Changes in precipitation extremes on the Black Sea Western Coast

Changes in daily extreme precipitations have been identified in many studies conducted at local, regional or global scales. For the Black Sea region, only little research on this issue was done. In this paper, the Black Sea Western coast covering Bulgarian, Romanian and partially Ukrainian coastlines was considered. The present study is focused on the analysis of the trends in daily extreme precipitations indices at a regional scale over 48 yrs (1961–2008). Data sets of daily precipitation recorded in 13 weather stations were analyzed. Among them, eight are located in Bulgaria, four in Romania and one in Ukraine. The main goal was to find changes in extreme daily rainfall using a set of 11 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the studied area. The indices series and trends were generated using RClimDex software. The results seem integrated to the global and European continental scales findings: increasing trends are dominant for almost all indices; most of the calculated slopes are statistically insignificant; the distribution of positive and negative slopes in the area is extremely irregular and the changes in Northern stations are more significant compared to those calculated for Southern stations.

► Extreme precipitations changes were identified using 11 indices. ► The increasing trends are dominant for most of the indices. ► Distribution of positive and negative slopes is irregular in the area. ► Changes in northern stations are more significant compared to those in the South. ► Increasing in CDD and decreasing in CWD are dominant for most of the stations.