Analysis of extreme precipitation timeseries in Serbia based on station data

Serbia lies between Central and Southern Europe and is characterised by a complex topography, with the Pannonian Plain in the north and the Dinaric Alps in the west and southwest. Three climate types characterise Serbia: continental climate in the north, temperate continental climate in the central part and modified Mediterranean climate in the south. Precipitation in Serbia is generally the result of passing cyclones and associated atmospheric fronts as part of the general circulation of the atmosphere in the mid-latitudes (Tošić et al., 2017). In recent decades, flash flooding resulting from extreme precipitation events has proven to be a great threat to human life and a great cause of economic strife (an estimate of 1.7 billion euros in damages in 2014 alone when catastrophic flooding occurred in Bosnia, Croatia and Serbia).The highest yearly 1-day precipitation (Rx1day) was analyzed on an annual and seasonal basis at ten stations in Serbia in the period 1961-2020. The modified Mann-Kendall test was used to examine the significance of the trend. An increase was observed in all annual time series of Rx1day. A significant positive trend was observed at 9 out of 10 stations. The Rx1day time series increased in Niš in southern Serbia, but not significantly. In addition, all fall and spring time series showed a positive trend, of which 8 and 5, respectively, were significant. In summer, 5 stations (Zrenjanin, Novi Sad, Veliko Gradište, Kragujevac and Zaječar) showed a significant positive trend, while 4 stations (Sremska Mitrovica, Belgrade, Loznica and Kragujevac) showed a positive trend and one (Niš) showed a negative but non-significant trend. In winter, a significant increase in Rx1day was observed at two stations (Kragujevac and Zaječar) and a negative trend at Veliko Gradište. The generalised extreme value function was calculated and analyzed for all of the available stations, for the periods of 1961-1990, 1990-2020 and 1961-2020 with the inclusion of return periods.The highest increase of Rx1day was observed in Novi Sad, both on an annual and seasonal basis. The highest summer value of Rx1day (116.6 mm) was measured in Novi Sad in 2018, which led to flooding in the city (Savić et al., 2020). This precipitation episode was determined to be caused by convective rainfall.Tošić, I., Unkašević, M., Putniković, S., 2017: Extreme daily precipitation: the case of Serbia in 2014. Theor. Appl. Climatol. 128, 785–794. doi:10.1007/s00704-016-1749-2Savić, S.; Kalfayan, M.; Dolinaj, D. Precipitation Spatial Patterns in Cities with Different Urbanisation Types: Case Study of Novi Sad (Serbia) as a Medium-sized City. Geogr. Pannon. 2020, 24 (2), 88–99. https://doi.org/10.5937/gp24-25202