فصلنامه مطالعات جغرافیایی مناطق خشک
پیاپی 53 (پاییز 1402)

 Among the common risks in arid and semi-arid regions is the risk of desertification. Iran's hydroclimatic situation has caused many parts of it to be exposed to this danger. Semnan province is one of the regions that has faced the expansion of desertification in recent years. Considering the importance of the subject, this study aims to evaluate the potential of desertification risk in the northern regions of Semnan province.

 The statistical information related to the population and climate of Semnan province, library information, and the 30-meter high SRTM digital model have been used as the most important research data. The most important software used were SPSS and ArcGIS, which were used to perform calculations and prepare final maps. The method used in this research was the DVI model.

 The results of this research have shown that 16.8% of the region's area, which mainly includes the western and southeastern regions of the studied region, is in the category of very high vulnerability potential against the risk of desertification. Also, about 60% of the region is in the class with high vulnerability potential, which indicates the region's high potential from the risk of desertification. The classes with medium and low vulnerability potential cover a total of 23.2% of the region.

 The findings show that many parts of the northern regions of Semnan province have a high potential in terms of desertification. Therefore, in order to prevent the spread of this danger, it is necessary to have the necessary programs to control the destruction of pastures and changes in land use.

Innovation: 

In this research, human parameters are considered. Also, the results of this research can be used in various civil and environmental planning.

 Iran is a vast country with a different climate due to its geographical location and topographical conditions. The current research was carried out to select the most appropriate drought index in Iran's climatic regions and investigate the probability of its occurrence through uncertainty methods. 

 In this research, in the first step, through multi-criteria decision-making methods, the most suitable index for each climate zone is selected based on the percentage of suitability, and finally, based on artificial neural network methods, probability analysis is calculated and the probability of the phenomenon occurring. In this research, after choosing the appropriate index, the statistical data of the country's synoptic station in a statistical period of 28 years (1990-2017) has been used to express the probability of drought, and the Kernel method has been used to converge the data.

 The final result of the cloud theory analysis of the studied data shows that in all the stations examined in the target year, i.e., 2017, the country of Iran and all the representative stations have shown climatic conditions close to the normal range. The highest likelihood of occurrence belongs to Tabriz station (96%) and Hamedan station (94%).

 Based on the results, the selective uncertainty model has a high ability in probability analysis and has predicted the probability of drought with an acceptable percentage of confidence.

Innovation: 

Due to the difference in climatic regions of Iran, the elimination of user intervention, and the use of scientific and mathematical calculations, the error rate in selecting the index is reduced. Then, with the help of uncertainty methods such as cloud theory, the ability to predict the probability of drought in the future increases.

With the increase in the population of cities, the term green space and the uses of urban green space have received more attention. Therefore, as the cities grow extensively, the need for green spaces is felt more and more daily, both for the direct use of citizens and in terms of refining the environment. The importance of green space in the urban environment is that it is considered one of the indicators of the development of societies, and it has benefits such as treatment of mental illnesses, a favorable environment for raising children, social integration, maintaining comfort, etc. In addition, these spaces are used for the general public to spend their free time, have fun, and socialize with friends and social and cultural gatherings. This research investigates the distribution of green spaces in Isfahan based on the approach to environmental justice.  

 The current research is applied and descriptive-analytical. The required information has been collected in a documentary-library way, and the data has been analyzed using expert judgment, the field survey method (observation and questionnaire), and the Analytical Network Process (ANP) model and DEMATEL.  

 The results show that among the factors related to the distribution of urban green space, among the four categories of social, economic, physical, and environmental factors, according to the respondents' opinion, physical factors weigh 54. 44% rank first, and social factors with a weight of 24.8% rank. Therefore, to achieve comprehensive development in green space, the city of Isfahan needs effective attention to social factors.

Innovation: 

The present research is one of the few types of research that have investigated the factors affecting the distribution of urban green spaces with the approach of environmental justice.

 This research investigates the effectiveness of watershed management activities carried out in the Badkash watershed. 

 All the watershed measures carried out in the area were visited. In connection with biological and biomechanical operations, the NDVI index was compared twice before and after the watershed operation to investigate vegetation changes. The comparison of erosion and sedimentation before and after the operation was carried out using the estimated model of preliminary studies (MPSIAC), and the effectiveness and efficiency of watershed operations on erosion and sedimentation, flood, and vegetation were investigated. 

 Measures taken in the area can trap sediments of about 7518733 cubic meters; of this tank volume, about 5754910 cubic meters have been trapped by the sediments brought upstream of the basin. The rate of specific erosion has increased from 8.74 tons per hectare to 7.46 tons per hectare, and the amount of sedimentation has also decreased significantly. Two areas of 200 and 58 hectares of the basin lands have also been subjected to the biomechanical operation of catchment crescents, and biological mounding operations have also been carried out inside the catchment crescents. 

 The results show that the temporal changes of the NDVI index for the entire area have a positive trend, and since 2018, with the implementation of biomechanical operations in the desired area, the value of this index has increased compared to the long-term average of the entire area.

Innovation: 

Until now, the evaluation of the effects of watershed management measures has been done less. Examining the effectiveness of these measures can help to continue these measures or change how they are implemented. This can help attract the attention of watershed decision-makers in the direction of investment.

Urban identity can change over time. Cities and urban spaces have had their own identity, but what exists today is nothing more than buildings and streets. Arg Street has been one of the important streets in the physical development of Mashhad in the modern era. The variety of cultural and recreational land uses (in the past) caused the formation of a new identity in this street, which has changed with time-lapse and the city's rapid growth. By identifying the components of past and present identification, this article focused on the effect of land use change on the amount of identification in this street. 

The research method is descriptive-analytical. Information was collected through field study and observation, supplemented with library sources. By identifying local experts, 100 questionnaires were completed on the past and present characteristics of Arg Street of Mashhad, and the data were analyzed with SPSS software.

The chi-square test results showed that the land use change did not contribute to the level of identification. The results of the Wilcoxon test also showed that religious and cultural land use has been more important in the past, and the importance of green space land use has also remained constant. Also, the findings indicate that with the change in land uses, the identity of Arg Street and the sense of attachment of the residents have also changed. Finally, the identity land uses the MACBETH method, and the m-Macbeth software has been ranked and evaluated.

 Land use change can significantly affect the identity dimensions of the place and the urban space and cause its status to be promoted or degraded.

Innovation: 

The findings of this study can inform city managers about land use changes and their effects on urban identity.

 Investigating the spatial and temporal distribution of lightning occurrence and the trend of lightning occurrence in Iran.

 Monthly spatial and temporal distribution of lightning occurrence investigated based on HRMC data in the range of 25° E - 65° E and 15° N - 42° N. The trend of lightning occurrence was studied based on LRMTS data in about twenty years (1995-2014) using a standardized regression slope.

 Iran is divided into eight regions based on the characteristics of lightning activity. The minimum of lightning and convective activities occur in the country's center and east. The maximum occurs in the northwest from June to August, in the west, southwest, and south from November to May, and in the south in September. The activity of the Red Sea convergence zone influences the maximum occurrence from December to May in the southwest and west of Iran. The most significant increase in the occurrence of lightning occurred in the southeast of Iran in the summer, the Caspian Sea in the winter, the area between the Black Sea and the Mediterranean in the fall, and finally, in the south of the Persian Gulf in the spring. The most significant decrease has been observed in the center of the Red Sea, the Black Sea, and the Mediterranean, respectively, in the summer season.

 Considering the effect of convective activities on Iran's rainfall regime, we can expect an effective change in the characteristics of Iran's rainfall regime due to global warming.

 It can be seen that their livelihood is dependent on agriculture. This article aims to investigate the perceived causes of farmers' vulnerability from the villagers' point of view with the structural equation modeling approach. 

 The current research is applied research regarding its purpose and causal research. The statistical population of the research consists of 2894 rural farmer households living east of the Zayandeh River basin in 1401. The statistical sample of 339 household heads was determined using Cochran's formula. This number was selected by a simple random sampling method. Data was analyzed using SPSS software and structural equation modeling (Smart PLS). The variables of social empowerment, management, water resources, infrastructure, and services are the observed variables. 

 The results show that the validity of all four measurement models on farmers' vulnerability is acceptable. According to the results, the t coefficients between the main research variables were above 2.58, meaning the relationship is significant and indirect. In this way, the dimensions of social empowerment, management, water resources, and infrastructure and services have a negative and significant effect on the vulnerability of farmers; the value of R2 shows that 76.7% of the vulnerability of farmers is explained by achieving the four dimensions, and then water resources with a coefficient of 0.89. , has had a more significant impact on farmers' vulnerability than other dimensions.

 To reduce farmers' vulnerability level, infrastructure and service indicators should be given more attention to improving the final outcome of farmers' vulnerability.Innovation: The innovation of this research is in the study area and its indicators.