Ali Jahani,
Volume 6, Issue 2 (9-2019)
Abstract
Risks assessment of forest project implementation in spatial density changes of forest under canopy vegetation using artificial neural network modeling approach
Nowadays, environmental risk assessment has been defined as one of the effective in environmental planning and policy making. Considering the position and structure of vegetation on the forest floor, the main role of forest under canopy vegetation cover can be noted in attracting and preventing runoff in the forest floor and reducing subsequent environmental risks. The purpose of this article is forest under canopy vegetation density changes modeling considering forest ecosystem structure and forest management activities as an environmental risk. The main objectives of this study were to: (1) model forest under canopy vegetation density in forest ecosystem to elucidate the ecological and management factors affecting on under canopy vegetation density; (2) prioritize the impacts of model inputs (ecological and management factors) on under canopy vegetation density using model sensitivity analysis and (3) determining the trend model output changes in respond to model variables changes.
In this study, Land Management Units (LMUs) were formed in the region considering ecological characteristics of land. LMUs were mapped out based on Ian McHarg’s overlay technique by ARC GIS 9.3 software. Ecological factor classes of an LMU differ from ecological factor classes of adjacent LMUs (at least in one ecological factor class). The following types of data were solicited for each LMU:
(1) Ecological variables: Altitude or elevation (El), Slope (Sl), Aspect (As), soil depth (SD), Soil Drainage (SDr),Soil Erosion (SE), Precitipation (Pr), Temprature (Te), trees Diameter at Breast Height (DBH), Canopy Cover (CC), and forest Regeneration Cover (RC).
(2) Management variables: Cattle Density (CD), Animal husbandry Dsitance (AD), Road Dsitance (RD), Trail Dsitance (TD), logs Depot Dsitance (DD), Soil Compaction (SC), Torist impacts (To), Skidding impacts (Sk), Logging impacts (Lo), Harvested trees volume (Ha), artificial Regeneration (Re) and Seed Planting (SP).
(3) Forest under canopy vegetation density: The percentage of under canopy vegetation density in each LMU was estimated by systematic random sampling method. In each LMU, a one square meter sample was taken. The average percentage of under canopy vegetation density in sample units of each LMU was calculated and used in the modeling process.
ANN learns by examples and it can combine a large number of variables. In this study, an ANN is considered as a computer program capable of learning from samples, without requiring a prior knowledge of the relationships between parameters. To objectively evaluate the performance of the network, four different statistical indicators were used. These indicators are Mean-Squared Error (MSE), Root Mean-Squared Error (RMSE), Mean Absolute Error (MAE), and coefficient of determination (R2).
Various MLFNs were designed and trained as one and two layers to find an optimal model prediction for the under canopy vegetation density and variables. Training procedure of the networks was as follows: different hidden layer neurons and arrangements were adapted to select the best production results. Altogether, many configurations with different number of hidden layers (varied between one and two), different number of neurons for each of the hidden layers, and different inter-unit connection mechanisms were designed and tested.
In this research, 129 LMUs were totally selected, then ecological and management variables were recorded in them. In the structure of artificial neural network, ecological and management variables were tagged as inputs of artificial neural network and the percentage of under canopy vegetation density was tagged as output layer. Considering trained networks (the structure of optimum artificial neural network has been summarized in Table1), Multilayer Perceptron network with one hidden layer and 4 neurons in each hidden layer created the best function of topology optimization with higher coefficient of determination of test data (which equals 0.857) and the lowest MSE and MAE (which are 0.866 and 0.736 respectively). Considering the results of sensitivity analysis, ecological and management variables like the forest canopy density, cattle density in forest, soil erosion and soil compaction respectively show the highest impact on forest under canopy vegetation density changes (Fig1).
Table1. The structure of optimum artificial neural network in forest under canopy vegetation density
| Output Layer |
First Hidden Layer |
Network features |
| Linear |
Hyperbolic tangent |
Transmission Layer |
| Gradient descent |
Gradient descent |
Optimization Algorithm |
| 0.7 |
0.7 |
Momentum |
| 1 |
4 |
Number of Neurons |
| -0.9 up to 0.9 |
-0.9 up to 0.9 |
Normalization |
Table2. The structure of optimum artificial neural network in test data
| MSE |
MAE |
RMSE |
R2 |
Data |
The structure of network( the number of neurons)-epoch |
| 0.716 |
0.678 |
0.846 |
0.931 |
Trainning |
Tanh(4)-160 |
| 0.793 |
0.703 |
0.891 |
0.894 |
Validation |
| 0.866 |
0.736 |
0.931 |
0.857 |
Test |
Fig1. The results of sensitivity analysis of artificial neural network model
Nowadays, artificial neural network modeling in natural environments has been applied successfully in many researches such as water resources management, forest sciences and environment assessment. The results of research declared that designed neural network shows high capability in forest under canopy vegetation density modeling which is applicable in forest management of studied area. Sensitivity analysis identified the most effective variables which are influencing under canopy vegetation density.
So, to identify hazardous LMUs in study area, we should pay attention to the canopy density of LMUs as the variable with high priority in determination of under canopy vegetation density. We believe that, in hazardous LMUs in forests, we should pay attention to some modifiable factors of LMU, which is cattle density in forest, by timely plan for livestock elimination. The forest under canopy vegetation density assessment model, in forest projects impact assessment, could be a solution in decision making about forest plan structure and implementation of similar projects in similar locations.
Keywords: Forest plan, Environmental impact assessment, Multilayer perceptron, under canopy vegetation, artificial neural network
Yousef Ghavidel, Manouchehr Farajzadeh, Bashir Ghahramani,
Volume 6, Issue 2 (9-2019)
Abstract
The application of Extreme value analysis method in heat wave hazard climatology; case study in Mid-Southern Iran
Abstract
Greenhouse warming poses the main cause of atmospheric hazards’ exacerbation and emergence in recent years. Earth planet has been witnessing frequent and severe natural hazards from the distant past; however, global warming has strongly influenced the occurrence of some atmospheric hazards, especially the ones induced by temperature and has increased the frequency and severity of those risks. Such extreme risks arising from temperature element and being affected by global warming could be referred to hot days and their frequency more than one day which undergo heat waves. Of the studies conducted worldwide in conjunction with the phenomenon of heat waves, the following can be pointed out; Schär (2015) has focused his studies on the Persian Gulf and the worst heat waves expected in this area. The recent work revealed an upper limit of stability which enables the adaptability of human body with heat stress and humidity. If people are exposed to a combination of temperature and humidity over long periods higher than this level, they will lead to hyperthermia and death, because heat dissipation from the body is physically impossible. Paul and al-Tahrir (2015) using a high-resolution regional climate model demonstrated that such a situation can occur much earlier. In Iran, in relation to heat waves, Ghavidel (2013) analyzed climatic risk of Khuzestan province in 2000 regarding super heat waves using the clustering approach. The obtained results unveiled the establishment of a low pressure at ground level and high pressure dominance at mid-altitudes up to 500 hp as well as the increase in atmosphere thickness having led to the ground overheating. Added to that, the source of heat entering into Khuzestan is advective and hot and dry air transport through Arabian Peninsula, Iraq and Africa. Ghavidel and Rezai (2014) addressed in a study to determine the temperature-related threshold and analyze the synoptic patterns of super heat temperatures in southeast region of Iran; the results of study approved that the only pattern effective on the occurrence of super heat days in Iran’s southeast is the establishment of the Grange’s heat low-pressure at ground level and subtropical Azores high elevation dominance at 500 hPa level. In this study, absolute statistical indicators, also recognized as above-threshold values approach, were used in order to identify, classify and heat waves synoptic analysis in the warm period of the year in the southern half of Iran. To use above-mentioned indicators, firstly daily maximum temperature statistics of studied stations with the highest periods were averaged every day once in June to September and once for the months of July and September. Using statistical indicators of long-term mean and standard deviation or base period, indicators would be defined for the classification of heat waves and days with peak extreme temperatures. In such classifications, usually long-term average or base period is multiplied by 1 to 3 to 4 times standard deviation and each time is account for the factor of each class.
To select the days for synoptic analysis, averaging was performed of all classified waves into four heat wave categories of low, intermediate, strong and super heat; accordingly based on the maximum blocks in each class of heat waves, days that had the highest temperature values were selected as the class representative for mapping and synoptic analysis.
This study dealt with investigating heat waves synoptic during the year’s warm period in the southern half of Iran. Studies showed that a variety of synoptic systems in the year’s warm period affect the study area. As well as, synoptic analyses concluded that in the southern half of Iran over the year’s warm period when occurring heat waves, low-pressure status dominates the ground level (caused by Gang’s low-pressure and local radiant mode); thus high-pressure status with closed curves is prevailing in atmosphere’s upper levels that gives rise to the divergence, air fall and Earth's surface heating. Studying the status of the atmosphere thickness in the days with the heat wave in the study area indicates its high altitude and thickness that this itself implies the existence of very hot air and susceptibility of the conditions for the occurrence of heat waves. In addition, wind maps at atmosphere’s different levels well illustrate the wind of very warm and hot air masses from the surrounding areas to the southern part of Iran; therefore it can be noted that aforementioned hot air masses mainly wind from places like different regions of the Arabian Peninsula, Iraq, North Africa and the low latitudes to the study area.
Keywords: Synoptic analysis, heat waves, maximum blocks, southern half of Iran.
Dr Moslem Savari, , , ,
Volume 6, Issue 2 (9-2019)
Abstract
Modeling Drought Effects on Sustainable Livelihoods of Small Scale Farmers in Rural Settlements of Kurdistan Province
1. Assistant Professor, Department of Agricultural Extension and Education, Khuzestan Agricultural Sciences and Natural Resources University
2. Professor at Department of Agricultural Management and Development at University of Tehran
3. Professor at Department of Agricultural Management and Development at University of Tehran
4. Professor at Department of Agricultural Management and Development at University of Tehran
Vulnerability and adaptation to climate change are local and context-specific, though connected to complex processes at multiple temporal and spatial scales. As such, there is a growing awareness that place-based studies of current and past responses to climatic stress can shed light on the capacity of a given system to respond to future climate change. There is also a growing appreciation of the importance of institutions—formal and informal—in shaping adaptation strategies and mediating the adaptive capacity of households and communities. While rural resource-dependent communities have historically coped with climatic fluctuations, whether such coping mechanisms are still successful today, and will be in the future, depends on the structure of supporting institutions and the way in which they mediate access to entitlements. Indeed, most social–ecological systems have undergone dramatic change in the last century due to climatic, landscape, and institutional shifts. Because coping mechanisms are developed in relation to particular landscapes, livelihoods, and institutions, social and ecological changes have altered relations across these elements, impacting the effectiveness of particular coping strategies. For instance, pastoralists have historically deployed a suite of coping mechanisms in response to the highly variable climate of semi-arid and arid landscapes. Yet, these capacities may be increasingly compromised in the rangelands of East Africa due to increasing exposure to climate extremes, such as flood and drought and shifting institutional environments. The mechanisms that pastoralists in East Africa historically utilized to cope with climate variability were part of a tightly coupled system where livelihoods, institutions, and landscapes were mutually reinforcing. Pastoralists’ livelihoods were co-produced with a savanna mosaic landscape managed as a common property system by formal and informal customary institutions.
Farmers frequently cope with risks due to the uncertainty of climatic conditions .Population growth, changes in agricultural policies, environmental regulations and the degradation of natural resources such as soil and water also present farmers with numerous challenges. Although farmers have experience in coping with a certain degree of uncertainty, increased climate variability and changes may cause severe problems. Drought in particular is a climatic disaster that creates substantial costs for farmers and affects their agricultural systems extensively. Drought is the most complex of all natural hazards . making the arid and semi-arid regions of the world vulnerable. Although drought has not been well documented , the resource-dependent sectors such as agriculture are the most vulnerable to the impact of this phenomenon. A review of the long-term annual precipitation trends indicated that drought had a worldwide return frequency of every 20e30 years . However, in the last 50 years, some countries such as Iran and Bangladesh have experienced approximately 27 and 19 drought events, respectively. Therefore, for arid and semiarid regions, drought is a recurrent feature that could lead to the loss of crop production, food shortages and starvation if not managed appropriately. According todrought impacts could be managed at macro (national), mesa (local) and micro (village and household) levels. However, the micro-level management (i.e., what the farmers do in response to drought) is of great importance. A review of the studies of farmers’ decision-making in response to climate variability revealed that most research has focused on the decision event and not on the entire process.
The main Purpose of this study was to modeling drought effects drought effects on sustainable livelihoods of small scale farmers in rural settlements. Statistical population of this study consisted of all Small-Scale Farming in Kurdistan province. Using Kerjcie & Morgan sampling table, 402 person were selected as the sample using stratified proportional sampling method. The instrument of the study was a questionnaire which its validity was confirmed by a Content validity and construct validity and its reliability was established by calculating Chronbach's Alpha and Combined reliability Coefficient (α>0.7).
The results of Man- Kendall test showed that the level of aquatic and dry crops, along with the amount of crop production, has increased over time but there is no statistically significant effect on dry production. Also, the results showed that in the economic aspect, the greatest impact on distribution of income and living expenses, in the social dimension, on location affiliation and security and social welfare, the environmental dimension has had an impact on environmental pollution and land resources and on institutional aspects more on the cooperation and participation of the people.
In addition, the results of structural equation modeling showed that drought had the most impact on sustainability livelihood dimensions, respectively, on social, environmental, economic and institutional dimensions.
Keywords
Sustainable livelihood, drought, small scale farmers, rural settlements, Kurdistan province
Hossein Hosseinekhah, Asghar Zarrabi,
Volume 6, Issue 2 (9-2019)
Abstract
Role mode combination decision Waspas in Identify zoning Seismic
(Case study: Population center, township Bahmaei in Kohgiluyeh and Boyerahmad province)
Hossein,Hosseinekhah[1], Asghar Zarrabi [2], Hamid Reza Varsi[3]
According placement Country of iran On the belt earthquake Alpine - Himalayas and Placement Partial of Iran Plateau Between two pages of Saudi Arabia (south) And Eurasia (north) And consequently the existence of active faults And the existence of seismic point And most importantly, record high intensity earthquakes, Etc in the township of Bahmei, in The present study will try, with Using the WASPA model, Identified and reviewed The Seismic zones. The main purpose of this study is Identify and zoning Earthquake risk in township Bahmaei and Secondary objectives research:
- Review and Assessment City Likak against earthquake risk.
- Identify and zoning district township Bahmaei against the danger of earthquakes.
- provide strategies to Reduce Damage and and physical and financial vulnerabilities of citizens.
According the nature of the subject and research objectives, Research Methodology Based on descriptive – analytical and functional. Collect dates provided in two part, weights and layers of information, based on Documentary method and using satellite images, Mapping organization, USGS organization. The statistical population of the research, the entire limits township Bahmaei based on dividing the national. Indicators used in the study, 10 key indicators, including Active faults, seismic areas, rivers, urban and rural settlements, the elevation, slope and more. To collect data Of the America Geological organization, National mapping organization, Satellite imagery and as well as to review and analyze data used is of ARC GIS software and Wapas model.
Results of the research show that from area 1245 square kilometers of Bahmei Township, there are 252.228 square kilometers, equivalent to 20 percent of the Township in an unsafe zone. 149 square kilometers equivalent to 12 percent is in the high risk zone and 167 square kilometers, equivalent to 13 percent in area with the high-risk. Also, of the area of 1245 square kilometers in the Township of Bahmei 386 square kilometers, equivalent to 31 percent is in the zone with low risk of the earthquake. The final weights achieved by each Propeller (weaknesses, strengths, opportunities and threats) in a separate and individual weighting with one another, have dominance of the dominating role of the matrix threat.
Results Research shows, 252 square kilometers, equivalent to 40 perecnt of Bahmaei township in zone safe, 386 square kilometers in the zone with low-risk, 289 square kilometers of the township In the zone with middle danger, 149 square kilometers of the township Equivalent with 12 percent of the township In zone with high risk and 167 square kilometers, equivalent to 13 percent is in the zone whit high-risk of the earthquake
The city Likak as Bahmaei township center is in zone with low very risk Compared to the risk of earthquakes. Also The results showed The 160 sq. Km of The central part of township Equivalent to 18 percent in zone with low-risk And 137 square kilometers, equivalent to %15 in zone whit high risk and 15 percent of central city The zone have very high hazard. Also the results showed of area 506 square kilometers Section Garmsar, 30 percent in the zone safe, %44 in the zone with low risk and 6 percent is in zone with the very high risk. The also results showed that 15 villages and villages (6%) are very vulnerable, 20 villages (8.43%) are in high danger zones and 112 villages are in zone with low risk.
Keywords: Waspas model, earthquake, Likak city, township Bahmae.
Jamileh Tavakolinia, Alireza Mehrabi, Ehsan Allahyari,
Volume 6, Issue 2 (9-2019)
Abstract
Today, air strike on installations and urban areas, is normal. As such, vulnerability assessment cities and provide the right solution for harm reduction is essential. The purpose of this investigation was to identify factors causing damage in the district of twenty in Tehran. The research method is descriptive-analytic and Data collection is library and field. Data analysis is based on using Ahp and GIS. Results show, In the district twenty , There are three zones vulnerable. Including, The old Central, The high-density Dolatabad and sizdah aban neighborhood. These zones are 34 percent of the land. The reason of it is Poor physical structure. Statistical Society is Twenty district in Tehran. Sample size is 384 people of residents of the district. Because, in this area there are strategic factors, is An important part of the tehran city. in the end, are provided The right solution of Reducing vulnerability.
Ahmad Porahmad, Hossein Hataminezhad, Keramatollah Ziyari, Seaideh Alijani,
Volume 6, Issue 2 (9-2019)
Abstract
A new Approach to Urban livability, Thermal Comfort as the Primitive Condition to enhance the livability: Case study, District 22 of Tehran.
Ahmad Porahmad: Professor of Urban Geography and Planning, University of Tehran
Hossain Hataminezhad: Professor of Urban Geography and Planning, University of Tehran
keramatollah Ziyari: Professor of Urban Geography and Planning, University of Tehran
Saeideh Alijani*: PhD candidate of Urban Geography and Planning, University of Tehran
The concept of urban livability is defined as the quality of life and wellbeing of urban residents. That is the interaction of people, environment and built environment. The residents can achieve happy life and well-being only when the nature surrounding them is happy and healthy. According to the range of welfare concept there is a spectrum of quantitative indicators that directly measure (human body temperature, heart rate, air temperature, wind speed ...) and qualitative indicators such as quality of life, pleasure and joy. The comfort and ease of environment are in the middle of the spectrum, in other words, the intrinsic concept of ambient comfort is environment. The inadequacy of natural environment will affect both indicators in the spectrum and lead to citizens' dissatisfaction and decline in social welfare and threaten the health of humans. Living in a salty marsh or very dry hot climate is never happy and satisfied. Accordingly, many concepts such as living quality, living environment, and quality of place, quality of life and sustainability are often used interchangeably with livability).
This research is trying to weight the natural environment at least equal to the other two components of the sustainable development triangle. Among the components of natural environment, climate is playing the most important and significant role. Urban climate affects all aspects of city including building interiors, city architecture and open spaces. Thermal comfort of open spaces promote the social life and interrelations of residents. Therefore, in order to promote the social relations and economic activities especial consideration should be paid to open spaces. Accordingly, two types of data were measured for calculating the thermal comfort in the district 22. Subjective and objective evaluations which present qualitative and quantitative data. Objective data includes micrometeorological measurements with mobile instruments. Subjective data evaluated actual sensation vote or perception vote of thermal comfort by people using the urban open spaces. To this goal, questionnaires were prepared and scattered through space users simultaneously with micrometeorological measurements. Subjective data evaluated perceptual sensation vote of thermal comfort by people using the urban open spaces in three hot days of August 2018. Nine points are selected for site measuring and field survey which are representative of two types of urban open spaces in this research:1) Urban park and 2) street. Four cardinal points were chosen adjacent to the Shohadaye Khalije Fars Lake inside the park located in sidewalk pathway around the Lake. Other five points were selected in streets with different orientation and aspect ratio through the district. The physiologically equivalent temperature (PET), mean radiant temperature (Tmrt), sky view factor (SVF) and aspect ratio (H/W) are the most important indicators in this research which were calculated for evaluating comfort in the district.
Results showed that urban open spaces in the district are discomfort and expose people to the extreme heat stress; over 40°C. This determines that, the natural environment especially around the Shohadaye Khalije Fars is not comfort. The questionnaire also indicated that people felt warm and dissatisfied.
There is a high linear correlation between thermal comfort and mean radiant temperature and globe temperature. Therefore, it is concluded that thermal comfort in the district, is directly affected by urban areas. Also in the streets with low SVF and high aspect ratio, PET were calculated more comfortable than other streets. Point 5 at Naghibzade street, confirmed the effect of urban geometry on thermal comfort. Otherwise, the lack of tremendous trees for creating shade is visible especially around the lake. The high linear correlation between Tmrt and SVF around the lake confirmed the openness of the area and the high amount of solar radiation. Therefore, planting more trees for creating the shade effect is necessary.
The perceptual analysis of thermal comfort indicated that by increasing of PET, people felt warmer. However, in a city like Tehran, people are more resistance to the heat stress. In addition, the characteristics of human body strongly depends on psychology and individual features and is a hard issue to predict. Otherwise, the people who felt warm were more than those felt slightly warm which indicates dissatisfaction of people. To be noticed that, thermal comfort of above 40 °C in summer is an alarm to urban planner and designers to rethink about climate consideration and global warming as a most important urban challenge in the district seriously. Besides, the consideration of thermal comfort and urban geometry should be imbedded into the comprehensive plan. This research proved that the climatic consideration for improving the quality of life and livability is important and urban designers and planners should rethink and review the comprehensive plan of Tehran to make a livable and sustainable city in the future.
Keywords: urban livability, climate comfort, sustainable development, urban sustainability, urban geometry, physiologically equivalent temperature, district 22 of Tehran.
Dr. Sahar Nedae Tousi, Ms Roza Hosseini Nejad,
Volume 6, Issue 2 (9-2019)
Abstract
Resilience, as a concept to confront abnormalities, surprises and unexpected changes in recent years has been raised as the ability of places, societies, and systems to respond to the dangers of tensions and pressures; so that the system can quickly return to pre-stressed situation, threats It accepts the future and confronts them. Central region of Iran according to the zoning studies of the national physical plan of Iran, including three provinces of Isfahan, Chaharmahal and Bakhtiari and Yazd, in a desert climate with many crises in the permafrost environment that has disturbed the state of resilience of the region, and as a result the scheme and target application regional resilience on policy and planning to reduce vulnerability and to cope with various trans-regional crises. Despite the fact that the concept of resilience at the level beyond the city has become apparent, there is still no clear framework for measuring this situation at the regional level. Based on this research, it is believed by the trans-regional and multi-dimensional nature of the resilience that by modifying and applying the concept of resilience to the integrated and multi-dimensional at the regional level, an appropriate framework for status measurement regional resilience in the form of a composite index and thereby risk reduction planning and promoting the resilience of the presentation To give. In this regard, the major purpose of the research is to develop an optimal framework for assessing, measuring and ranking the resilience situation in the central region of Iran. The results show that Chaharmahal and Bakhtiari province have the highest resilience and then there are two provinces of Isfahan and Yazd, respectively. In the meantime, Yazd province has the lowest resilience among the provinces of the central region; therefore, it is necessary to focus on planning and allocating resources to promote and improve priority sectors. Responding to resilience agendas requires the adoption of transregional planning and decision-making approaches such as environmental regionalism.
Dr Hamid Ghorbani, Dr Abbas Ali Vali, Mr Hadi Zarepour,
Volume 6, Issue 2 (9-2019)
Abstract
Drought is one of the most complex and unknown natural phenomena that causes a periodic water crisis in the affected areas. Increasing water demand on the one hand and the experience of droughts in the province in recent years have led to the water crisis. Knowing the drought is one of the requirements for water crisis management. The purpose of this study was to analyze the trend of the SPI drought index in Isfahan province using nonparametric Sen’s slope test, Pettitt’s change point test and Man-Kendall test. From the monthly climatic data of 10 synoptic stations with a length of 27 years (1990-2017) for time series The results of applying Mann–Kendall and Sen’s slope tests based on SPI Index for 9, 12, 18, 24 and 48 month time periods, shows drought trend is significantly increasing for all stations out of Ardestan, Esfahan and Shahreza stations. In Ardestan station, the drought trend is significantly decreasing for 9, 12, 18, 24 and 48 month time periods and in Isahan station, the drought trend is significantly decreasing for only 48 month time period, and in Shahreza statition, the drought trend is significantly increasingonly for only 18 month time period.
Despite all stations, the drought trend for one month time period, is significantly increasing just for Naein station.
In addition, applying Mann–Kendall test on monthly rainfall for all station shows downward but not significant trend.
Finally, applying Pettitt’s change point test based on SPI Index for 9, 12, 18, 24 and 48 month time periods indicates the existence of a significant change point. For same periods we observe no change point for the monthly rainfall in all stations.
In summation, considering the SPI drought index, about 59% of all stations show significant downward trend bases on Mann-Kendall test and 60% of all stations show significant slope based on Sen's slope test and 75% of all stations show significant change point based on Pettitt's test. In general, for drought analysis using different time periods for the SPI index, in a short time period. (such as 6 months) drought is more frequent but shorter, and as the period increases the duration of drought also increases but frequency decreases. All together, we are facing a water crisis in Isfahan province and we must manage water demand very urgently.
Dr Abolfazl Meshkini, Mr Ali Mohammad Mansourzadeh, Mr Zeynab Shahrokhy Far, ,
Volume 6, Issue 3 (9-2019)
Abstract
Identifying spatial patterns in vulnerability involves a comprehensive look at vulnerable points. And provides analytical power to the authorities. Therefore, it is necessary to recognize patterns of vulnerability so as to minimize the amount of damage to them in the event of a crisis. The city of Tehran, as the political and administrative center of the country, is faced with a variety of risks due to demographic burden and physical development. In this research, we tried to analyze the spatial distribution pattern of urban vulnerability to natural hazards in social and physical dimensions in Tehran's 7th region. The method of this descriptive-analytic study and the model used for trigonometric fuzzy logic. The results indicate that: According to the z score, the positive values are 1.96 up, which form the clusters of hot spots in the southeastern region of the arena; It is a sign of more vulnerability in these areas. Also, negative values of 1.96 and less, which are statistically significant and blue, have formed cold spots, And it is interpreted that low vulnerability zones are clustered in space and are mainly located in the northwest. Therefore, the lower the color range in the red and blue areas was less statistically significant to the point where this positive net worth is 1.65 that in this situation, the spatial behavior of the vulnerability is considered to be non-significant in terms of hot or cold clusters with high and low values and spatial autocorrelation that the map is also displayed in yellow.
Gholam Hassan Jafari, Hazhir Mohamadi,
Volume 6, Issue 3 (9-2019)
Abstract
The consequence of human activities caused destructive and irreversible problems to the original state in the few past decades that has attracted the attention of all walks of life. The sinkholes are one of the mentioned effects in different parts of the planet such as Iran, Hamadan and especially have been happened in Kaboudarahang-Famenin plain. Researchers believe that the most important consequences of the indiscriminate withdrawal of groundwater and illegal wells and the activities of Shahid Mofatteh thermal power plant change the parameters of soil caused appearance sinkholes in that area. All of the geological information, faults, hydrological, elevation, slope, aspect, and land use investigated by topographical geological maps, also digital elevation models and Google Earth image processes used for the study on the extraction and sinkholes due to the numbers and distribution of wells were assigned in GIS software. The results show that the level of groundwater, geology, land use and height of the range are the most effective factors in the creation of sinkholes; but the efficiency of surrounding factors and in somewhere farther from the sinkholes. The construction of Ekbatan dam on the most important river as the main water provider of understudy plains, the development of Hamadan city and changing the surrounding land use in Bahar county to agricultural, prevent from reaching water to the Kabodarahang and Famenin plains as a former and increasing the water demand in downstream is caused numerous sinkholes that was provided with favorable conditions than before (the dissolution of limestone).
Zahra Taghizade, Ahmad Mazidi,
Volume 6, Issue 3 (9-2019)
Abstract
Abstract
Urban heat island (UHI) is one of the environmental phenomenon which has made difficult environmental conditions for citizen. This study aims to evaluate the spatial and locational variability of Esfahan urban heat island according to the role of land use. Thus an area about 190.2 square kilometers (km2) in Esfahan, as the microclimate, was studied. In order to analyze the relationship between land use and land cover changes on Esfahan urban heat island, the images of Landsat 7 (TM and ETM +) and Landsat 8 (OLI / TIRS) on 20 July 1989, 17 August 2005, 18 August 2014 have been used. The results show that the urban areas has experienced 31% changes in positive direction; while the agricultural sector and green space havehad a reduction of 25% in their area. The analysis of the intensity of heat island show that heated cores are related topoor and barren lands with about 37/33 and 36/5. Although the most area of thermal classwere related to warm thermal class in 1989 and 2005, the average thermal classes were about 63/8%in 2014. Moreover, the locational variation distribution of Esfahan heat island shows that the locationof the heat island has gradually changed. For example in 2014 it included small parts in the south of the city, military zones and barren lands in the south, some parts in the north west and north east areas and small areas in the east of Esfahan. This means that urban development isn’t the main factor of the surface temperature increase and urban heat development, but rather the type of land use has influenced the decreasing or increasing of air temperature.
.
Gholamreza Janbazghobadi,
Volume 6, Issue 3 (9-2019)
Abstract
Abstract
Fire in natural resources is one of the crises that causes irreparable damage to ecosystems and the environment every year. The purpose of this research is to attempt to study areas of risk aversion and to prepare a map of forest fire hazard area by integrating topographic data and other additional information from a GIS system for Golestan province. In order to carry out this research, firstly, with the removal of the recorded data related to the situation of fires occurred in 2009 and 2010, the domain of all natural resources of Golestan province was carried out. In order to identify areas with high fire potential, static parameters were used to control the burning of forest forests (elevation, slope, slope direction, land use / land cover, evaporation rate). Each of the static parameters is divided into different classes And to each class, using bachelor's knowledge and review of research, ground data and the results of the above studies are weighted from one to ten. In the following, by using overlap of these layers with different weights, areas with high fire potential were identified for the forests of Golestan province. Finally, all weights were summed up, the final weight was obtained and a fire hazard map was prepared. The Arctic GIS9.2 software has been used to generate a fire hazard map. Also, The fire risk index (FRSI), the Normalized Difference Vegetation Index(NDVI), and the zoning map, have a fire hazard in the risk category (very low to high) ). The results showed that most of the fires occurred in hardy and covered with forested areas, as well as in the forested areas with a crown and an intermediate cover, and in the next stage, in the woods and shrubland areas. In calculating the calculation of fire density in altitudes, the results showed that approximately 90 percent of fires occurred in average altitudes between 700 and 1500 meters. Overall, the findings showed that 90 percent of burns occurred continuously in areas With fire hazard, 30% in hazardous areas and 60% in extreme areas, so that its Galikesh, Minoodasht, , Azadshahr has high risk of high fire.
- Amin Salehpour Jam, - Jamal Mosaffaie, - Mahmoudreza Tabatabaei,
Volume 6, Issue 3 (9-2019)
Abstract
Investigation of desertification trend needs an understanding phenomena creating changes singly or action and reaction together in the manner that these changes end up in land degradation and desertification. In the investigation of pedological criterion affecting on land degradation in alluvial fans, first, maps of slope classes, land use and geology were created, then a map of units was founded by overlaying and crossing these maps and grid layer created by extension of ET GeoWizards in ArcGIS 10.3 software. In this research three indices of erodibility, salinity and permeability of soil were considered, finally according to the seven level scales, each of them was shown as the classified map. In this research, nonparametric methods of Friedman and Kendalls' W rank tests were used to prioritize the options, in the manner that after defining crisp numbers in seven level scales, the rank means were calculated. The rank means obtained from Friedman and Kendalls' W rank tests alter from 7/00 to 17/33. Obtained results from the nonparametric methods showed that 74/18 % (4245/77 ha) and 25/82 % (1477/67 ha) of the area were classified into two classes of medium and very heigh desertification potential, respectively. The results also showed that the youngest and old gravel fans of the area have desertification potential of very high (798/75 ha) and low (152/23 ha), respectively.
Mohammad Javanbakht, Hosein Hoseini,
Volume 6, Issue 3 (9-2019)
Abstract
Abstract
Introduction
Vulnerability is the limitation of a society to a risk and to dominate it for all physical, economic, social and political factors, which adversely affects the ability of the community to respond to those events. An earthquake is a natural phenomenon that will be irreversibly damaged. It has caused severe humanitarian earthquakes in the minds of a compilation of an infrastructure program to reduce the risks and damage caused by it. The country's geostationary characteristics have suggested earthquakes as one of the most destructive factors in the destruction of human life. Historical surveys show that vast areas of our country suffered financial and financial losses due to this natural disaster. According to the United Nations, in 2003, Iran ranked first in the number of earthquakes with a high intensity of 5.5 millimeters among the countries of the world.
Earthquake is a natural hazard that often causes too many losses and casualties. Iran is country with a lot of earthquakes and and Khorasan Razavi province which is studied in this study also experiences a large number of this natural hazard and 71% of the surface area of this province is in the range of medium, high and too high hazard of earthquake. One of the important sectors in which the effect of the earthquake damage very large is power transmission lines. Transmission of oil and gas products by pipelines is one of the most appropriate, inexpensive, fast and reliable methods. These lines are mostly buried in terms of safety and social considerations. In engineering collections, such structures are considered as vital arteries. Due to the fact that pipelines are spreading widely, therefore, due to the vulnerability of the transmission lines, it can damage the economy of the country.
Methodology
In this study the vulnerability of the network lines of power transmission of Khorasan Razavi province against earthquake were studied. The aim of the present study was applicable and method of study was descriptive-analytic. To prepare a map of the extent of the vulnerability, the fuzzy gamma method was used. Effective parameters for this research include proximity to a fault line, geological structure, land slope, population density of urban and rural areas, distance from the communication lines. One of the most important fuzzy operators for overlapping indices is the GAMMA operator. Gamma operator is the general mode of multiplication and addition operators.
Mrs Elham Fahiminezhad, Dr M Ohammag Baaghide, Dr Iman Babaeian, Dr Alireza Entezari,
Volume 6, Issue 3 (9-2019)
Abstract
Changes in the mean and the extreme values of hydroclimatic variables are two
prominent features of the future climate. Therefore, simulating the climatic
behavior of Shandiz catchment area, an important tourist area in the northeast of
the country, will play an important role in identifying the climate condition and
potential vulnerability of these areas in the coming decades of climate change.
In this study, we will
evaluate the effects of climate change on extreme values of the basin micro scaling
precipitation and temperature in CanESM2 model using SDSM model and
simulating runoff with SWAT model in future decades.
To achieve this goal, the daily temperature and precipitation statistics of the 30
statistical years (1961-1990) of Mashhad synoptic station have been
used. The data of the CanESM2 general circulation model under RCP2.6, RCP4.5
and RCP8.5 scenarios are also used to predict precipitation, the minimum and
maximum temperature for 2041 to 2100.
According to the results, the annual precipitation rises 37 to 54 percent from 2041
to2070 compared to the observation period, and the increase in rainfall of the
2071-2100 rises 52 to 66 percent. Precipitation extreme values, the mean of
maximum and minimum temperatures in future periods in all seasons of Mashhad
station will increase compared to the observation period (1961-1990).In future decades, the average maximum temperature in Mashhad will increase from 4.6 to 0.65 degrees Celsius
and the average minimum temperature will increase 53/1 to 22/4.
By introducing micro scaled time series of the maximum temperature, temperature,
and micro scaled precipitation by SDSM model to SWAT model, the monthly time
series of Shandiz watershed runoff at Sarasiab Station was simulated for the two
periods of 2041-2070 and 2071-2100 under three distribution scenarios of RCP2.6,
RCP4.5 and RCP8.5. For this purpose, first, the model was calibrated and validated
using Shandiz hydrometric station runoff for 2003-2012, and the values of R2 were
65 and 52, respectively. Subsequently, with the introduction of micro scaled time
series of maximum and minimum temperatures, and micro scaled precipitation by
SDSM model to SWAT model, the average annual trend shows that runoff
increases in the coming decades. The lowest average annual increase for runoff is
in 2041-2070 and RCP4.5 scenario, with an increase of 56.1% over the observation
period. The highest increase of average annual monthly runoff is from 2071 to2100
under RCP 2.6 scenario with 53% to 104% runoff compared to the observation period.
Dr Abbas Ali Vali, Dr Sayyed Hojjat Mousavi, Mr Esmaeil Zamani,
Volume 6, Issue 3 (9-2019)
Abstract
Introduction
Dust storms as one of the environmental hazards of the arid regions of the globe, including the southern, southwestern, eastern and central parts of Iran, has caused many environmental problems that confirm the need for studying and crisis managing its in scientific and executive congresses. Therefore, the present study attempts to evaluate the effects of climate elements on temperature, precipitation, humidity, evapotranspiration and vegetation index on the frequency of dust storms in Yazd province during the period of 5 years (2009-2014).
Data and Methodology
So, after determining the synoptic stations of the area, the dust data were extracted based on the code of the present weather phenomena and the values of the climatic elements. In the next step, their spatial zonation was determined through the interpolation method. Then, using the MODIS images, EVI index data were calculated according to the principle of time matching. Finally, a variety of simple and multiple regression models were fitted to estimate the occurrence frequency of dust, and the most appropriate relationships with higher preference values were reported.
Findings and Conclusions
The results showed that there was a significant relationship between the total dust with evapotranspiration and relative humidity with a R square of 0.973 and 0.614 and the standard deviation of 24.104 and 92.477 at sig. level of 99% and 95%. Also, there is the maximum significant relation between external dust with evapotranspiration and relative humidity with a R square 0.968 and 0.621, and the standard deviation was estimated to be 0.173 and 75.427 at sig. level of 99% and 95%, respectively. Internal dusts with evapotranspiration and maximum temperature with a R square of 0.770 and 0.377 and standard deviation of 15.1751 and 64.22 have a significant relationship with sig. level of 95%. The results of the total, external and internal dust storms with climatic elements and vegetation cover showed a significant correlation with the R square of 0.994, 0.988 and 0.956 and the standard error of estimation of 18.13713, 24.2555551 and 10.49989 at sig. level of 99% and 95%, respectively, which indicates the systematic function of climatic elements and vegetation cover in the occurrence of dust.
Reza Reza Borna, Shahla Shahla Ghasemi, Farideh Farideh Asadian,
Volume 6, Issue 3 (9-2019)
Abstract
Today, the impact of climate is considered on the life, health, comfort, activity and behavior in a form of the branch of science such as human biology. Due to difference of frequency people with each other, the sensibility of every one from weather can be different from the other one that's why the climate can’t be totally undesirable or the climate can be totally desirable for all the people, so we can say that all of climatic elements are affected on human comfort but the effect of some of them is quite cleared and the effect of the others is mild and sometimes invisible. The greatest effect on comfort and discomfort can be included temperature, humidity and solar radiation. The aim of this research is to investigate and determine the area risk of climatic comfort. For this purpose, the temperature, precipitation and humidity data have been extracted for Khuzestan province form Esfarazi database. In this approach, first different properties of the temperature, precipitation and humidity for the area with climatic discomfort have discussed based on the conditional probability distribution. This study has been identified the areas of climatic comfort in Khuestan province using multivariate analysis (Cluster analysis and Discriminant analysis) and spatial autocorrelation pattern (Hot Spot index and Moran index) with an emphasis on architecture. The results showed that the risk area of climate comfort is included mostly of the western parts of Khuzestan province namely the border areas with Iraq and some parts of southern of province .On the other hand ,trend analysis the range of this area to climatic discomfort indicated that it has increased significantly in recent periods .The results also showed that the local distribution of precipitation in all periods in the areas of climatic discomfort has been a high the coefficient of variations.
Mr Mohamad Khalaj,
Volume 6, Issue 3 (9-2019)
Abstract
Abstract
Seismic potential investigation of Tehran as the capital of Iran is an essential issue because their accumulation around a fault may indicate its seismic potential. Stress trajectories for this estimate are useful. In this research, fault slip data is used for paleo stress analysis. Base on that, the study area divided into 6 stable stress regions and the mean stress tensor related to each region determined. Then the mean stress tensor rotated based on Anderson’s theory representing a compressional tectonic regime. The Stress trajectory map drew based on rotated mean stress tensor acting on the regions during geological time. The resulted map showed the arrangement of sigma1 trajectories in the area obeyed the overall tectonic regime in Iran and limited converge through the junction ignoring addition in stress magnitude and seismic hazard in the junction of major faults.
Given the importance of Tehran as the political-economic capital of the country, and its location in Alborz Basin with high faults density. and due to the seismic background of the area, the necessity of seismic risk assessment in this area becomes more evident. In this research, we have attempted to produce and present a map of faults in the Tehran wide area, focusing on faults in the eastern part of Tehran, Mamlouk, Ghasre Firozeh and the margins, with accurate structural elements and drawing of the stress trajectories, convergence of the trajectories, and stress accumulation at convergence sites, assess seismic hazard at this location based on longitudinal stress data (Katsushi Sato, 2011; Yamada and Yamaji, 2002; Yamaji, 2000; Sippel et al., 2009).
Based on field observations and data collected, scratch faults were selected for collecting and analysis of longitudinal paleo stresses as they record all deformation stages. After collecting the fault data, we stabilized them using the Multiple Inverse Method (MIM) and zone boundaries, and by drawing a
Mohr's circle (without scale) for each range, seismic potential analysis was performed (Katsushi Sato, 2011; Yamada and Yamaji, 2002; Yamaji, 2000; Sippel et al., 2009).
To separate the stress phases, obtain the reduced stress tensor, obtain different stress and stress parameters, and plot the stress trajectories, the study area had to be divided into smaller ranges. It is not possible to determine the size of the stress components and the principal stresses by longitudinal stress methods and it is not possible to draw a scaled circle. Therefore, it is possible to draw a circle without scales for fault data only. This circle enables the overall analysis of the field shape, the arrangement of the data in the graph, and the comparison of the relative components of the fault data stress. By the Mohr's circle (without scale) method, the principal minimum stress and the maximum stress difference (s
1 - s
3) are considered as base (0) and unit (1), respectively, and assume the same size with respect to the relation (F = (s
2 - s
3) / (s
1 - s
3)) between the calculation of the middle stress field shape and the field shape factor. Studies show that tensile tectonic structures are not dominant structures in the region. For the kinetic analysis of fault data, precise rock mechanics such as the internal friction angle and the Amonton-Columbus criterion cannot be used precisely. But given the arrangement of the fault data, a large degree of comparison can be made between the kinetic features and especially the fault dynamics of each range. Therefore, the main maximum stress must be horizontal. Assuming that all the faults are coherent and based on Anderson's theory of faulting that the main minimum stress is vertical in the compressive stress regime, the position of the principal stress axes of each range is returned to the conditions of the fault formation (vertical minimum stress). In all ranges, the principal minimum stress is near vertical. After rotation of the data and the vertical axis of the minimum stress was set, the trajectory maps were drawn for horizontal stresses (main and maximum stresses).
A study based on longitudinal stress studies and Andersen's theory introduces the main maximum stress trend N017E, which is in good agreement with the general crustal shortening trend of the Central Alborz (Vernant et al., 2004). Therefore, the major faults of the region do not have a significant impact on the disturbance of the stress field within the region and, in fact, the convergence of these faults does not lead to the convergence of stress trajectories. The positioning of the poles of the fault plates on the main stress plates indicates that along with the crustal deformation in this part of Alborz, the regional structures have been rotated and decomposed. In fact, the reason for the polarization of fault plates on the main stress sheets with zero shear stress is that the rotation and positioning of faults coincide with the rotation and deformation of other geological structures and phenomena such as folds and joints. The arrangement of the poles of the fault plates in the Mohr's circle indicates that the faults in zone 3 have less dynamic potential than elsewhere.
Keywords: Stress Trajectory, Multiple Inverse Method, Convergent Faults, Seismic Hazard, Mamlouk, Ghasre Firouzeh.
Mr Masoud Jalali, Mr , Mr Abdullah Faraji, Mr Ali Mohammad Mansourzadeh, Mr Sayyed Mahmoud Hosseini Seddigh,
Volume 6, Issue 4 (2-2020)
Abstract
Analysis and zoning of thermal physiological stresses in Iran
Abstract
Human health is influenced by weather variables in all circumstances, including atmospheric pressure, humidity and temperature around them. Based on climate hazard and climate changes, different parts of human life and economic and social strategies such as health, hydrological pollutants And agriculture had a profound effect, including the discussion of the effects of thermal stress on human health over the last few decades, and has become a major issue in the world's scientific circles. Heat and cold stresses, the exposure of humans to extreme heat and cold, are part of the extreme events, often encountered by people during daily activities or in the workplace, and affecting human physical activities. It is important that, if the body is not cooled through transpiration or cooling mechanism, severe deaths are inflicted on human health; therefore, the person has to reduce his activity in order to reduce the adverse effects of heat stress. Hence, many researchers consider the thermal stress component more important than other components in assessing human health.
In this study, using the physiological equivalent thermometer of PET thermal stress assessment and zoning of human thermal physiological stresses in Iran, with the length of the common statistical period from 1959 to 2011, and for the arsenal of thermal physiological stresses of Iran Forty stations have been used as representatives of Iranian cities. To calculate the physiological equivalent thermal temperature, all the effective meteorological elements in the human energy bill are measured at an appropriate height of climate biology, such as 1/5 meters above the Earth's surface. Data on climatic elements are provided by the Meteorological Organization of Iran. In the absence of data for some courses, linear regression method was used to reconstruct these missing data. After calculating the indices, the frequencies were also monitored and finally, using the GIS technique, the Kriging method of the study area was based on the frequency of occurrence of the indicators. Therefore, in order to achieve the results and objectives of the present study, software such as SPSS for data normalization as well as missing data was analyzed and analyzed using Ray Man's model based on meteorological elements to calculate the equivalent thermal physiological temperature of humans. Also, using the GIS software and Ordinary Kriging method, the best interpolation method was used to zon the human cysiological stresses.
Today, in the planning of human health and comfort, the study of the physiological thermal stress plays an important role. In this regard, weather conditions can be used in the long-term planning of climate and in the short term planning of atmospheric conditions. In the present study, using the thermophysical Thermal Equivalent Thermal Index (PET), the climate climatic Atlas of Iran was prepared on a monthly basis. Calculated values for 40 stations in the country with a total statistical period of 52 years (1959-2011) were prepared. The results of this study showed that the spatial distribution of the physiological equivalent thermal temperature index in the country follows the altitudes, roughness and latitude. Accordingly, the low values of the indicator, which relate to the stresses of the cold, are consistent with the high and mountainous regions as well as the high latitudes, and vice versa, the thermal stresses occur in low and low elevations, as well as low latitudes, which of course, severe heat stresses occurred in the summer. Because throughout this season, the entire country of Iran is dominated by high tidal altitudes at high and low levels of ground pressure (1000 hp) with its warm and dry air, causing extreme heat and The term effects of heat waves on humans, heat loss, thermal contraction of the muscles and skin dryness, infectious or skin diseases, inflammation, sunburn, dizziness, fatigue, and mortality due to an increase in allergies can be mentioned. Significant differences in the environmental conditions of the mountainous masses of Kerman, Yazd and Sistan and Baluchestan provinces with their surrounding areas or low and low northern areas, and especially the Moghan Plain and Sarakhs plain, located in the upper latitudes of the country The issue is that the role of elevation in spatial distribution of the country's climate is much more colorful than factors such as latitude and longitude. The results of the analysis of the monthly thermal physiological stress maps showed that in terms of the area without tension, the march of the month with 47/8% of the area (778424/2km2) is in the first place and has the most favorable environmental conditions, The moon with 43/5 percent of the area (709275/2km2) is in the second position and also in March with 22.6 (359128/9km2) in the third, August and the last month. The highest thermal stresses (29
Dr. Firouz Mojarrad, Dr. Hassan Zolfaghari, Mr. Mehdi Keyghobadifar,
Volume 6, Issue 4 (2-2020)
Abstract
Analysis of the Characteristics of Sultry Days in Iran
Extended Abstract
Sultry phenomenon occurs due to the combined effect of high temperature and humidity. Sultry intensity increases with increasing relative humidity and decreases with decreasing temperature. This phenomenon has a tremendous impact on comfort and other human activities. Various indices have been used to study this phenomenon in Iran and in the world. According to previous studies, and as far as information is concerned, there has not been a comprehensive study across Iran on the characteristics of sultry days based on degree of severity. Therefore, the purpose of this study is to investigate the frequency, duration and severity of sultry days and its temporal and spatial analysis throughout Iran.
To do this research, daily temperature, relative humidity and partial water vapor pressure of 101 synoptic stations were used for a 28-year period (1987-2014). In choosing the indices of sultriness, the goal was to select indices that show the sultry state on a daily scale. For this purpose, in the first stage, 16 empirical sultry or sultry-related indices were used, all of which used climatic parameters such as temperature, relative humidity, water vapor pressure and cloudiness to calculate the sultry state or comfort. Among them, 13 indices were eliminated because they surveyed the phenomenon on a monthly or annual basis or were not consistent with the objectives of this study. Finally, according to the objectives of the study, three indices were chosen: 1- Sultry Intensity Index (Lancaster-Carstone empirical equation), 2- Partial Water Vapor Pressure Index (partial water vapor pressure equal to or greater than 18.8 hPa), and 3- Heat Index (HI).
The results of this study showed that two indices of Sultry Intensity and Partial Water Vapor Pressure are suitable for explaining the conditions in Iran and their outputs are not significantly different. But Heat Index did not lead to desirable results. According to the results of the Sultry Intensity Index, the sultry phenomenon is not comprehensive in the country and is limited to 21 stations adjacent to the Caspian Sea coasts in the north (besides Parsabad Moghan Station) and the Persian Gulf coasts (besides Ahwaz station) and the Oman Sea coasts in the south. In other parts of the country, due to their internal and leeward position, being away from moisture sources, poverty or lack of vegetation and insufficient penetration of wet and rainy systems, there is no sultry condition and, on average, even one day is not seen with sultry circumstances. On the southern coasts, on average, sultry conditions begin on April 3 and end on November 16. Therefore, in this area, 7 months and 11 days of the year have sultry conditions. This is natural due to the lower latitude and the Azores high pressure sovereignty in the south. But on the northern coasts, the sultry period is shorter and with a 48-day delay compared with the southern coasts, the average sultry day begins on May 22 and ends on October 12. Therefore, the duration of the sultry period is on average 4 months and 19 days. In terms of the number of sultry days, the most frequencies belong to the southern coasts stations. The largest number of sultry days related to the Chabahar port on the coasts of the Oman Sea with 291 days, followed by Jask port with 264 days. The lowest number of sultry days is also from Ahwaz station with 1 day and then Mahshahr port with 42 days. Among the stations on the southern coasts, the Oman Sea stations compared with the Persian Gulf stations have more sultry days due to lower latitudes, Azores high pressure sovereignty and Southeast Asian monsoon moisture influence. In contrast, the number of sultry days on the northern coasts is much lower and averages 140 to 150 days a year. Sultry severity is also less, so that there are no extreme severe sultry days in any of the stations on the northern coasts. But the number of extreme sultry days is remarkable on the coasts of the South, to 160 days in the port of Chabahar and 111 days in the port of Jask. At Parsabad Moghan in the north and port of Mahshahr in the south, due to distance from the coast and lack of sufficient moisture, the duration and severity of sultry is much lower and there are basically no days of severe and extreme sultry states. The annual trend of the number of sultry days at any station is not significant.
Keywords: Sultry, Temperature, Relative Humidity, Sultry Indices, Iran