Analysis of Standardized Precipitation Drought Indices in the Cities of Ardebil Province

The aim of this study was to analyze rainfall drought indices to predict and reduce their negative effects in Ardebil province, which involved a descriptive-analytical study in terms of research type. Data were collected using documentary method. Accordingly, the information of mean rainfall and mean temperature on a monthly basis in synoptic stations of Ardebil, Germi, Parsabad, Meshkinshahr and Khalkhal were received from the Meteorological Organization in Ardebil province for the period (1996-1996). Dip and Dic software were used to analyze the SPI and CZI indices data in each of the 5 synoptic stations of the province. Drought zoning was then performed in two scales of 6 and 12 months, from IDW interpolation, in ArcGIS software. The innovation of the present study was the use of if-then rules in MATLAB software in combining drought indicators in the field of climatology. The results showed that very severe droughts at the 12-month scale were less than at the 6-month scale, and in all 5 stations studied, the number of moderate droughts was more than severe and very severe ones. Also, the highest frequency of drought was observed in Ardebil city and the lowest in Germi station. Similarly, a comparison of the two indicators displayed that their performance did not differ much; but it turned out that the SPI index, could reveal the number of droughts better than the CZI index.