Showing 35 results for Index
Esmail Heydari Alamdarloo, Hassan Khosravi, Sahar Nasabpour Molaei,
Volume 19, Issue 54 (9-2019)
Abstract
Proper climate and adequate knowledge tourism and can be as an attractive or unpleasant factor for tourists. The purpose of this research is to evaluate the tourism climate of Yazd province as one of the most important provinces in the arid regions of the country. For determining the tourism presence comfort in the Yazd province, Tourism Climate Index (TCI) was used. In order to investigate tourism climate index data from 17 meteorological stations was used. Then by calculation sub-indexes and TCI, zoning of TCI and sub-indexes for Yazd province was done with ArcGIS environment. The results showed that October, May, November and April are the best months for tourism activities in Yazd province, and January, July, February and December have the lowest average of TCI index respectively. The most changes in TCI occurs in July and the lowest changes is in October. According to Scott & McBoyle classification, the TCI annual classification shows that Yazd province is placed in two classes: Bi-modal shoulder peak and Dry season peak. Generally, the mountainous area with an altitude of more than 2,700 to 3,000 meters and their surrounding areas when rainfall and lower temperatures is not a limiting factor have the best tourism conditions in the dry season. Other areas with less height of 2700 to 3000 meters have the best climatic conditions for tourism in the spring and autumn.
Dr Mahmoud Hooshyar, Dr Behrouz Sobhani, Nader Parvin,
Volume 19, Issue 54 (9-2019)
Abstract
Early heat waves are extreme events that cause heavy losses in plant and animal life and cause many social and economic problems for communities. The purpose of this study was to identify synoptic patterns and statistical analysis of preterm heat waves in northwestern Iran. To do this, the maximum daily temperature data of March 14th was used for fourteen synoptic stations in the northwest of the country during the statistical period (1333-1393) Hijri Shamsi. Then, on the basis of the threshold, the Baldy index was selected for 61 days of heat wave. All statistical characteristics of the data were processed in SPSS software. They were The elevation data of the middle atmosphere of the atmosphere was extracted from a NCEP / NCAR database on a network with an arc 2/5 × 2/5 degree on the 0 to 70 degree eastern longitude and 0 to 60 degrees north latitude. The matrix was made up of 864 columns in 40 rows, with rows of days with thermal waves and elevation data on the columns on the middle of the atmosphere. The analysis of the basic components was performed on the algebraic data matrix matrix And 12 components that account for about 93 of the variations in pressure levels above 500 hp, were identified. To identify the coherent patterns, cluster analysis was performed on the scores of the components by the WARD integration method. Five types of pre-heat generation waveform patterns were identified. The results of this study showed that the premature heat waves in the northwest of Iran are due to high altitude formation in southern Arabia, the Aden valley and the center of Sudan at a level of 500 hpa and the formation of Sudan's low pressure in the sea level and the discharge of its tabs to the north and northeast of the region The case study (Northwest of Iran) also includes events occurring.
Dr. Ebrahim Fattahi, Shookat Moghimi,
Volume 19, Issue 54 (9-2019)
Abstract
In this study in order to monitor snow cover, the Moderate Resolution Imaging Spectroradiometer (MODIS) optical images were used, while for detection of snow covered areas, the snow index-NDSI, was applied. The results showed - according to the climatic conditions of the region- during the following months: December, January, February and March, most of the area is covered by snow and the maximum extent of snow cover occurred in January. In West Azerbaijan province there is found a negative trend of snow cover with a drastically reduction in January, as well as the provinces East Azerbaijan and Ardebil showed the decreasing of snow cover in this month. The results of this study show that, changes in snow cover imply a rise in temperature in this region leading to the reduction of snow cover in January. This trend represents global warming and climate change impacts on snow cover in the study area. Investigation of extreme indices confirms the assumption that by taking temperature increase into consideration, regional winter precipitation pattern has been changed from snow to rain, causing the reduction of snow storage in the catchment of study area. In addition ,the extreme temperature index study in the period of 2011- 2040 and the baseline by considering climate change approach in North West of Iran by using outputs of general circulation models under A2 scenario and downscaling models LARS-WG indicates the number of frost days or the number of icy days decreased compared to the baseline which is not unexpected according to reports by the Intergovernmental Panel on Climate Change (IPCC) as well as several studies confirmed global warming. Moreover, indices such as growth period increased, while diurnal temperature variation decreased compared to the baseline confirming snow cover reduction in the region as a threat of snow storage in the region.
Dr Sayyad Asghari, Roholah Jalilyan, Dr Noshin Pirozineghad, Dr Aghil Madadi, Milad Yadeghari,
Volume 20, Issue 58 (9-2020)
Abstract
Water is one of most important human needs for life. According to importance of subject, discussion of management and utilization of water resources has become one of the most important global issues. Remote sensing data are often used in water body extraction studies and type of remote sensing data used plays an important role in water body extraction. In this study, ability of Landsat satellite with application of water indices, to extraction of Gamasiab River in Kermanshah and comparing these indices have been investigated. Specific feature of Low width and shallow rivers has increased the complexity of studies of such rivers using available data. Water body extraction from remote sensing images has been over the past two decades. Water indices were first developed using Landsat TM and Landsat ETM. But its better performance in Landsat 8 is well documented by the researchers. In this study, NDWI, MNDWI, AWEI_nsh, AWEI_sh and WRI indices were used. With extracting optimal threshold from histogram of indices and applying this threshold, the study area was classified into two classes of water and non-water. Then overall accuracy and kappa coefficient values were taken from each of the indices. Finally, AWEI index with overall accuracy of 99.09% and a Kappa coefficient of 0.98 was the best response among the indices in the study area. The results this study showed that approach can easily extract water from satellite imagery.
Miss Ameneh Naghdi, The Doctor Ezzatolah Mafia, The Doctor Mehdi Vatanparast,
Volume 21, Issue 60 (3-2021)
Abstract
Themain purpose of this research is to analyze status of resilience indicesin the worn out and old fabricof Farujcity. Inthis regard, 32 indicators in four dimensions of physical-environmental, social, economic and institutional-managerial were selected based on theoretical studies of the research. In the next step, a questionnairebased on these indicators was designed and distributed among the residents of the study area. A total of 380 households participated in completion of questionnaires. Then, the
collected data were entered into SPSS and analyzed by single sample t-test.Four dimensions of resilience were compared with each other and based on average scores. The results indicated that resilience in the institutional-management dimension with the average score of 2.70 is ranked first. Thesecond rank of resilience was for the physical-environmental dimension with a mean score of 2.47. Finally, social and economic dimensions were ranked third and fourth, respectively. Inanother section of the study, the importance coefficient of each indicator was estimated based on experts' opinions. Then, the results were integrated and indicators with higher priorities were identified. In this method, we are looking for indicators with a low average score but a high coefficient of importance. Based on the analysis, we found nine indicators with these characteristics, of which we can refer to indicators such as access to temporary accommodation, awarenessabout the occurrence of natural and human disasters in the neighborhood, the level of awareness about reactions, how to behave appropriately during the crisis, job security, financial strength of residentsto participate in resolving the crisis, and the extent to which the insurance organizations support the residents.
Sayyed Mohammad Hosseini, Fakhry Sadat Fateminiya,
Volume 21, Issue 61 (6-2021)
Abstract
In this study, used the data of the Modis satellite. Satellite in the province of Hamadan for a period of 15 years to study and monitor the status of the leaf area index. The leaf area index data were analyzed. After extraction from the Modus website, coding was done in software and then extracted from the maps. Finally, the annual time series of leaf area index was obtained and its relation with rainfall and average temperature during these years. In order to investigate better, the cells above the one representing a better condition and higher leaf area density. In this regard, the years 2002, 2008 and 2011 were (0.01, 0.03, and 0.03%) of the lowest pixels higher than 1 and 2016 with 0.24 and 2014, 2009 and 2010 with 0.07 pixels higher than 1, the highest number of pixels. The common aspect of all years shows that in terms of pixels above the common places, all the years: the southern Hamadan gardens in the south of the Moradbeyk Valley, the Nahavand West fields, the south-east Malayer Gardens, the protected area Lashgar in the south-east of Malayer. The only difference seen in different years is the number of pixels. Finally, the time series of the data were the highest in 1389 and the lowest level of leaf area in the years 1381 and 2008.
Farshad Pazhoh, , Mehry Akbary, Mohammad Darand,
Volume 21, Issue 62 (9-2021)
Abstract
The aim of this study is to identify the spatial distribution of Vertically Integrated Moisture Flux Convergence (Vertically Integrated) Moisture Flux Convergence) on Iran’s atmosphere. To achieve this aim, the monthly ECMWF gridded data used during the period from 1/1979-12/2013. First, based on the specific humidity content in the atmosphere, troposphere divided into three layers (850-1000hPa), mid (700-775hPa) and upper (500-600hPa). In order to achieve VIMFC spatial variations on Iran, spatial self-correlation methods of globular moron and hot spots used at 90, 95, 99 and 99/99 percent significance levels. The results of this study showed that the spatial distribution of VIMFC in Iran during the first layer of troposphere and especially during warm months of year has a high cluster pattern and in cold months of the year and in the third layer of troposphere cluster pattern decrease. Based on the hot spots index in the first layer of troposphere low height regions, in the second layer of troposphere the high regions of the Alborz, zagros and central mountains and in the third layer of troposphere alpine regions of central and eastern Iran's mountains has positive spatial self-correlation (hot spots). The results show that in winter and autumn during the second period (1999-2013), the range of hot spots of the VIMFC show a significant reduction compared to the first period (1979-1998) on Iran.
Dr. Vahab Amiri,
Volume 21, Issue 63 (12-2021)
Abstract
In this study, the hydrogeochemical status of groundwater resources is evaluated using chemical analysis of 346 samples supplied from 10 springs. Based on Gibbs and van Wirdum diagrams, interaction with rock and sedimentary formations is the dominant process of controlling water chemistry. Based on the Chadha diagram and output of AquaChem program, the amount of alkali earth elements (Ca and Mg) is more than alkali ones (Na and K) and the value of weak acidic anions (CO3 and HCO3) is more than strong acidic anions (Cl and SO4). Therefore, the dominant hydrochemical facies in water samples are Ca-Mg-HCO3 and Mg-Ca-HCO3. In this plain, carbonate and probably halite dissolution are the causes of Ca, HCO3 and Cl abundance in water samples. All samples showed the HCO3+SO4 of less than 5 meq/l and demonstrate that the dominant process affecting water chemistry is the calcite and dolomite dissolution. Ion exchange between fine-grained materials of the aquifer and water solution has occurred very vastly. Based on chloroalkalin (I, II) indices, about 5.49% of samples exhibited the reverse ion exchange. Calculation of the saturation index showed that all samples are undersaturated with respect to anhydrite, aragonite, calcite, dolomite, gypsum, and CO2. Besides, the saturation index of water samples for calcite and aragonite is greater than anhydrite, dolomite, and gypsum. Analysis of principal components affecting water chemistry showed that about 82% of changes in water chemistry is controlled by 4 factors which factor 1 including Ca and HCO3, factor 2 including Na and Cl, factor 3 including Mg and SO4 and finally factor 4 including pH.
Abdolmajid Ahmadi, Ebrahim Akbari, Javad Jamalabadi, Maryam Alemohammad,
Volume 22, Issue 64 (3-2022)
Abstract
Awareness of the status of vegetation, land use change and surface temperature in each region, and the timing and location of their changes over time are important for micro and macro planning. In order to make optimal use of land, knowledge of land use changes is necessary, which is usually possible by detecting and predicting land use changes. Measuring the role of researches and researchers has been instrumental in the study of natural resources, especially vegetation, surface temperature and user variations in each location, as well as the availability of information for different times for valuable studies. In this study, ETM and OLI were used to study the process of land use change, vegetation cover, surface temperature, and hazards caused by them in perennial seasons. The results show that the area of use changes over the period 2000-2010 has decreased the area of use of the developed area, agricultural and growing gardens and the area of land and rangelands. Artificial vegetation has risen in aggregate and rangeland lands are showing a decreasing trend. Due to the importance of vegetation and its role in reducing the temperature of the earth's surface, the trend has been decreasing in regions with intensive vegetation and high temperature. Also, in the period from 2010 to 2017, the range was further increased and the city's growth continued sporadically, causing environmental changes and rising temperatures in the city. The change in the city's increased range has increased environmental risks, including the loss of good agricultural land and the increase in the temperature of the city. Due to the fact that most agricultural land is located in the vicinity of the city under cultivation of saffron, which in the warm seasons does not have surface coatings, changes in the type of cultivation can also affect the temperature of the earth.
Msc Taraneh Mirgheidari, Dr Behzad Rayegani, Dr Javad Bodagh-Jamali,
Volume 22, Issue 65 (6-2022)
Abstract
This study was conducted with the aim of providing a remotely sensed water quality index in Assaluyeh port using remote sensing technology. so, according to the region conditions, studying of scientific resources and access to satellite data, the parameters of heavymetals, dissolved ions, SST, chlorophyll-a and pH were selected. Then, by reviewing sources, the product MYD091km, MYD021km, MOD021km, MOD091km and level2 images of chlorophyll-a and SST of MODIS sensor were used after preprocessing operations. Also In-situ data were collected Simultaneously with the capture of satellite images in August 2014. Then, the relationships between the water quality parameters and MODIS data, with (R2) from 0.59 to 0.94 and (RMSE) from 0.07 to 0.1 were obtained. Next the images of the MODIS sensor from 2015 to 2017 were prepared and the models were applied to them, then the layers were standardized by fuzzy logic. Also time series of SST data from 2003 to 2017 were prepared and for each month the average pixel values were calculated and based on this, from 2015 to 2017, the variation of this parameter was standardized. Finally, an effective index for assessing the quality of coastal waters was provided by time series of satellite images and the waters of Assaluyeh port were zoned. The results showed that the water quality in 2015 and 2016 has shifted from poor to very poor status in 2017. Based on the results, with the development of a proposed index, in future studies a continuous assessment of environmental monitoring is possible.
Khadijeh Haji, Abazar Esmali-Ouri, Raoof Mostafazadeh, Dr Habib Nazarnejad,
Volume 22, Issue 66 (9-2022)
Abstract
Also, because of human activities and natural phenomena, the face of the earth has always undergone a change. Therefore, for optimal management of natural areas, awareness of the ratio of land cover/land use changes is a necessity. Therefore, extraction of land use maps as the most important goal in the management of the natural resource can be considered. The purpose of the present study was to evaluate land cover/ land use changes at the Rozechai Watershed during the period of 30-years 1985-2015 using Landsat 5 and Landsat 7 satellite imageries such as TM and ETM+ sensors; plus, land use maps were prepared using TerrSet software and object-oriented classification in 1985 and 2000 years. As well as the land use map of procurement by the geographical organization in 2015 has been used. The results show that rangelands level has the highest percentage among all land use types during the period of 30 years, but between 1985 and 2000, and 2000 to 2015, the level of rangelands has a decreasing trend indicating the destruction trend in the region of the replacement of moderate- poor rangelands and good rangeland by dry farming. Also, the tables of obtained from the error matrix indicate that the observed values in the diameter of the error matrix are much larger than the values outside the diameters. Thus, the overall accuracy for the years 1985, 2000, and 2015 were 97, 90 and 96 percent, and The values of Kappa index were 91%, 84% and 94% respectively, indicating a high degree of accuracy in the object-oriented approach to classification.
Ms Zienab Hosinpoor, Dr. Aliakbar Shamsipour, Dr. Mostafa Karimi, Dr. Faramarz Khoshakhlagh,
Volume 23, Issue 68 (3-2023)
Abstract
Heat waves are important phenomena in Iran, And its upsurge in recent years seems to have a high upside trend.This climate has a negative impact on agriculture, forest fire and forestry, water resources, energy use and human health.The purpose of the research is to explain the frequency, time distribution, continuity of thermal waves, and the identification of its occurrence in the southern foothills of central Alborz.Therefore, using the statistical methods and maximum daily temperature data of Tehran (Mehrabad), Qazvin and Semnan stations for the statistical period of 30 years (1966-2016), the mentioned characteristics were extracted.In the first step, the nonparametric method of Kendal was used to understand the variability and awareness of the monthly trend of maximum temperatures in the study period.In order to determine the severity, duration and frequency of heat wave events, the percentiles (95.98) and normalized temperature deviation (NTD) were used.The results of the study showed that the frequency of short-wave heat waves was higher.Most frequencies are related to 2-day waves, respectively, and Tehran (Mehrabad), Semnan and Qazvin stations are more frequent.The highest frequency of annual events was detected at stations in Tehran (11 waves in 2010), in Semnan (9 waves in 2015) and Qazvin (7 waves in 2015), respectively.The highest frequency of monthly heat wave events was recorded in June and September.The highest continuation (15 days) was obtained in March 2008 with the percentile method at Mehrabad station.In the normalized deviation method, the temperature was calculated as a warm wave (12 days) in 2008.The highest annual frequency of heat loss occurred in all three stations in 2015.The evolution of the process indicated an increase in the incidence of thermal waves in the cold period of the year But in other chapters, no meaningful changes were made.As it says, the decline in cold winter temperatures is on the southern slopes of Alborz.The results of the two methods showed that in the normalized deviation of the temperature, the number of thermal waves more than the percentile method was recorded, but in the percentile method, the thermal wave was more prominent in the cold period of the year.
Hadi Zare Khormizie, Hamid Reza Ghafarian Malamiri,
Volume 23, Issue 69 (6-2023)
Abstract
Knowledge of rangeland vegetation characteristics as well as factors affecting it in environmental planning, land management and sustainable development is very important. However, regional and up-to-date maps of pasture vegetation cover are not always available. In this study, in order to plot the vegetation cover percentage of the rangelands and monitor its changes in drought and wet periods, NDVI products of MODIS sensor during the years from 2000 to 2017 with a spatial resolution of 250 m and a 16-day time resolution, and The SPI drought index were used. The study area is the part of the rangelands located in the Southern province of Yazd. In 2013, in order to provide ground truth data, a field work was done to take the sampling rate of vegetation from the rangeland level in the study area. According to the results, the NDVI index has a good ability to map vegetation cover, so the coefficient of determination (R2) between this index and the sample points was 0.71. Based on the results, the average vegetation cover of the studied area was 11.3% during the years 2000 to 2017. The highest and lowest amount of vegetation cover in the study area was in 2000 and 2002, with moderate mild conditions and very severe drought, respectively (14.6% and 9.2% respectively). The most important factors influencing the vegetation cover in the study area are rainfall and drought periods, so that the coefficient of determination (R2) between the SPI drought index and the average vegetation percentage was 0.85. In general, based on the results there is a high potential for assessing and monitoring rangeland vegetation changes using satellite data and remote sensing technique.
Dr Raoof Mostafazadeh, Engr. Roghayeh Asiabi-Hir, Engr. Seyed Saied Nabavi,
Volume 23, Issue 69 (6-2023)
Abstract
Drought is the main causes of significant water imbalance, increase of crop losses or limitation in water consumption, and finally large number of socioeconomic and environmental problems. Precipitation amount is the most important climatic variables that its spatiotemporal variability has a great influence on water resources availability along with the effects of climate change. The Angot index is an indicator to determine the climatic cycles of precipitation as the ratio between the average values of multiannual precipitation over wet and dry periods which highlights the climate significance of monthly precipitation to detect dry or rainy intervals. The aim of this study is to assess and calculation of the Angot inxed in analysis of dry and wet periods of monthly rainfall in rain gauge stations of Ardabil province. The maximum values of Angot index were observed in November and May months. The results proved the suitability of the Angor index in determining wet and dry months and the comparison of the employed index with other common drought indices (e.g. Standardized Precipitation Index) and also different climatic zones of Iran needs further investigations.
Hajar Jahanshahi, Hamidreza Varesi, Masoud Taghavei,
Volume 24, Issue 74 (9-2024)
Abstract
In fact, the growth of urban consciousness is a wise strategy to drive urban development and control dispersion and drive urban growth toward sustainability. The purpose of this study was to evaluate the rate of Bushehr city area in terms of growth indices. In this regard, this research is a goal-oriented, applied-developmental one, and a combination of documentary, analytical, causal and survey methods. Reliability of the research instrument based on Cronbach's alpha coefficient of the research was 0.749 which is higher than 0.7 and is appropriate. The statistical population of the study is Bushehr inhabitants which according to Cochran formula is estimated 384 samples. According to the statistical population, the questionnaire was distributed randomly among the citizens. In order to compare between two regions, T-test with two independent samples was used for evaluation of urban smart growth in District 1 and 2 of Bushehr. In this test, the first option to be considered is the significance level while the significance level or sig between the two regions is less than 0.05 indicates a significant difference between the two regions and vice versa. Significance level analysis (0.000) shows that there is a significant difference between the two regions in terms of urban smart growth. Meanwhile, the mean of Region 1 with 3.21 was higher than that of Region 2 with 2.86. Although there is a significant difference in Bushehr region in terms of smart growth indices, this difference is not significant and in general Bushehr regions are not in a good position in terms of smart growth indices.
