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.

scholarly journals Swell hindcast statistics for the Baltic Sea

Ocean Science ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. 1815-1829
Author(s):  
Jan-Victor Björkqvist ◽  
Siim Pärt ◽  
Victor Alari ◽  
Sander Rikka ◽  
Elisa Lindgren ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Wind Waves ◽  
Time Lag ◽  
World Ocean ◽  
Wave Climate ◽  
Local Wind ◽  
Pressure System ◽  
Weather System ◽  
Open Sea ◽  
Cross Correlation Analysis

Abstract. The classic characterisation of swell as regular, almost monochromatic, wave trains does not necessarily accurately describe swell in water bodies shielded from the oceanic wave climate. In such enclosed areas the locally generated swell waves still contribute to processes at the air and seabed interfaces, and their presence can be quantified by partitioning wave components based on their speed relative to the wind. We present swell statistics for the semi-enclosed 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 in 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 mostly below 0.4 – significantly less than in the World Ocean. Certain coastal areas were swell dominated over half the time, mostly because of weak winds (U<5 m s−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 suggest that the swell is partially detached from the local wind waves, although not necessarily from the weather system that generates them because the highest swell typically arrives with a roughly 10 h delay after the low-pressure system has already passed.

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.

Organohalogens of Natural and Industrial Origin in Large Recipients of Bleach-Plant Effluents

1991 ◽  
Vol 24 (3-4) ◽  
pp. 373-383 ◽  
Author(s):  
A. Grimvall ◽  
H. Borén ◽  
S. Jonsson ◽  
S. Karlsson ◽  
R. Sävenhed
Keyword(s):  
Baltic Sea ◽  
Point Sources ◽  
The Baltic Sea ◽  
Long Distance ◽  
Long Distance Transport ◽  
Open Sea ◽  
Receiving Waters ◽  
The Baltic ◽  
Organic Halogens

The long-term fate of chlorophenols and adsorbable organic halogens (AOX) was studied in two large recipients of bleach-plant effluents: Lake Vättern in Sweden and the Baltic Sea. The study showed that there is a long-distance transport (&gt;100 km) of chloroguaiacols from bleach-plants to remote parts of receiving waters. However, there was no evidence of several-year-long accumulation of chloro-organics in the water-phase. A simple water-exchange model for Lake Vättern showed that the cumulated bleach-plant discharges from the past 35 years would have increased the AOX concentration in the lake by more than 100 µg Cl/l, if no AOX had been removed from the water by evaporation, sedimentation or degradation. However, the observed AOX concentration in Lake Vättern averaged only about 15 µg Cl/l, which was less than the average AOX concentration (32 µg Cl/l) in the “unpolluted” tributaries of the lake. Similar investigations in the Baltic Sea showed that non-point sources, including natural halogenation processes, accounted for a substantial fraction of the AOX in the open sea. The presence of 2,4,6-trichlorophenol in precipitation and “unpolluted” surface waters showed that non-point sources may also make a considerable contribution to the background levels of compounds normally regarded as indicators of bleach-plant effluents.

Petroleum hydrocarbons - a necessity of monitoring in a dredged material in the Polish coastal zone

2018 ◽  
Vol 33 (1) ◽  
pp. 50-60
Author(s):  
Marta Staniszewska ◽  
Helena Boniecka
Keyword(s):  
Baltic Sea ◽  
Coastal Zone ◽  
Petroleum Hydrocarbons ◽  
The Other ◽  
Dredged Material ◽  
The Baltic Sea ◽  
Legal Standards ◽  
Open Sea ◽  
Long Time ◽  
The Baltic

Petroleum hydrocarbons (PHCs) are toxic for the water organisms and in sediments they may last for a very long time. The Baltic Sea is an area exposed to the PHCs due to highly developed shipping. In Poland, there is a lack of legal standards specifying guidelines regarding handling dredged material containing PHCs, excavated in waterways, roadsteads, and in port basins, and there are no standards specifying their acceptable concentration in sediments. Therephore petroleum hydrocarbons in the excavated dredged material are rarely examined at the Polish coasts. In years 2009-2018 only 4% of sediments were examined in terms of their content. Indicated that only the sediments from the open sea did not contain PHCs, the other ones were very or moderately contaminated with PHCs. Collected results clearly indicate that sediment should be monitored in terms of the PHC content, in most cases should not be thrown back to the sea. In most cases they may be stored onshore, but only on wastelands, mainly industrial and transport areas. Some of them may also be used in the areas of cleaner lands, i.e. forests, wood- and bush-covered lands, recreation and leisure areas.

scholarly journals PFASs in Finnish Rivers and Fish and the Loading of PFASs to the Baltic Sea

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 870 ◽  
Author(s):  
Junttila ◽  
Vähä ◽  
Perkola ◽  
Räike ◽  
Siimes ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Surface Waters ◽  
Aquatic Environment ◽  
Perca Fluviatilis ◽  
Quality Standard ◽  
Clupea Harengus ◽  
The Baltic Sea ◽  
Open Sea ◽  
Polluted Sites ◽  
The Baltic

The concentrations of per- and polyfluoroalkyl substances (PFASs) in the Finnish aquatic environment were measured in riverine waters and in inland, coastal and open sea fish. In addition, the PFAS load to the Baltic Sea from 11 rivers was calculated. Measurements show that PFASs, including restricted perfluorooctane sulfonic acid (PFOS), are widely present in the Finnish aquatic environment. At three out of 45 sampling sites, the concentration of PFOS in fish exceeded the environmental quality standard (EQS) of the Water Framework Directive (WFD). The annual average (AA) ∑23PFAS concentration in surface waters ranged from 1.8 to 42 ng L−1 and the concentration of PFOS exceeded the AA-EQS in three out of 13 water bodies. In European perch (Perca fluviatilis) and Baltic herring (Clupea harengus membras), the ∑PFAS concentration ranged from 0.98 to 1 µg kg−1 f.w. (fresh weight) and from 0.2 to 2.4 µg kg−1 f.w., respectively. The highest concentrations in both surface water and fish were found in waters of southern Finland. The riverine export of ∑10PFAS to the Baltic Sea from individual rivers ranged from 0.4 kg yr−1 to 18 kg yr−1. PFAS concentrations in fish of point-source-polluted sites and coastal sites were higher compared to fish of open sea or diffusely polluted sites. The PFAS profiles in surface waters of background sites were different from other sites. This study shows that PFASs are widely found in the Finnish aquatic environment. Different PFAS profiles in samples from background areas and densely populated areas indicate diverse sources of PFASs. Although atmospheric deposition has a substantial influence on PFAS occurrence in remote areas, it is not the dominant source of all PFASs to the aquatic environment of Finland. Rather, wastewaters and presumably contaminated land areas are major sources of PFASs to this aquatic environment.

scholarly journals Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea

2013 ◽  
Vol 10 (7) ◽  
pp. 4529-4546 ◽  
Author(s):  
H.-G. Hoppe ◽  
H. C. Giesenhagen ◽  
R. Koppe ◽  
H.-P. Hansen ◽  
K. Gocke
Keyword(s):  
Time Series ◽  
Baltic Sea ◽  
Global Climate ◽  
Time Lag ◽  
Vertical Mixing ◽  
Bacterial Biomass ◽  
Glucose Turnover ◽  
Positive Trend ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the conversion of the political system in the southern and eastern border states, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, bacteria number, bacterial biomass and bacterial production, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. Strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen, even in the surface layer, was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. The long-term seasonal patterns of all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables (as well as precipitation) and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll, which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ −60%), followed by chlorophyll (−50%) and bacterial biomass (−40%). Considering the circulation of surface currents in the Baltic Sea we interpret the observed patterns of the microbial variables at the Boknis Eck time series station as a consequence of the improved management of water resources after 1989 and – to a minor extent – the trends of the climate variables salinity and temperature.

Pomphorhynchus laevis parasite of flounder Platichthys flesus as a biological indicator of pollution in the Baltic Sea

2001 ◽  
Vol 81 (1) ◽  
pp. 165-166 ◽  
Author(s):  
M. Chibani ◽  
M. Ziółkowska ◽  
A. Kijewska ◽  
J. Rokicki
Keyword(s):  
Baltic Sea ◽  
Relative Density ◽  
Biological Indicator ◽  
The Baltic Sea ◽  
Platichthys Flesus ◽  
Open Sea ◽  
Biometric Measurements ◽  
The Baltic ◽  
Pomeranian Bay ◽  
Age And Sex

Six hundred and seventy nine specimens of Platichthys flesus (L.) were caught in summer (July–September) 1998 and 1999 from three regions of the Polish zone of the Baltic Sea: the Gulf of Gdańsk, the Pomeranian Bay and the open sea off Łeba. The biometric measurements (length, weight, age) and sex of the specimens were recorded. The specimens were examined for occurrence of parasites. The intensity, relative density and prevalence of infection were calculated.

Model analysis of the currents and wind waves in the Vistula Lagoon of the Baltic Sea

Oceanology ◽  
2012 ◽  
Vol 52 (6) ◽  
pp. 748-753 ◽  
Author(s):  
B. V. Chubarenko ◽  
L. V. Leitsina ◽  
E. E. Esiukova ◽  
D. N. Kurennoy
Keyword(s):  
Baltic Sea ◽  
Wind Waves ◽  
Model Analysis ◽  
Vistula Lagoon ◽  
The Baltic Sea ◽  
The Baltic ◽  
The Vistula Lagoon

scholarly journals Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea

2012 ◽  
Vol 9 (12) ◽  
pp. 18655-18706 ◽  
Author(s):  
H.-G. Hoppe ◽  
H. C. Giesenhagen ◽  
R. Koppe ◽  
H.-P. Hansen ◽  
K. Gocke
Keyword(s):  
Time Series ◽  
Baltic Sea ◽  
Global Climate ◽  
Time Lag ◽  
Vertical Mixing ◽  
Bacterial Biomass ◽  
Glucose Turnover ◽  
Positive Trend ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the Western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the collapse and conversion of the political system in the Southern and Eastern Border States, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, the bacterial variables, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. The strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen even in the surface layer was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. In the long run all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables as well as precipitation and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ −60%), followed by chlorophyll (−50%) and bacterial biomass (−40%). Considering the circulation of surface currents in the Baltic Sea we conclude that the improved management of water resources after 1989 together with the trends of the climate variables salinity and temperature were responsible for the observed patterns of the microbial variables at the Boknis Eck time series station.

scholarly journals Spatio-temporal variation in stable isotope and elemental composition of key-species reflect environmental changes in the Baltic Sea

2021 ◽  
Author(s):  
Camilla Liénart ◽  
Andrius Garbaras ◽  
Susanne Qvarfordt ◽  
Jakob Walve ◽  
Agnes M. L. Karlson
Keyword(s):  
Stable Isotope ◽  
Baltic Sea ◽  
Temporal Variation ◽  
Food Web ◽  
Elemental Composition ◽  
Environmental Changes ◽  
The Baltic Sea ◽  
Open Sea ◽  
The Baltic

AbstractCarbon and nitrogen stable isotope ratios are increasingly used to study long-term change in food web structure and nutrient cycling. We retrospectively analyse elemental composition (C, N and P) and stable isotopes (δ13C, δ15N) in archived monitoring samples of two important taxa from the bottom of the food web; the filamentous ephemeral macroalgae Cladophora spp. and the blue mussel Mytilus edulis trossulus from three contrasting regions in the Baltic Sea (coastal Bothnian Sea and Baltic Proper, open sea central Baltic). The aim is to statistically link the observed spatial and interannual (8–24 years’ time-series) variability in elemental and isotope baselines with their biomass trends and to the oceanographic monitoring data reflecting the ongoing environmental changes (i.e., eutrophication and climate) in this system. We find clear differences in isotope baselines between the two major Baltic Sea basins. However, the temporal variation in Mytilus δ13C was similar among regions and, at the open sea station, mussels and algae δ13C also correlated over time, likely reflecting a global (Suess) effect, whereas δ15N of both taxa varied with local and regional dissolved nitrogen concentrations in water. δ15N in source amino acids allowed detection of diazotrophic N in Mytilus, which was masked in bulk δ15N. Finally, Cladophora N:P reflected regional nutrient levels in the water while P%, which differed for both taxa, was linked to food quality for Mytilus. This study highlights the potential of a multi-taxa and multi-stable isotope approach to understand nutrient dynamics and monitor long-term environmental changes.

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