Drought Monitoring in Iran by Palmer Severity Drought Index (PDSI) and Correlation with Oceanic Atmospheric Teleconnection Patterns

In this study، we used monthly Palmer Severity Drought Index (PDSI) data of National center of oceanic atmospheric administration (NOAA) during 1/1950 to 12/2005 (56 year). The time and space resolution of data is monthly and 2. 5*2. 5 degree respectively. Therefore 26 pixels located in Iran political boundary. A matrix 26*672 carried out that pixels located on rows and month located on column. The cluster analysis by Ward method showed that Iran classified to four regions. The most drought severity occurred during year 2000 in northwestern of Iran. It seems that location of regions related to the atmospheric passing route on Iran and their effective radius. There is a significant correlation between teleconnection patterns and drought in Iran. The effect of teleconnection patterns is different for regions. In total، in autumn there is a highest correlation between teleconnection patterns and Drought.