فصلنامه جغرافیای طبیعی
پیاپی 61 (پاییز 1402)

The aim of this study is to evaluate the performance of two precipitation datasets, CHIRPS and ERA5-Land, in detecting droughts using the Standardized Precipitation Index (SPI) over Iran. To achieve this, the raster data of the two datasets were evaluated using the standardized precipitation index in 11 time steps, along with precipitation data from 110 meteorological stations and correlation analysis. The study results revealed that both CHIRPS and ERA5-Land datasets exhibited a high degree of correlation with station data in time steps ranging from 1 to 12 months across Iran, except for the northern region (RCHIRPS = 0.56, RERA5 = 0.76). Furthermore, the ERA5-Land dataset demonstrated an acceptable level of performance in higher time steps (24-72 months) compared to CHIRPS. Additionally, the study revealed that the areas affected by drought were relatively similar between both datasets for time steps up to 12 months, although the reliability of CHIRPS was questionable at higher time steps. Moreover, based on the results, it was found that in general, the accuracy and capability of databases in high time steps, with a statistical period length of 30-40 years, have been significantly reduced, and for longer time steps, a longer statistical period should be used.

The occurrence of heatwaves, even in short time periods, can disrupt daily life and many social activities for residents. This phenomenon, when it persists for longer durations, may cause environmental and agricultural damage. The objective of this research is to extract and introduce synoptic patterns that lead to the creation of heatwaves in the southern coastal cities over the past 33 years. To achieve this goal, using the Z-score index and other selected criteria, heatwave samples were extracted for all selected stations. Based on the selected criteria, 90 heatwave samples were extracted for the 33-year statistical period. Then, using the factor analysis method and visual inspection with 1000 hPa weather data, dominant and frequent synoptic patterns were extracted. The results of this research showed that seven factors and 14 frequent patterns are the most dominant synoptic patterns that create heatwaves during the cold season in southern Iranian cities. Among these patterns, the first factor of the Sudan-Turkmenistan low-pressure pattern and, among the effective systems in creating high heatwave temperatures, the Sudan low-pressure system had the most significant role in the structure of synoptic patterns. In this pattern, the Sudan low-pressure system is combined with a northeast expansion towards the South and the warm air movement of the Hadley cell, causing an abnormal rise in temperatures at coastal stations. The core heat of this pattern is located over Sudan and Saudi Arabia. In the boundary layer to the middle troposphere, the Arabian trough rotates over the region, creating dynamic

In recent years, land use changes in Isfahan city and its surroundings have been increasing, and these changes have been caused by factors such as population growth, economic interests, and changes in society's needs. The current research was conducted with the aim of investigating the temperature changes of Isfahan city and its surroundings in a forty-year period (1979-2018). The current research is based on the purpose of applied research and its method is descriptive-analytical according to the subject of the research and its nature, and to investigate the temperature changes affected by the changes in land use and urban development of Isfahan city, temperature data from The city of Isfahan and the area of ​​50 kilometers around the city of Isfahan have been collected from the database of the European Center for Medium-Range Weather Forecasts (ECMWF). To verify the accuracy, the data of meteorological stations of Isfahan, Isfahan Airport and Najaf-Abad have been compared and evaluated. became. The results of the research show that in this 40-year period, we have seen a significant increase in the average annual temperature from 0.06 degrees in the eastern area of ​​Isfahan city to 0.11 degrees in the western area. This means that the average temperature of Isfahan city and its surrounding areas has increased between 2.5 degrees and 4 degrees during a period of 40 years.

In order to study the development of karst, using the hydrological and hydrochemical characteristics of the springs in Roein Basin, 19 springs were identified in the study area.To calculate and analyze parameters such as discharge and hydrograph of springs, Recession Coefficient, volume of dynamic storage, Estimate of recession coefficient, drawing Piper diagram, ratio of calcium to magnesium, saturation index, determining the type of reservoir rock. And the karst geomorphology of the study area was investigated.The hydrograph of the springs in the study area shows the delay time between the peak rainfall and the peak discharge in the springs, where the maximum discharge of the spring reaches its maximum with a delay of about two or three months. The low Recession Coefficient and the volume of dynamic storage of the aquifer indicate the low development of karst. The saturation index shows that the spring water samples collected from the study area are all saturated and supersaturated. Piper's diagram in the study area showed that most of the springs have bicarbonate-calcic-magnesic type. Based on the index of Ca/Mg ratio, they have a dolomite aquifer. The type of reservoir rock in the region showed that the type of reservoir rock in the region is dolomite and calcareous dolomite and the geomorphology and field observations in the region showed that there are no advanced karst forms in the region.It can be said that the karst system of the region is not developed and many karst geomorphological forms are not observed in the region.

Geotourism is one of the important types of ecotourism with a responsible and conservation-oriented approach that emphasizes the popularization of earth sciences and the cultural, social and economic development of the local community. The purpose of this research is to investigate the geotourism capabilities of East Azarbaijan Province using the Pavlova, Kubalikova and Hadzik model. Three study areas including the geotourist areas of Kandavan, Zanouzgh and Ashtabin have been selected. Based on Paulova's model, the results showed that the Kandavan geotourism area with the highest score in the positive factors promoting the competitiveness of geotourist destinations includes natural wealth with a score of (7) and the highest value among the negative items of competitiveness, budget deficit and the lack of skilled professionals with a score of (5) It creates the most negative impact on the attraction of tourists. Also, the results of the Kobalikova model showed that the Kandavan region has the highest score compared to other regions with a value of (9.25). In the Hadzik model, according to the study of scientific and surplus values according to the opinion of experts and tourists, the results showed that the average scores of the items in Kandavan geotourism area with the highest score are in the first priority. Therefore, it can be concluded that by evaluating and identifying the geotourism potentials of East Azarbaijan Province and developing the capabilities, it will lead to the development of geotourism areas and attracting tourists.

The aim of this study was to design an environmental planning model for blown sand mitigation in Sistan and Baluchestan railway tracks and stations among three-step approach. To begin, interviews were conducted with 16 university experts, managers and senior experts of railway facilities and environmental organization about blown sand mitigation in Iran. The data were coded and 77 components were identified in the form of 21 categories. Then the research model was designed and the hypotheses were identified based on the grounded theory (GT). Secondly, structural equation modeling (SEM) using Amos software was performed to fit the model. Next, interpretive structural modeling (ISM) was applied in order to prioritize, communicate and sequence between the components. The priorities of the influential components of the environmental planning model for blown sand mitigation in Sistan and Baluchestan railway tracks and stations were classified into six levels based on the expert opinions. Among them, two indicators of identification the existing conditions and the requirements for blown sand mitigation in railway tracks and stations and the goal setting for them based on their existential mission were proposed as the most effective levels. Finally, removing legal obstacles and formulating policies compatible with the environment and considering the long-term, medium-term and short-term planning of stabilization of blown sands based on executive power in order to determine applicable goals in policy priorities were proposed as solutions for controlling blown sand hazards along the Sistan and Baluchestan railway.