There was a level service in Kronstadt, Russia, as early as 1707 . In 1840, at the suggestion of the hydrograph Michael Reineke, a marker was placed on the Blue Bridge over the Kronstadt Obvodny Canal ( Cyrillic Обводный канал ), which corresponded to the mean sea level of the Gulf of Finland from 1825 to 1839.
In 1976/77 the Kronstadt level was introduced as the reference level for the Soviet Union . To the Eastern bloc to ensure a uniform height system, many states took the CMEA and Yugoslavia also the level of the level as the basis of their static head systems. In the GDR , this altitude system was known as altitude zero (HN or HN76) .
location
The gauge (in the sense of a water level measuring device) is at the foot of the Kronstadt fortress on the Baltic island of Kotlin in the Gulf of Finland . The island is connected to the mainland by a road causeway; the former small town is now part of St. Petersburg.
Wind drift
The Kronstadt gauge is not representative of the entire Baltic Sea due to possible drift currents . In order to investigate the influence of wind drift on water levels in the Baltic Sea, German oceanographers have created meteorological forecast models. They analyze the air pressure distribution of typical weather conditions over the North Sea and Baltic Sea area with the level fluctuations against the mean water and the water level in the Bay of Kiel .
User states
The Kronstadt level reference is used in various countries.