Quality assessment of the hiromb water level forecast for the Polish coastal zone

The aim of this paper is to compare the observed water level and the results of HIROMB model for the same period. Real sea level values, collected in the data base of the Institute of Meteorology and Water Management in Gdynia were measured by Polish water gauges situated along tlze west part of coast and around the Gulf of Gdansk. The analysed data were from the period 15.08.1998 - 28.05.1999, and the forecast lead time was equal to 24 hours. The assumed reference level, equal to 500 cm, caused too high forecast levels and marked differences between observed and computed sea levels. In order to improve the results of modelling a new reference level has been established. Having introduced the new reference level, a better agreement between the observed and computed values was obtained in most cases. The validation of modelled results was carried out by means of the chosen statistical indicators