, we use a circulation type classification technique for identifying ten different circulation types for each calendar month in the 1961–2020 period. Results indicate that changes between the two periods can partly be related to changes in large-scale circulation due to changes in the frequencies of different circulation types. However, it is also clear that the contribution from frequency-related changes to the total change is comparatively low for most months and that changes also within the circulation types are required to explain the total change. The main conclusion of the study is that during the last 30 years it has mostly been warmer than in the preceding 30 years for the same type of weather situation for all months in the year. Consequently, internal climate variability, as represented by changes in the large-scale atmospheric circulation, cannot explain the observed changes in the Scandinavian temperature and precipitation.
Şen, O., Saçu, Ş., Erdik, T., Öztürk, İ., & Stanev, E.V. (2022): Assessing the potential impacts of the Canal Istanbul on the physical oceanography of the Turkish Straits System. Continental Shelf Research, 2022, 104723, ISSN 0278-4343, doi:10.1016/j.csr.2022.104723
Abstract:
The Turkish Straits System (TSS) is a region of intense mixing between the Black Sea and the Mediterranean Sea exerting crucial control on the water & substance exchange through the Bosphorus and Dardanelles straits between these two sea basins. A waterway project, namely the Canal Istanbul, was proposed to be built within this system parallel to the Bosphorus. Even tough environmental impacts of the project have been of concern, a few studies that address these scientific and public concerns under the light of scientific methods are available. In order to fill this gap in the literature, a three-dimensional hydrodynamic model with realistic forcing has been set up for long-term integration. The study includes simulating of two scenarios for the adjacent basins; (i) existing configuration of the TSS, and (ii) the proposed extension with the recent planned route of Canal Istanbul that was added to the validated model. The results reveals that the canal project would increase the exchange flow between the Black Sea and the Mediterranean Sea in both directions while causing slight changes in temperature & salinity along the TSS. Findings of this study can be used in further research that would analyze the impacts of the proposed Canal Istanbul on the water quality and ecosystem of the TSS.
