Synoptic Analysis of Heavy Rainfall in Northwest of Iran (With an Emphasis on Patterns of Atmospheric Thickness)

In this study, the heavy rainfall of Northwest of Iranhas been analyzed using environmental circulation approach. Isohyte maps were depicted using Kriging method on 14*14 km pixels from 21/3/1961 up to 31/12/2004 (a17508× 533 matrix). Based on these interpolated data we selected super heavy rainfalls for all in Northwest of Iran as a whole. Heavy rainfall and their locations have been detected from 00 to 1200 E and 00 to 800 N in the five this levels (1000, 925, 850, 700, 600 and 500 hPa level) at 00:00, 06:00, 12:00 and 18:00 UTC. The results of this study showed that four thickness circulation patterns play role in producing these super heavy rainfalls. In analysis of these precipitations one representative day was introduced for every circulation pattern. The analysis showed that the circulation patterns 2 justify the most of precipitations. These findings can play an important role in forecasting the precipitation and preventing from flooding in the region.