Analysis of pattern and conditions of flood-producing rainfall in the years 2004 to 2014 in the Germi City, Ardabil Province

Abstract

The occurrence of heavy rains often leads to destructive floods, thus exploring the dominant pattern of climatic systems provides the possibility of its analysis and forecasting. Thus, the aim of this study is identifying the patterns and synoptic conditions of heavy rainfall and generated flood event in the Germi area. The recorded data of an 11 year period (2004-2014) were used in this study which is including synoptic maps of geopotential, sea level pressure, jet streams, temperature, runoff, Omega and perceptible water were investigated. The results showed that the concurrence of rainfall variable in the study area is due to a combination of local and extra-local factors. The location of the Germi area in the path of entering Caspian air masses, Anticyclone and Western cyclones, experienced heavy rainfall in every year. The results indicated that the most recorded heavy rainfall events were observed during the April, May, and June months having 36.3, 46.2, and 37.4 rainfall amount, respectively, which is responsible for the occurrence of most natural hazards, including floods in the spring season. The maximum value of rainfall was observed in June 2014 with 120.8 mm rainfall value. The main cause of heavy rainfalls in the studied temporal and spatial extent can be attributed to existing the low-pressure center over the Study area, as well as the formation of two simultaneous waves along with a blocking center over the Mediterranean Sea and two low-pressure area.

Keywords

• spatial pattern
• rainfall-runoff
• heavy rainfall
• flood forecasting
• synoptic analysis