نشریه کاوش های جغرافیایی مناطق بیابانی
سال هفتم شماره 1 (بهار و تابستان 1398)

Drying of fine sediments and clay in the environment of a playa causes shrinkage stress and the formation of cracks and polygons followed by the formation of the mud polygons. Many factors such as moisture content, temperature, type of clay minerals, topography, salinity, and biotic disturbance affect the distribution and evolution of these multifaceted morphometries. Therefore, the study of the fractal properties of these forms can shed light on the process of their change in response to environmental conditions. The present study was conducted to investigate the pattern of micro-landforms in the western part of Meyghan playa. Based on this, about 300 clay polygons were photographed in June 2018 through field observations to apply the geo-Fractal model. Then, using the AutoCAD software, the perimeter and the area of each microform were accurately measured, and the fractal dimensions of the perimeter and the area as well as the DAP values were calculated by the Excel software. Based on the results, clay polygon patterns showed three classes of moderate, high and very high chaos with the DAP values of 1.73, 1.91 and 2.8 respectively. Therefore, it can be argued that, on the one hand, short-term developments have caused the disturbance of muddy polygons in the region. On the other hand, the intensity of changes in the perimeters of these shapes, which is probably due to the reduced moisture content, increased sediment concentration, salt accumulation on the edges, and margin uplift, was more than the intensity of change in their area. Such a phenomenon reflects the infinite geometry of the fractal dimensions of clay polygonal perimeter in Meyghan playa.

One of the main challenges in urban development processes in developing countries is the change that increasingly occurs in heat islands. Their rapid growth has created many problems for urban management and planning processes. The present study aims to reveal heat island changes using Landsat satellite data during the 1991-2016 statistical period. The satellite images have been pre-processed in four stages, including basic processing, extraction of impenetrable educational levels, assessment of the accuracy, assessment of the accuracy of classification, and retrieval of ground temperature. The results of Kappa coefficient accuracy extraction show that the images of 2016 are more accurate with a coefficient of 0.8341. In terms of location, warm cores match arid lands and poor areas that are clustered in the north and south of the city and in vegetation-free areas. Heat islands are also observed in the city center as small thermal wells. Investigation of how heat island intensity is related to the type of land cover reveals a negative correlation between construction density and vegetation on one hand and surface temperature on the other. Therefore, it can be said that humidity and coveredness of the ground the factors that moderate the heat island in the city of Esfahan.

As the study area, the worn-out texture of Bojnourd was found to be incapable of accommodating those who commute in it, especially as a context in which urban problems of Bojnourd are accumulated. It is due to the excessive use and fatigue of this part of the city. This research is descriptive-analytic in terms of the methodology, and its nature is theoretical-practical in terms of purpose. Collection of the data was done through three methods of field work, library study as well as using software and applied models. To analyze the data, the multivariate weighting method was used according to the coefficient and the different impact of each criterion on the vulnerability. Also, AHP-FUZZY technique was used for weighting the variables. Neighborhoods were then extracted and identified, and, using the Arc GIS 10.4.1 software, neighboring maps was developed. In addition, the weighted maps were given fuzzy functions and standard privacy that they lacked through a fuzzy membership program. Finally, using the Fuzzy overly as a tool with a 0.9 gamma, a risk map was derived for Birjand old texture. The results show that there is almost no place in the old texture that is left undamaged. In this case, the most vulnerable part is from the center of the texture to the western margin of the city. Also, the overall risk profile of the area indicates that the whole worn-out part of Bojnord is at a moderate to high risk.

The over-exploitation of groundwater has led to many problems in the country. Since groundwater level is a variable that varies over the time and place, it can be considered as a spatio-temporal dataset. The purpose of this study is to investigate the spatial-temporal variation of the groundwater level in Jask plain from 1997 to 2013 to determine the spatial trend of groundwater changes. First, interpolation was carried out based on the Kriging and the Radial Basis Functions (RBF), and then accuracy was evaluated using MBE, MAE and RMSE statistics. The findings suggested that, compared with RBF, Kriging can estimate groundwater levels more accurately in the study area. Consequently, for each time in the study period, a groundwater level map was produced based of the method. To identify the spatial variability of the groundwater level, R2 and Man-Kendall test were used. The results of the R2 statistics indicated a significant variation in the water level. Similarly, the results of the Man-Kendall test showed a decreasing trend in the north-to-northwest margin with a high intensity of nearly -1. Generally, in different parts of the study area, the process of change has a specific and meaningful pattern.

Climate zoning is the identification of zones with the same climate. With the expansion of quantitative methods, traditional methods of cluster classification have been replaced by new methods, such as various interpolation methods in the field of climatological zoning studies. In this study, we evaluated the zoning of radiation effects on the administrative spaces of Kerman city. Accordingly, the ordinary Kriging interpolation method is used along with circular, Gaussian, and spherical models for data interpolation with error criteria including root square error (RMS), its standardized value (SRMS), standard mean (Ms Mean Mean), and Mean Square Error (ASE). These factors are intended for accuracy evaluation. This research is a descriptive-analytical study on the basis of spatial analysis using the GIS system. The results of the final maps produced for climate zoning (radiological factors) showed that the angle of the sun shine is right in the equinoxes and horizontal in the revolutions. Therefore, radiation is more in the offices uptown and less in the ones downtown. The latter case is due to the presence of mountains in the south of the city. Also, solar radiation is maximal in the northern and eastern regions while it is the lowest in the west and the south. In proportion to the AD months and with regard to the amount radiation in offices in equinoxes and revolutions, it was found that the Gaussian distribution spectrum and the angle of radiation have the greatest effect on the offices in the north of the city, which is due to the position of those buildings to the sun.

The rapid changes in land use and land cover in the suburbs of large cities of Iran, including the city of Arak, as an industrial metropolitan city, have caused many problems in recent decades, including degradation of natural resources, environmental pollution and poor urban development. In most cases, this has been caused by an unjustified land use change. The study of changes and destruction of resources in past years, the feasibility and prediction of these changes and the pattern of urban growth in the coming years can be an important step in planning and optimal using of resources in the future. In this study, by using Landsat multispectral satellite imagery of 2000, 2018, and 2028, lateral information, Markov chain model, and artificial neural networks, the changes that have occurred in land use and land cover in Arak over the course of 28 years were investigated. To reveal the changes, the conversion rate for each course was obtained in four classes. To investigate the images, they were corrected, and then the best bands were selected for combining the bands. In the following, the classification of rates of maximum probability and evaluation of the accuracy of the classification as well as the overall accuracy were performed with kappa coefficient. Finally, by using the Markov forecasting model and the LCM modeling approach, land use change was predicted for the year 2028. The results indicated the excessive expansion of the built areas, severe degradation of agricultural lands during the period of 2000-2010, sharp decline of barren lands, their conversion to the lands built within the boundaries of the city, and the reduction of mountainous lands in the period of 2010-2018. Modeling the changes also showed that in the period of 2018-2028, the city will grow from the north and northeast to the south and southwest (i.e. toward the mountainous and garden lands of the two villages annexed to the city).

The characteristics of Sistan plain, such as river sedimentation, blowing of erosive winds, especially 120-day winds, and the droughts in the past 20 years have made a suitable situation for wind erosion. One of the concrete symbols of wind erosion is sand displacement. Since the regions of sand displacement in this study were residential, the aim of this study was set to conduct a morphometric analysis of sand dunes, their displacement speed, and their role in posing hazards to these areas. To analyze the role of morphometric parameters in the displacement of barkhans, out of 10 barkhans formed in two wind erosion centers, seven were selected. Then, during the 120-day wind period in Sistan area, their displacement was detected and documented. Afterwards, using the SPSS software, the regression analyses were done on the length, width, height, area, and the displacement of the ​​barkhans. The results indicated a negative correlation between the length of the barkhans and their displacement, while there was no significant correlation between the other parameters and the displacement.

In recent decades, with the development of various methods in the field of satellite image classification and change detection, there has been an increasing advancement in choosing the best and accurate method for preparation of maps of lands use and land cover. The aim of this study is to compare some algorithms which are used in land cover classification in arid lands of Ardakan plain, Yazd. For this purpose, the satellite images of the plain were categorized into four classes of bare lands, residential areas, rangelands, agricultural and road. Then, training samples were collected by using 1: 20000 aerial photos, satellite images, and Google Earth as well as through field visits Next, considering the characteristics of the images, the land use classes in the study area were defined. After the amount of differentiation of the classes was determined, land cover classification was done through Mahalanobis distance, maximum likelihood, support vector machine, minimum distance, binary encoding, parallelepiped, neural network, and spectral angel mapper. The results of the accuracy assessment of these eight methods showed that maximum likelihood, Mahalanobis distance, and support vector machine have the best performance in land use mapping in arid lands.

Natural hazards have always happened suddenly, and human societies have suffered a lot from them. One of the ways to cope with those hazards is to increase the resilience of communities against them. The purpose of this study is to investigate the extent to which rural and urban communities are discriminated against natural hazards. The present research is descriptive-analytic in terms of method and applied in term of purpose. The statistical population of the study consists of all the heads of urban households (147,717) and rural familes (21,763) in Zahedan. Among them, a sample of 322 was elicited by using Cochran's formula, and the participants completed questionnaires. In this research, descriptive and inferential statistics were used to analyze the data. The results of the research show that the level of economic, socio-cultural and infrastructure resilience in urban societies is higher than that in rural societies. In other words, the resilience of urban communities in these three indicators is desirable, but it is undesirable in rural communities. It is only in the social capital index that the resilience of rural communities is higher than that in urban societies. Also, in this very index, rural communities rank higher than the average, while urban ones are lower than desirable.

Artificial recharge projects are one of the most important strategies for sustainable management of groundwater resources. Several projects have been designed and implemented in the country over the past years. Evaluating the performance of these projects is very important. This paper aims to investigate the effect of Ardo artificial recharge project on the groundwater resources of Borazjan plain. To this purpose, the physico-chemical parameters of the wells adjacent to the project have been investigated spatially and temporally in a four-month period from December to April, 2015. Parameters such as electrical conductivity (EC), temperature, and major cations and anions were measured and monitored in this study. The effect of the spreading of Ardo basin on the groundwater was investigated using time series diagrams and the maps of the groundwater physico-chemical parameters. The results showed an asymmetric recharge pattern around the spreading artificial basin. It was also found that the recharge front of the basin extends from the side of the basin to its northwest. From the temporal viewpoint, the highest recharge occurs in the months of February and March. According to the results, the role of the basin in recharging the groundwater tables is more than 50% near the basin and its northwest. Also, the artificial recharge project has a positive impact on the groundwater quantity and quality.

In this study, a statistical approach was used to identify the problems of Mehr housing project in the city of Yazd. The data were collected in the form of documents (e.g. articles, books, magazines, and web sites on the Internet) and through field work (i.e. questionnaire, interview and observation). The main variables of the research were a set of 46 items extracted according to the statistical principles and the data. The study sample consisted of 150 experts who were familiar with the conditions of Mehr housing. The data were analyzed through factor analysis with the SPSS and Excel software programs. According to the data, the variables were prioritized in five stages as fllows: the first stage with the variable of lack of coordination among the excavation and building foundation projects based on the area profile with the load factor of 0/884, the second stage with the variable of per capita religious inappropriate spaces with the load factor of 0/837, the third stage with the variable of undesirable internal architectural patterns with the load factor of 0/0767, the fourth stage with the variable of designing structures not on the basis of modern systems with the load factor of 0/862, and the fifth stage with the variable of incompatible residential unit area with the load factor of 0/757.

Since long, mineral-industrial development in central Iran has been considered as a driving force for the development of the regional and national economic sectors in the country. Previously, little attention was paid to the fragile and vulnerable environment of mines, and the prospective effects of the development of those environments were ignored. In this regard, the present study uses strategic planning methods to look for appropriate strategies to reduce the negative impacts of the developmental plans and projects in mine-rich regions. The research is applied from the perspective of nature and descriptive-analytical from the perspective of the method. Using SWOT and QSPM models, strategic planning is performed of the effects of Chadormalloo mine on the settlements of the city of Bahabad. In terms of strategic planning, the study area is in an offensive position. In this situation, through appropriate strategies for sustainable development, efforts should be made to exploit the opportunities and strengths of the region. In this case, plans can be implemented for the employment of the indigenous drought-affected people along with complementary strategies for the utilization of the potentials of Chadormalloo mineral complex.