فصلنامه جغرافیای طبیعی
پیاپی 58 (زمستان 1401)

This research tries to assess the emission and concentration of surface Ozone related to the synoptic weather patterns in general circulation of atmosphere. 2020 – 2021 is the time and Tehran is the place of this research. Based on the defined scenarios, the extreme emission day, the pure day accompanied with stability and instability of the atmosphere, air pressure in sea level and 500 hpa. Skew-T chart from Mehrabad airport were analyzed. The emission datum was taken from the six stations of the air quality control organization in Tehran. The analysis was done daily and seasonally. The result of the research shows that in 24 hours emissions the most concentration happens in the mid-day and last until 6 in the evening. Among the seasons, summer has the most concentration because of the dominance of high pressure in atmosphere, increase in surface temperature high radiation and wind speed. More than 6 m

The purpose of this study is flood risk zonation using Hierarchical Analysis Process (AHP) and Geographic Information System (GIS) in Sarcheshmeh Copper Complex. In order to prepare a flood zoning map in the study area, seven main criteria including slope, land use, vegetation, lithology, drainage network density, topographic wetness index (TWI) and Stream power index (SPI) were selected and studied. In the next step, based on the AHP method, a matrix of pairwise comparisons of criteria and sub-criteria was prepared and their opinions were recorded in Expert Choice software by interviewing experienced experts and the weights of criteria and sub-criteria were calculated. Finally, the flood risk map in GIS environment was produced using the linear weight combination (WLC) method by converting each criterion into a raster layer based on AHP weights, which shows an area of 7.6 square meters of high and very high risk in the region. This map shows the high risk of flooding around the Pit Mine area due to the high altitude and slope in this section. Also, the risk of flooding is high at the site of the new acid plant and gas power plant within the complex. Elsewhere in the complex, flood risk is low and moderate. The results of this study can help experts and planners to determine the development process of the plant, mine and planning to reduce flood risk in the complex.

The 7/3 Richter earthquake of November 2016 in Sarpol Zahab, in addition to the loss of life and property, left many geomorphic effects. In this research, an attempt is made to identify the complications and evaluate the volume of these changes. First, based on the topography, the study area was divided into two parts: mountains and plains, and then the geomorphic effects caused by the earthquake were identified and investigated using aerial photos and satellite images and field visits. Then, the map of the Geological and Mineral Exploration Organization of the country was digitized using the ARC GIS software, and the slope map was prepared from the digital elevation model in the ARC GIS software. These data were used to better display the effect of faults, terrain, formations, domain instabilities and the cause of geomorphic effects caused by earthquakes. The results showed that the presence of resistant layers of Asmari limestone on the Aghajari, Marni and Gachsaran sandstone formations and the weakness and erodibility of these formations cause many geomorphological effects caused by earthquakes such as slope instabilities (Landslides, rockfalls, Deposit flows), ruptures, liquefaction, fluctuations of the underground water level. In addition to the identification of geomorphological effects caused by earthquakes, their location and location in relation to other geological factors were mapped and the role of geomorphological effects in creating secondary hazards and the comparison of these effects in two topographical units of mountains and plains were investigated.

Weather is considered as one of the most important factors shaping tourism, and tourism centers owe their existence and values to many factors, especially suitable weather conditions. In this research, in order to evaluate and zoning the ecotourism calendar in Kurdistan, Kermanshah and Hamadan provinces, Riemann model and Physiological Equivalent Temperature Index (PET) have been used. The comfort conditions of the tourism climate and heat and cold stresses in different days and months of the year were evaluated using the PET index and then zoned in the GIS environment by considering the altitude. The results of the research showed that in most parts of the western region of the country, such as the cities of Sanandaj, Hamedan and Kermanshah, the time of climatic comfort for tourism activities occurs in two separate periods. From the end of May to the middle of October, heat stress is observed and from the beginning of December to the end of March, cold stress is observed in the border areas of Kermanshah.Finally, tourism climate maps of the western region of the country were prepared based on altitude changes and taking into account the relationship between the physiological temperature index and altitude, and by analyzing these maps, suitable times for activities such as mountain climbing in the important heights of the region such as Alvand, Chihel Cheshme, Peru and Shahu were identified.

Drought is one of the most destructive climatic phenomena whose impact is more significant at the regional scale. The importance of drought in an area such as Maharloo Bakhtegan is more important due to the strategic conditions of the region, the extent of agricultural lands and the existence of Maharloo and Bakhtegan lakes. The purpose of this study was to assess drought using remote sensing, spatial statistics, and GIS in the Maharloo-Bakhtegan basin. In this study, to evaluate the effect of drought on vegetation, Madis images were used to calculate the normalized vegetation index (NDVI) and then the changes in vegetation area were investigated. The results showed that the area of vegetation decreased in the studied years. Reasons for these changes can be attributed to reduced winter rainfall, land-use changes, increased off-season grazing, and bushes. The results indicate the drought in the region. Also to study drought in Maharloo-Bakhtegan basin, meteorological data for estimation of normalized precipitation index (SPI) and spatial statistical analysis, from 6 selected synoptic stations (Shiraz, Zarghan, Droodzan Dam, Eqlid, Neyriz, and Abadeh) used from 1999 to 2018. The results of the Moran index for drought showed that the values for different years have a positive coefficient and close to one during the statistical period, indicating that the SPI drought index data have a cluster pattern. The results of the Z standard score and P-value also confirmed the clustering of the spatial distribution of drought.

Today, the vulnerability of cities and especially old and worn-out structures against earthquakes is an important issue for environmental risk experts. The city of Kerman, due to its location in the tectonic zone of central Iran and having large and deep faults and fractures from a geological point of view, can be the source of huge crises, severe losses and casualties; Therefore, in this research, first, by using ASTER satellite images of 2007, the worn-out tissues of Kerman city were identified using SVM. In this study, the kappa coefficient of 76% was determined for all classes, and the kappa coefficient of 59% of the worn-out tissue was determined. The city of Kerman was identified. The results showed that the support vector machine classification method has the ability to detect nearly 75% of the worn-out fabric of the area, and the SVM method has worked very well in identifying the six areas of worn-out urban fabric.