Climate Change and Climate Disaster

Abstract The geographical location of Ardabil Province in northwestern Iran has resulted in a highly irregular precipitation system in both spatial and temporal dimensions. The concurrent influence of local and external factors on its climate subjects the Sabalan basin to diverse meteorological phenomena. Consequently, the present study aimed to identify days characterized by heavy and widespread precipitation coinciding with peak discharge levels. To achieve this, daily data from 45 synoptic and rain-gauge stations (affiliated with the Ministry of Energy), alongside discharge data from the Doust-Beiglou hydrometric station, were utilized. Heavy precipitation days were identified using the 95th percentile criterion. Widespread precipitation days were subsequently selected based on a positive anomaly of the 75th percentile of the area affected by heavy rainfall. Following the identification of these events, atmospheric patterns were classified using upper-air data through Cluster Analysis and Lund’s Correlation Method. The results indicate that the Mediterranean cyclone, the Siberian High, atmospheric cut-off lows, and the activity of the Polar Vortex play significant roles in the occurrence of heavy and widespread precipitation within the Sabalan drainage basin.