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Drought trend evaluation and its impact on vegetation cover changes of Sarakhs county
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Mohadese Namazi    , Morteza Akbari * , Hadi Memarian , Zahra Asadolahi |
| Associate Professor, Department of Desert and Arid Zones, Faculty of Natural Resources and Environment, Ferdowsi University of Mashhad, Mashhad, Iran, Email: m-akbari@um.ac.ir; desertology@gmail.com |
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Abstract: (836 Views) |
| Vegetation cover is one of the basic and key ecological factors in arid regions, which will be severely affected by the drought process. As a result of these impacts, there will be increased intensity of soil erosion and soil degradation. Therefore, the present research was conducted to evaluate the process of drought and its impact on changes in vegetation in Sarakhs county in Khorasan Razavi province. In this research, the climate data of precipitation and monthly temperature of synoptic and evapotranspiration stations in a period of 21 years (2000 to 2021) were used to estimate the standardized precipitation-evaporation-transpiration index (SPEI). To investigate the vegetation changes, the images of ETM+ and OLI satellite sensors and the difference vegetation index (NDVI) were used. The index SPEI was calculated in the software environment R. Prediction of future vegetation cover changes is done using the Markov model and in the IDRISI-TerrSet software environment. Finally, the correlation between two indicators of drought and vegetation was compared with a linear regression test. The results of this research showed that the highest level of drought in the years 2000, 2010, and 2020 occurred in Sarkhas city at moderate and severe levels. The investigation of changes in vegetation cover in 2030 showed that the soil without cover increased compared to the year 2020, and the area of land with other classes, including vegetation with medium, high, and thin density, has decreased. Correlation analysis between vegetation cover and drought indicators showed that the highest correlation value of 0.59 at the significance level of 0.01 has been observed, and in the years 2000 and 2020, the correlation coefficient was higher at 0.52 and 0.51, respectively. The results of examining the relationship between the NDVI vegetation cover index and SPEI climatic index indicated the existence of a positive relationship between these indices. |
Article number: 4 |
| Keywords: Climate change, Google Earth Engine System, land degradation, Markov model, linear regression |
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Full-Text [PDF 1447 kb]
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Type of Study: Research |
Subject:
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