Geography and Environmental Planning
Year:2018 | Volume:29 | Issue:3 (71) |Papers Count:8

Vegetation is the mirror of climate. So getting information on vegetation status, such as their extent and distribution, is of great importance. It is very difficult and costly to gather information about continuous vegetation changes with conventional methods. Therefore, remote sensing is a very useful method that provides a wide view of a region. The purpose of this study is to examine the average long-term average of Iran's coatings with the help of Normalized Difference Vegetation Index (NDVI). In this paper, the 16 days data of NDVI data of MODIS Aqua from 13/4/1381 to 13/12/1393 were exploited from MODIS web page and then in the base of 10 billion of codes, the long term mean of 16 days NDVI of Iran during the years was calculated. As the NDVI of above 0. 2 represents vegetation, the long term mean of vegetation was calculated for each of the 16 days. The findings showed that Iran’ s vegetation in the period of December 26th to January 9th is minimum covering about 8 percent of Iran's territory, and from April 15th to May 1th is maximum with 30 percent of coverage.

Studying hydrodynamic and hydro-chemical properties of springs can be an indicative of the karst development in a karst media. The aim of this study is to determine the hydrodynamic behavior of karstic aquifers and karstification degree of the Alashtar and Nourabad regions by analyzing the physicochemical properties and falling limb of springs hydrographs analysis. To achieve goals of this research, 10 main draining springs were chosen. After the survey of geomorphological, climatic, hydrodynamic, hydro chemical, physiographic properties and several field study, by using Malic and Vojtkova method, the karstification degree was determined. According to the Hydrodynamic Study, Amir, Chenareh and Honam springs and Abdolhosseini and Niaz springs have 2. 5-3 degree of karstification. Also the groundwater flow sub-regimes type is the combination of two or more subregimes with merely laminar flow characterized by different discharge. Zaz and Ahangaran springs have 4 and 4. 3 degree of karstification, respectively, and discharge hydrogram is composed of a subregime with turbulent flow and a sub-regime with laminar flow. Golembahri, Laghari and Teymour springs have 5. 5 degree of karstification and complex discharge regime, a combination of one subregime with turbulent flow and two sub-regimes with laminar groundwater flow. According to the hydrochemical analysis, increasing magnesium ions (Mg), higher cation and anion, increasing in Electrical conductivity (EC) and total hardness (TH) and also lowering the ca/Mg in the Alashtar unit, indicate the presence of dolomitic karstic aquifers, small joints, more contact between water and rock and finally less evolution of karst in Alashtar.

The purpose of this study is to assess the quantitative relationship between the volume of alluvial fans and its relation to active tectonics in the southern slopes of Joghatay Mountains. To achieve this objective, first, the range of alluvial fans, Angle Broom (S) and alluvial fans radius (R) in the software Arc / Gis using digital maps and digital elevation model (DEM) were determined. Then, the difference between the height between the top and base of the alluvial fans (h) was calculated and, based on the above parameters. In order to evaluate the effects of other variables such as tectonic and geomorphic characteristics like lithology using some integral index over the facade (Hi), the index of mountain front sinuosity (Smf), index basin asymmetry (Af), transverse topographic symmetry (T), index ( SL), (BS) and the ratio of valley floor width to depth Valley (Vf). The results of the mean of all indices indicate that 61. 55% of the region is located in the active to semi-active tectonic state, which reveals the role of tectonic factors in providing sediment and increasing the volume of alluvial fans in the region. In addition, the common role of lithological factors and tectonic forces can be pointed out. Due to the nature of some of the faults in the region, the soft and loose deposits including Flysch and neogen marls on hard Conglomerate formation have caused the sediment load more to the regional currents and contributes to the development of alluvial fans in the region. Also, the elevation of alluvial fans sediments and the change in the surface of the local area as a result of the faults activity has resulted in the deep excavation of the base of the rivers. This, in turn, contributes to the development of the alluvial fans as a result of base digging and solid loading, leading to the formation of multi-part and fragmented alluvial fans. In order to homogenize the basins in terms of area, they were divided into three groups and these relationships were analyzed in each group. The results indicate that there is a direct and significant relationship between the feeding basin and the volume of alluvial fans, while there is no such relationship between the slope of the basin and the volume of alluvial fans.

The main goal of this study is to evaluate the wind energy potential in Chaharmahal and Bakhtiari Province to identify suitable rural areas for obtaining wind energy. In order to reach this goal (useing 7 meteorology stations information in the province from 2008 to 2016), the Weibull distribution was used for potentiometric; meanwhile, Kriging was applied to interpolate the area. Weibull estimate was done by using the torque method and the codes was written in Maple software. The steps were: measuring Weibull distribution parameters at different heights; calculating monthly and annual (PA); and EA was earned from calculation of data once in three hours in all synoptic stations. The results showed that only Saman district is appropriate to create wind energy and the other areas are not suggested for this purpose. Another result of the study was the wind potential interpolation maps with rural area distribution and without dispersion of them.

Lakes act as a system. Climate, mathematical position, physiographic features (including basin area, perimeter, length, shape, slope, aspect and time of concentration), rugged topography and gravity center (geometric gravity center of basin, geometric gravity center of lake, hydrological gravity center and geomorphological gravity center) are among the affecting factors of lakes survival or destruction. With regard to the peaks, the topographic lines and waterways of the 14 Iranian basins (Urmia, Gavkhoni, Maharloo, Meighan, Qom, Duranjyr, Jazmurian, Abarkuh, Bafegh, Ardestā n, Yazd, Qatruyeh, Sirjan and Lut) have been delineated according to the peaks, topography and drainage lines in 1/50000 topographic maps and by the use of Arc GIS software. Altitude of water and dry equilibrium line in some of lakes such as Urmia, Gavkhoni, Meighan, Qom and Maharloo was extracted from the source documents. For the rest of basin lakes, reflected evidence in topographic maps was used. In climatic calculations, temperature and precipitation of the database Asfezari with 50 years duration was used. Lake water volume was calculated according to the altitude of water and dry equilibrium line and the volume of annual rainfall was computed based on basin area in geographic information system. By dividing the volume of lake's water by the volume of precipitation, runoff coefficients have been estimated. Afterwards, geomorphological gravity center and lake and basin's geometric gravity center were determined. Hydrological gravity center was estimated based on river's discharge data. Analyzing the result of holes, runoff coefficient showed the fact that Lut, Dranjyr, Gavkhoni, Abarkuh and Qom basins have allocated the lowest runoff coefficient. The similar coefficients of Gavkhoni and Qom basin's with Lute basin, represent how distanse between basins’ topographic center and geometric center can affect the amount of runoff coefficient. High runoff of Qatruyeh, Ardestā n and Sirjan watersheds are as the result of complaining the lowest part of topography with geometric center of the basin. Gravity center of lake have located in the topographic center of Bafgh basin and, this affected the location of Meighan and Maharloo basins accordingly.

Perception is a collection of external stimulus processes driven by schemas. Foreign stimulants include a wide range of which one of its most important elements is the climate. The goal of this research is to investigate the link between micro-climate and space in the human mind as well as the analysis of the impact of the climate on the perception of urban space. This research targets the Park of El Gholi in the city of Tabriz and attempts to prove this hypothesis that: the micro-climate is an important part of the detailed perception of a space; and also is a key factor in shaping our mental schemas against a space, and the way we understand the space. The research has been performed in a qualitative method using cognitive maps and interview with sample candidates, which is one of the most utilized tools in studying the link between climate and space. The results show that for an urban space to achieve success and be accepted by all its users as well as the presence of people in it, the conditions of the space’ s micro-climate should be taken into account. Because, the climate is considered as a determinative factor in shaping desired mental schemas from a space by people, and the climate as an ecological factor, has an important impact on people perception from a known space.

One of the goals of geomorphologists in working with the models of different landforms is to obtain better relations in realizing the physical realities of environment. In this study, the efficiency of geomorphometric parameters in increasing the accuracy of landslide sensitivity zoning maps has been evaluated. First, the zoning map was prepared via using the first 9 effective parameters in the landfall occurrence including slope, aspect, elevation, land use, lithology, distance from roads, rivers and vegetation index (NDVI). In the next step, the geomorphometric parameters involve in the occurrence of landslide including topographic location index (TPI), surface curvature, curved sections, slope length (LS), Topographic wetness index(TWI), stream flow power (SPI), surface area ration index (SAR), were added to the model and then plotted to the map. In the last step, the zoning maps of the two approaches were evaluated using the ROC curve. For preparing zoning maps, a new hybrid model was used. In order to determine the weight of the criteria, the multivariate regression method was used and the frequency ratio method was used to determine the weight of the classes. Finally, the linear regression relationship of the type of audit analysis was used as the basis of preparation and comparison of landslide sensitivity map and applied to the two approaches without using geomorphometric indices. The findings of this research indicated that geomorphometric indices have a significant effect on increasing the accuracy of the identification of landslide sensitive areas and increasing the accuracy of the zoning map from 0. 731 to 0. 938. These indices have also increased the resolution of the slip layers. According to the results of the topography location indices parameters, surface curvature and surface ratio have the highest influence on the accuracy of zoning maps. Based on the results of zoning with geomorphometric parameters, 8/68 percent (6737 ha) of the region are at very high risk and 15. 3% (11906 ha) have been identified as high-risk areas. Considering the high power of geomorphometric parameters in determining the sensitive areas of slip, it is recommended to use these parameters in landslide zonation.