1Meteorological and Hydrological Service of Croatia - Croatia
2Departments of Mathematics, University of Zagreb - Croatia
In continental part of Croatia operational hail suppression is conducted more than 30 years. The protected area is extents on 25 177 km2, and is covered with about 490 hail suppression stations which are managed with 8 radar centers.
This paper shows statistical analysis of parameters connected with hail occurrence on hail suppression launching stations in western part of protected area in 1981-2000. period. Because of disruption in hail suppression system during independence war in Croatia, it is considered that in 1991-2000. period hail suppression couldn't act properly. Because of that, it was made comparison of hail suppression data for two periods, 1981-1990. (this period is characterized with full application of hail suppression technology), and 1991-2000. In aim of better comparison, protected area is divided into quadrants (9x9 km), in the way that in every quadrant is at least one hail suprression station. Discriminant analysis for yearly values, in each quadrant, of number of cases with solid precipitation, hail damage, heavy hail damage, number of active hail suppression stations, number of days with solid precipitation, solid precipitation damage, and heavy solid precipitation damage, number and duration of air traffic control ban was done. All together there was 2500 cases with mentioned 8 variables for western part of protected area.
Results show statistically significant differences in number of launching stations with positive correlation and number of cases with air traffic control ban which have, like all other variables, negative correlation.