Showing 17 results for Changes
Zahra Hedjazizadeh, Sayyed Mohammad Hosseini, Ali Reza , Shokofe Layeghi,
Volume 0, Issue 0 (3-1921)
Abstract
Drought is a natural hazard that annually causes significant economic, social, environmental, and life-threatening damage in vast areas of the Earth. The damages caused by this phenomenon are intangible but very extensive and costly, which, if necessary, remote sensing techniques can be a useful tool in monitoring drought due to high temporal accuracy, wide spectral coverage, ease of access, no need for atmospheric correction and ground referencing. In recent years, the province of Hamedan has faced many problems due to frequent droughts. Therefore, the present study focused on investigating and monitoring drought in Hamedan province using the Temperature Condition index and its impact on the vegetation cover of the province using Advanced Very High Resolution Radiometer (AVHRR) and National Oceanic and Atmospheric Administration (NOAA) remote sensing data. First, the relevant data was extracted from the Nova star database, and finally, the spatiotemporal behavior of the vegetation cover drought index was examined on 1528 pixels in Hamedan province. The spatial resolution of the data used in this study is 4 kilometers. First, the relevant data were extracted from the Navstar database and ultimately, the spatiotemporal behavior of the drought index and vegetation cover was examined. The results indicate that drought has significantly increased the vegetation cover of Hamedan province based on remote sensing data. Kendall's coefficients indicate the presence of decreasing trends in vegetation cover at a 95 Percent confidence level. Only in May, June, and December has there been a slight decrease in vegetation cover within the extent of drought in the province. The spatial behavior analysis of the drought index on vegetation cover showed that February, March, as well as April have experienced more severe droughts within Hamedan province.
Hossein Asakereh, Mehdi Dostkamian,
Volume 15, Issue 36 (6-2015)
Abstract
All the water vapor of atmosphere is contained in a column of the atmosphere that is capable of precipitation and it is from the ground to the final of water vapor called perceptible water. This element influenced by topography and height. The purpose of this study is survey about impact of local and spatial factors on distribution of perceptible water maximums in Iran.For this reason, pressure data, especially moisture, orbital and meridional components extracted from NCEP/NCAR and analysis. Correlation and regression methods were used in this study. In order to better survey about perceptible water gradient changes and gradient changes of maximum of perceptible water has been calculated. Results showed that among the spatial factors, height has greatest impact on the spatial distribution of the maximum of perceptible water. Unlike many scientists who believe that by increasing the latitude perceptible water reduced, this rule is less In Iran atmosphere. However, most of the gradient changes of perceptible water occurred in some parts of the Zagros highlands, West and South West. The results of cycle analysis showed that the maximums of perceptible water in Iran have short term cycles between 2 to 4 years.
Ahmad Mazidi, Mahdi Narangifard,
Volume 16, Issue 40 (6-2016)
Abstract
Expansion of urban areas has impacted on climate in local and global scale. As a result, residents’ life would be influenced accordingly. In this study, the effects of changes in land cover and land use change on climate of Shiraz and Fasa were studied in a long-term period. To ensure the normal data, Kolmogrov-Smirnoff test was employed. The minimum and maximum temperature parameters and relative humidity were evaluated using non-parametric Mann-Kendall and regression method in a 45-year period (1966-2010). The results showed a decreasing trend for the minimum temperature and humidity for Fasa and minimum and maximum relative humidity for Shiraz whereas other quantities showed an increasing trend. The study examined the effects of land use changes and land cover types in the 23-year period (1987-2010) using images of LANDSAT satellite of TM sensor on temperature pattern in two cities. During these 23 years, a reduction of 113 square kilometers for barren land of Shiraz and 5/7 square kilometers for barren land of Fasa and extending 110 kilometers residential users and 3/5 square kilometers in Shiraz and Fasa were reported.
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Volume 16, Issue 42 (12-2016)
Abstract
In Iran the issue of occurring natural disasters, particularly mesoscale convective systems. They are important on one hand, because of their increasing intimidations and causing damages and on the other hand, because of their increasing abundance, time of duration, and happening. Therefore life cycle, constituton condition and mesoscale convective systems features in west of Iran using satellite and extention area index and thresholds of brightness temperature 221 and 243 K have been studied. After their statistic analysis, based on mesoscale convective system importance, life and daily cycle, behavior parameters, and synoptic conditions of this system life cycle were analysed. Most of the systems have been formed in southeastern Iraq and in western Zagros hillsides. Wile puberty stages (the maturity) and their expandings were increased with the height increase; in turn, declining of the systems began by passing Zagros chain mountains. The system extention area at the system life cycle starting increases with a smooth process; whereas the reduction process of the system extention area at the declining stage was severe and sudden.
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Volume 17, Issue 46 (12-2017)
Abstract
This research tends to analyze and assess the impact of intercity flows rate on land use changes around the community roads of the cities of Babol, Ghaem Shahr and Sari. This research is descriptive-analytic and performed in quantitative method. A wide range of techniques including gravity model, flow analysis model, entropy analysis and GIS software environment were applied for performing required analysis. Research findings show that increase in passenger transfer and cargo transit in the community roads of the cities of Babol, Ghaem Shahr and Sari, resulted in increase in applications for land use changes around these roads; of course, the impact of passenger transfer (with correlation coefficient of 0.72) was higher than cargo transit (with correlation coefficient of 0.43). Concerning their existing interactions and multicenter of the studied area (based on entropy analysis), codification of control system and integrated spatial management is hereby suggested in form of a comprehensive urban plan toward supervising and managing land use changes in suburban areas of the aforesaid cities.
Dr Sayyad Asghari, Hadi Emami,
Volume 19, Issue 53 (7-2019)
Abstract
Earth surface temperature is an important indicator in the study of energy equilibrium models at the ground level on a regional and global scale. Due to the limitation of meteorological stations, remote sensing can be an appropriate alternative to the Earth's surface temperature. The main objective of this study is to monitor the surface temperature and its relationship with land use, which is monitored using satellite imagery. For this purpose, the images were first obtained and the necessary pre-processing was applied to each one. Then it was compared to modeling and classification of images. Firstly, in order to investigate the changes in user-orientation, a user-defined classification map for each object was extracted using the object-oriented method. Then, to investigate the land use change, a map of user-landing changes map was extracted in an 18-year time period (2000-2017). Finally, in order to monitor the surface temperature, the surface temperature map of Ardebil was extracted. The results showed that there is a strong relationship between land use and surface temperature. As a user, urban users have a temperature of about 41 ° C (2017), which is also due to heat-absorbing urban temperatures. This is despite the fact that the use of hydrocarbons is due to a lower heat absorption of 34 ° C (2017). This shows the role of different uses in determining surface temperatures. Also, the relationship between surface temperature and vegetation cover was investigated in this study. The results showed that areas such as soil and urban areas with a lower coverage than areas such as agriculture and pasture, have a higher temperature. Because the coating is always an obstacle to the entry of heat, it has an inverse relationship with superficial heat.
Miss Rahimeh Rostami, Dr. Ali Mohammad Khorshiddust, Dr. Mohammadreza Nikjoo, Dr. Hassan Mahmudzadeh,
Volume 19, Issue 55 (12-2019)
Abstract
The drying of Lake Urmia has had many environmental impacts on the surrounding areas of the lake. In this research, efforts have been made to identify vegetation coverings that are compatible with the study area and then it use of multiplicative decision-making models for identify areas susceptible to cultivation of these products. In the present study, following the study of species in the region of rapeseed, was selected as a suitable halophytes plant. Initially, using Landsat 5 and 8 images, the changes in the land use type and vegetation cover type of the region were investigated from 2000 to 2016, and after calculating the changes, the potential planting of the halophytes plant was sought. The ANP Fuzzy method was used to estimate the ability to cultivate rapeseed. Main criteria used in this research are topography, soil and meteorology. The topographic sub criteria are included: height, slope and tilt direction, soil criteria including soil texture, soil salinity, and soil pH and soil organic matter. Finally, the criteria for meteorological data are total annual precipitation, Relative humidity, average annual temperature, maximum annual temperature and annual minimum temperature. These layers first be changed to fuzzy and then, applying the weight of each of the following criteria, a map of the main criteria of soil, topography and meteorology was prepared and finally, by combining these three main parameters, the potential mapping was obtained. The results indicate a 25.43 percent reduction in water content and an increase of 21.03 percent in saline areas between 2000 and 2016, and the results of identifying areas susceptible to cultivation of halophytes plants have identified 14.28 percent of the study area suitable for rapeseed cultivation.
Siyamack Sharafi, Masoud Sadeghirad, Zahra Javadi Nia,
Volume 20, Issue 56 (3-2020)
Abstract
the occurrence of landslides in the direction of rivers, especially in the mountainous regions of Zagros range are processes that block rivers and form lake barriers. Della Landslide is an example of such landslide that occurred in the course of Shimbar River drainage and eventually created Lake Shimbar. geoarchaeological field studies performed on this slide using topographic maps, geological, digital model of the area, satellite images and Arc GIS software on the landslide and basin lake Shimbar resulted in the identification of the causes of landslides and changes in three stages of the lake. This study eventually rebuilds Paleogeomorphology of landslide area and the lake's dam Shimbar. The results showed that the main cause of the occurrence of landslides were tectonic processes in the region and based on archaeological evidence and the archaeological excavation of the canal, the landslides occurred before 2000 years ago. The formation and changes in the scope and depth of the lake Shimbar in 3 stages blocked the migration routes in area for a long time.
Dr Mohammad Ebrahim Afifi,
Volume 20, Issue 56 (3-2020)
Abstract
Land use maps are considered as the most important sources of information in natural resource management. The purpose of this research is to review, model, and predict landslide changes in the 30-year period by LCM model in Shiraz. In this research, TM Landsat 4, 5 and OLI Landsat 8 images were used for 1985, 2000 and 2015 respectively, as well as topographic maps and area coverage. Subsequent validation and detection of changes were made using the prediction model of variation The use of LCM markov and the model of user change approach. The images were classified into four classes of Bayer, garden, urban lands, and arable land for each of the three periods. According to the results, aquaculture is the most dynamic user in the area, which has led to an upward trend during 1985-2015, so that the amount (4337 ha, 12.7%) has been added to this area. The Bayer user change trend was also a downward trend during 1985 to 2015, reducing the 99.1995 hectares of this class. The results of the change in the 1985 changes with a kappa coefficient of 0.88, in the 2000 period with a CAAP of 0.77, and in the period 2015 with a Kappa coefficient of 0.92. The results of the change detection in 2030 are such that if the current trend continues in the region, 20.33% will be added to the crop category, so that in 2030, agricultural cropping will be 95.60% of the area of the area Gets In the Bayer and Garden uses 21.22% and 0.21% of the total area of each user has been reduced and has been added to the urban area. The prediction map derived from the Markov chain model is very important for providing a general view for better management of natural resources.
Dr Hossein Asakereh, Nasrin Varnaseri Ghandali,
Volume 22, Issue 64 (4-2022)
Abstract
Change in precipitation features is one of climate change outcome. Change in precipitation amount, especially in warm season, may influences climato-environmental phenomenon as well as human activity. In current research the decadal changes of monthly precipitation over the Caspian coast of Iran territory was evaluated. Accordingly, a large number of rain gauge stations (385 stations), where rainfall is measured painstakingly, have been used. these stations are under the supervision of Meteorological Organization of the country and Ministry of Energy. Since the original dataset pertaining to the precipitation prior to 1966 had noticeable missing values, and the data after 2016 were not accessible, a continuous time period from January 1966 to December 2016 was selected. From the daily precipitation of aforementioned stations contour maps were created using an ordinary Kriging method. The spatial resolution of these precipitation maps was 3 km * 3 km. Our finding showed that during the under investigation period the maximum gradient of precipitation moved from coastal parts toward mountainous area. Decrease in the area with high precipitation and increase in the low precipitation area is an other prominent decadal characteristics. According to the previous study, these changes might attributed to changes in systems which effect precipitation in the Caspian coast of Iran (northward movement in polar vortex, sub-tropical high pressure and cyclone truck). In addition, increasing temperature trends in the summer tend to decrease temperature spatial differences. Therefore, the convectional precipitation during summer has been decreased.
Asghar Teymouri, Dr Jamileh Tavakolinia, Dr Abolfazl Meshkini,
Volume 22, Issue 65 (6-2022)
Abstract
Increasing urbanization in the urbanized world has posed major challenges to the sustainability of metropolitan areas, especially in developing countries in various aspects of sustainable development, and has provided them with the prospect of unsustainable development. Excessive land use and its consequent land use changes and land cover are one of the environmental problems caused by the high concentration of population and activity in metropolitan areas. This study is an applied one in order to monitor the environmental changes caused by spatial expansion of Tehran metropolitan area by descriptive-analytical method and by using remote sensing and GIS techniques land use changes and land cover caused by spatial expansion of Tehran metropolis. Has evaluated and analyzed Tehran. The results indicate that the area of land increased from 34316.1 hectares in 1365 to 68252 67.95 in 1595/6117 hectares related to changes in agricultural lands, orchards and water area. Be it. The results of the Markov Chain Model prediction of the probability of land use changes and land cover up to 1405 also indicate that land use and land cover changes will continue in favor of constructed lands. It is concluded that Tehran's metropolitan area has expanded beyond the demographic and ecological thresholds and has led to a significant structural disruption to the environment by moving toward the natural environment. Accordingly, the need to pay attention to new approaches to urban development as well as to provide decentralization scenarios can be a major step towards resolving environmental problems caused by over-spatial expansion.
Negar Ghasemi, Marzieh Alikhah Asl, Mohammad Rezvani,
Volume 22, Issue 66 (10-2022)
Abstract
Study of resources changes in previous years could be useful in the planning and optimal using of resources to control inappropriate changes. Because land use changes occur on large-scale, remote sensing technique is a useful and valuable tool for monitoring the changes. The aim of this research is land cover changes detection in a period of 32 years in Pishva town with using remote sensing technique .First TM, ETM and OLI images for the years 1986, 2002 and 2018 were collected respectively and after geometric and radiometric corrections, images were classified by using maximum likelihood classification methods. Kappa and overall indexes were used to calculate classification accuracy. Results showed in past 32 years, bare land and irrigated land have decreased while residential and greenhouse areas have increased. Classification accuracy showed that OLI, ETM and TM sensors have high accuracy respectively with kappa 0.96, 0.80 and 0.76 and also overall indexes of 97.56, 86.54 and 86 percent. Based on results, in the first period (1986-2002) 27.6%, in the second period (2002-2018) 29.60% and in the third period (1986-2018) 31.8% of area land cover have been changed. Results showed land cover changes in the area is related to climate changes like low precipitation, drought and social condition like population and food need increasing and economic condition like high production and efficiency.
Dr Amir Saffati, Dr Ezatallah Ghanavati, Mr Hamid Alipour Dezdouli Asl,
Volume 23, Issue 68 (4-2023)
Abstract
Studying the morphology of the rivers and identifying the causes of these changes are widely useful in determining the evolution of rivers and planning the maintenance of the river system. The Karun River, between Bandar-e-Khoramshahr and the constant flow of water in the country, plays an important role in the country's water cycle. Due to the morphological changes of this river that have disrupted the normal functioning of the river, it is necessary to investigate the morphological changes and its causes. In this study, with the aim of investigating these changes with satellite imagery, Landsat images for 1990, 2005 and 2018 were prepared and morphological changes were extracted after required processing. The results show that out of the 36 investigated sections, the width of the river has decreased in 29 sections so that it has narrowed to 450 m around Ahwaz. In order to investigate the causes of changes, the effective parameters in changes such as precipitation, discharge, runoff coefficient, waterway length, permeability coefficient, landform, lithology, land use change, wasteland, slope percentage, drainage density and vegetation density, land Theology and floodplains, To assess the hazards of the area, were used. Floodplain parameter was extracted using ANP_Fuzzy model and landslide and land use parameters were extracted using SVM model. Among the factors affecting these changes that were investigated using logistic regression models and factor analysis were land use changes, vegetation density and sediment yield. These changes have resulted in the destruction of natural habitats along the river, the ability to self-purify water, sudden floods, threatening and damaging human structures, agriculture, and so on.
Mr Alireza Thernasab, Dr Leila Ebrahimi, Dr Ameneh Haghzad, Dr Mehrdad Ramezan Por,
Volume 23, Issue 71 (1-2024)
Abstract
Today, urban and rural planning and management programs need to obtain accurate spatial information at successive times about land use changes. The main purpose of this study is to study and evaluate land use changes due to physical development with respect to 4 land uses in Bayer, agricultural lands, water zones and man-made lands in Pakdasht. Data were collected through Landsat satellite images from 2019 and 1989 captured by OLI and MSS5 sensors with a resolution of 30 m, which transformed Landsat 8 and 7 satellite images to 15 m in ENVI 5.3 software. These images were classified in ENVI 5.3 software based on the maximum likelihood algorithm. Then the accuracy of the maps obtained from the maximum likelihood algorithm was estimated. Fragstats software was then used to extract land cover metrics at two levels of the classroom and the simulator. A total of 15 landslides were quantified in the years 1989 to 2019 (1368-1688). According to the results, the area of residential land has increased during the years under study so that its share has increased from %7.1 in the region to %19.5.
Dr Raoof Mostafazadeh, Dr Fariba Esfandiary, Miss Mahnaz Hamzeei, Miss Nazila Alaei,
Volume 24, Issue 72 (6-2024)
Abstract
The purpose of this study was to evaluate the temporal variations of vegetation cover of Gharesou River riparian area in Ardabil province using landscape metrics over a period of 8 years which is important for morphology assessment and river ecosystem protection planning and management. The Google Earth imagery for the years 2011, 2016, 2019 due to their live view and high resolution were used to map the Gharesou River riparian area vegetation. Correlation analysis in R environment was used to evaluate the relationship between landscape metrics in the study time period. The results showed that there is an increase in the number of patches, which showed an increase in landscape fragmentation of the riparian area vegetation. Landscape connectivity index was 91.52% to 95.49% in this region during the study period, indicating the removing small patches of vegetation communities around the river. The number of patches in the present study showed an increasing trend, which was the highest amount at 2019 year. The results of changes in the width of the Gharesou River showed that the river width in 2019 was 27.43m and 3.97 m, respectively. Comparison of river width values over the three study periods indicates an increasing trend in river widths, which may be due to the limitation of river width by human activities or the protection of river banks to protect agricultural lands against flooding effect. Also, the correlation of river width showed that the correlation between time period 2019 and 2016 was 0.63 and significant at 0.001 levels. The lowest correlation between the period 2019 and 2011 was 0.30 at 5% significant level. In conclusion, the results of changes in riparian area communities can be linked to the extension of agricultural land adjacent to the main river course.
Hamed Heidari, Darush Yarahmadi, Hamid Mirhashemi,
Volume 24, Issue 75 (2-2025)
Abstract
Human interventions in natural areas as a change in land use have led to a domino effect of anomalies and then environmental hazards. These extensive and cumulative changes in land cover and land use have manifested themselves in the form of anomalies such as the formation of severe runoff, soil erosion, the spread of desertification, and salinization of the soil. The main purpose of this study is to reveal the temperature inductions of the land cover structure of Lorestan province and to analyze the effect of land use changes on the temperature structure of the province. In this regard, the data of land cover classes of MCD12Q2 composite product and ground temperature of MOD11A2 product of MODIS sensor were used. Also, in order to detect the temperature inductions of each land cover during the hot and cold seasons, cross-analysis matrix (CTM) technique was used. The results showed that in general in Lorestan province 5 cover classes including: forest lands, pastures, agricultural lands, constructed lands and barren lands could be detected. The results of cross-matrix analysis showed that in hot and cold seasons, forest cover (IGBP code 5) with a temperature of 48 ° C and urban and residential land cover (IGBP code 13) with a temperature of 16 ° C as the hottest land use, respectively. They count. In addition, it was observed that the thermal inductions of land cover in the warm season are minimized and there is no significant difference between the temperature structure of land cover classes; But in the cold season, the thermal impulses of land cover are more pronounced. The results of analysis of variance test showed that in the cold period of the year, unlike the warm period of the year, different land cover classes; Significantly (Sig = 0.026) has created different thermal impressions in the province. Scheffe's post hoc analysis indicated that this was the difference between rangeland cover classes and billet up cover.
Reza Kheyroddin, Nazanin Mostafavi Esfahani,
Volume 24, Issue 75 (2-2025)
Abstract
Landuse planning goals as the main core of urban planning are classified and studied from different aspects. The inclusion of additional value of surplus funds in the city can highlight capital funding. Following this, changes in urban land demand as the spatial changes of activities and functions occur.The commercialization of residential areas and the tendency of residential landuse changes are the disadvantages of these changes,which constitute a major part of residential neighborhoods of Tehran metropolis ,especially the northern neighborhoods of the city. The main structure of Nasr neighborhood in the 2th district of Tehran is based on Gisha street. The most important issue is multiplicity of commercial land uses in the Gisha street. According to the observations there is a bank in every 45metres of the street , while the performance radius of bank activities is defined in the region scale. It is argued that land price growth, financial and speculative justifications of these changes can cause pressure on the environment.Therefore, according to the above mentioned factors,the main objective of this study is identifing the factors affecting landuse changes in the Gisha street.
The research method in this study is documentary , local survey as well as the use of factor analysis in order to determine factors affecting landuse changes.By using this method, accessibility,landeconomics and activity distribution and neighborhood structure were considered as three factors affecting land use changes in the Gisha street .
Finally, in order to plan to control the speculative consequences of these changes , the analysis of external and internal factors with regard to indicators in questionnaire, SWOT table and finally defensive strategy to offer strategies and policies was adopted these strategies were presented in two categories: sustainable management of income sources of urban management and control of changes in land use changes.
