| چکیده انگلیسی مقاله |
Extended Abstract: Introduction: Drought is a phenomenon that has occurred over and over again in almost every kind of weather and has always led to the phenomenon of drought due to the presence of Iran in the dry belt of the world and the creation of specific synoptic conditions. With drought, Iran is in difficulty in supplying water and food, so assessing the drought situation is very important. In this study, drought characteristics have been used to evaluate the drought situation in Isfahan province. Considering that in studies conducted so far, limited evaluation indicators, shorter review periods, and rarely inverted interpolation analysis for classification The results of this study, using a relatively long (> 27 years old) and monthly and monthly precipitation, have six MCZI, CZI, ZIS, SPI, DI and PNPI indices simultaneously in semi-arid, dry regions. And deserts have not been studied. In order to reduce damage, comprehensive drought plans are essential for the province materials and methods: Study area and data: Isfahan province has geographical coordinates of 30 degrees 43 minutes to 34 degrees and 27 minutes north latitude and 49 degrees and 38 minutes to 55 degrees 32 minutes east length and area of 107145 square kilometers (equivalent to 3.6 percent of the total area of Iran) moderate The rainfall in the study area is 130 mm per year. This rainfall is less than half the country's average rainfall and one sixth is the global average In this study, in order to study the drought indices of Isfahan province, 27 year precipitation data of 12 stations in the province and adjoining areas were used with good statistical quality. Case Study Indicators: In this study, six drought indexes based on rainfall were selected to evaluate drought indices and indicators of Isfahan province. The basis of drought indicators is often based on the estimation of precipitation deviation from the long-term average over a given period. General features and formulas used to calculate each of the drought indicators are:,,,,and each of the indicators has different classes of drought. Evaluating the Efficiency of Drought Indicators: In this study, the meteorological drought is based on the assumption that the minimum rainfall during the long term of the weather represents a very severe or severe meteorological drought that occurred in the studied area. In order to investigate this hypothesis, rainfall at each station was determined using drought indices and the indicators that were most consistent with the climate conditions were identified. Finally, using reverse bundling methods using ArcGIS software tools including Arc View, Arc Info, superior index maps were developed. Findings and Results: In the first stage of this research, in order to better evaluate the spatial variations of rainfall in the selection of stations, in addition to the quantity and quality of data, latitude and longitude, and altitude from the sea level, the 27-year time base (from 2019-2017) as the common statistical basis for the study of time variation Precipitation was taken into consideration. Then, the accuracy and homogeneity of the data and the incomplete statistics of precipitation of the stations were reconstructed using correlation method and normal ratio method. In the second stage, using the moving average method, dry and wet periods were measured by long-term rainfall data with continuity periods and drought severity using different drought indices. Then, to determine the hypothesis, the minimum rainfall was determined at each station and then evaluated using drought indices. Using inverted interpolation method and using the GIS environment and based on available spatial distribution data, an interpolation map was prepared and using the superior climatic index (CZI, DI, SPI and PNPI) during the 27 year statistical period (1990- 2017), drought zoning maps were prepared monthly, quarterly, and five-monthly and annual. Discussion and Conclusion: The results showed that the ability of the SPI, DI, PNPI, ZSI, CZI and MCZI indices is based on the relationships defined in the climatic drought conditions. Drought indicators at different stations have different results that can be seen even at nearby stations. The reason for this is the high rainfall variation in the study area. Among the indices, the DI ranked first, the second highest SPI, the third highest CZI, and the PNPI index, the ZSI index, and the MCZI index in the next ranking. Therefore, in order to zoning the drought, the first three indicators are used. Although the results of the hypothesis test showed that the SPI index and Decile precipitation (DI) index were consistent with the minimum rainfall year, but showed a severe and severe drought occurrence in all stations, and, in terms of other indicators, had more performance. Display Severe drought , But the range of monthly and annual Deciles of Index Index (DI) is slightly higher than other indicators in the charts. Especially in the graphs shown by the decimal index (DI), it seems a small increase in the rate of drought and tropical manifestations. It can be said that according to this study, precipitation index fluctuations (DI), although according to other indicators, are more marked in monthly and annual rainfall graphs. Based on the calculations, six climatic indicators at annual time scale showed that SPI, ZSI and CZI indices are consistent with drought persistence and drought severity. The results of selected criteria show that in the years 1994 to 1995, 2001 to 2005 and 2008 severe drought occurred in most parts of the province. From the station's point of view, the highest drought frequency in the studied area for DI, SPI, ZSI and CZI indicators from Natanz and Kebootar Abad stations and the longest drought resistance in different time scales in the study area; DI: Kabottarabad Station from 2007 to 2009 and Naine Station from 1993 to 1995 on a seasonal scale is the longest drought. According to the SPI index, the Neen Station spent the longest drought from late 1999 to the beginning of 2007 on a 24-month scale from 2001 to early 2007 at Reza Station. |