Assessment of a Number of Cases of Drought Indexes at Three Stations of Fars Province

In this paper, drought in three stations in Fars province has been investigated based on the three indicators of SIAP, PNPI and RAI. After calculating the coefficients of drought indices for the three stations, considering the growth rate of the indices, the coefficient of variation, correlation and trend rate of the indices, each of the indices has been compared among the stations, and each of the indices is evaluated at the stations. The results of the growth rate showed that there is a close relationship between the growth rate of the SIAP and the PNPI indices in Shiraz station and between the PNPI and RAI indices in Abadeh station. Regarding the dispersion coefficient, it can be stated that the least dispersion is in the RAI index in the Abadeh station. But the lowest dispersion in the SIAP and PNPI indicators are in Shiraz Station. Regarding the coefficient of correlation among the indicators and the statistical period, the situation is the same, so that the highest correlation is between the RAI index and the years in question at Abadeh station. However, the highest correlation exists between SIAP and PNPI indices with the years of statistical period in Shiraz station. Finally, the results of the general trend of the indices in the three stations are relatively the same.