Recent sea level activities in Croatia

Ivica Vilibić; Gordana Beg Paklar; Srđan Čupić (HHI); Vlado Dadić; Nenad Domijan (HHI); Zvonko Gržetić (HHI); Damir Ivanković; Nenad Leder (HHI); Hrvoje Mihanović (HHI); Mirko Orlić; Miroslava Pasarić; Zoran Pasarić; Mladen Srdelić (HHI); Goran Strinić (HHI);

Godina: 2005


An overview of recent international and national efforts and activities directed towards the improvement of tide gauge network on the eastern coast of the Adriatic Sea is given in the paper. Present sea level related activities are introduced by the institutional structure in Croatia, followed by a summary of recent projects and programmes. A major technological step occurred in the sea level recording, acquisition and data storage through the upgrade of tide gauges with a/d converters and GSM communication package. Therefore, the availability of the data is shortened from a couple of months, which were needed to collect and digitise the charts, to a day, as the data is downloaded once a day. However, a number of technological problems have been recorded in the first year of operation (systematic drift at some stations, communication problems), although substantial improvements have been achieved through the upgrade of tide gauges (removal of clock errors, chart positioning and digitising errors, availability of high-frequency data, easier and cheaper maintenance). In addition, Bakar tide gauge is equipped by the KALESTO radar gauge, installed just a few hundred meters from the existing long-term station. The first year of the data has been preliminary analysed, revealing no existing problems in the radar system. The initiation of measurements of vertical land movements at the Split tide gauge has been recently achieved, as a Continuous GPS antenna and receiver (CGPS) has been installed in 2004 at the roof of the Split Harbour tide gauge. Preliminary analysis of the data, carried in the Norwegian Mapping Authority, showed that the number of measurements and the number of outliers is normal, the mean residual for the code measurements is very good and the mean residual for the phase measurements is acceptable. In addition, a lot of effort has been put into the rescue of historical sea level records, both by digitising and scanning of the charts, which will prevent data loss in case of their ruination or disappearance. Finally, a number of web pages have been created in the last few years, comprising near-real time sea level graphs as well as general information on the sea level monitoring and research in the Adriatic Sea.