Identification of Circulation Patterns to Visualize the Great Torrent in Karun River

In the paper daily precipitation and discharge of Karun to Shalu basin in 1992-1993 has been analyzed by using daily height geopotential of 500 hpa for a region bounded between 10 to 60 north degree and 10-70 east degree. Applying a cluster and integration analysis on component scores is showed that there are six main circulation patterns. These patterns are divided into two groups, Low-lying and high-lying. Each especial pattern trends to appearing in certain period of the year. The low- lying and trough patterns provide dynamics conditions for instability which are seen in the cold period of the year. The high-lying and nigh discharges provide dinamics conditions for stability which are seen in the warm period of the year. The survey of the connection between these patterns to precipitation and discharge of Karun shows that the low- lying patterns have relative signification to precipitation and discharge but this association is more powerful to precipitation. Our researches showed that the circulation patterns of 500 hpa may be benefit as a strong tool to describe and explain a great deal of variance of precipitation and runoff of Karun basin. The low- lying patterns are mostly seen in winter by notice to seasonal behaviour of these disorders. The high- lying patterns are mainly seen in summer with poor precipitation.