عنوان مقاله [English]
نویسنده [English]چکیده [English]
To identify the main patterns of the 1000-500 hPa thickness during the super and overall heavy rainfall, we applied environment to circulation approach. Based on the threshold of upper 99 percent, we selected 125 days of the super and overall heavy rainfall from IRIMO database. Using the cluster analysis, main patterns were recognized. The analysis of 1000-500 hPa thickness maps showed that six patterns of thickness are the main factors for super heavy rainfalls. Although six patterns have been identified, Black Sea Trough has been seen in all Patterns with a little shift in its situation. In all patterns, a strong baroclinic situation has been seen due to interface of cold air from upper latitudes and warm air from lower latitudes (especially from northwest of Africa and Saudi Arabia). This baroclinic condition over Iran plays a fundamental role in heavy rainfall events of the country.