Showing 28 results for Index
Mohammad Saghebi, Ezatollah Mafi, Mehdi Watanparast,
Volume 0, Issue 0 (3-1921)
Abstract
Nowadays, addressing approaches such as livability for today's cities as concepts that play an important role in reducing social, economic and environmental problems of cities is an inevitable necessity. In fact, livability is a concept with all angles and mental and objective dimensions Is concerned with human beings and seeks to create a healthier and more livable urban environment for current citizens of future generations; Therefore, livability is a new concept and approach in the paradigm of sustainable urban development, which some consider one of the greatest ideas of urban planning in modern times. In livable city, the goal is not only to meet the physical needs of urban society, but also to create a sense of citizen satisfaction According to this, the main purpose of this research is an analysis of urban livability in Bojnourd with emphasis on security index.
The purpose of the present study is applied and in terms of method: descriptive-analytical. Using GIS software, maps related to the status of each of the objective sub-indicators based on Bojnourd city police stations have been drawn. For mental indicators that have 8 items, a questionnaire The sample size in the whole city of Bojnourd is 383 people. The results of this study show that police station area 13 of Bojnourd (in region one) is the best area in terms of security index. The worst area in terms of security is related to police station area 12 (area two) in terms of index. It is security.
- Nazir Ahmad Hashem Zehi, - Gholamreza Miri, - Masoumeh Hafez Rezazadeh,
Volume 0, Issue 0 (3-1921)
Abstract
Utilizing neighborhood capacities and redefining the role of citizens at the urban neighborhood level has led to a new approach called neighborhood-based participation; Because many urban challenges are rooted in the lack of citizen participation. The city of Zahedan is no exception. In order to achieve neighborhood-based participation, it is very important to pay attention to and strengthen some indicators. The purpose of this study is to measure the effective indicators in improving neighborhood-based participation to improve urban services in the city of Zahedan. The research method is descriptive-analytical and based on data collection in the field through a questionnaire. The statistical population of the study consists of 587730 citizens living in Zahedan. The sample size was calculated using the Cochranchr('39')s formula of 322 people. Examination of 5 variables of reliability, accountability and responsibility, reliability, empathy and attention and tangible and tangible factors show that all 5 variables were significant at the level of less than 0.05. Examining the difference between the mean and t-test statistics confirmed that citizens do not trust the performance of the municipality and managers. Also, one-sample t-test shows that the indicators of transparency, empowerment, economic base, value bases and sense of place are equal to 0.000 and less than 0.05 are significant. This article points to the impact of these indicators on improving neighborhood-based participation. Based on the results of the structural equation model, the greatest effect is related to the transparency index with 0.19, then the sense of spatial belonging with 0.15. Also, one-sample t-test shows that voluntary contributions (mean difference of 0.510), financial (mean difference of 0.611) and intellectual (mean difference of 0.486) with a significance level of less than 0.05 can have a great impact on Improve neighborhood-based participation and improve the quality of municipal services.
Mrs Azam Abbaspour, Dr Iraj Ietessam, Dr Hamid Majedi, Dr Azade Shahcheragi,
Volume 0, Issue 0 (3-1921)
Abstract
In todaychr('39')s world, housing and shelter have overshadowed many aspects of human life. Providing adequate housing, especially for low-income urban groups, is one of the most important issues and challenges facing all countries. The desirability of the environment of residential complexes built for low-income groups has always been a challenging issue. In the programs and plans prepared for these groups, due to the huge flood of applicants and also the limited resources and credits, quantitative goals have often been pursued and qualitative goals have been abandoned. A study of the housing pattern of this group in cities shows that attention and application of effective indicators of housing sustainability is one of the categories that should be considered in the process of housing planning. This article, with the aim of analyzing the factors affecting the housing survival of low-income groups, has reviewed the theoretical literature and tested research hypotheses. The statistical population of the study is the residents of Mehr dwelling in Sirjan. After distributing the questionnaire, data analysis was used at two levels of descriptive and inferential statistics. The validity of the structure was confirmed by factor analysis. The reliability of the instrument was also calculated using Cronbachchr('39')s alpha coefficient test of o.7. Data analysis was performed from Sstructural Equation Modeling using Smart PLS software. Findings indicate the relationship between quantitative and qualitative indicators of housing on durability. Quality index with cultural and social criteria and components such as security, privacy, sense of place, user participation has the greatest impact on Durability of low-income housing in Sirjan.
, Dariush Sattarzadeh, Lida Balilan, Akbar Abdollahzadeh Tarf, Mahsa Faramarzi Main,
Volume 0, Issue 0 (3-1921)
Abstract
Abstract
Providing suitable urban spaces, especially open and natural spaces, has an undeniable effect on achieving health-oriented cities and especially ensuring the mental health of citizens. The aim of this study was to investigate and explain the effect of social indicators of public spaces on the mental health of citizens. This research is applied in terms of purpose type and descriptive-analytical method. A survey method (questionnaire) was used to collect research data. The statistical population of the study was the residents of Ardabil. The sample size was estimated to be 384 using the Cochran's formula. The research hypotheses were tested through structural equations using Amos software. The results showed that social factors have a positive and significant effect on the mental health of citizens in public spaces of the city. The value of the path coefficient obtained for the effect of the social factor on the mental health of citizens is equal to 0.52 so that this factor is able to predict 0.27 of the variance of the dependent variable, ie the mental health of citizens. The results also showed that social indicators, namely security, social relations and sociability of urban public spaces have a positive and significant effect on the mental health of citizens. Among social indicators, security index has the highest coefficient of path.
Mr Fazllollah Karimi Ghotbabadi, Dr Ali Zangiabadi,
Volume 0, Issue 0 (3-1921)
Abstract
Earthquakes resilience, which is actually how social, economic, institutional, geographical, etc. capacities of societies are affected by earthquakes, is one of the issues that should be considered in any society. It is worth noting that the type of attitude towards the issue of resilience and how to analyze it on the one hand, plays a key role in how to recognize resilience and its causes, and on the other hand also influences policies and measures to reduce risk and how to deal with it. The purpose of this study is to rank the resilience of new urban Habitations in the Isfahan Metropolitan earthquake risk using a combined index. Due to the studied components and the nature of the subject, the approach of this research is "descriptive-analytical". The statistical population of this study includes 6 new urban Habitations of Shahin shahr, Majlesi, Sepahan shahr, Fooladshahr, Baharestan and Shahid Keshvari. This research is applied in terms of purpose and in the research literature section, information has been collected through the library method. Based on the results of POSET, Majlesi, Baharestan, Foolad shahr, Sepahan Shahr, Shahin Shahr and Shahid Keshvari Habitations with the sum of options 3, 6, 7, 8, 11 and 14 in terms of the combined index of resilience against earthquake risk, respectively. They have 1-6. Therefore, in order to reduce the adverse effects that resilience has on any community, paying attention to the capacities of each Habitation is one of the issues that should be considered in every community to prevent human and financial losses caused by possible accidents.
Mr Danesh Nasiri, Dr Reza Borna, Dr Manigheh Zohorian Pordel,
Volume 0, Issue 0 (3-1921)
Abstract
Widespread and frequent droughts in recent decades in Khuzestan province have become one of the most important challenges of this province. The use of remote sensing products in temporal and spatial monitoring of drought can play a key role in managing this risk and reducing and adjusting its destructive effects. The main goal of this research is to provide a remote sensing index for temporal and spatial monitoring of drought in Khuzestan province and its validation using station meteorological drought indices. In this research, by using the products of vegetation (MOD13C2) and land surface temperature (MOD11C3) of MODIS sensor, a drought index based on vegetation called VHI plant health index was produced. SPI Meteorological Drought Index, which was based on station rainfall data during the statistical period of 2000-2012, was used to evaluate and quantify this index. The comparison of VHI drought index with three-month SPI meteorological drought index values showed a significant correlation between 0.68 and 0.75. By identifying 4 years with widespread and relatively severe drought in Khuzestan province (based on both VHI and SPI indices), which included the years 2000, 2005, 2012, 2015, the spatial distribution pattern of meteorological drought and VHI plant drought to In general, it indicated that the northern parts of the province were generally involved in mild to moderate droughts and the southern parts were generally involved in moderate to severe droughts. The spatial correlation matrix based on the number of 2500 pixels with dimensions of 5x5 km, which included VHI and SPI values of selected drought years, indicated the existence of a significant spatial correlation between the two mentioned indicators. In the widespread drought of 2000, at the level of Khuzestan province, two drought indices VHI and SPI, the correlation was equal to 0.47, and in 2005, equal to 0.35, and
Majid Goodarzi, Ali Ashkboos, Behnam Mohammadi,
Volume 0, Issue 0 (3-1921)
Abstract
The intermediate development approach suggests that empty lands and the inner destructive structure of cities should be targeted for development instead of taking the peripheral lands of the cities under construction. Considering this importance, in this article, an attempt has been made to identify and prioritize the obstacles to the intermediate development of Zabol using Chang’s technique. The present applied study employed a descriptive-analytical research method and library and survey research (field studies) data collection techniques. The statistical population for identifying the obstacles of intermediate development consisted of all the residents of Zabol city in 2023. The sample size was calculated as 384 via Cochran’s formula. The purposive sampling method was employed to collect the data. Cronbach’s alpha coefficient calculated the research instrument’s reliability as 0.80. The obstacles were identified using a sample t-test in SPSS, and the upcoming obstacles were prioritized. The required data were collected from the existing facts of the city and through a questionnaire distributed among 20 related experts. Then, data and information were analyzed using Chang’s technique (AHP-FUZZY). The research results showed that the most important obstacle to implementing the intermediate development plan of Zabol city is the economic index, with a final weight of 483.
Firooz Mojarad, Razieh Kheiri, Zahra Noorisameleh,
Volume 14, Issue 35 (3-2015)
Abstract
Iran's Potential for the occurrence of drought at various severities illuminates the need to examine this phenomenon with new indexes. The major deficiency of the current indexes is that they cannot monitor the droughts in daily scale. Effective Drought Index (EDI) overcomes this defect. The goal of this study is to analyze the frequency of daily droughts by EDI in 43 synoptic stations in a 30-year period. Accordingly, the frequency of daily droughts in the stations was calculated by EDI during the seasons and the year. Then the stations were divided into five groups using cluster analysis based on total frequency of mild to most severe droughts (categories 1 to 4), and frequency patterns in each group were examined. The results showed that the most severe droughts have not happened in the stations except for Gorgan, Zanjan and Torbat-Heydariyeh. In contrast, the frequencies of mild, moderate and severe droughts, all being equal, are much more than most severe droughts, and their frequencies are almost equal. In 56 percent of the days, a variety of droughts (mild to most severe) has occurred in the whole country. Based on the output maps, frequency distribution of droughts in the country does not follow a certain geographical pattern, so it could be cocluded that all types of droughts have happened in all regions of the country. However, maximum total frequency of daily droughts (mild to most severe) is observed in the east and center parts. The decrease in the EDI values over time shows the tendency of the most stations towards drought.
Behroz Sobhani, Ata Gafarigilandeh, Akbar Goldost,
Volume 15, Issue 36 (6-2015)
Abstract
Drought defined as a climatic phenomenon with the humidity and rainfall shortage as compared with normal conditions. This phenomenon affects on all of aspects of human activities, severely. while, studies associated with this phenomenon on the basis of appropriate methods are very low. In the present study, effort has been made to analyze the drought state in Ardabil province by means of software system capabilities in MATLAB and SEPI index in two temporal scales of 6 and 12 months. The climatic data of synoptically stations of Ardabil were used, Parsabad and khalkhal countian in Ardabil province. Results of study show that SEPI index reflects the features of two SPI and SEI indices well. And also enters temperature in the studying of drought conditions as one of the effective parameters in changing of drought intensity. Therefore, the investigation into drought with SEPI index is better than SPI index. Studies associated to drought on the basis of SEPI index shows that drought process is increasing in Ardabil province. Temperature also has an increasing flow with higher intensity. Longest temporal continuation of drought in province, has occurred in Parsabad station in temporal scale of 12 months, from June, 1998 to November, 1999 in 18 month period. The greatest percentage of drought occurrence is in Parsabad station and the minimum of that is observed in Khalkhal station.
[1] - Akbar Goldust: PhD student's of climatology in environmental planning Mohaggeg Ardabil University
Esmaeail Ahmadi, Zahra Hejazizadeh, Bohlol Alijani, Mohammad Saligheh, Hassan Danaie Fard,
Volume 15, Issue 36 (6-2015)
Abstract
The more exposure to Climate change / variability, the more vulnerability and a community with low adaptive capacity and high sensitivity is more vulnerable. Vulnerability reduction depends on adaptation policy and strategies. Designing and assessing these strategies require climate vulnerability (CV) measuring. To produce a new CV index, as a main propose of this study, first: The score of exposure factor for two five span years was calculated based on four synoptic stations data (Zabol, Zahedan, Iranshahr and Chabahar). Second: The scores of adaptive capacity and climate sensitivity were determined using all of the country census and yearbook data for 1385 and 1390. Third: Due to the nature and factors of vulnerability, a climate vulnerability index was developed based on the multiplicative-exponential model (CVIMEM). Forth: The index was calculated for the province and sub regions. The result shows, although the Sistan and Baluchistan (SB) adaptation capacity was increased, but because of the increased exposure and sensitivity, this province is 16.3% more vulnerable. Area with very high vulnerability label expanded from 57.5% to 100%, which reflects the spatial expansion of vulnerability over SB. The overall result is that vulnerability reduction needs for accurate and continuous measurement, on the increase adaptation capacity and mitigate climate sensitivity.
, , , , ,
Volume 16, Issue 41 (9-2016)
Abstract
Drought phenomenon with different goals including planning, water sources management and dealing with the problems due to water shortage has been investigated by most scholars. This research examined the relationship between drought and the normalized difference vegetation index (NDVI)in Qorveh and Dehgolan region in Kurdistan, Iran. To determine years with meteorological drought, index of Standard Z during a 20 year period time (1387-1368) has been applied. The results of the statistical data in Ghorveh station in 2008 with total annual rainfall of 155 mm and Z index of -2.31, in 2000 with total rainfall of 253.1 and Z index of -1.5 and in 2001 with 239.5 rainfall and Z index of -1.22. Were determined as drought indeces. MODIS satellite images were used to assess the ecological drought. Associated with each image to a randomly selected sample of 500 places in the software ERDAS, NDVI values were calculated for these images. satellite image processing results and Normalized Difference Vegetation Index (NDVI) indicates a low index values in the years 2000, 2001 and 2008 Were determined as ecological drought years of 2001 samples had the lowest NDVI and central parts of the area under irrigation has almost lost its vegetation.
Mohamad Reza Mobasheri:, Samira Ranjbar,
Volume 17, Issue 44 (6-2017)
Abstract
The goal of this study is to identify farms which are affected by wheat rust disease. For this, the sensor data of Landsat 7 satellites in growing season of 2013 and 2014 along with some laboratorial data containing reflectance spectrum of leaf and leaf health degree in different levels of disease are used. The reflectance values of leaf are collected by an ASD spectroradiometer in the range of red and near infrared spectrum. The spectral are simulated for Landsat sensor bands using their spectral response functions. Then with the index of DVI and data obtained for leaf health, the Wheat Health Index was introduced. The correlation coefficient obtained is 0.82 and the relevant RMSE is 0.089 which is really good result for diagnosing highly advanced disease. The results show that, this index has a good performance in wheat high growing season when the greenness is high. It can diagnose regions that are healthy from those whom are blighted. Because the WHI index is a spectral index and is sensitive to leaf color, if the acquired images are close to the harvesting time, its performance will be weakened. The selected region in this survey is located in Fars, province, Saadatshahr city.
Firouz Mojarrad, Amanollah Fathnia, Saeed Rajaee Najafabadi ,
Volume 17, Issue 44 (6-2017)
Abstract
The aim of this study was to provide a reliable estimate of the amount of solar radiation in Kermanshah province by using “Liu and Jordan” model in order to develop solar sites. The amount of atmospheric elimination in each month was calculated using an index called clearness index (
) and the results were applied on different slopes, aspects and heights. Then, according to the obtained results, amounts of direct, diffuse and total radiation were calculated in different slopes of the region and the relevant maps were consequently drawn. The results showed that the minimum amount of atmospheric elimination and thus the maximum amount of received radiation in the province occurs in late spring and summer due to the increase of clearness index () with a maximum of 1360 cal/cm2/day in May. the least amount of received radiation occurs in Janury equal to 386.3 cal/cm2/day. Radiation variations at the provincial level are high between lowlands and highlands in Janury and December, according to the angle of radiation and significant elevation changes in the region. However, in summer, distribution of surface radiation is almost identical because of high solar radiation, and thus standard deviation amount of received radiation is reduced. The highest amount of radiation is received in Javanrood city as much as 528.1 cal/ cm2/day due to greater heights, and the lowest amount is received in Qasr-e Shirin city as much as 443.6 cal/ cm2/day due to lower heights.
Alimohammad Khorshiddoust, Behrooz Sarraf, Bagher Ghermez Cheshmeh, Mrs Fatemeh Jafarzadeh,
Volume 17, Issue 47 (12-2017)
Abstract
In recent years, the severe fluctuations in precipitation have affected various parts of the country. On the southern coasts of the Caspian Sea, precipitation as one of the important climatic parameters has undergone changes due to global climate change. In the present study, we tried to evaluate the effect of climate change on rainfall in this region by applying a suitable model. In this study, observational period rainfall (1961-2001) was analyzed. the output of the HadCM3 model was used. At first, seven synoptic stations were selected and their data were analyzed in terms of accuracy, and length of statistical period, and lost data was restored. The AOGCM data were simulated using the SDSM model and the rainfall values were simulated for the observation period. After confirming the matching of the simulated data with observational data, the values of the Future (2039-2011) is estimated. The estimation errors of the SDSM model were calculated monthly by MBE and MAE criteria, and then compared. The output of the SDSM model was used to study the total annual precipitation in days with rainfall of more than 1 mm in the observation period and the upcoming period (2011-2039) by the R-Climdex model and the values of the PRCPTOT index Became zoning in the Future. The results showed that the model error in season with high rainfall is more than seasons with low rainfall. On a monthly scale, the maximum error occurred in the months of September, October, November and December. The maximum error in the fall and the minimum error was calculated in the spring and April and May months. According to the results, the total annual rainfall in the period of 2039-2011 will decrease in Anzali, Babolsar, Gorgan and Noshahr stations and rainfall will increase in stations of Astara, Ramsar and Rasht. Geographical distribution of selected were 5 sites in the Khuzestan, 20 sites in Bushehr, 24 sites in Hormozghan and 12 sites in Sistan and Baluchistan provinces. In total, 9000 sites were selected with a 2 km2 were suitable for large scale microalgae cultivation. The total area of these sites were estimated to be 18000 km2. The highest number of proper sites were found in Hormozghan province and lowest numbers of sites were found in Khuzestan province. The availability of technical service, carbon dioxide point resources from oil and gas units are an advantages for microalgae related activities in the Bushehr and Khuzestan provinces. The higher quality of water in the Sistan and Baluchistan province is an advantages for development of microalgae biomass production in the area.
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Fakhri Sadat Fateminia, Behrouz Sobhani, Seyed Abolfazl Masoodian,
Volume 18, Issue 48 (4-2018)
Abstract
This study was performed to evaluate the extent of leaf area in Iran from (2002) to (2016) using Remote sensing. For this purpose, we extracted data collection and leaf area index for the Iranian territory from MODIS website. The database was established with programming in MATLAB software to perform mathematical and Statistical calculations repeated. After the analysis of the data in this software a monthly average long-term map was developed. The maps show that the central, East and South-East are almost empty of leaf area or seen very sparse in some areas. In contrast areas of leaves in the northern and western parts of Iran, are good, which generally includes fields, except forest Arasbaran and Hirkany. Precipitation and the temperature, is the main factors for the growth and development of plants, that these two conditions are enumerated in the west due to being on the way of westerly winds. Lowest leaf area index is for January and February and the highest average of leaf area is for May and June. Next, study of 15 years of leaf area index data by cluster analysis based on the calculation of Euclidean distance and Ward method, showed that all 12 months fit in the two main groups and, in fact, divided for two periods of strong and weak vegetation. In this analysis, , April during the cold period and October in the warm period of the year as the transition months and they are located on a separate cluster
Meysam Toulabi Nejad, Dr Zahra Hejazizadeh, Mrs Atefeh Bosak, Mrs Nasrin Bazmi,
Volume 18, Issue 49 (5-2018)
Abstract
The purpose of this study was to investigate the effects of the North Atlantic Oscillation on the middle levels of Atmosphere and precipitation changes in the West of country. To do this, first monthly rainfall data of 17 synoptic stations of the West Country in period of 30 years from 1984 to 2014 of country were collected from Meteorological Organization. As well as North Atlantic Oscillation data and anomalies geopotential height data, sea level pressure and precipitation were received from NOAA. To clarify the relationship between the NAO index phase with precipitation of west of Iran used Pearson correlation coefficient was at least 95%, (P_value = 0.05). Finally, using synoptic maps, spatial relationships among data, were analyzed. The results indicate that between North Atlantic Oscillation changes with middle level height anomalies of the Atmosphere and the amount of precipitation in West of Iran in January, March, April and November there is communication and concurrency. The results showed that , at a time of sovereignty positive phase of the North Atlantic oscillation , an average of height atmospheric middle level in mid - western Iran 17 meters long - term and less than the average rainfall per month 23.5 mm increased and wetly sovereign. But when phase of governance is negative, high atmospheric middle level anomaly to an average of 20 meters more than normal. As a result, the drought will prevail in the west and precipitation in the region each month will face a reduction of 30 mm. In general, we can say that droughts more severe than wet coincide with the negative phase of the North Atlantic Oscillation is positive phase.
Adel Nabi Zadeh Balkhanloo, Zahra Hejazizadeh, Parviz Zeaiean Firoozabadi,
Volume 18, Issue 50 (6-2018)
Abstract
Continuous decline in Lake Urmia water levels In recent years, the decline of rainfall and river flows and constant droughts has become the main concern of the people and the people. To study climate change and increase of temperature in the catchment area of Lake Urmia, two factors for measuring the temperature and properties of satellite images were used which indicate the importance of land surface temperature changes (LST) and normalized vegetation differences (NDVI). This study was carried out using the satellite data of the periodic watershed (2008-2008) to investigate the spatial relationship between NDVI-Ts and NDVI-ΔT to investigate the actual agricultural drought occurrence. The goal is to extract the VTCI (vegetation temperature index) index, which is capable of identifying drought stress at regional scale. The results showed that the slope is negative for the warm edge, where it is positive for the cold edge. The gradient gradient shows that the maximum temperature is reduced when the NDVI value increases for any interval. The slope on the cold edge indicates that the minimum temperature rises when the NDVI value rises. Overall, at the warm and cold edges, it has been observed that the drought trend over 2009-2008 is higher than in 2010. In the days of Julius Day 257, the slope of the cold edge from 2008 to 2010 is decreasing. But at the hot edge, intercept pixels for 2008 is more than 323 degrees Kelvin, where in 2009-2010 it is less than 323 degrees Kelvin. In general, the correlation coefficient (R2) is different in the TS-NDVI spacing between (0.90-0.99). The present study showed that with the integration of satellite satellite data with meteorological data, the VTCI threshold for drought stress varies from year to year depending on the data conditions.
Esmail Heydari Alamdarloo, Hassan Khosravi, Sahar Nasabpour Molaei,
Volume 19, Issue 54 (12-2019)
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 (12-2019)
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 (12-2019)
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.
