Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625519
O. Nikitin
Historical time series of monthly mean values of sea level were compiled for all stations in the Gulf of Finland for time periods starting from the beginning of sea level observations at each station and until station closing, or the year 2005 for Russian, 2004 for Finnish and 1991 for Estonian stations. These data were analysed for trends for a common period from 1920 till 1991. It was found that along the northern coast of the Gulf of Finland, the sea level trends change from minus 3-4 mm/year along the western part of this coast (at Turku and Hanko) to plus 1,5 mm/year along the eastern part of the coast (at Lisiy Nos). Along the southern coast of the Gulf of Finland, the sea level trends change from west to east (from station to station) not as regularly as along the northern coast. However, trend values along the southern coast are considerably less than along the northern coast. It was therefore concluded that within the limits of errors of trend calculations, the sea level trends along the southern coast also change from small negative values in the west (at Ristna, Poosaspea) to plus 1,4 mm/year in the east (at Lomonosov). At the head of the Gulf (at Port of Nevskaya), the positive trend was the largest: 3,3 mm/year. Relative to the global sea level rise (about 2 mm/year during the last century) trend values are negative in all points except Saint Petersburg. Their spatial distribution is consistent with the map of post-glacial uplift in Fennoscandia (Ekman, 1996).
{"title":"Variation of sea level trends along the coast of the Gulf of Finland","authors":"O. Nikitin","doi":"10.1109/BALTIC.2008.4625519","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625519","url":null,"abstract":"Historical time series of monthly mean values of sea level were compiled for all stations in the Gulf of Finland for time periods starting from the beginning of sea level observations at each station and until station closing, or the year 2005 for Russian, 2004 for Finnish and 1991 for Estonian stations. These data were analysed for trends for a common period from 1920 till 1991. It was found that along the northern coast of the Gulf of Finland, the sea level trends change from minus 3-4 mm/year along the western part of this coast (at Turku and Hanko) to plus 1,5 mm/year along the eastern part of the coast (at Lisiy Nos). Along the southern coast of the Gulf of Finland, the sea level trends change from west to east (from station to station) not as regularly as along the northern coast. However, trend values along the southern coast are considerably less than along the northern coast. It was therefore concluded that within the limits of errors of trend calculations, the sea level trends along the southern coast also change from small negative values in the west (at Ristna, Poosaspea) to plus 1,4 mm/year in the east (at Lomonosov). At the head of the Gulf (at Port of Nevskaya), the positive trend was the largest: 3,3 mm/year. Relative to the global sea level rise (about 2 mm/year during the last century) trend values are negative in all points except Saint Petersburg. Their spatial distribution is consistent with the map of post-glacial uplift in Fennoscandia (Ekman, 1996).","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"7 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87059207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625533
S. Fassler, N. Górska
EU environmental protection policy, based on a sustainable development approach, requires fast and non-expensive methods of marine ecosystem monitoring. Acoustic techniques, which satisfy these requirements, are widely used as a reliable method of fish stock assessment. Systematic acoustic surveys are conducted in the Baltic Sea in order to estimate the abundance of ecologically and commercially important fish populations such as herring (Clupea harengus) and sprat (Sprattus sprattus). An important requirement for acoustic abundance estimation is the species specific target strength (TS)-to-fish length relationship to convert acoustic energy into numbers of fish. TS is a measure of a fishpsilas potential to reflect sound and one of the major challenges in the Baltic Sea is the development of a reliable TS-length relationship for Baltic herring. Currently, a TS relationship originally determined for North Sea herring is used for the assessment of Baltic herring. In situ TS measurements of Baltic herring conducted in different parts of the Baltic Sea during different seasons demonstrated that Baltic herring have a higher TS than herring living in the north-east Atlantic such as Norwegian spring-spawning or North Sea herring. Additionally, there is a strong variability in Baltic herring TS in different regions and seasons (up to 8 dB). To obtain an accurate TS-length relationship the impact of the biological difference between different herring stocks on the variability of the measured Baltic herring TS should be understood. The presented paper deals with these two important issues. A detailed comparison between the acoustic backscattering properties of Baltic and Norwegian spring-spawning herring was made. The effect of different physical, environmental and biological (depth, acoustic frequency, salinity, fish orientation, fat content and condition) factors on the backscattering of the Baltic herring stock is shown. It is suggested that a different TS-to-fish length relationship should be used for Baltic herring than the one that is currently applied.
{"title":"Investigation of the target strength-to-length relationship of Baltic herring (Clupea harengus) for use in biomass estimation","authors":"S. Fassler, N. Górska","doi":"10.1109/BALTIC.2008.4625533","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625533","url":null,"abstract":"EU environmental protection policy, based on a sustainable development approach, requires fast and non-expensive methods of marine ecosystem monitoring. Acoustic techniques, which satisfy these requirements, are widely used as a reliable method of fish stock assessment. Systematic acoustic surveys are conducted in the Baltic Sea in order to estimate the abundance of ecologically and commercially important fish populations such as herring (Clupea harengus) and sprat (Sprattus sprattus). An important requirement for acoustic abundance estimation is the species specific target strength (TS)-to-fish length relationship to convert acoustic energy into numbers of fish. TS is a measure of a fishpsilas potential to reflect sound and one of the major challenges in the Baltic Sea is the development of a reliable TS-length relationship for Baltic herring. Currently, a TS relationship originally determined for North Sea herring is used for the assessment of Baltic herring. In situ TS measurements of Baltic herring conducted in different parts of the Baltic Sea during different seasons demonstrated that Baltic herring have a higher TS than herring living in the north-east Atlantic such as Norwegian spring-spawning or North Sea herring. Additionally, there is a strong variability in Baltic herring TS in different regions and seasons (up to 8 dB). To obtain an accurate TS-length relationship the impact of the biological difference between different herring stocks on the variability of the measured Baltic herring TS should be understood. The presented paper deals with these two important issues. A detailed comparison between the acoustic backscattering properties of Baltic and Norwegian spring-spawning herring was made. The effect of different physical, environmental and biological (depth, acoustic frequency, salinity, fish orientation, fat content and condition) factors on the backscattering of the Baltic herring stock is shown. It is suggested that a different TS-to-fish length relationship should be used for Baltic herring than the one that is currently applied.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"1 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89835790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625524
M. Lilover, A. Stips
Three time series of shear microstructure measurements (duration 13, 24 and 14 h respectively) were performed in 3 different wind forcing regimes as well as in 3 different background density stratification and current velocity shear situations at the entrance to the Gulf of Finland, in July 1998. Vertical shear of current velocity was enhanced by near-inertial waves during the first (A1) and third (A3) time series. We compared a Richardson number based parameterization and an estimation using the two equation k-epsiv turbulence closure (General Ocean Turbulence Model, GOTM) with ldquomeasuredrdquo eddy diffusivities. For two out of the three time series eddy diffusivities calculated via a Richardson number parameterization and via simulation using the k-epsiv model agreed well with the experimental data. However, in the case of relatively high current velocity shear and weak background density stratification (time series A3) both applied methods resulted in a remarkable discrepancy against the measured eddy diffusivity. On the contrary, calculations with a new parameterization scheme, which considers the internal wave kinetic energy fitted well for all three time series. Similarly the modified k-epsiv simulations which considered the internal wave energy level better matched the measured profiles.
{"title":"Observation, parameterization and simulation of turbulent mixing in the Gulf of Finland, the Baltic Sea","authors":"M. Lilover, A. Stips","doi":"10.1109/BALTIC.2008.4625524","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625524","url":null,"abstract":"Three time series of shear microstructure measurements (duration 13, 24 and 14 h respectively) were performed in 3 different wind forcing regimes as well as in 3 different background density stratification and current velocity shear situations at the entrance to the Gulf of Finland, in July 1998. Vertical shear of current velocity was enhanced by near-inertial waves during the first (A1) and third (A3) time series. We compared a Richardson number based parameterization and an estimation using the two equation k-epsiv turbulence closure (General Ocean Turbulence Model, GOTM) with ldquomeasuredrdquo eddy diffusivities. For two out of the three time series eddy diffusivities calculated via a Richardson number parameterization and via simulation using the k-epsiv model agreed well with the experimental data. However, in the case of relatively high current velocity shear and weak background density stratification (time series A3) both applied methods resulted in a remarkable discrepancy against the measured eddy diffusivity. On the contrary, calculations with a new parameterization scheme, which considers the internal wave kinetic energy fitted well for all three time series. Similarly the modified k-epsiv simulations which considered the internal wave energy level better matched the measured profiles.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"138 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82852162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625565
T. Kutser, L. Metsamaa, A. Reinart, L. Sipelgas, R. Uiboupin, E. Vahtmäe
The paper summarizes remote sensing studies carried out by Estonian scientists in investigation of the Baltic Sea. Mainly satellite remote sensing results obtained in different applications are shown.
本文总结了爱沙尼亚科学家在波罗的海调查中进行的遥感研究。主要展示了在不同应用中获得的卫星遥感结果。
{"title":"Baltic Sea from space. An Estonian experience","authors":"T. Kutser, L. Metsamaa, A. Reinart, L. Sipelgas, R. Uiboupin, E. Vahtmäe","doi":"10.1109/BALTIC.2008.4625565","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625565","url":null,"abstract":"The paper summarizes remote sensing studies carried out by Estonian scientists in investigation of the Baltic Sea. Mainly satellite remote sensing results obtained in different applications are shown.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"25 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83463122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625496
V. Tunnicliffe, Chris R. Barnes, Neptune Canada, Richard Dewey
VENUS (Victoria Experimental Network Under The Sea) is an advanced multi-node cabled ocean observatory now operational in the coastal ocean and NEPTUNE Canada (North-East Pacific Undersea Networked Experiments) is deploying into the deep ocean with on an 800 km loop with high power delivery. The abundant power, high bandwidth communications and hundreds of sensors delivering data in real or near real time will offer a new approach to acquisition of knowledge and interpretation of the ocean environment. Coupled with a powerful data repository and delivery system, ocean researchers have a powerful tool to explore ocean conditions. The development of cabled observatory technology is crucial given the current crises facing the ocean environment.
{"title":"Major advances in cabled ocean observatories (VENUS and NEPTUNE Canada) in coastal and deep sea settings","authors":"V. Tunnicliffe, Chris R. Barnes, Neptune Canada, Richard Dewey","doi":"10.1109/BALTIC.2008.4625496","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625496","url":null,"abstract":"VENUS (Victoria Experimental Network Under The Sea) is an advanced multi-node cabled ocean observatory now operational in the coastal ocean and NEPTUNE Canada (North-East Pacific Undersea Networked Experiments) is deploying into the deep ocean with on an 800 km loop with high power delivery. The abundant power, high bandwidth communications and hundreds of sensors delivering data in real or near real time will offer a new approach to acquisition of knowledge and interpretation of the ocean environment. Coupled with a powerful data repository and delivery system, ocean researchers have a powerful tool to explore ocean conditions. The development of cabled observatory technology is crucial given the current crises facing the ocean environment.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"145 8 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83081602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625555
M. Migliaccio, F. Nunziata, A. Gambardella
Synthetic aperture radar (SAR) oil spill observation is not at all an easy task since the presence of many natural phenomena and surfactants call for complex and time-consuming classification techniques, generally based on the use of ancillary external data. In this study, polarization diversity is employed to assist oil spill observation techniques. The polarization signature, commonly used for land application, is firstly read in terms of a sea surface scattering mechanism with and without surface slicks. Experiments, accomplished over multilook complex (MLC) C-band SIR-C/X-SAR data, show that the polarization signature can be useful both for observing oil spills and for distinguishing between oil spills and biogenic look-alikes.
{"title":"Polarimetric signature for oil spill observation","authors":"M. Migliaccio, F. Nunziata, A. Gambardella","doi":"10.1109/BALTIC.2008.4625555","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625555","url":null,"abstract":"Synthetic aperture radar (SAR) oil spill observation is not at all an easy task since the presence of many natural phenomena and surfactants call for complex and time-consuming classification techniques, generally based on the use of ancillary external data. In this study, polarization diversity is employed to assist oil spill observation techniques. The polarization signature, commonly used for land application, is firstly read in terms of a sea surface scattering mechanism with and without surface slicks. Experiments, accomplished over multilook complex (MLC) C-band SIR-C/X-SAR data, show that the polarization signature can be useful both for observing oil spills and for distinguishing between oil spills and biogenic look-alikes.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"6 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89508747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625532
S. Niiranen, T. Stipa, A. Hirvonen, J. Paakkonen, A. Norkko
After World War II, some 13 000 t of active chemical warfare agents (CWAs) were destroyed by dumping them into the Bornholm Deep. Recently, due to munition shell and container corrosion, potential CWA leakages are considered as a viable risk to marine organisms. Here, an Ecopath with Ecosim (EwE5.1) - software is used to study the bioaccumulation of a persistent CWA-like contaminant within the Baltic Sea food web with four different scenarios that describe differential water-column mixing and biomass changes in temporal and spatial resolution. In Bornholm, such bioaccumulation is of a particular concern, as the dumpsite coincides with fertile fishing grounds and is one of the main breeding areas for Baltic cod. According to our model, cod accumulated the contaminant most of all fish species studied. However, the magnitude of bioaccumulation, in all species, was very much affected by whether the CWA-contaminant was homogenously mixed within the whole water-column, or existed only in the near-bottom layer. In the latter scenario, the only pelagic groups accumulating the contaminant were fish. The dispersal of the contaminant, also, varied according to the mixing and was more widespread when the contaminant had access to surface water layers and was advected by surface water currents. The effects were more local when the contaminant was restricted to near-bottom water.
第二次世界大战后，大约13000吨活性化学战剂(CWAs)被倾倒在博恩霍尔姆深渊中。近年来，由于弹药外壳和容器的腐蚀，潜在的水轮机泄漏被认为是对海洋生物的一种可行的风险。在这里，Ecopath with Ecosim (EwE5.1)软件被用于研究波罗的海食物网中持久性cwa样污染物的生物积累，并采用四种不同的情景来描述不同的水柱混合和时空分辨率的生物量变化。在博恩霍尔姆，这种生物堆积特别令人担忧，因为垃圾场与肥沃的渔场重合，是波罗的海鳕鱼的主要繁殖区之一。根据我们的模型，在所有研究的鱼类中，鳕鱼积累的污染物最多。然而，在所有物种中，cwa污染物是在整个水柱中均匀混合，还是仅存在于近底层，对生物积累的大小有很大影响。在后一种情况下，积累污染物的唯一远洋生物是鱼类。污染物的扩散也随混合的不同而不同，当污染物进入地表水层并被地表水气流平流时，污染物的扩散范围更广。当污染物被限制在接近底部的水时，影响更局部。
{"title":"Modelled bioaccumulation of chemical warfare agents within the Baltic Sea food web","authors":"S. Niiranen, T. Stipa, A. Hirvonen, J. Paakkonen, A. Norkko","doi":"10.1109/BALTIC.2008.4625532","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625532","url":null,"abstract":"After World War II, some 13 000 t of active chemical warfare agents (CWAs) were destroyed by dumping them into the Bornholm Deep. Recently, due to munition shell and container corrosion, potential CWA leakages are considered as a viable risk to marine organisms. Here, an Ecopath with Ecosim (EwE5.1) - software is used to study the bioaccumulation of a persistent CWA-like contaminant within the Baltic Sea food web with four different scenarios that describe differential water-column mixing and biomass changes in temporal and spatial resolution. In Bornholm, such bioaccumulation is of a particular concern, as the dumpsite coincides with fertile fishing grounds and is one of the main breeding areas for Baltic cod. According to our model, cod accumulated the contaminant most of all fish species studied. However, the magnitude of bioaccumulation, in all species, was very much affected by whether the CWA-contaminant was homogenously mixed within the whole water-column, or existed only in the near-bottom layer. In the latter scenario, the only pelagic groups accumulating the contaminant were fish. The dispersal of the contaminant, also, varied according to the mixing and was more widespread when the contaminant had access to surface water layers and was advected by surface water currents. The effects were more local when the contaminant was restricted to near-bottom water.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"117 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73128537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625539
E. Kriezi, B. Broman
A hindcast wave database and a wave database based on future climate scenarios for the Baltic Sea, Kattegat and Skagerrak is under development. The wind force used for the wave simulation is coming form the RCA model and the future wind from RCA is based on global climate model ECHAM4 for one emission scenario (IPCC SRES A2). The phase averaged spectral model SWAN (Simulated WAves Nearshore) model is used for simulating the wave field. The model is driven by atmospheric forcing and it simulates waves generated by the wind and their propagation both in deep water and near shore areas. When realistic winds are provided the model has an outstanding performance. Winds from the Mesan reanalysis and the RCA model were used as forcing for the SWAN model simulating short hindcast storms for the validation of the wave model in connection with the winds. RCA results appeared to underestimate extreme winds. A correction was introduced which used an empirical relation between 3-second gust and the wind velocity. The model data were compared with observational data. Statistical parameters like scatter index, bias and symmetric slope were used to judge the quality of the data. The performance of the wave model with Mesan is very good. Model and observed data appear to have a good correlation. The performance with RCA is worse and it underestimates the wave height during extreme wind events. The performance when using corrected RCA winds is improved and data give better statistical values when they are compared with observations. The reason for using RCA forcing was the length of RCA data, 40 years of hindcast, and the 50 years of future winds based on global climate scenarios. The corrected coefficient was applied to the RCA and used to force SWAN. Only one year of hindcast has been performed initially while the 40 year run is planned to be performed in the near future. Moreover, a run based on future scenario has been performed. Six month is 1970 were run as control period and 6 months in 2020 as a future projection, giving insight to some of the possible changes in the future wave climate. Thirty years of control run and thirty years of future projection are in progress.
{"title":"Past and future wave climate in the Baltic Sea produced by the SWAN model with forcing from the regional climate model RCA of the Rossby Centre","authors":"E. Kriezi, B. Broman","doi":"10.1109/BALTIC.2008.4625539","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625539","url":null,"abstract":"A hindcast wave database and a wave database based on future climate scenarios for the Baltic Sea, Kattegat and Skagerrak is under development. The wind force used for the wave simulation is coming form the RCA model and the future wind from RCA is based on global climate model ECHAM4 for one emission scenario (IPCC SRES A2). The phase averaged spectral model SWAN (Simulated WAves Nearshore) model is used for simulating the wave field. The model is driven by atmospheric forcing and it simulates waves generated by the wind and their propagation both in deep water and near shore areas. When realistic winds are provided the model has an outstanding performance. Winds from the Mesan reanalysis and the RCA model were used as forcing for the SWAN model simulating short hindcast storms for the validation of the wave model in connection with the winds. RCA results appeared to underestimate extreme winds. A correction was introduced which used an empirical relation between 3-second gust and the wind velocity. The model data were compared with observational data. Statistical parameters like scatter index, bias and symmetric slope were used to judge the quality of the data. The performance of the wave model with Mesan is very good. Model and observed data appear to have a good correlation. The performance with RCA is worse and it underestimates the wave height during extreme wind events. The performance when using corrected RCA winds is improved and data give better statistical values when they are compared with observations. The reason for using RCA forcing was the length of RCA data, 40 years of hindcast, and the 50 years of future winds based on global climate scenarios. The corrected coefficient was applied to the RCA and used to force SWAN. Only one year of hindcast has been performed initially while the 40 year run is planned to be performed in the near future. Moreover, a run based on future scenario has been performed. Six month is 1970 were run as control period and 6 months in 2020 as a future projection, giving insight to some of the possible changes in the future wave climate. Thirty years of control run and thirty years of future projection are in progress.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"31 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76921194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625516
S. Glenn, Clayton Jones, M. Twardowski, L. Bowers, J. Kerfoot, J. Kohut, D. Webb, O. Schofield, Observation Lab
Storm-induced sediment resuspension events are examined using physical/optical sensors deployed on Slocum Gliders. Two types of storm response are found. In summer, the intense seasonal stratification limits sediment resuspension even during hurricanes. In contrast, winter storms suspend sediment throughout the full water column. The fall transition between seasons starts with surface cooling that preconditions the shelf for mixing during fall storms. Focusing on a classic fall northeaster, sediment resuspension was limited to below the weakening pycnocline early in the storm. After the pycnocline was eroded, particles immediately filled the water column. The optical signals suggest that suspended particles are likely similar materials, which implies the reduced slope of the backscatter profiles is caused by an increase in vertical transport or turbulent mixing. Wave bottom orbital velocities during this time were decreasing, and glider vertical velocities show no indication of enhanced vertical velocities reflecting full water column Langmuir cells. We conclude the enhanced mixing is related to the interaction of the surface and bottom boundary layers as the stratification is eroded, and the observed variability is associated with the tide.
{"title":"Observing storm-induced sediment resuspension processes in the mid-atlantic bight with Slocum Gliders","authors":"S. Glenn, Clayton Jones, M. Twardowski, L. Bowers, J. Kerfoot, J. Kohut, D. Webb, O. Schofield, Observation Lab","doi":"10.1109/BALTIC.2008.4625516","DOIUrl":"https://doi.org/10.1109/BALTIC.2008.4625516","url":null,"abstract":"Storm-induced sediment resuspension events are examined using physical/optical sensors deployed on Slocum Gliders. Two types of storm response are found. In summer, the intense seasonal stratification limits sediment resuspension even during hurricanes. In contrast, winter storms suspend sediment throughout the full water column. The fall transition between seasons starts with surface cooling that preconditions the shelf for mixing during fall storms. Focusing on a classic fall northeaster, sediment resuspension was limited to below the weakening pycnocline early in the storm. After the pycnocline was eroded, particles immediately filled the water column. The optical signals suggest that suspended particles are likely similar materials, which implies the reduced slope of the backscatter profiles is caused by an increase in vertical transport or turbulent mixing. Wave bottom orbital velocities during this time were decreasing, and glider vertical velocities show no indication of enhanced vertical velocities reflecting full water column Langmuir cells. We conclude the enhanced mixing is related to the interaction of the surface and bottom boundary layers as the stratification is eroded, and the observed variability is associated with the tide.","PeriodicalId":6307,"journal":{"name":"2008 IEEE/OES US/EU-Baltic International Symposium","volume":"180 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2008-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77320935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-27DOI: 10.1109/BALTIC.2008.4625490
A. Erichsen, J. Sørensen, I. S. Hansen, F. Moehlenberg
The Waterforecast (http://www.waterforecast.com) has been operated since year 2001 providing a daily 5-day forecast on physical parameters such as wave climate, water levels, currents, salinity and temperature. However, also biogeochemical parameters have been included in the forecasts since 2001 providing similar 5-day forecasts for parameters such as dissolved oxygen and chlorophyll-a. Until now, data assimilation has not been carried out systematically. However, through different projects (MARCOAST (http://gmes-marcoast.com) and BALANCE (http://balance-eu.org)) new assimilation techniques have been implemented and tested improving the performance of the model forecast. Data assimilation has been carried out for physical parameters on basin to global scales for more than a decade and is now also advancing to regional systems forecasting, revealing some of the problems of data assimilation in frontal areas. Also, different modeling groups around the Baltic Sea work on improving biogeochemical model results by assimilation or by using more simple techniques attempting to improve forecasts of especially cyano-bacteria in the Baltic Sea. We have now successfully combined advanced data assimilation and water forecasting of both satellite images and profile measurements carrying out hindcast modeling of oxygen concentrations in the Baltic Sea and transition area and on-line assimilation of satellite images of SST and chlorophyll-a providing updated and improved forecasts on the state of the Baltic Sea, the North Sea and interconnecting seas.
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