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Tartu, Estonia

Founded in 1938, the Estonian Academy of science is Estonia's national academy of science in Tallinn. As with other national academies, it is an independent group of well-known scientists whose stated aim is to promote research and development, encourage international scientific cooperation, and disseminate knowledge to the public. As of December 2012, it had 75 full members and 15 foreign members. Since November 2004, the president of the Academy is Richard Villems, a biologist from the University of Tartu. Wikipedia.

Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Eelsalu M.,Tallinn University of Technology
Renewable Energy | Year: 2014

We analyse the wave energy resource theoretically and practically available in a semi-sheltered shelf sea of moderate depth and with relatively severe but highly intermittent wave climate on the example of the Baltic Sea. The wave properties along the entire eastern Baltic Sea coast, from the Sambian (Samland) Peninsula to the eastern Gulf of Finland, are reconstructed numerically for 1970-2007 with a spatial resolution of 3 nautical miles (5.5km) and temporal resolution of 1h using the third generation wave model WAM. Owing to the shallowness of the sea (54m on average) the finite-depth dispersion relation is used in the estimates of the wave energy resources in the nearshore, at depths of 7-48m where the WAM model provides adequate results. The average wave energy flux (wave power) over the 38 years in question is about 1.5kW/m (at selected locations up to 2.55kW/m) in the nearshore regions of the eastern Baltic Proper but much smaller, about 0.7kW/m, in the interior of the Gulf of Finland and the Gulf of Riga. The total theoretical wave energy resource in the entire study area is about 1.5GW. The existing and proposed marine protected areas limit the available wave energy resource down to ~840MW. The production of grid energy is complicated because of extremely high intermittency and strong seasonal variation of the wave properties and frequent presence of sea ice. Although the wave energy resources are of obvious interest at some locations, their use for supplying power into the grid is questionable and probably not feasible in the conceivable future. © 2014 Elsevier Ltd. Source

Viikmae B.,Tallinn University of Technology | Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences
Journal of Marine Systems | Year: 2014

The spatial pattern of hits to the nearshore by tracers originating in a major fairway in the Gulf of Finland and transported by surface currents is analysed based on Lagrangian trajectories of water parcels reconstructed using the TRACMASS model from three-dimensional velocity fields by the Rossby Centre circulation model RCO for 1987-1996. The probabilities for a hit to different parts of the nearshore and the ability of different sections of the fairway to serve as starting points of tracers (equivalently, certain type of nearshore pollution) have extensive seasonal variability. The potential of the fairway to impact the nearshore in this manner is roughly inversely proportional to its distance from the nearest coast. A short section of the fairway to the south of Vyborg and a segment to the west of Tallinn are the most probable starting points of tracers. The most frequently hit nearshore areas are short fragments between Hanko and Helsinki, the north-eastern coast of the gulf to the south of Vyborg, and longer segments from Tallinn to Hiiumaa on the southern coast of the gulf. © 2013 Elsevier B.V. Source

Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Viska M.,Tallinn University of Technology
Journal of Marine Systems | Year: 2014

Alongshore variations in sediment transport along the eastern Baltic Sea coast from the Sambian (Samland) Peninsula up to Pärnu Bay in the Gulf of Riga are analysed using long-term (1970-2007) simulations of the nearshore wave climate and the Coastal Engineering Research Centre (CERC) wave energy flux model applied to about 5.5. km long beach sectors. The local rate of bulk transport is the largest along a short section of the Sambian Peninsula and along the north-western part of the Latvian coast. The net transport has an overall counter-clockwise nature but contains a number of local temporary reversals. The alongshore sediment flux has several divergence and convergence points. One of the divergence points at the Akmenrags Cape divides the sedimentary system of the eastern coast of the Baltic Proper into two almost completely separated compartments in the simulated wave climate. Cyclic relocation of a highly persistent convergence point over the entire Curonian Spit suggests that this landform is in almost perfect dynamical equilibrium in the simulated approximation of the contemporary wave climate. © 2013 Elsevier B.V. Source

Soomere T.,Tallinn University of Technology | Soomere T.,Estonian Academy of Sciences | Raamet A.,Tallinn University of Technology
Journal of Marine Systems | Year: 2014

The analysis of decadal changes to the average and extreme wave properties in the Baltic Sea is performed based on the wave hindcast for the entire Baltic Sea 1970-2007 using the wave model WAM and adjusted geostrophic winds under the assumption of no ice cover. The overall wave activity in the entire basin has limited variations over the 38. years of simulations. The local wave properties reveal strong decadal-scale signal in many parts of this water body. Its amplitude is up to 15% of the long-term average value of the significant wave height. The typical time interval between episodes of high or low annual average significant wave height is 10-12. years. The analogous interval between episodes of high and low 99%-iles of wave heights is about 5. years. Changes to the wave properties in different sea areas may be completely different in different decades. The overall maximum in the simulated annual mean significant wave height has drifted from an area between Gotland and Öland in the 1970s to the northern Baltic Proper at the turn of the millennium. © 2013 Elsevier B.V. Source

Tempel E.,Tartu Observatory | Tempel E.,Estonian National Institute of Chemical Physics and Biophysics | Stoica R.S.,Lille University of Science and Technology | Stoica R.S.,Institute Of Mecanique Celeste Et Calcul Dephemerides | And 2 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013

Galaxies are not distributed randomly in the cosmic web but are instead arranged in filaments and sheets surrounding cosmic voids. Observationally, there is still no convincing evidence of a link between the properties of galaxies and their host structures. However, by the tidal torque theory (our understanding of the origin of galaxy angular momentum), such a link should exist. Using the presently largest spectroscopic galaxy redshift survey (Sloan Digital Sky Survey), we study the connection between the spin axes of galaxies and the orientation of their host filaments. We use a 3D field of orientations to describe cosmic filaments. To restore the inclination angles of galaxies, we use a 3D photometric model of galaxies that gives these angles more accurately than traditional 2D models. We found evidence that the spin axes of bright spiral galaxies have a weak tendency to be aligned parallel to filaments. For elliptical/S0 galaxies, we have a statistically significant result that their spin axes are aligned preferentially perpendicular to the host filaments; we show that this signal practically does not depend on the accuracy of the estimated inclination angles for elliptical/S0 galaxies. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

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