Drought is one of the natural hazards, which during its occurrence has damages and effects of irreparable damage in various sectors of agriculture, economics, and so on. In recent years, different regions of the world have experienced more severe drought (Mirzai et al., 2015: 98). Also, drought is one of the most important natural disasters affecting agriculture and water resources, which is abundant especially in arid and semi-arid regions (Shamsenya et al., 2008: 165).Drought changes are well-suited for optimal management of water resources utilization (Alizadeh, 2017: 169). Drought is also referred to as a climate phenomenon with a lack of humidity and rainfall relative to normal conditions. This phenomenon strongly affects all aspects of human activity (Zeinali and Safarian Zangier, 2017). Regarding the studies done inside and outside of the country, this study attempted to model and monitor the drought phenomenon in southwest of Iran using a new index.
Material and method:
In this study, drought modeling in southwest of Iran was carried out using climatic data of rainfall, temperature, sunshine, minimum relative humidity and wind speed monthly (6 and 12 months scale) for the period of 31 years (1987 - 2018) in five provinces of Khuzestan, Lorestan, Ilam, Kermanshah and Hamedan in 15 stations using a new index modeling called the TIBI Architectural Index, fuzzyized from four indices (SET, SPI, SEB, MCZI) The World Meteorological Organization was used. Fuzzy index T.I.B.I The fuzzy index (T.I.B.I) is presented to resolve some of the disadvantages of the SPEI index. The index T.I.B.I was derived from the integration of the indicators (SET, SPI, SEB, MCZI), which is the result of drought fuzzy modeling architecture that is designed using fuzzy logic in a fuzzy inference system.
Monitoring of drought fluctuations based on four integrated indicators in T.I.B.I In order to investigate the effect of drought fluctuations in drought conditions of stations, it is possible to find changes in the parameters (SET, SPI, SEB, MCZI) in the TIBI index, Checked. Considering the large number of stations studied, for the sake of better understanding, only the drought series chart, East Islamabad station at two 6 and 12-month scale was presented in Figures 7 and 8 (Figures 7 and 8). The above-mentioned red dot indicates a 6-month drought margin with a value of 0.44 and more, and represents a 0.44 and a magnitude 12-month scale. The analysis of these forms shows that at Islamabad-West station at 6 and 12-month scale, the temperature was different in the drought environment, which was decreasing in the 6-month scale from April 1994 to August 1997, and after This month has been gaining momentum, from July 1996 through 2003, an incremental increase. If the impact of rainfall on a 12-month scale is weaker than the 6-month scale. Between May 1994 and November 1997, the declining trend followed by a 12-month-long drought after June 1997 to December 2002, followed by a similar pattern. And the indicators (SET, SPI, SEB, MCZI) affect the TIBI index and show some trends, indicating that the new TIBI fuzzy index reflects the four indicators well and the scale Drought classes were presented in Table 5. The T.I.B.I index on a 12-month scale shows a sharper shape than scale 6.
One of the natural hazards that has affected the country in recent years is the dangers of drought. One of these areas affected by drought was the southeastern part of Iran, where researchers conducted many studies to monitor drought in Southwest Iran with different models but did not adequately address the issue. Is The purpose of this study is to model and monitor the drought phenomenon in southwest of Iran using a new fuzzy index in the 6 and 12-month scale. In the study area, the intensity and frequency of drought are more than 6 months on a 12-month scale. Drought persistence is more than 12 months old. Short-term droughts were less sustained and affected by rainfall and temperature parameters. While the severity of drought in the long periods of time was less responsive to temperature and precipitation variations.The trend of drought in the south-west of Iran was increasing and the temperature trend was more rapid, increasing and increasing trend. The highest frequency of drought occurrence was at the 6th and 12th month scale, Islamabad-West station and the lowest rate was 6 Hamadan airport scale and 12-month scale Khorram Abad station. The percentage of drought frequency in Hamedan Nogheh, Islamabad and Zarapulzahab stations was higher than the 6-month scale in the 12-month scale.
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