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Showing 4 results for Arabi
Sahar Darabi Shahmari, Amir Saffari,
Volume 6, Issue 2 (9-2019)
Volume 6, Issue 2 (9-2019)
Abstract
Landslide susceptibility mapping is essential for land use planning and decision-making especially in the mountainous areas. The main objective of this study is to produce landslide susceptibility maps (LSM) at Dalahoo basin, Iran using two statistical models such as an index of entropy and Logistic Regression and to compare the obtained results. At the first stage, landslide locations identified by Natural Resources Department of Kermanshah Province is used to prepare of LSM map. Of the 29 lanslides identified, 21 (≈ 70%) locations were used for the landslide susceptibility maps, while the remaining 8 (≈ 30%) cases were used for the model validation. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, distance to faults, distance to rivers, distance to roads, land use, and lithology were extracted from the spatial database. Using these factors, landslide susceptibility and weights of each factor were analyzed by index of entropy and Logistic Regression models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and the areas under the curve (AUC) were calculated. The verification results showed that the index of entropy model (AUC = 86.08%) performed slightly better than conditional probability (AUC = 80. 13%) model. The produced susceptibility maps can be useful for general land use planning in the Dalahoo basin, Iran.
Hossein Varjavand Naseri, Asghar Tahmasbi, Hasan Darabi, Ahmadreza Yavari, Mohammadjavad Amiri, Gholamreza Nabi Bid Hendi,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
Extended Abstract:
The increasing challenge of water in many regions of the country is rooted in inappropriate governance of water resources at the basin levels. Investigating the interactions of different stakeholders and institutional arrangement affecting it is one of the key elements of governance system. The most important obstacle to achieving the optimal governance model of water resources in developing countries is the unknown path from governmental management, to good governance. The analysis of stakeholders and influential entities on their interactions is considered as one of the important pillars of governance assessment frameworks.
Accordingly, the purpose of this study is to evaluate the water resources of Zayandeh roud basin from the perspective of interactions between actors and formal institutions affecting their interactions. In this regard, it is attempted to answer two main questions: firstly, what is the organizational structure in management of Zayandeh roud?, Second, how far are the organizations’ policies and programs involved in the management of the watershed ?
In this study, Isfahan, Chaharmahal - bakhtiari , Khuzestan and Yazd which are related to the river basin issues, were selected for social network analysis. Organizations and governmental and non- governmental institutions related to the process of sustainable management were questioned. In this regard, according to the numerous studies conducted in the field of Zayandeh roud and Gavkhoni wetland , the number of organizations and related institutions were identified. Then, the network matrix of actors’ policy and collaboration was formed and centrality indices of input and output grades and betweenness centrality indices were measured through Ucinet software.
There are a wide range of active actors in management of Zayandeh roud river basin, each in an attempt to obtain more water resources from this river. As mentioned in the conceptual framework of the research, two key aspects are investigated. Key stakeholders analysis and their role in water resource management and review of actors ' policies in water resource management in two dimensions of belief in changing policies, and the need to change policy from the viewpoint of other actors. Accordingly, the research findings are presented in the following parts.
Accordingly, the purpose of this study is to evaluate the water resources of Zayandeh roud basin from the perspective of interactions between actors and formal institutions affecting their interactions. In this regard, it is attempted to answer two main questions: firstly, what is the organizational structure in management of Zayandeh roud?, Second, how far are the organizations’ policies and programs involved in the management of the watershed ?
In this study, Isfahan, Chaharmahal - bakhtiari , Khuzestan and Yazd which are related to the river basin issues, were selected for social network analysis. Organizations and governmental and non- governmental institutions related to the process of sustainable management were questioned. In this regard, according to the numerous studies conducted in the field of Zayandeh roud and Gavkhoni wetland , the number of organizations and related institutions were identified. Then, the network matrix of actors’ policy and collaboration was formed and centrality indices of input and output grades and betweenness centrality indices were measured through Ucinet software.
There are a wide range of active actors in management of Zayandeh roud river basin, each in an attempt to obtain more water resources from this river. As mentioned in the conceptual framework of the research, two key aspects are investigated. Key stakeholders analysis and their role in water resource management and review of actors ' policies in water resource management in two dimensions of belief in changing policies, and the need to change policy from the viewpoint of other actors. Accordingly, the research findings are presented in the following parts.
- decision making and facilitating information flow
- Power and control of actors in the network of organizational collaboration
- Co - ordination role in the enterprise - cooperative network
The findings of this research show that in the dimension of capacity and flow of information watershed management, Regional water organization in Isfahan province and in the next rank of water resources management, Zayandeh roud coordination council and Isfahan provincial governor are organizations that have high output degree and can play a key role in information flow. In other words, information that is necessary for the actors and other organizations is better flowed by these organizations.
In terms of supervision on the network of interactions and control over other actors in the basin, which was measured with the degree of centrality of input, Isfahan parliament representatives in the first and the agriculture jihad of Isfahan province gained the highest rank respectively. After these organizations which are mainly government and dependent entities, non - governmental organizations of three other provinces have the lowest rank in terms of ability to control the network. The lower power of NGOs in the social network of the organization indicates a low planning system for the management of the watershed. Comparative studies in the river basin show that the feature of the extent and diversity in the social - ecological system of a watershed among several distinct political areas can reveal the importance of the position of organizations that have a bargaining power in the watershed management network.
Betweenness centrality index in information exchange network has a fundamental role. The actors with the intermediary rate and high control power among the organizational stakeholders are the same organizational entrepreneurs who have an important role in establishing relationships and increasing interactions among other actors. If the actors with high degree of mediation are removed from the network, information exchange in the network will be disrupted.
It is obvious that without knowing these corporate entrepreneurs or in other words, actors with high mediation ability in the exchange information network, any activity in the direction of comprehensive management of land and sustainable development will be associated with time and cost. In connection with the task of coordination in watershed management, the Jihad of agriculture organization, department of environment and water room committee of Isfahan have obtained the highest degree of betweenness centrality which seems to be a suitable place due to their organizational functions. In this regard, attention and reinforcement of organizations such as NGOs and parliament representatives of three other provinces and provincial governor of these three provinces with low degree of betweenness centrality can be suggested. The lack of such interaction is undoubtedly one of the challenges facing sustainable management of the region. According to the results of other studies, it can be said that to achieve sustainable and integrated management of land and preservation of natural areas, it is necessary to study the pattern of relationship between organizational stakeholders.
The results show that the Regional water organization of Isfahan province and the Zayandeh roud coordination council have a higher position in decision making and information flow. On the other hand, the high performers of water resources such as Iran’s water resources management company and the Zayandeh roud coordinating council and in the next level, Regional water organization, the provincial governor and the parliament representatives of Isfahan are the best critics of the watershed governance. In contrast policies of jihad agricultural organization, farmers and Regional water organization of Isfahan have been criticized by other actors.
In terms of supervision on the network of interactions and control over other actors in the basin, which was measured with the degree of centrality of input, Isfahan parliament representatives in the first and the agriculture jihad of Isfahan province gained the highest rank respectively. After these organizations which are mainly government and dependent entities, non - governmental organizations of three other provinces have the lowest rank in terms of ability to control the network. The lower power of NGOs in the social network of the organization indicates a low planning system for the management of the watershed. Comparative studies in the river basin show that the feature of the extent and diversity in the social - ecological system of a watershed among several distinct political areas can reveal the importance of the position of organizations that have a bargaining power in the watershed management network.
Betweenness centrality index in information exchange network has a fundamental role. The actors with the intermediary rate and high control power among the organizational stakeholders are the same organizational entrepreneurs who have an important role in establishing relationships and increasing interactions among other actors. If the actors with high degree of mediation are removed from the network, information exchange in the network will be disrupted.
It is obvious that without knowing these corporate entrepreneurs or in other words, actors with high mediation ability in the exchange information network, any activity in the direction of comprehensive management of land and sustainable development will be associated with time and cost. In connection with the task of coordination in watershed management, the Jihad of agriculture organization, department of environment and water room committee of Isfahan have obtained the highest degree of betweenness centrality which seems to be a suitable place due to their organizational functions. In this regard, attention and reinforcement of organizations such as NGOs and parliament representatives of three other provinces and provincial governor of these three provinces with low degree of betweenness centrality can be suggested. The lack of such interaction is undoubtedly one of the challenges facing sustainable management of the region. According to the results of other studies, it can be said that to achieve sustainable and integrated management of land and preservation of natural areas, it is necessary to study the pattern of relationship between organizational stakeholders.
The results show that the Regional water organization of Isfahan province and the Zayandeh roud coordination council have a higher position in decision making and information flow. On the other hand, the high performers of water resources such as Iran’s water resources management company and the Zayandeh roud coordinating council and in the next level, Regional water organization, the provincial governor and the parliament representatives of Isfahan are the best critics of the watershed governance. In contrast policies of jihad agricultural organization, farmers and Regional water organization of Isfahan have been criticized by other actors.
Zahra Arabi, Ayub Badragh Nejad,
Volume 8, Issue 4 (3-2022)
Volume 8, Issue 4 (3-2022)
Abstract
Introduction
Drought is one of the environmental disasters that is very frequent in arid and semi-arid regions of the country. Rainfall defects have different effects on groundwater, soil moisture, and river flow. Meteorological drought indices are calculated directly from meteorological data such as rainfall and will not be useful in monitoring drought if the data are missing. Therefore remote sensing technique can be a useful tool in drought measurement. Drought is a recognized environmental disaster and has social, economic, and environmental impacts. Shortage of rainfall in a region for long periods of time is known as drought. Drought and rainfall are affecting water and agricultural resources in each region.
Materials & Methods
The present study is a descriptive-analytic one with emphasis on quantitative methods due to the nature of the problem and the subject under study. In this study, the Tera Sensor Modis satellite images from 2000 and 2017 were used to verify the existence of wet and drought phenomena. In the next step, by examining the rain gauge and synoptic data of the existing stations and using a standardized precipitation index model of three months (May, June and April), the sample was selected. Next, we compared the temperature status indices (TCIs) and vegetation health indices (VHIs) in these three months to determine the differences in these indices over the three months. Modi satellite Tera satellite was used to find out the vegetation status in the study area. Subsequently, using the condition set for the NDVI layer, the vegetation-free areas were separated from the vegetated areas. Experimental method was used to determine the threshold value of this index. For this purpose, different thresholds were tested, with the optimum value of 1 being positive. NDVI is less than 1 plant-free positive and more than vegetation-free. MODIS spectral sensing images for ground surface temperature variables, with a spatial resolution of 1 km, including bands 31 (bandwidth 1080/1180 central bandwidth / 11.017 spatial resolution 1000 m) and 32 bands- 770/11 Central Wavelength Band 032/12 Spatial Resolution Power (1000 m) Selected for months that are almost cloudless. All images have been downloaded from the SearchEarthData site and have been edited. The total rainfall of June, April, and May for the 20-year period was provided by the Meteorological Organization of Iran. ARC GIS software and geostatistical methods were used to process the Excel data. Also, to estimate the correlation between the data Pearson's correlation coefficient was used.
Results & Discussion
The standardized precipitation index is a powerful tool in analyzing rainfall data. The purpose of this study was to compare the relationship between remote sensing indices and meteorological drought indices and determine the efficiency of remote sensing indices in drought monitoring. Correlation between variables with SPI index was evaluated and calculated. The results of the indicators are different, so a criterion should be used to evaluate the performance of these indicators. SPI index on quarterly time scale (correlated with vegetation) as the preferred criterion Selected. According to the results of correlations, the TCI index with the SPI index had a strong correlation with other indices. In the short run, this index has the highest correlation with thermal indices at 1% level. The correlation between meteorological drought index and plant water content and thermal indices increases with increasing time interval. Positive correlation between vegetation indices and plant water content with meteorological drought indices indicates that trend of changes is in line. Therefore, the TCI index makes drought more accurate and is a better method for estimating drought.
Conclusion
The results showed that among the surveyed fishes, the highest drought trend was observed in the eastern part of these provinces and covered more than 50% of the area. The trend of changes in this slope was statistically significant. According to the results of correlations, the TCI index with the SPI index had a strong correlation with other indices. It can also be concluded that the Modis images and the processed indices along with the climate indices have the potential for drought monitoring. Using maps derived from drought indices can help improve drought management programs and play a significant role in mitigating drought effects.
Keywords
Drought, remote sensing, correlation, climate index.
Drought is one of the environmental disasters that is very frequent in arid and semi-arid regions of the country. Rainfall defects have different effects on groundwater, soil moisture, and river flow. Meteorological drought indices are calculated directly from meteorological data such as rainfall and will not be useful in monitoring drought if the data are missing. Therefore remote sensing technique can be a useful tool in drought measurement. Drought is a recognized environmental disaster and has social, economic, and environmental impacts. Shortage of rainfall in a region for long periods of time is known as drought. Drought and rainfall are affecting water and agricultural resources in each region.
Materials & Methods
The present study is a descriptive-analytic one with emphasis on quantitative methods due to the nature of the problem and the subject under study. In this study, the Tera Sensor Modis satellite images from 2000 and 2017 were used to verify the existence of wet and drought phenomena. In the next step, by examining the rain gauge and synoptic data of the existing stations and using a standardized precipitation index model of three months (May, June and April), the sample was selected. Next, we compared the temperature status indices (TCIs) and vegetation health indices (VHIs) in these three months to determine the differences in these indices over the three months. Modi satellite Tera satellite was used to find out the vegetation status in the study area. Subsequently, using the condition set for the NDVI layer, the vegetation-free areas were separated from the vegetated areas. Experimental method was used to determine the threshold value of this index. For this purpose, different thresholds were tested, with the optimum value of 1 being positive. NDVI is less than 1 plant-free positive and more than vegetation-free. MODIS spectral sensing images for ground surface temperature variables, with a spatial resolution of 1 km, including bands 31 (bandwidth 1080/1180 central bandwidth / 11.017 spatial resolution 1000 m) and 32 bands- 770/11 Central Wavelength Band 032/12 Spatial Resolution Power (1000 m) Selected for months that are almost cloudless. All images have been downloaded from the SearchEarthData site and have been edited. The total rainfall of June, April, and May for the 20-year period was provided by the Meteorological Organization of Iran. ARC GIS software and geostatistical methods were used to process the Excel data. Also, to estimate the correlation between the data Pearson's correlation coefficient was used.
Results & Discussion
The standardized precipitation index is a powerful tool in analyzing rainfall data. The purpose of this study was to compare the relationship between remote sensing indices and meteorological drought indices and determine the efficiency of remote sensing indices in drought monitoring. Correlation between variables with SPI index was evaluated and calculated. The results of the indicators are different, so a criterion should be used to evaluate the performance of these indicators. SPI index on quarterly time scale (correlated with vegetation) as the preferred criterion Selected. According to the results of correlations, the TCI index with the SPI index had a strong correlation with other indices. In the short run, this index has the highest correlation with thermal indices at 1% level. The correlation between meteorological drought index and plant water content and thermal indices increases with increasing time interval. Positive correlation between vegetation indices and plant water content with meteorological drought indices indicates that trend of changes is in line. Therefore, the TCI index makes drought more accurate and is a better method for estimating drought.
Conclusion
The results showed that among the surveyed fishes, the highest drought trend was observed in the eastern part of these provinces and covered more than 50% of the area. The trend of changes in this slope was statistically significant. According to the results of correlations, the TCI index with the SPI index had a strong correlation with other indices. It can also be concluded that the Modis images and the processed indices along with the climate indices have the potential for drought monitoring. Using maps derived from drought indices can help improve drought management programs and play a significant role in mitigating drought effects.
Keywords
Drought, remote sensing, correlation, climate index.
Nader Shohani, Lotfali Kozegar Kalj, Sajad Darabi, Said Yousefi Babadi,
Volume 9, Issue 1 (5-2022)
Volume 9, Issue 1 (5-2022)
Abstract
Pandemic Covid-19 (Corona); Tehran's resilience against it
Nader Shohani; Assistant Professor, Department of Geography and Urban Planning, Payame Noor University. Tehran Iran
Lotfali College Potter; Associate Professor, Department of Geography and Urban Planning, Shahid Beheshti University, Tehran, Iran
Sajjad Darabi; PhD Student, Department of Geography and Urban Planning, Shahid Beheshti University, Tehran, Iran
Saeed Yousefi Babadi; PhD student, Department of Geography and Urban Planning, Shahid Beheshti University, Tehran, Iran
Abstract
One of the dangers that has caused cities to face a serious crisis is the outbreak of Covid-19 disease. The corona pandemic has taken cities out of their normal routine. Therefore, cities seek to return to their past conditions and urban resilience as soon as possible. Research Method In this descriptive-analytical study, using field survey, four economic, social, managerial-institutional and infrastructural dimensions in the form of 29 items have examined the resilience of Tehran against Corona pandemic. In research, support and advocacy for affected businesses, insurance coverage, support for affected manufacturing sectors, are in the most unfavorable situation. The results obtained from the final table of Vikor technique show that the economic index with a score of 1 is the most important component of resilience against coronavirus, which is lower than other components of resilience. After that, the managerial-institutional component with a score of 0.94 and the infrastructure component with a score of 0.92 in the next ranks are the most important components of Tehran's resilience against coronavirus. The results show that the metropolis of Tehran is not in a favorable position in relation to the corona virus and is not resilient to selected indicators and the economic index has the most impact and the social index has the least impact on the resilience of Tehran.
Keywords: Urban Resilience, Covid 19, Pandemic, Tehran
Pandemic Covid-19 (Corona);
Tehran's resilience against it
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