Precipitation analysis of the wider area of the Triglav national park for the period 1961-2009

Abstract

The annual rainfall series were analyzed for the 18 meteorological stations in the wider area of the Triglav National Park for the period 1961-2009: the amount of annual rainfall, the number of days with 24-h rainfall totals exceeding 5, 10, 20, 50, 100, 150 mm and the number of 48-h rainfall totals exceeding 50, 100 and 150 mm. For snow cover, duration and the trend of days with snow cover were analyzed. The maximum annual precipitation over the entire period has been in Žaga by Bovec (2972 mm) and the minimum in Rateće (1532 mm). High interannual rainfall variability was noticed during period observed, more than twice as much rain has fallen in the wettest periods as in the driest periods. There were some significant differences between the decadal precipitation amounts. At most stations, the wettest period was 1961-1969 and the driest were 1980-1989 and 2000-2009. Heavy 24-h and 48-h rainfalls were measured at all stations, variability in the number of extreme rainfall events has increased with the amount of rainfall. The maximum number of days with day-rainfall above 5 mm was measured in Vogel (90), and above 10 mm (69) and 20 mm (44) in Kneške Ravne. Žaga had the highest number with rainfall above 50, 100 and 150 mm and Rateče the lowest one. The snow season has shortened in recent years, negative trends were observed at all stations in the number of days with snow cover. The significant trend rates ranged from -4.3 days/decade in Žaga to -14.9 days/decade in Stara Fužina.