Study the effect of meteorological droughts on the quantity and continuity of the surface runoff in an arid region (A Case study: Kerman province)

Drought is one of the most prevalent and dangerous disturbances around the world, which cause significant economic and agricultural losses. Kerman province located in the center of Iran is in the first places of drought. The purpose of this research was to investigate the meteorological and hydrological drought condition of the study area. The relationship between meteorological and hydrological drought was also investigated. For this propose, 11 hydrometric stations and 10 precipitation hydrometric stations were extracted. The hydrological and drought indicators were measured using SPI and SRI were calculated at different time scales. Then, the relationship between meteorological drought and hydrological drought, as well as the relationship between meteorological drought with hydrological drought occurring with different time delays, were analyzed using Pearson correlation. The comparison between SPI and SRI indexes showed that in all meteorological stations, drought periods have increased since 2000. The highest correlation between these two types of droughts in the region was related to 48 month periods. The results showed that hydrological drought severity is more than meteorological drought in the region. At the beginning of the study period, meteorological droughts have not an important different with hydrological droughts; however, since the year 2004, the severity of hydrological drought has increased continuously in the region. The correlation between SPI and SRI index at different stations was not the same. The results of the Pearson correlation between SPI and SRI index with delay of 1, 2, 3 and 4 months showed that the highest correlation between SPI and SRI were occurred for the same period. These results also indicate that meteorological droughts immediately affect the river flow and consequently, the hydrological drought was happened