Journal of Spatial Analysis Environmental Hazards

Analyzing synoptic-dynamic patterns and examining the trend of changes in wide snowfall in the western half of Iran

Bohloul Alijani

In this research, the most important synoptic patterns of widespread snowfall in the western half of Iran have been investigated. For this purpose, the data of current weather code and snow depth of 36 synoptic stations during the statistical period of 1371-1400, for the months of October to March, were received from the Meteorological Organization of the country. In order to investigate wide snowfalls, the days when more than 70% of the studied area saw snowfall at the same time were extracted as a wide day. In order to perform synoptic-dynamic analysis of wide snowfalls in the western half of Iran, the classification method using cluster analysis was used and maps of representative days were drawn, including atmospheric temperature, moisture flux, geopotential height, tovai, front formation, jet stream, omega index, and orbital and meridian wind data. Trend analysis was also performed using the Mann-Kendall test. The results showed that 4 models justify the widespread snowfall in the studied area in the best way. According to the results in all the models, at sea level, the collision of cold and dry air of northern latitudes with warm and humid air of southern latitudes has caused the formation of frontal fields in the western half of Iran. At the level of 500 hectopascals, the intensification of the meridional currents in the western winds caused the creation of closed centers and as a result the flow changed in the direction of the westerly winds, and the location of the western half of Iran in the east of Naveh Al-Aghti and Sardchal has provided the necessary conditions for air to rise. Also, there was no trend in the number of snow days in the western half of Iran at the significant levels tested. But; The number of snow days has been decreasing over time. In general, it can be concluded that due to the warming of the earth and climate change, the number of snowy days has decreased and these changes have led to a significant shortening of the snow season.

Assessment of subsidence risk in Eyvanakey plain using Environmental factors and radar images

Amir Saffari

Subsidence is one of the most important natural hazards that has affected many plains of the country in recent years. Eyvanakey plain in Semnan province is among the plains that have faced this danger. Due to the importance of the subject, in this research, the evaluation of the subsidence risk and the estimation of the subsidence rate in this plain have been done. In this research, Sentinel 1 radar images, Landsat satellite images and SRTM 30 meters high digital layer are used as the most important research data. The most important research tools are GMT, ArcGIS and Super Decisions. Also, Fuzzy-ANP logic and SBAS time series models have been used in this research. This research has been done in two stages, in the first stage, the assessment of the subsidence risk and in the second stage, the estimation of the rate of subsidence in Eyvanakey Plain. Based on the results, 251 square kilometers of the study area (equivalent to 58.5% of the area) has a high and very high risk of subsidence, which mainly corresponds to the southern areas of the Eyvanakey Plain. Also, the results of the SBAS time series method have shown that the Eyvanakey plain has subsided between 28 and 533 mm during a period of 6 years. Considering that, the high risk class has the highest amount of subsidence in the study area, so it can be said that there is a strong relationship between the subsidence risk classes with radar images and the accuracy of the results of the subsidence risk classes is confirmed.

Assessing the Spatial-Physical Resilience of District 2 of Karaj Metropolitan Area Based on Sustainability Criteria in Facing Environmental Hazards

Navid Saeedi Rezvani

introduction: Resilience is the key to urban sustainability, and by reducing vulnerability, it creates a sustainable environment for cities and plays a fundamental role in reducing urban vulnerability to environmental hazards.
Methods: The present research method is descriptive-analytical and applied in terms of purpose. The aim is to measure the resilience level of District 2 of Karaj and identify its strengths and weaknesses in facing environmental hazards. The research combines data from statistical documents, written reports, and questionnaire data obtained from surveys. The statistical sample consists of 30 experts related to crisis management in District 2 of Karaj, selected through the snowball sampling method. Data analysis was performed using mean statistics, standard deviation, and factor analysis.
Results: The results indicate that enhancing the resilience of this area through improving the quality of physical infrastructure, better construction management, adherence to architectural standards, and urban planning principles can reduce vulnerability and create a sustainable and resilient environment. Additionally, the evaluation of building sustainability shows that the average index in District 2 was 4.45. The average indices for spatial organization were 4.43, geographical characteristics were 4.57, and infrastructure sustainability was 4.8. This indicates a favorable status of resilience and sustainability indices in District 2 of Karaj.
Conclusions: Factor loadings show that the coefficients are above 0.6, confirming the validity of the resilience indices. Therefore, the urban resilience and sustainability of the region can be evaluated as favorable to highly favorable.

Analysis of Convective Rainfall Events in Chaharmahal and Bakhtiari Province

Ahmad Mazidi*

Objective: Chaharmahal and Bakhtiari Province, due to its mountainous location and exposure to Mediterranean and Sudanese synoptic systems, has experienced intense rainfall events and considerable hydrological fluctuations in recent years. These conditions have often led to flash floods and posed serious threats to regional water resources. Accordingly, this study aimed to analyze rainfall intensities, estimate their values for different return periods, and construct Intensity–Duration–Frequency (IDF) curves as well as spatial distribution maps for four synoptic stations: Kouhrang, Farsan, Shahr-e-Kord, and Borujen.
Methods: Precipitation data over a 20-year period (2000–2020) were collected, and rainfall intensities were calculated for durations ranging from 15 to 1440 minutes. Maximum rainfall intensities corresponding to return periods of 2, 5, 10, 25, 50, 100, and 200 years were then estimated using several statistical distributions, including Gumbel, Normal, Pearson type V, and Weibull. Goodness-of-fit tests were applied to identify the most suitable distribution. In addition, spatial interpolation methods within a GIS environment were employed to illustrate spatial patterns of rainfall intensity across the province.
Findings: Results indicated that the Gumbel distribution provided the best fit to the observed data. It was also revealed that rainfall intensity decreases with increasing duration, while it increases with longer return periods. Spatial analyses showed that the highest intensities occur in the northwestern mountainous areas, particularly at Kouhrang station, and gradually decrease toward the southern and eastern parts of the province.
Conclusion: The findings confirm that statistical distributions—particularly the Gumbel model—enable accurate modeling of extreme rainfall events in Chaharmahal and Bakhtiari Province. Moreover, the spatial variability of rainfall intensity highlights the necessity of incorporating such patterns into hydrological infrastructure design, flood management, and water resource planning.
Keywords: Intensity–Duration–Frequency (IDF), Convective Rainfall, IDF Curves, Spatial Distribution, Chaharmahal and Bakhtiari

Analyzing the effects of risks and hazards of rural ecosystems on the development of various types of rural tourism

Objective: A major part of rural risk, such as production risks, economic risks, and severe climate changes, is related to agricultural risks, which have significant negative impacts on the agricultural sector. This study aimed to investigate the effects of risks and hazards of the rural ecosystem on the development of various types of rural tourism in the rural tourism area of Mahmoudabad County, located in Mazandaran Province, in order to examine the development of various types of rural tourism as a strategy for resilience and adaptation of villagers, as well as a preventive strategy in villages against economic, environmental, and social shocks, as well as reducing vulnerability and diversifying the rural economy.
Methods: The research method is applied in terms of purpose and descriptive (non-experimental) and correlational (variance matrix analysis) in terms of data collection method with the aim of showing the relationship between variables. The study population included all 88 villages in Mahmudabad city. The data collection tool was a researcher-made questionnaire and the respondents were the villagers. The structural equation modeling (SEM) method based on Smart-PLS was used to analyze the data.
Results:
The results of the research on prioritizing dimensions and hazard and risk items for rural ecosystem assessment show that economic, environmental, and social risks were ranked in priorities one to three, respectively. Based on the path coefficient (pc), only the direct effect of environmental pressure (with a path coefficient of 0.338 and a T-value of 2.467) was significant. About 30 percent of the changes in the development of tourism types are explained by the proposed model with the direct effect of environmental hazards and the indirect effect of economic hazards and social hazards.

Conclusions: As a general conclusion, the types of rural tourism in the region should be given serious attention as opportunity driven entrepreneurship and necessity driven entrepreneurship. In this regard, recognizing ecological values through education and long-term propaganda for the sustainable development of rural livelihoods with emphasis on the development of green tourism, ecotourism, and agrotourism is recommended

Evaluation of Green Infrastructure Benefits Using I-Tree Canopy Software (Case Study: El-Goli Park, Tabriz)

Javad Imani Shamloo

Objective: The study aims to evaluate the ecological, environmental, and economic services provided by urban vegetation within the El-Goli green network in Tabriz. Specifically, it focuses on assessing the role of green infrastructure in mitigating urban environmental challenges through carbon sequestration, air pollution reduction, and surface runoff management. The research seeks to provide insights that support informed urban planning and the sustainable expansion of green spaces.
Methods: This study is a quantitative research that employed library-based methods (literature review, definitions of urban green infrastructure, and expert opinions) and field observations, combined with statistical analysis using i-Tree software for data collection. Data analysis was conducted using a descriptive-analytical approach, and the results are presented in tables.
Evaluation Parameters: The ecosystem services assessed in this study include carbon sequestration and storage, air pollution reduction, and stormwater management.Assessment Parameters: Key ecosystem services evaluated include carbon capture and storage, air pollution reduction, and surface runoff management.
Results: The El-Goli green network in Tabriz sequesters approximately 75.84 tons of carbon annually.
The green network removes about 2,077 tons of air pollutants per year.
Among the pollutants analyzed, ozone was the most effectively removed, while carbon monoxide showed the lowest removal rate.
The findings underscore the significant role of the El-Goli green network in improving urban air quality and contributing to climate change mitigation.
Conclusions:
This study used i-Tree Canopy 7.1 to assess the ecosystem services of El-Goli Park in Tabriz from ecological and economic perspectives. The vegetation area was measured, and trees and shrubs were counted to estimate carbon storage, air pollutant removal, and surface runoff mitigation. Results showed that the park annually sequesters 75.84 tons of carbon, removes 2,077 kg of air pollutants, and mitigates 1.92 liters of surface runoff. Considering the software’s limitations, it is recommended that ecosystem productivity in the park and other urban green spaces be enhanced through the protection of valuable trees, increasing effective plant species, developing dense vegetation cover, and implementing bioretention networks.

The role of indigenous and expert knowledge in land governance: a comparison of customary system and compartment boundaries considering ecological factors in the Hyrcanian forests

Malihe Erfani

Objective: Livestock grazing in the Hyrcanian forests is one of the oldest forms of traditional land use, practiced within locally defined areas known as customary systems. In contrast, formal forest utilization is conducted through management plans divided into compartments. This study aimed to examine the role of ecological factors in shaping the boundaries defined by local communities (customary systems) and by experts (compartments) in parts of the Nowshahr forests, including the Namkhaneh and Garazbon series.
Methods: The ecological factors analyzed included vegetation type, main and sub-rivers, ridge, ravine, hillsides, and aspect. Boundary maps of customary system and compartment were compared with ecological boundary maps in a Geographic Information System (GIS). Since roads play a determining role in compartment boundaries, their influence was also examined.
Results: Results showed that 90.02% of customary system boundaries aligned with ecological factors, while only 4.5 km did not. Moreover, 81.29 km and 85.2 km of compartment boundaries (equivalent to 90.22% and 94.56%) were determined by ecological factors, respectively, and by the combined effect of ecological factors and roads. In total, 8.81 km of compartment boundaries were not consistent with ecological factors, which decreased to 4.9 km when road influence was considered. Among ecological variables, vegetation type and aspect had the greatest effect on boundary formation. All major rivers contributed to defining boundaries, representing 17% of customary system boundaries and 9% of compartment boundaries. Less than one kilometer of roads did not coincide with compartment boundaries, while about 32% of compartment boundaries overlapped with roads.
Conclusions: These findings indicate that traditional knowledge used in defining customary system is rooted in a deep understanding of structural factors of ecology, whereas expert-designed compartment boundaries also incorporate management and accessibility considerations alongside ecological ones.