National network of mareographic stations for monitoring of the Black Sea level
JOINT PROJECT OF
Agency for Geodesy, Cartography and Cadastre National Institute of Geophysics, Geodesy and Geography Institute of Oceanology
The Network consisted of four mareographic stations for monitoring of the Black Sea level – in Varna, Irakli, Burgas and Ahtopol.
The purpose of the mareographic stations is to carry out permanent registration and monitoring of the sea level. The principal stations in Varna and Burgas are functioning form 1928 which make the temporary series of registrations of the sea level especially valuable in the context the global climatic changes. The mareographic stations in Irakli and Ahtopol are working from 1970.
The maintaining and scientific provision of the mareographic stations and measurements are carried out together with National Institute of Geophysics, Geodesy and Geography (NIGGG), Department of Geodesy, and the Agency for Geodesy, Cartography and Cadastre (AGCC) according to the Law on geodesy and cartography, with the active cooperation of the Institute of Oceanology (IO) at Bulgarian Academy of Sciences.
In the execution of Annex 4 of the Framework agreement between AGCC and NIGGG for “Implementing in working rate of the mareographic stations from the National Mareographic Network”, and together with IO, during 2013 were putted into operation the principal stations in Varna and Burgas. In these two stations are installed modern radar mareographs. The old mareographic equipment ( type A. Ott-Kempten ) is working jointly with the radar mareographs , which will allow the homogeneity of the temporary series with measurements Black Sea level from 1928 up to now. In the mareographic station in Varna is installed GPS receiver for monitoring of the current crustal motions.The installment of GPS receiver in the station in Burgas is forthcoming.
The values of the Black Sea level in Varna and Burgas are correlated to the European Elevation System according to the Decree for definition, realization and maintaining of the Bulgarian Geodetic System. More about the definition and realization of the European Elevation System used by now could be found here.
Time format is UTC
In historical approach in Bulgaria the elevation systems in use are Black Sea - from 1930 to 1958, Baltic – from 1958 to 2010, and European from 2010.
The results from the processing and analysis of the moreographic data from the stations in Varna and Burgas for the period 1928 – 2011 could be seen on the graphics:
Change of the sea level in mareographic station in Varna.. The calculated century trend is 1.4±0.4 мм/year.
Change of the sea level in mareographic station in Burgas.. The calculated century trend is 2.0±0.4 мм/year.