ارزيابي روش هاي مختلف تعيين شدت خشك سالي و انتخاب مناسب ترين روش براي كشور ايران

The Evaluation of different methods for determining drought intensity and selecting The best one for Iran

Drought is one of the worst chronic and the most harmful natural disasters, and in recent decades, it has been the large frequency natural disaster affected human population. Drought in world climatic researches is one of the main issues that is widely considered, but in Iran it is considered less than other countries. The aim of this study is to determin the best method for drought intensity evaluation among the percent normal methods, deciles method and standard precipitation index. In this case first 40 synoptic stations in the country that have 37 years data from 1966-1967 to 2003-2004 selected, and by using the above three methods, the number of drought years for each station is defined, and then by using regression analysis, the best method for drought intensity evaluation in Iran climatic condition is determined. Results showed that to determine the drought intensity in Iran and the climatic conditions for 12 months scale, percent of normal is the best one.