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Showing 10 results for bayat

Hakimeh Behboudi, Mohammad Saligheh, Ali Bayat, Akram Zakeri, Fatemeh Jamali,
Volume 15, Issue 36 (6-2015)
Abstract

Understanding weather zoning and knowing homogeneous climate regions are essential for land use and regional planning. The aim of this study was to compare three different geographical climate of Iran, the Caspian coastal, mountainous and arid interior of the provinces of Mazandaran, Semnan, Tehran, Qazvin, Qom, and Markazi. In order to do this study, climatic data of 56 synoptic and climatology stations and 19 climatic elements were used by using cluster analysis and factor analysis models. For this purpose, a matrix with dimensions of 56 x 19 and the R configuration and as a database was used for segmentation. By applying factor analysis based on principal components analysis with Varimax orthogonal rotation it was determined that in the climate of these three regions, four factors of humidity, temperature, dust and thunderstorms are affecting more than 85% of the total variance of the climate of this region. The hierarchical cluster analysis method and integration into the matrix of factor scores, four main and several sub-region areas were identified.The main areas are hot, dry desert area, ​​low rainfall mountain slopes, the mountainous and cold and semi-rainy regions and high rainfall and finally the moderate high rainfall. The study of four areas and their local and regional conditions shows that the neighborhood with humidity source such as the Caspian Sea and rough configurations such Alborz Mountains play a decisive role in the formation of north sub-areas.
Dr Maryam Bayatvarkeshi, Ms Rojin Fasihi,
Volume 18, Issue 48 (3-2018)
Abstract

Modeling provides the studying of groundwater managers as an efficient method with the lowest cost. The purpose of this study was comparison of the numerical model, neural intelligent and geostatistical in groundwater table changes modeling. The information of Hamedan – Bahar aquifer was studied as one of the most important water sources in Hamedan province. In this study, MODFLOW numerical code in GMS software, artificial neural network (ANN) and neural – fuzzy (CANFIS) method in NeuroSolution software, wavelet-neural method in MATLAB software and geostatistical method in ArcGIS software were used. The results showed that the accuracy of methods in estimation of the groundwater table with the lowest Normal Root Mean Square Error (NRMSE) include Wavelet-ANN, CANFIS, geostatistical, ANN and numerical model, respectively. The NRMSE value in Wavelet-ANN method as optimization method was 0.11 % and in numerical model was 2.2 %. Also the correlation coefficients were 0.998 and 0.904, respectively. So application of neural combination models, specially, wavelet theory in estimated the groundwater table is most suitable than geostatistical and numerical model. Moreover, in the neural intelligent models were applied latitude, longitude and altitude as available variables in input models. The zoning results of groundwater table indicated that the decreased trend of groundwater table was from the west to the east of aquifer which was in line with the hydraulic gradient.
 

Nasser Bayat, Seyed Ali Badri,
Volume 18, Issue 49 (3-2018)
Abstract

This research is conducted on tourist segmentation in the touristy catchment area of Kolan river in Malayer Township. The statistical population is tourists who travel to the area for recreation, tourism and leisure. The research tool is a self-administrated questionnaire. By the method of Simple random sampling we collected a total of 200 questionnaires of tourists in the study area. Descriptive statistics and exploratory factor analysis and cluster analysis was used to analyze the research data. Based on the results of factor analysis were identified even major factor in tourists' motivations at the regional level, including: Rurality, sense of place and place belonging, rest and relaxation, nature-based tourist activities, group outdoor recreational activities, purchase the rural production, excitement and novelty, spirituality and solitude. According to this motivational factors final result of tourism segmentation shows that tourism demand in the market consisted 7 difference segments. cluster 1 with a diverse motivation of 12%, cluster 2 with togetherness motivation 17%, third cluster as a younger age group with adventure motivation 18.5%, cluster 4 with rurality motivation 15%, fifth cluster whit shopping motivation 10%, sixth cluster with sense of place and desire for comfort and rest 19.5%, and seventh cluster with a particular tendency to sense of place 7.5% of the sample population as a whole. The results could be utilize in order to optimize the use of available resources in the area by managers and local authorities, as well as owners of tourism businesses, compatible with the actual needs of  various sectors in rural tourism market.

Mr Sirous Hashemi Darebadami, Dr Ali Darvishi Boloorani, Dr Seyed Kazem Alavipanah, Mr Mohammad Maleki, Mr Reza Bayat,
Volume 19, Issue 52 (3-2019)
Abstract

The term urban heat island (UHI), described the phenomenon of climate change in urban areas compared with surrounding rural areas. UHI effects include: increasing in energy and water consumption, air pollution expansion and interfering in thermal comfort. Surface urban heat island (SUHI) contains patterns of land surface temperature (LST) in urban areas that has interaction with UHI in urban canopy layer and urban boundary layer and investigate with thermal remote sensing. SUHI has diurnal and seasonal variations so requires multi-temporal data to analysis SUHI. In this study, the multi-temporal MODIS (Aqua and Terra) data product were used to analyze the SUHI in day and night in Tehran metropolitan. Physical and biophysical surface properties such as: land cover/land use (LULC), elevation, albedo, vegetation index (NDVI) and impervious surfaces index (NDBI) were used to interpretation of the LST and SUHI changes. The results showed that SUHI in Tehran, has spatial-temporal diurnal and seasonal variation. So that during warm days the surface urban cool island (SUCL) is formed in Tehran. At night times, SUHI index values was different between 2 and 5 ° C (maximum in the spring). The results also showed that different of land cover thermal properties, albedo and elevation was the most important factors is the diurnal changes of SUHI while phonological changes of vegetation and albedo, was the most important factors in seasonal changes of SUHI.


Dr. Ali Bayat, Mr. Saeed Mashhadizadeh Maleki,
Volume 19, Issue 53 (6-2019)
Abstract

Precipitable Water Vapor (PWV) is one of the most important quantities in meteorology and climate studies. PWV in Earth's atmosphere can be measured by Sun-photometer, the Atmospheric Infrared Sounder (AIRS), and radiosonde from surface, atmosphere and space-based systems, respectively. In this paper, we use PWV measured by Sun-photometer located in Institute for Advanced Studies in Basic Sciences (IASBS), AIRS and 29 Iranian synoptic stations data include temperature, dew-point temperature, pressure and relative humidity. For validation of AIRS data, the correlation coefficient between AIRS and Sun-photometer data calculated. The correlation is 90%. Average of PWV measured with sun-photometer and AIRS are 9.8 and 10.8 mm, respectively. Pearson's correlation coefficients between PWV of AIRS  data set and temperature, dew-point temperature, pressure and relative humidity for synoptic stations are calculated. Correlation between PWV and temperature, dew-point temperature, pressure, and humidity are 73%, 74%, -40% and -30%, respectively. PWV and temperature correlation coefficient map shows a positive trend between latitude and correlation coefficient. Rising a degree in latitude lead to increasing 2.8 percent in the correlation coefficient.

Mrs. Atefeh Shahmohammadi, Dr. Ali Bayat, Mr. Saeed Mashhadizadeh Maleki,
Volume 20, Issue 58 (9-2020)
Abstract

Urban development and air pollution are among the most important issues related to climate. The expansion of urbanization and urban development, population growth, industrial development and excessive use of fossil fuels significantly increased air pollution and it is more than the capacity of the environment. In our country, the emissions of air pollutants in some metropolitan areas have reached a dangerous level, Mashhad is considered to be the most polluted cities of the country in some days of the year. Nitrogen dioxide is one of the indicators of air pollution. In this study, the OMI data and atmospheric parameters such as wind, surface temperature, and horizontal visibility data for the period from 2004 to May 2016 were used to investigate the air pollution in Mashhad. The results show that the maximum (minimum) nitrogen dioxide levels occur in the cold (hot) season. The highest amount of nitrogen dioxide in January is equal to 5.56 × 1015  molec/cmand its lowest value in September is 4.18 × 1015  molec/cm2. Standard deviation of nitrogen dioxide also indicates that the greatest changes occur in cold seasons. Also, the results showed that the dominant wind in the city of Mashhad is from the south, and most of the winds are slow. Correlation coefficient of nitrogen dioxide with wind and surface temperature is -0.36 and -0.57, respectively, which shows the higher importance of temperature in nitrogen dioxide changes in Mashhad city. The correlation coefficient of nitrogen dioxide with horizontal visibility is -0.15, which indicates that with increasing nitrogen dioxide contamination, horizontal visibility decreases. Spectral analysis of least squares of the six and twelve-month periods of rotation was observed, they were also statistically significant. After eliminating the significant components of the time series of the average monthly nitrogen dioxide, the trend was calculated. The amount of nitrogen dioxide in each year for Mashhad was 2.41 × 1013  molec/cm2.

Dr. Ali Bayat, Mr. Ahmad Assar Enayati , Mrs. Azimeh Toshani,
Volume 21, Issue 62 (9-2021)
Abstract

In this paper, aerosol optical depth measured by Caliop, MODIS, MISR, and OMI satellite sensors is compared with Sun-photometer data located in the Institute for Advanced Studies in Basic Sciences (IASBS) from December 2009 to December 2013 over Zanjan city. We computed figures for root mean square error (RMSE), mean absolute error (MAE) and root mean bias (RMB) between space-born and ground-based sensor measurements. The results show that the Caliop and MISR sensors have the highest correlation (0.61 and 0.54), respectively, with Sun-photometer measurements over Zanjan area. MISR, Caliop, and OMI sensors have the closest aerosol optical depth data to the Sun-photometer measurements (the fitted line slope is 0.68, 0.61 and 0.59, respectively) which represents the appropriate model used in the sensors to extract the aerosol optical depth. The variable monthly AOD figures obtained with different sensors indicate underestimation by MODIS and Caliop instruments (0.32 and 0.83 respectively) over Zanjan city relative to the Sun-photometer data, and overestimation by OMI and MISR instruments (1. 23 and 1.08 respectively).

Leyla Ghasemi, Farveh Farveh Rahmani, Tahereh Bayat,
Volume 22, Issue 64 (3-2022)
Abstract

Humans in the course of urban development in order to conduct the affairs of the citizens have attempted to establish a municipal entity and the duties and responsibilities to municipalities are considered. municipal performance analysis can be the best way to ensure proper duties as mayor. this study aimed to evaluate the satisfaction level of citizens the function and importance of the services that municipalities offer is made. the research method is descriptive-analytical and data collection method based on the Library, and field documents (questionnaires, respectively). Spss software was used for data analysis. statistical methods used in this paper Methods of Correlation Kendall's t-test and Kruskal-Wallis test.the results indicate that the satisfaction of the citizens of the municipality varies according to their age. satisfaction of citizens less than 40 years of municipal performance is much lower than average. and satisfaction of citizens over 40 years, is mediocre. Citizens' satisfaction with the quality of service and how information is below, but the degree of satisfaction of the authorities, employers and employees, is moderate. Among development duties-technical, service and social-cultural municipalities of the perspective of citizens in the region, there are significant differences in terms of importance. In a manner that is most important tasks of municipal services.

 
Mrs. Atefeh Shahmohammadi, Dr. Ali Bayat, Mr. Saeed Mashhadizadeh Maleki,
Volume 22, Issue 67 (12-2022)
Abstract

Air pollution is one of the major problems in large cities, which can be harmful to human health and the environment. Isfahan is one of the most polluted cities in Iran.
 Its geographic location and low wind speed, industrial activities, transportation, agriculture, and other human activities have created critical air pollution conditions for the city. Nitrogen dioxide is an important pollutant of air pollution, which is monitored using ground stations and satellite measurements. In this paper, daily data of nitrogen dioxide from Ozone Monitoring Instrument (OMI) satellite sensor, wind and surface temperature of Isfahan Meteorological Station data were used between October 2004 and May 2016. The average amount of nitrogen dioxide in the measured range is .The highest amount of nitrogen dioxide ( ) was observed in December and the lowest ( ) was observed in July. The standard deviation of the winter season ( ) is higher than the summer season ( ). The correlation coefficient of nitrogen dioxide with wind and temperature was -0.41 and -0.54, respectively, which indicates the higher importance of temperature in nitrogen dioxide changes. After the formation of the time series, the average monthly nitrogen dioxide content was determined using spectral analysis of least squares of statistically meaningful peaks corresponding periods. These statistically meaningful peaks corresponding periods have been eliminated from the mean monthly nitrogen dioxide time series, and with the linear fit on the residual time series, the trend has been calculated. The nitrogen dioxide trend for Isfahan is per year with 95% confidence.
 
Dr. Ruhallah Moradhaseli, Dr. Ali Bayat, Mrs. Fateme Radmehri,
Volume 23, Issue 70 (9-2023)
Abstract

Aerosol optical depth in 550 nm and angstrom exponent measurements with MODIS have been studied with 1-degree resolution for the period 2006-2017 in the middle east. Moreover, tropospheric aerosol optical depth and depolarization ratios measured at 532 nm with CALIOP have been studied for same area and same period of time too. These parameters have been classified seasonally. Optical depth results show high values for the region especially in spring and summer seasons. During the cold seasons, optical depth values are much less compared with their values at warm seasons. At spring, dust sources located in northern Iraq and those located in central and northern parts of Arabian Peninsula are much more active. Sources located in southern parts of Arabian Peninsula get more active by summer. Angstrom exponent results show that in arid and semi-arid parts of middle east, aerosol sizes are mainly in coarse mode. In arid parts of Iraq and Arabian Peninsula coarse mode particles are dominant during 4 seasons, but for arid parts inside Iran coarse mode is dominant during warm seasons and a modification in suspended particle sizes can be seen during cold seasons. Depolarization measurements of CALIOP show that almost in all seasons, non-spherical particles are ready in middle east atmosphere which is usual for an area inside the dust belt.


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