Droughts Zoning Caspian Plain with using SPI and CZI Indices

Drought is one of the atmospheric phenomena that adverse effects on various sectors environmental, economic and social gradually identified and is tangible and that is the reason it is also called creeping disaster. In this study, droughts zoning for five years consecutive caspian plain with using spi and czi indices with Arc Gis for stations synoptic: Astara, Inchebron, Bandar anzali, Babolsar, Ramsar, Rasht, Ghaemshar, Gafarhaji, Gorgan and Noushar collected. For this purpose, total rainfall for 25 years 1986 to 2010 was considered .The results indexs show that, most wet year for stations Astara with index respectively 2.6 and 2.22 in 2000 year and most dry year for station Babolsar in 2010 year with index respectively -2.86 and -2.39. Based maps drought five year in 1990 most of the drought in the eastern part of the caspian plains and other areas faced with lower rates. in 1995 year the drougt has led to the central plain and in 2000 year area west and central plains experienced drought magnitude is different. in 2005 year drought with differeant magnitude occurred in all parts of the plains and also in 2010 year all part plain caspian withness drought and process drought has decrease in east to west plain caspin.