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Showing 24 results for Hejazizadeh
Statistical Analysis of the Possibility of Hail in Northern Zagros
Mr Mohammad Reza Salimi Sobhan,, Mrs Zahra Beygom Hejazizadeh , Mrs Fariba Sayadi, Mrs Fatemeh Qaderi,
Volume 24, Issue 75 (12-2024)
Abstract

In examining natural hazards, such as hail, statistical analyzes can play a significant role. Due to the great importance of economic and side losses of hail in the northern part of Zagros with maximum frequency and damage, the necessity of studying its temporal and spatial location is felt very distinctly. Therefore, in order to estimate and estimate the probability of occurrence of this phenomenon, 10 hail data data of 10 synoptic stations of the region were used during the statistical period of 2014- 1992. In choosing the best method for calculating the distribution of precipitation probabilities, different types of probability distributions of discrete random variables were tested by means of both Kolmogorov and Anderson-Darling testsThe results showed that the good Poisson distribution test had a good fit for hail occurrence at a high level of 90.99%. Baneh station with the maximum frequency of hail precipitation has the lowest probability (0.023%) and Pearnshahr station has the most probable days without hail (0.39%). Therefore, the probability of occurrence of hail in Baneh has a higher percentage. In the next round, the negative binomial model satisfies the observations of this type of precipitation well. The calculation of probabilistic distributions by these two methods showed that the probability of occurrence of hail with the frequency of 1 to 6 times and more in the region and the highest probability is related to the frequency of 3 occurrences of 0.20%. At a frequency of 1 to 6 times, the probability of occurrence of this phenomenon is 5 times more than the probability that it will not occur, which indicates the region's high vulnerability to this type of climate risk.

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Analysing the trend of land changes and urban development of Shushtar by using remote sensing data
Mr Milad Khayat, Ms Atefeh Bosak, Dr Zahra Hejazizadeh, Dr. Ebrahim Afifi,
Volume 25, Issue 76 (3-2025)
Abstract
By employing urban growth and development modeling, it is feasible to delineate a developmental trajectory that aligns with the specific circumstances of a city, considering environmental factors, natural elements, and population dynamics. The aim of this research is to propose an urban development model for Shushtar, which can serve as a valuable tool for analyzing the intricate processes of urban transformations. To accomplish this objective, two datasets were utilized: urban land use maps (including educational spaces, healthcare facilities, residential areas, etc.) and Landsat satellite imagery for key land uses such as rivers, barren lands, and forests, spanning three time periods: 1991, 2004, and 2014. These datasets were processed using GIS and MATLAB software. Existing urban land use maps were digitized and subsequently updated using Landsat satellite imagery. Subsequently, influential parameters in urban development were introduced as inputs to the Adaptive Neuro-Fuzzy Inference System (ANFIS) algorithm. After training the model for the years 1991 and 2004, the predicted results of urban development using the algorithm were compared with the actual situation in 2014, demonstrating a high accuracy of 93.7%. The land use change map, resulting from the change detection process, can be generated based on multi-temporal remote sensing images and their integration with urban land use maps, enabling an analysis of the associated consequences. The use of intelligent algorithms in this research has facilitated modeling with a high level of accuracy. The obtained results are deemed acceptable, and this development has also been predicted for the upcoming years.

The study of synoptic-dynamic patterns and trends of snow cover changes in the northeast of Iran
Sharifeh Zarei, Dr. Bohloul Alijani, Dr. Zahra Hejazizadeh, Dr. Bakhtiar Mohammadi,
Volume 25, Issue 78 (9-2025)
Abstract
This study investigates the most significant synoptic patterns associated with widespread snowfall in the eastern half of Iran. To achieve this, weather code data and snow depth records from synoptic stations in the eastern half of the country were obtained from the Iranian Meteorological Organization for the statistical period of 1371-1400 (1992-2021), focusing on the months of October to March. Days with simultaneous snowfall covering more than 70% of the study area were identified as widespread snowfall events. For the synoptic-dynamic analysis of these events, a classification method utilizing cluster analysis was employed. Maps of representative days were generated, including variables such as atmospheric temperature, moisture flux, geopotential height, vorticity, front formation, jet stream location, omega index, and meridional and zonal wind data. Additionally, trend analysis was conducted using the Mann-Kendall test. The results revealed that three primary synoptic patterns are responsible for widespread snowfall in the study area. These patterns include: (1) high-pressure systems over Siberia and central Europe coupled with low-pressure systems over eastern Iran; (2) high-pressure systems over western Iran paired with low-pressure systems over Sudan; and (3) high-pressure systems over central Europe combined with low-pressure systems over eastern Iran and Afghanistan. In all patterns, the intensification of meridional flows in the westerly winds, along with the formation of high- and low-pressure centers, creates blocking conditions that disrupt the westerly flow and promote upward air motion. The concentration of negative omega fields and positive relative vorticity advection, coupled with the positioning of northeastern Iran in the left exit region of the Subtropical Jet Stream, contributes to significant atmospheric instability and widespread snowfall in the region. Furthermore, the trend analysis indicated that, although there is no statistically significant trend in the number of snowfall days in northeastern Iran, the overall number of snowfall days has decreased over time.

Investigating the effect of Tehran city morphology on the formation of heat islands with emphasis on air performance
Dr Fariba Sayadi, Dr Zahra Hejazizadeh,
Volume 25, Issue 79 (12-2025)
Abstract
Considering that urban land-use change in metropolises such as Tehran has been increasing in recent decades; Therefore, the formation of the thermal island phenomenon in the city can be studied as one of the environmental problems. Increasing construction, density, and building heights will change the complexes' geometry and shape, followed by changes in climatic conditions and micro-urban climates. Therefore, in this study, we tried to investigate urban geometry's effect on forming a thermal island in Tehran. The study region in this research includes regions one, two, and three of Tehran.
The methods used in this research included (1) Oak's numerical equation and algorithm design to simulate the intensity of the heat island. In the first stage, digital GIS data including building blocks (parcels) in polygon format and street widths, which were prepared and prepared by Tehran Municipality based on the 2016 detailed audit plan, were used. (2) Modeling was performed in Envi-met software to study the effect of city geometry on wind. The results of the studies showed that the two factors of building height and street width (ratio (H/W)) play an important role as two key factors in studying urban geometry; therefore, in studying the intensity of the heat island, the factor of building height and high-rise construction can play an important role in the formation of the heat island. However, the higher the height of the building compared to the width of the streets, the more it acts as a barrier against the heat island. The intensity of the heat island adjusted with the Oak equation showed that the factor of building roughness coefficient can be an important factor in adjusting the intensity of the heat island. Spatial analysis of images and outputs of the Envi.met model showed that the two main factors of construction density And the height of the building has a greater impact on wind speed transmission than the slope and topography of the area. Therefore, in the study of urban design for future studies, appropriate planning and proper management of resources are needed for the climatic comfort of residents, which can be designed to be beautiful and safe cities by considering the principles of architectural safety.

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