Geocentric Changes of the Mean Sea Level of the Baltic Sea from Altimeter and Tide Gauge Data

The global mean sea level is one of the most important indicators of climate changes. Until recently, changes in ocean level were determined from tide gauge observations, currently from satellite altimetry. The main objective of this work is to analyse the available data from the satellite altimetry in order to determine the trend in the Baltic sea level changes. We used these data to investigate regional trend at selected eight tide gauge stations. In the first step sea level anomaly were extracted from the multi mission global product available at CMEMS and next analysed using Ferret and Hector software. Furthermore absolute mean sea level computed from tide gauge data and GNSS observations was taken from the SONEL web page. The results were compared and this comparison shows some differences in both method of the order of 1 mm/year and significant difference of the order 2.4 mm/year at station Helsinki.