Coastal erosion in the Baltic Sea from Google Earth Engine

Supervisors: Nadezhda Kudryavtseva, Senior Research Scientist, Tallinn University of Technology

Contact: Nadia Kudryavtseva, nadezhda.kudryavtseva (at) taltech.ee, Department of Cybernetics, School of Science, Akadeemia 21, room B215, 12618 Tallinn, Estonia, https://www.researchgate.net/profile/Nadia_Kudryavtseva

Coastal zones are the most heavily populated and developed land zones in the Baltic Sea region. However, due to the increase in storms duration and severity, the Baltic Sea coasts experience intense coastal erosion. The recent studies showed qualitatively where the sandy beach erosion occurs in the Baltic Sea, but there is practically no information about the quantitative changes, how fast the shoreline is moving. Usually, the local measurements are challenging and are performed only for a few locations, making it impossible to assess the broad picture of the beach erosion. However, recently the Google Earth Engine made available petabytes of optical satellite images captured since 1984 covering the whole Baltic Sea together with a possibility of cloud computing. In this project, we are going to develop algorithms for the Google Earth Engine and assess the rate of shoreline changes for a few test sites with available data so we can compare the satellite-derived results with the local measurements.

Required: good programming skills (at least one programming language) and willing to learn fast Python programming, a good level of English, general knowledge of statistics

Skills that will be developed during the project: programming, geospatial analysis, statistics, data analysis, data science, technical writing, presentation

The detailed study of current and changing wave conditions in Estonian harbours

Supervisors: Nadezhda Kudryavtseva, Senior Research Scientist, Tallinn University of Technology

Rain Männikus, Coastal and structural engineer, EstKONSULT, Tallinn University of Technology

Contact:    Nadia Kudryavtseva, nadezhda.kudryavtseva (at) taltech.ee, Department of Cybernetics, School of Science, Akadeemia 21, room B215, 12618 Tallinn, Estonia, https://www.researchgate.net/profile/Nadia_Kudryavtseva;    

 The knowledge of long-term and short-term wave conditions has great importance for the design purposes, coastal protection, and sediment transport. In semi-sheltered seas, like the Baltic Sea, due to the limited size of the water body, small changes in the wind force and direction can lead to significant spatiotemporal variations. As a consequence, wave properties in different sea areas of the Baltic Sea may vary significantly. Several pieces of evidence were recently obtained that the Baltic Sea wave conditions are changing. Therefore, determining the variability of the wave climate is required for engineering and coastal planning to minimise the coastal menaces and economic losses in the future in these areas and to update the estimation of the risks for the specific sites. However, it is not clear what is happening on the local scales, along the Estonian coast. The most economically important areas are the ports and harbours and, therefore, the project will focus on detail assessment of wave conditions in a few Estonian harbours, such as Käsmu, Kihnu, and similar. During the project, the local wave measurements will be analysed and checked and compared to numerical models. Using historical measurement and model data, we are going to check if the wave conditions are changing in the major Estonian harbours and perform an assessment of how it is going to affect the port management and economy.

Required: general programming skills (Matlab), a good level of English

Skills that will be developed during the project: data analysis, problem-solving, time series analysis, numerical modelling, technical writing, presentation

The superluminal motion of galactic jets: revising the jet speeds with machine learning algorithms

Supervisors: Nadezhda Kudryavtseva, Senior Research Scientist, Tallinn University of Technology

Andrea Giudici, Research Scientist, Tallinn University of Technology

Contact: Nadia Kudryavtseva, nadezhda.kudryavtseva (at) taltech.ee, Department of Cybernetics, School of Science, Akadeemia 21, room B215, 12618 Tallinn, Estonia, https://www.researchgate.net/profile/Nadia_Kudryavtseva

Some fascinating galaxies with active nuclei eject the matter in the form of a jet from the galactic centre with the speeds close to the speed of light. For the observer on Earth, though, the motion appears to be superluminal, reaching up to 9 speed of lights. The movement is observed in radio frequencies with multiple radio telescopes working together (using very long baseline interferometry) which allows reaching a very high resolution of milliarcseconds, or parsec scales. Quite often multiple blobs of matter are moving together with different speeds and trajectories which really complicates the picture. Currently, finding the trajectories and identifying the features in active galactic nuclei jets are performed by hand so the detected motion of the jets and its kinematics are highly dependent on the researcher and how the features and patterns are connected. In this project, you will apply emerging and novel methods of machine learning techniques and feature classification in order to detect the moving matter in the jets and robustly and accurately estimate the speeds and kinematics of the jets. This will allow automating the pattern recognition and further compute the statistics of velocities, accelerations, and curvature in a large number of sources.

Required: good programming skills (at least one programming language) and willing to learn fast and test multiple machine learning algorithms in R or Python, a good level of English, general knowledge of physics, general knowledge of statistics

Skills that will be developed during the project: programming, machine learning, statistics, data analysis, data science, technical writing, presentation

Further reading:

-          A possible jet precession in the periodic quasar B0605–085. N.A. Kudryavtseva, S. Britzen, A. Witzel et al., 2011, Astronomy & Astrophysics 526, A51, https://arxiv.org/abs/1007.0989

-          The kinematics in the pc-scale jets of AGN-The case of S5 1803+ 784, S. Britzen, N.A. Kudryavtseva, A. Witzel et al., 2010, Astronomy & Astrophysics 511, A57, https://arxiv.org/abs/1001.1973

-          See movies of motion in the galactic jets http://www.physics.purdue.edu/astro/MOJAVE/movies.html

-          MOJAVE XIII. Parsec-Scale AGN Jet Kinematics Analysis Based on 19 years of VLBA Observations at 15 GHz. Lister et al. 2016, https://arxiv.org/abs/1603.03882