Baltic Sea Level: Past, Present, and Future

2019 ◽  
Author(s):  
Ralf Weisse ◽  
Birgit Hünicke
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Water Surface ◽  
Wind Waves ◽  
World Ocean ◽  
The Baltic Sea ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Mean Sea Level ◽  
The Baltic

A multitude of geophysical processes contribute to and determine variations and changes in the height of the Baltic Sea water surface. These processes act on a broad range of characteristic spatial and timescales ranging from a few seconds to millennia. On very long timescales, the northern parts of the Baltic are uplifting due to the still ongoing visco-elastic response of the Earth to the last deglaciation, and mean sea level is decreasing in these regions. Over centuries, the Baltic Sea responds to changes in global and North Atlantic mean sea level. Processes affecting global mean sea level, such as warming of the world ocean or melting of glaciers and of polar ice sheets, do have an imprint on Baltic Sea levels. Over decades, variations and changes in atmospheric circulation affect transport through the Danish Straits connecting the Baltic and North seas. As a result, the amount of water in the Baltic Sea and the height of the sea level vary. Similarly, atmospheric variability on shorter timescales down to a few days cause shorter period variations of transport through the Danish Straits and Baltic Sea level. On even shorter timescales, the Danish Straits act as a low pass filter, and high frequency variations of the water surface within the Baltic Sea such as storm surges, wind waves, or seiches are solely caused internally. All such processes have undergone considerable variations and changes in the past. Similarly, they are expected to show variations and changes in the future and across a broad range of scales, leaving their imprint on observed and potential future Baltic Sea level and its variability.

scholarly journals Sea Level Dynamics and Coastal Erosion in the Baltic Sea Region

2021 ◽  
Author(s):  
Ralf Weisse ◽  
Inga Dailidiene ◽  
Birgit Hünicke ◽  
Kimmo Kahma ◽  
Kristine Madsen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Coastal Erosion ◽  
Data Availability ◽  
The Baltic Sea ◽  
Mean Sea Level ◽  
The Past ◽  
Coastline Change ◽  
Baltic Sea Region ◽  
The Baltic

Abstract. There are a large number of geophysical processes affecting sea level dynamics and coastal erosion in the Baltic Sea region. These processes operate on a large range of spatial and temporal scales and are observed in many other coastal regions worldwide. Together with the outstanding number of long data records, this makes the Baltic Sea a unique laboratory for advancing our knowledge on interactions between processes steering sea level and erosion in a climate change context. Processes contributing to sea level dynamics and coastal erosion in the Baltic Sea include the still ongoing visco-elastic response of the Earth to the last deglaciation, contributions from global and North Atlantic mean sea level changes, or from wind waves affecting erosion and sediment transport along the subsiding southern Baltic Sea coast. Other examples are storm surges, seiches, or meteotsunamis contributing primarily to sea level extremes. All such processes have undergone considerable variations and changes in the past. For example, over the past about 50 years, the Baltic absolute (geocentric) mean sea level rose at a rate slightly larger than the global average. In the northern parts, due to vertical land movements, relative sea level decreased. Sea level extremes are strongly linked to variability and changes in the large-scale atmospheric circulation. Patterns and mechanisms contributing to erosion and accretion strongly depend on hydrodynamic conditions and their variability. For large parts of the sedimentary shores of the Baltic Sea, the wave climate and the angle at which the waves approach the nearshore are the dominant factors, and coastline changes are highly sensitive to even small variations in these driving forces. Consequently, processes contributing to Baltic sea level dynamics and coastline change are expected to vary and to change in the future leaving their imprint on future Baltic sea level and coastline change and variability. Because of the large number of contributing processes, their relevance for understanding global figures, and the outstanding data availability, we argue that global sea level research and research on coastline changes may greatly benefit from research undertaken in the Baltic Sea.

scholarly journals Decomposing Mean Sea Level Rise in a Semi-Enclosed Basin, the Baltic Sea

2019 ◽  
Vol 32 (11) ◽  
pp. 3089-3108 ◽  
Author(s):  
Ulf Gräwe ◽  
Knut Klingbeil ◽  
Jessica Kelln ◽  
Sönke Dangendorf
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Ocean Model ◽  
Spatial Variations ◽  
The Baltic Sea ◽  
Baltic Basin ◽  
Mean Sea Level ◽  
A Value ◽  
Regional Ocean Model ◽  
The Baltic

Abstract We analyzed changes in mean sea level (MSL) for the period 1950–2015 using a regional ocean model for the Baltic Sea. Sensitivity experiments allowed us to separate external from local drivers and to investigate individual forcing agents triggering basin-internal spatial variations. The model reveals a basin-average MSL rise (MSLR) of 2.08 ± 0.49 mm yr−1, a value that is slightly larger than the simultaneous global average of 1.63 ± 0.32 mm yr−1. This MSLR is, however, spatially highly nonuniform with lower than average increases in the southwestern part (1.71 ± 0.51 mm yr−1) and higher than average rates in the northeastern parts (2.34 ± 1.05 mm yr−1). While 75% of the basin-average MSL externally enters the Baltic basin as a mass signal from the adjacent North Sea, intensified westerly winds and a poleward shift of low pressure systems explain the majority of the spatial variations in the rates. Minor contributions stem from local changes in baroclinicity leading to a basin-internal redistribution of water masses. An observed increase in local ocean temperature further adds to the total basinwide MSLR through thermal expansion but has little effect on the spatial pattern. To test the robustness of these results, we further assessed the sensitivity to six different atmospheric surface forcing reanalysis products over their common period from 1980 to 2005. The ensemble runs indicated that there are significant differences between individual ensemble members increasing the total trend uncertainty for the basin average by 0.22 mm yr−1 (95% confidence intervals). Locally the uncertainty varies from 0.05 mm yr−1 in the central part to up to 0.4 mm yr−1 along the coasts.

scholarly journals Impact of accelerated future global mean sea level rise on hypoxia in the Baltic Sea

2016 ◽  
Vol 49 (1-2) ◽  
pp. 163-172 ◽  
Author(s):  
H. E. M. Meier ◽  
A. Höglund ◽  
K. Eilola ◽  
E. Almroth-Rosell
Keyword(s):  
Baltic Sea ◽  
Sea Level Rise ◽  
Sea Level ◽  
The Baltic Sea ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
The Baltic ◽  
Global Mean

scholarly journals Sea level dynamics and coastal erosion in the Baltic Sea region

2021 ◽  
Vol 12 (3) ◽  
pp. 871-898
Author(s):  
Ralf Weisse ◽  
Inga Dailidienė ◽  
Birgit Hünicke ◽  
Kimmo Kahma ◽  
Kristine Madsen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Coastal Erosion ◽  
Data Availability ◽  
The Baltic Sea ◽  
Mean Sea Level ◽  
The Past ◽  
Coastline Change ◽  
Baltic Sea Region ◽  
The Baltic

Abstract. There are a large number of geophysical processes affecting sea level dynamics and coastal erosion in the Baltic Sea region. These processes operate on a large range of spatial and temporal scales and are observed in many other coastal regions worldwide. This, along with the outstanding number of long data records, makes the Baltic Sea a unique laboratory for advancing our knowledge on interactions between processes steering sea level and erosion in a climate change context. Processes contributing to sea level dynamics and coastal erosion in the Baltic Sea include the still ongoing viscoelastic response of the Earth to the last deglaciation, contributions from global and North Atlantic mean sea level changes, or contributions from wind waves affecting erosion and sediment transport along the subsiding southern Baltic Sea coast. Other examples are storm surges, seiches, or meteotsunamis which primarily contribute to sea level extremes. Such processes have undergone considerable variation and change in the past. For example, over approximately the past 50 years, the Baltic absolute (geocentric) mean sea level has risen at a rate slightly larger than the global average. In the northern parts of the Baltic Sea, due to vertical land movements, relative mean sea level has decreased. Sea level extremes are strongly linked to variability and changes in large-scale atmospheric circulation. The patterns and mechanisms contributing to erosion and accretion strongly depend on hydrodynamic conditions and their variability. For large parts of the sedimentary shores of the Baltic Sea, the wave climate and the angle at which the waves approach the nearshore region are the dominant factors, and coastline changes are highly sensitive to even small variations in these driving forces. Consequently, processes contributing to Baltic sea level dynamics and coastline change are expected to vary and to change in the future, leaving their imprint on future Baltic sea level and coastline change and variability. Because of the large number of contributing processes, their relevance for understanding global figures, and the outstanding data availability, global sea level research and research on coastline changes may greatly benefit from research undertaken in the Baltic Sea.

PRESENT VARIATIONS OF THE BALTIC SEA LEVEL AND WATER BALANCE

2018 ◽  
Author(s):  
С. Гордеева ◽  
S. Gordeeva ◽  
В. Малинин ◽  
V. Malinin ◽  
М. Дрозд ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
World Ocean ◽  
The Baltic Sea ◽  
Steric Sea Level ◽  
Sea Level Fluctuations ◽  
North East ◽  
The North ◽  
Ocean Level ◽  
The Baltic

The Baltic Sea level fluctuations have significant trends. The sea level rises in all Baltic coastsb with at different rates. Sweden coast "breathes" as well as the World Ocean level. Sea level rising on the south and the north-east coast of the Baltic Sea is lower. The trend component is not determined by interannual variations of steric sea level, the vertical water exchange and baltic river runoff. Consequently, the secular trends in sea level are caused by long-term changes in the resulting flow of water through the Danish straits. This is confirmed by changes in salinity of the Baltic Sea.

scholarly journals Swell hindcast statistics for the Baltic Sea

2021 ◽  
Author(s):  
Jan-Victor Björkqvist ◽  
Siim Pärt ◽  
Victor Alari ◽  
Sander Rikka ◽  
Elisa Lindgren ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Wind Waves ◽  
Time Lag ◽  
World Ocean ◽  
Local Wind ◽  
The Baltic Sea ◽  
Weather System ◽  
Open Sea ◽  
Cross Correlation Analysis ◽  
The Baltic

Abstract. Swell dominates the global sea state and therefore significantly contributes to processes at the air and seabed interfaces. Nonetheless, smaller enclosed seas are detached from the global swell climate. We present swell statistics for the Baltic Sea using 20 years of swell partitioned model data. The swell significant wave height was mostly under 2 m, and in the winter (DJF) the mean significant swell height was typically less than 0.4 m; higher swell was found at limited nearshore areas. Swell waves were typically short (under 5 s), with mean periods over 8 s being rare. In open-sea areas the average ratio of swell energy (to total energy) was below 0.4 – significantly less than in World Ocean. Certain coastal areas were swell dominated over half the times, mostly because of weak winds (U < 5 ms−1) rather than high swell heights. Swell dominated events with a swell height over 1 m typically lasted under 10 h. A cross-correlation analysis indicates that swell in the open sea is mostly generated from local wind-sea when wind decays (dominant time lag roughly 15 h). Near the coast, however, the results suggests that the swell is partially detached from the local wind-waves, although not necessarily from the weather system that generates them.

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