Warunki hydrologiczne Zatoki Gdańskiej ze szczególnym uwzględnieniem Zatoki Puckiej

Abstract

Hydrological conditions of the Puck Bay as the part of Gulf of GdańskA b s t r a c t. Changes of sea level as well as sea ice conditions, observed on the tide-gauges determine the hydrological conditions in a given basin. The sea level is the altitude of the sea water table with regard to an adopted reference point—in the case of the of Gulf of Gdańsk this is the system of precise levelling NN55. The reference level along the Polish coast is close to the mean multi-annual sea level, which, determined for Puck as the arithmetic mean is equal to 502 cm and for Gulf of Gdańsk is equal to 500 cm. Hydrological conditions define the basin capacity and its capability for water exchange and flooding as well as obstruction for navigation and ports activities. The study focused on description of hydrological condition of Gulf of Gdańsk with particularly emphasis for the Puck Bay (a small, shallow bay on the west-southern  part of Gulf of Gdańsk) for period 1959–2008. The course and variability of water levels and sea-ice in the Gulf of Gdańsk and the Puck Bay were analysed on the basis of data from three stations of IMGW (Institute of Meteorology and Water Management) situated in Gdańsk and Puck and at Hel. Maximal annual sea levels oscillated during the investigated period: for Gdańsk from 551 cm to 644 cm (November 2004), Hel from549 cm to 622 cm (January 1994) and for Puck from 542 cm to 626 cm (November 1992). Changes of minimal annual sea levels were observed as equal to: Gdańsk — 414 cm (November 1979) to 485 cm, for Hel from 412 cm (November 1979) to 479 cm and for Puck from 409 cm (December 1979) to 477 cm. The variability of mean annual sea levels, calculated for Puck and Hel, were similar from 490/489 cm to 517/516 cm; the mean multiannual sea levels were equal to 503 cm (Puck) and 504 cm (Hel). In Gdańsk, the range of changes of annual mean sea levels were greater: from 493 cm to 524 cm with mean multiannual level of 508 cm. The sea ice conditions appeared to be characterized the biggest diversity: the maximum number of the days with sea-ice were observed on the Puck Bay during the winter 1995/96 as equal to 130, where in Gdańsk were 76 days (1962/63) and in southern Hel — only 49 days (1986/87).