Azadeh kazemi; Hamid Reza Jafari; Ali Torabian; Ali Akbar Matkan
Volume 12, Issue 2 , July 2014
Abstract
Remote sensing system, especially hyperspectral remote sensing require fundamental knowledge of spectral reflectance of chlorophyll a (chl a) for recognizing eutrophication of inland waters. The first objective of this study was to prepare and investigate the significant differences between the spectral ...
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Remote sensing system, especially hyperspectral remote sensing require fundamental knowledge of spectral reflectance of chlorophyll a (chl a) for recognizing eutrophication of inland waters. The first objective of this study was to prepare and investigate the significant differences between the spectral signature of water samples with different amount of chlorophyll a (chl a) of Anzali wetland in 15 cm depth. This was carried out using a full range spectrometer during the spring 2013. The second objective of this study was to discriminate the spectral signature of water samples with different amount of chlorophyll a (chl a) of Anzali wetland in 30 cm depth. A total of 500 water sample spectral curves of illuminated and shaded samples were acquired of 80 water samples with different amount of chlorophyll between 2.07 and 23.9 mg/l. Following the measurements, chlorophyll and total phosphorus of the samples were extracted in laboratory. One important index related to chlorophyll a of water was calculated and statistically analyzed. We conclude that band ratio model in 15 cm depth of water samples has the most relation with chlorophyll a content in comparison with the other indices. This result has been proved by statistical results obtained by chlorophyll and total phosphorus data in lab.
Hamid Reza Jafari,; Mohammad Hamzeh,; Hossein Nasiri; Yusef Rafii
Volume 8, Issue 3 , April 2011
Abstract
Rapid urban growth and industrialization have caused many environmental problems in a number of cities around the world. Knowledge about land cover/land use changes in the long term is very important for urban managers and policy makers in order to evaluate and predict the resulting problems. Remote ...
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Rapid urban growth and industrialization have caused many environmental problems in a number of cities around the world. Knowledge about land cover/land use changes in the long term is very important for urban managers and policy makers in order to evaluate and predict the resulting problems. Remote sensing is an effective tool for monitoring these changes in urban areas and its periphery. Over recent decades, Yasouj City has developed and affected its surrounding environment due to urban growth and immigration. The objective of this research is to develop a Decision Tree and data mining based conceptual model for land cover change detection using a Landsat Thematic Mapper (TM) and ancillary data in the central Section of Boyerahmad County from 1990 to 2009. Based on findings of the study, the overall six-class classification accuracies for 1990 and 2009 were, respectively, 93.16% and 93.37%. The overall accuracy of land cover change maps, generated from post-classification change detection methods and evaluated using two approaches, ranged from 85.6% to 86.98%. The maps also showed that between 1990 and 2009 the urban area increased by approximately 19.28% while agriculture and forest decreased by 31.76% and 7.32% respectively.
Hassan Hoveidi; Gholamreza Nabi Bidhendi,; Hamid Reza Jafari,; Touraj Nasrabadi; Toktam Shahriari
Volume 5, Issue 2 , January 2008
Abstract
During recent years, surface water resources supplying Tehran's potable water – Karaj, Lar and Jajrood Rivers – are contaminated with different microorganisms due to population growth. Additionally, the amount of organic materials generating odor, taste and color in the surface water has ...
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During recent years, surface water resources supplying Tehran's potable water – Karaj, Lar and Jajrood Rivers – are contaminated with different microorganisms due to population growth. Additionally, the amount of organic materials generating odor, taste and color in the surface water has increased sharply. By considering the trihalomethane (THM) production potential of dissolved chlorine in reaction with innocuous humic substances, future use of chlorine as a disinfectant in Tehran's drinking water is clouded in uncertainty. Accordingly, the use of ozone as another alternative was taken in to consideration for disinfection of drinking water in this mega city. In order to evaluate advantages and disadvantages of water ozonation a pilot with a generating capacity of 4 gr ozone per hour was designed. This study was performed between April and September 2005 and Tehran Pars water treatment plant in the Northeast of Tehran was chosen for the case study. Bacteria removal was considered to be at highest level in all monthly samples. Different ozone contact times and dosages were tested in the deactivation of nematodes and the results showed the perfect removal in specified periods. Although the initial investment for construction and implementation of the required apparatuses is relatively high, since the raw material for ozone generation is air, the use of ozone is financially justifiable during the predicted time of operation. Moreover, the transfer and storage of ozone is much easier in comparison with chlorine which is currently in use. Unlike chlorine, the use of ozone as a disinfectant does not have the potential of THMs generation. On the other hand, ozone must be generated on site and is instable in water. Therefore, a continuous and precise monitoring and maintenance process must be taken in to consideration. Furthermore, due to high corrosive potential of ozone, special resistant materials must be used in the applied instruments.
