Comparison of extensometric results measured in the Vyhne Tidal Station (Slovakia) and in the Sopronbánfalva Geodynamic Observatory (Hungary)

Two extensometer stations have been set up at the margin of the Pannonian Basin to monitor tectonic movements as well as Earth tides and related phenomena. Because the Sopronbánfalva Geodynamic Observatory (SGO) in Hungary and the Vyhne Tidal Station (VTS) in Slovakia are located in different geological, topographic, and tectonic environments, the analysis and comparison of the extensometer data measured here provides a useful opportunity to interpret the observed data. The tectonic deformation at the SGO shows an average contraction of: −2.94 μstr y−1 (1 μstr is 10−6 relative deformation) which can be explained by the uplift of the Alps and the anticlockwise motion of the Adria microplate, causing compression in the Eastern Alps. At the VTS an average compression of −14.8 nstr y−1 (1 nstr is 10−9 relative deformation) was measured which can be explained by the NW compression direction in this area. The measured deformations in both observatories show a good agreement with the results of GPS measurements. The deformation at the VTS is characterized by small dilatation anomalies caused by the different topographic, tectonic environment and probably by the high heat flow in the area of the station. At this station the calculated amplitude factors for O1, P1, K1, M2 are 1.01482, 1.21691, 0.83173, 1.09392 and the ocean load corrected values are 1.10817, 1.35717, 0.92809, 1.28812, respectively. At the SGO the calculated amplitude factors for the same tidal components are 0.58776, 0.38967, 0.41548, 1.00564 and the ocean load corrected values are 0.98893, 1.89117, 1.00430, 1.04962, respectively. These results show that the effect of the ocean tide loading is greater at Sopronbánfalva, than at Vyhne. Based on the comparison, we can say that the result of the local strain measurement can be considered realistic.

Effect of non-tidal station loading on Lunar Laser Ranging observatories and on the estimation of Earth orientation parameters

<p>The distance between the observatories on Earth and the retro-reflectors on the Moon has been regularly observed by the Lunar Laser Ranging (LLR) experiment since 1970. In the recent years, observations with bigger telescopes (APOLLO) and at infra-red wavelength (OCA) are carried out, resulting in a better distribution of precise LLR data over the lunar orbit and the observed retro-reflectors on the Moon, and a higher number of LLR observations in total. Providing the longest time series of any space geodetic technique for studying the Earth-Moon dynamics, LLR can also support the estimation of Earth orientation parameters (EOP), like UT1. The increased number of highly accurate LLR observations enables a more accurate estimation of the EOP. In this study, we add the effect of non-tidal station loading (NTSL) in the analysis of the LLR data, and determine post-fit residuals and EOP. The non-tidal loading datasets provided by the German Research Centre for Geosciences (GFZ), the International Mass Loading Service (IMLS), and the EOST loading service of University of Strasbourg in France are included as corrections to the coordinates of the LLR observatories, in addition to the standard corrections suggested by the International Earth Rotation and Reference Systems Service (IERS) 2010 conventions. The Earth surface deforms up to the centimetre level due to the effect of NTSL. By considering this effect in the Institute of Geodesy (IfE) LLR model (called ‘LUNAR’), we obtain a change in the uncertainties of the estimated station coordinates resulting in an up to 1% improvement, an improvement in the post-fit LLR residuals of up to 9%, and a decrease in the power of the annual signal in the LLR post-fit residuals of up to 57%. In a second part of the study, we investigate whether the modelling of NTSL leads to an improvement in the determination of EOP from LLR data. Recent results will be presented.</p>

A Comparison between Coastal Altimetry Data and Tidal Gauge Measurements in the Gulf of Genoa (NW Mediterranean Sea)

Satellite altimetry data from X-TRACK products were analyzed for an overall assessment of their capability to detect coastal sea level variability in the Ligurian Sea. Near-coastal altimetry data, collected from 2009 to 2016 along track n.044, were compared with simultaneous high frequency sampled data at the tidal station in Genoa (NW Mediterranean Sea). The two time series show a very good agreement: correlation between total sea level elevation from the altimeter and sea level variation from the tidal gauge is 0.92 and root mean square difference is 4.5 cm. Some relevant mismatches can be ascribed to the local high frequency coastal variability due to shelf and harbor oscillation detected at the tidal station, which might not be observed at the location of the altimetry points of measurement. The analysis evidences discrepancies (root mean square difference of 4.7 cm) between model results for open sea tides and harmonic analysis at the tidal station, mainly occurring at the annual and semiannual period. On the contrary, the important part of dynamic atmospheric correction due to the inverse barometer effect, well agrees with that computed at the tidal station.

Simulation Model to Assess Tidal Potential Energy in East Coast of Malaysia Using GIS

This article studies the GIS simulation of yearly power generation in five different tidal stations in the East Coast region of Malaysia. The tidal stations are Geting, Tanjung Gelang, Tioman, Tanjung Sedili and Cendering. The tidal station in Geting is not analysed in this study because the tidal range is insignificant. After analysing the lagoons nearby to the four tidal stations, Tanjung Gelang and Tanjung Sedili are chosen in this study based on their natural characteristics and geomorphology of lagoons. The simulation model is based on yearly power generation using tidal barrage. This article also looks into the model in terms of mapping using GIS software to obtain bathymetry and tidal range data. Bathymetry data in GIS format is obtained from NOAA (National Oceanic and Atmospheric Administration) and tidal range data is obtained from ‘Jabatan Ukur dan Pemetaan Malaysia’. The latest tidal data up to date is the year 2011. The minimum depth of tidal basin should be 3.0 meter. Using GIS software to analyse bathymetry and tidal range data, the results are then combined to find yearly generation power output in the two tidal stations and are plotted in one map for each tidal station. The area of basin in Tanjung Gelang and Tanjung Sedili are 17.736 km2 and 27.919 km2. The calculation includes the important parameters such as area of basin, tidal range, number of tide cycles per year, and number of hours per tide. From the results and analysis, it is concluded that Tanjung Sedili and Tanjung Gelang produce 1.528 x 108 kWh and 1.294 x 108 kWh as their yearly power generation in 2011.