Geodetic determination of the surface topography of the Baltic Sea

1997 ◽  
Vol 20 (4) ◽  
pp. 307-316 ◽  
Author(s):  
Juhani Kakkuri ◽  
Markku Poutanen
2017 ◽  
Vol 45 ◽  
pp. 51-63
Author(s):  
Czesław Koźmiński ◽  
Bożena Michalska

Purpose. Determination of size, variability and gradient of cloudiness on the Polish coast of the Baltic sea during the summer half-year and identification of zones with variable suitability for recreation due to cloudiness. Method. The research is based on daily values of cloudiness in the warm half-year (April-September) recorded on a scale from 0 to 8 octants, obtained from six meteorological stations located on the Polish coast of the Baltic sea during the period 2000–2016. Methods of linear regression were used in the analysis of temporal variations of cumulative monthly deviations in cloudiness for consecutive years from the mean multiannual value. In terms of recreational suitability, days were categorised into four classes according to cloudiness. Three zones of varying conditions for recreation were identified. Results. The essential characteristic of cloudiness on the Polish coast of the Baltic sea is very high variability from one day to another and the resulting change in the value of solar radiation, which, consequently affects bioclimatic stimuli. Cumulative deviations of monthly cloudiness values from the mean multiannual value show a decrease in cloudiness in April, June and July, and an increase in the remaining months of the warm half-year. It is possible to distinguish three periods regarding increased frequency of clear and moderately clear weather lasting continuously for at least 3 and 5 days on the coastal zone in summer. The Polish coast of the Baltic sea is marked by three zones of varying conditions for recreation due to cloudiness in the summer – moderately favourable, favourable and very favourable. Research and conclusion limitations. Lack of access to time-specific results of cloudiness measurement. Practical implications. The results obtained in the course of this research may be used by individuals as well as the organizers of their stays, and for the purpose of characterisation of bioclimatic conditions of the coast. Originality. In view of the recent climatic changes recorded over the last 30 years, the present research demonstrates the current cloudiness level on the Polish coast of the Baltic sea. Type of research. Presentation of the results of empirical research.


Author(s):  
Kristjan Tabri ◽  
Sören Ehlers ◽  
Mihkel Kõrgesaar ◽  
Kaarle Ståhlberg ◽  
Martin Heinvee

A Ship collision accident represents a daily threat for vessels operating in dense traffic zones. The collision consequences may include loss of life or severe injuries if passengers are on board. The latter would be the case for ROPAX vessels, which are fairly dominant in the Baltic Sea connecting various member states. Furthermore, their routes tend to be in cross-traffic with the cargo vessels travelling through the full extent of the Baltic Sea. Therefore, it is of utmost importance to be able to assess the collision consequences for ROPAX vessels operating in the Baltic Sea with sufficient accuracy. This will result in an overview of possible damage scenarios for the actual traffic situation at a given location. As an example location the dense cross traffic between Helsinki and Tallinn will be analyzed and discussed. The analysis procedure combines three steps: (1) determination of possible accidental scenarios based on traffic statistics; (2) assessment of the structural resistance of the colliding ship and (3) the evaluation of selected accidental scenarios using a time-efficient semi-analytical approach. The level of structural resistance of the chosen ships is assessed in a quasi-static manner using finite element method. This information is the basis for the calibration of a semi-analytical collision simulation model used to simulate large number of the accidental scenarios typical to the selected location. The presented results will be limited to the initial choice between vessels and dimensions, respectively masses, but the procedure can easily be extended to cover a vast amount of colliding vessels. However, the actual collision risk can be obtained using the presented results if the traffic along the vessels route is known.


Author(s):  
Christian Kaehler ◽  
Christian Schlamkow ◽  
Fokke Saathoff

Large parts of the Baltic Sea coast in Germany are protected by dikes against storm surges and floods. The dikes are designed to resist storm surges and floods, also taking into consideration of climate changes and sea level rise. To ensure the protective function the safety standards of the dikes are validated in regular intervals. This paper presents an approach to determine combined probabilities of occurrence of water level and wave heights for three selected sections. The probabilities of occurrence for defined return periods have been calculated by comparing several Copula models from the Archimedean Copula family.


1993 ◽  
Vol 45 (2) ◽  
pp. 127-142 ◽  
Author(s):  
John E. Lewis ◽  
Matti LeppäRanta ◽  
Hardy B. Granberg

mSystems ◽  
2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Lisa Zeigler Allen ◽  
John P. McCrow ◽  
Karolina Ininbergs ◽  
Christopher L. Dupont ◽  
Jonathan H. Badger ◽  
...  

ABSTRACT Inferred virus-host relationships, community structures of ubiquitous ecologically relevant groups, and identification of transcriptionally active populations have been achieved with our Baltic Sea study. Further, these data, highlighting the transcriptional activity of viruses, represent one of the more powerful uses of omics concerning ecosystem health. The use of omics-related data to assess ecosystem health holds great promise for rapid and relatively inexpensive determination of perturbations and risk, explicitly with regard to viral assemblages, as no single marker gene is suitable for widespread taxonomic coverage. Metagenomic and metatranscriptomic data were generated from size-fractionated samples from 11 sites within the Baltic Sea and adjacent marine waters of Kattegat and freshwater Lake Torneträsk in order to investigate the diversity, distribution, and transcriptional activity of virioplankton. Such a transect, spanning a salinity gradient from freshwater to the open sea, facilitated a broad genome-enabled investigation of natural as well as impacted aspects of Baltic Sea viral communities. Taxonomic signatures representative of phages within the widely distributed order Caudovirales were identified with enrichments in lesser-known families such as Podoviridae and Siphoviridae. The distribution of phage reported to infect diverse and ubiquitous heterotrophic bacteria (SAR11 clades) and cyanobacteria (Synechococcus sp.) displayed population-level shifts in diversity. Samples from higher-salinity conditions (>14 practical salinity units [PSU]) had increased abundances of viruses for picoeukaryotes, i.e., Ostreococcus. These data, combined with host diversity estimates, suggest viral modulation of diversity on the whole-community scale, as well as in specific prokaryotic and eukaryotic lineages. RNA libraries revealed single-stranded DNA (ssDNA) and RNA viral populations throughout the Baltic Sea, with ssDNA phage highly represented in Lake Torneträsk. Further, our data suggest relatively high transcriptional activity of fish viruses within diverse families known to have broad host ranges, such as Nodoviridae (RNA), Iridoviridae (DNA), and predicted zoonotic viruses that can cause ecological and economic damage as well as impact human health. IMPORTANCE Inferred virus-host relationships, community structures of ubiquitous ecologically relevant groups, and identification of transcriptionally active populations have been achieved with our Baltic Sea study. Further, these data, highlighting the transcriptional activity of viruses, represent one of the more powerful uses of omics concerning ecosystem health. The use of omics-related data to assess ecosystem health holds great promise for rapid and relatively inexpensive determination of perturbations and risk, explicitly with regard to viral assemblages, as no single marker gene is suitable for widespread taxonomic coverage.


Sign in / Sign up

Export Citation Format

Share Document