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Joan Amini, Mehri Akbari, Zahra Hejazizadeh, Ali Akbar Shamsipur,
Volume 0, Issue 0 (3-2007)
Abstract

Green spaces have a key role in moderating urban micro-climatic conditions, beautifying urban landscapes, citizens' leisure time, and also reducing noise and air pollution and absorption of Aerosols. In addition to the significant advantages of green space, water consumption and irrigation needs is one of the main limitations of green space development in Tehran that nowadays faced to critical water shortage. Calculating water footprint in green spaces, as the total amount of fresh water required to maintain green space throughout the year, is one of the indicators by which the compatibility of tree and plant species with climatic conditions can be assessed. The main object of this study is to estimate the water footprint of Laleh Park in Tehran province of Iran. The Green space soil water balance (SWB) model was used to calculate water footprint in this park. The required data that including: average daily temperature, total precipitation and moisture depth of zero to 30 cm of soil, were obtained from the Geophysical meteorological station of Tehran for 2018. Data related to soil water drainage were also estimated based on standard laboratory samples of green space soils. The results indicated that in the warm months (June to September) of the year, the total water footprint of Laleh Park in Tehran was 4 to 5 thousand cubic meters per month (m3/m), while the winter months (December to March) total estimated water footprint were less than 1400 cubic meters per month. The generalization of 30 Centimeters depth soil moisture data of the geophysical meteorological station to Laleh Park, released that, in the warm month of the year, Green Water (groundwater or surface water) had the largest portion (more than 90%) in the water footprint of Laleh Park, While in the winter months (December and to march), the green water (water from snow and rain) is main participant in providing soil moisture, more than 90% of the total water footprint of Laleh Park  has related to this source.

Hamzeh Alizadeh, Mehry Akbary, Zahra Hejazizadeh, Mohamad Ahmadi,
Volume 0, Issue 0 (3-2007)
Abstract

Kermanshah province, especially Ravansar city is one of the important regions of the country in the agricultural and horticultural sector, most of the time the hail phenomenon causes significant damage to these sectors. One way to reduce this damage is to install an anti-hail system. To achieve this goal, 37 station hail data were clustered and three main clusters were obtained representing hail days; Each of the clusters has been plotted and analyzed in terms of geopotential height of 500 hPa, moisture level of 700, and map of 1000 to 500 hPa of temperature and omega. The results of the study of hail patterns show; A low-altitude system is essential in the Middle East; To direct hot and humid air from the southern offerings to the region; At the same time, it is necessary to have high instability and weak static stability in the atmosphere on the surface of the earth, as well as the presence of sufficient moisture that can provide showers. Hierarchical analysis (AHP) method was used for location in GIS environment and parameters such as (slope, slope direction, temperature, humidity ...) were evaluated. These criteria were classified as operating maps, each separately and were scored according to the degree of priority in establishing the device. The final map shows the location of the system: Parts of the northwest of the region (Mansour Aghaei and Ghori Qaleh) and northeast of the central part of Ravansar and parts of the southwest of the area due to the appropriate geographical conditions and appropriate to them, sufficient temperature and humidity and the direction of the southwest slope, and having Favorable conditions for severe instability followed by hail; Anti-hail system is very important for construction in these areas. In general, about 32.6 square kilometers have relatively favorable conditions and about 3 square kilometers have very favorable conditions for the construction of the system.
Ms Asieh Asgari Dastnaei, Dr Amir Gandomkar, Dr Morteza Khodagholi,
Volume 0, Issue 0 (3-2007)
Abstract

Teleconnection patterns represent large changes that occur in the pattern of atmospheric waves and tornadoes and affect temperature patterns in large areas and are also used to predict average weather conditions over time periods, usually several months or annually. In this study, the effects of 26 Teleconnection patterns with the average monthly maximum temperature on a quarterly and annual basis were investigated. In this study, 4 synoptic stations of Borujen, Shahrekord, Lordegan and Koohrang in Chaharmahal and Bakhtiari province were analyzed. Data were analyzed using descriptive statistics, correlation and Mann-Kendall test. The results showed that the patterns of PNA, WP, NAO, SOI, TNA, TSA, WHWP, Niño 4, NP, Trend, AO, AAO, AMO, AMM, NTA, CAR and GMLO have a positive relationship with all stations studied and The patterns of EA WR, Niño 3, ONI, MEI V2, Niño 1 + 2, Niño 3.4 and TNI had a negative relationship with all studied stations.
 
Dr Hassan Kharajpour, Dr Zahra Hejazizadeh, Dr Bohloul Alijani, Dr Mohammad Hossein Nasserzadeh,
Volume 0, Issue 0 (3-2007)
Abstract

      Considering the undeniable impact of agricultural plants on climatic and regional changes, it seems necessary to conduct regional research to understand the reaction of each agricultural plant in different stages of growth in relation to weather elements. If the temperature of the air along with the warm cloud is lower or higher than a certain threshold, its development will stop. Between the two limits, there is an optimal temperature where the plant grows the fastest. Temperature and clouds are both the most important climatic elements in agriculture. Both climatic parameters together cause stress in wheat and lower the productivity of the product. Considering the strategic nature of wheat, in order to increase the level of production, in the present research, while taking advantage of the experiences and methods and models used in foreign and domestic researches, it was practical in Kermanshah province due to the extent of the land under wheat cultivation and The significant amount of production, which has a special place in this field at the level of the country, the determination of the statistical threshold and the synoptic analysis of warem cloud temperatures on the performance of the wheat crop are investigated. According to the investigations and consultations with agricultural engineers, the maximum temperature along with cloudy days causes the phenomenon of greenhouse and excessive heat, which causes the fall of flowers, rot, sterility of pollen grains, fruit reduction, Premature aging and poverty become seeds, and this phenomenon occurs mostly in the months of May and June.

Mahnaz Sadeghi, Zahra Haejazi Zade, Mohhamad Saligeh,
Volume 0, Issue 0 (3-2007)
Abstract

The purpose of this study is to increase awareness and flexibility towards climate change and its effects on the environment through education. In the first step, to achieve the reproduction of climatic data and compare the scenarios of the general circulation model of the atmosphere, three important climatic parameters including precipitation, minimum temperature and maximum temperature were used and also SDSM software was used to predict the data. In this study, two stations of Zabol and Chabahar were used during the statistical period of 1961-2005. Three scenarios of RCP2.6, RCP4.5 and RCP8.5 in the period 2020-2050 were used to compare the results of the CanESM2 general circulation model, which is mentioned in the fifth IPCC report. The results of CanESM2 model showed that the minimum and maximum temperature and precipitation in the studied stations will have an increasing and decreasing trend in the future, respectively, in other words, the effects of climate change will be more obvious. In the second step, a questionnaire was distributed to teachers and students in Zabol and Chabahar in the education department; The results of validation of Cronbach's alpha test indicate that this questionnaire had good validity and reliability. The selection of the statistical population was purposeful; That is, from all the related schools, schools were purposefully selected at the discretion of the professors and were also evaluated and questioned. Analysis of the results of questionnaires related to teachers and students showed that the research hypothesis was confirmed according to T-Test.
Dr Mohammad Hossein Nasserzadeh, Dr Ali Reza Karbalaee Doree, Mr Mohammad Siah Kamari,
Volume 0, Issue 0 (3-2007)
Abstract

Drought is one of the natural disasters whose long-term effects affect the economy and society. This phenomenon is considered a challenge in arid and semi-arid regions, including Iran. Nowadays, the use of remote sensing methods can help us in understanding the drought behavior of vegetation. In order to monitor and analyze the behavior of drought in Kermanshah province, the data of Sanjande Weathers products (VIIRS) and AVHRR data indexed by NOAA STAR were used. In this study, the Vegetation Health Index was used in the period of 1982-2021 in a seven-day format with a spatial resolution of 4 x 4 km. After extracting the data in the Kermanshah area, the vegetation drought trend was investigated on 65,387 cells using the Mann-Kendall test. The results showed that in the winter season, the trend of vegetation cover in the western areas of the province was decreasing and significant at the level of 0.05. While in the northern, central and eastern regions of the province, the trend is increasing and significant. In the spring and summer seasons, especially the months of June, July, August and September, which correspond to the dry months of the year, the size of the areas with a significant decreasing trend of vegetation cover has increased, while in the autumn season, with the beginning of the water year, the size of the areas with a decreasing trend has decreased. 
Mohammad Radman, Mohammad Saligheh, Mohammad Hossein Naserzadeh,
Volume 0, Issue 0 (3-2007)
Abstract

In order to comprehend the water flow characteristics and variations of the Karun River, we examined the Zaz, Bazoft, and Beshar sub-basins from its main branches. The reason for choosing these basins was the proximity to the catchment centers of the Middle Zagros and their location upstream of the dams.
 Iran Water Resources Management Company provided all the required data (from the water year
1356-57 to 1395-96), and we analyzed them using Kolmogorov-Smirnov tests, data skewness, skewness, and Pearson correlation. Then, we performed the linear regression test to determine the effect of temperature and precipitation on river discharge, and they conducted the Mann-Kendall test to identify the trend and jump points. The results of the data analysis showed that all of them are in normal conditions, although they have some elongation and skewness. The Pearson correlation test revealed a correlation between meteorological and hydrometric data.
 The regression model used shows the changes in precipitation and discharge (unlike temperature and discharge) well. The significance number of all stations in the model is less than 0.05, which shows that the changes that occurred between predictor and dependent variables are significant. We see the high performance of the model in explaining the changes in discharge compared to precipitation. According to the regression charts, the decreasing trend of precipitation and discharge and increasing temperature are clear in all three basins.
The Mann-Kendall test reveals a significant trend of increasing temperature in Bazeft and Bashar basins, a decreasing trend of discharge in Bazeft and Bashar basins, and a decreasing trend of precipitation in Zaz and Bazoft basins.except for the temperature of the Zaz basin, all variables show mutations in mutation basins.
 

Atefeh Rezaei Talei, Zahra , Buhlol Alijani, Hematolah Roradeh, Taher Safarrad,
Volume 0, Issue 0 (3-2007)
Abstract

The role of regional and extra-regional forcings causes changes in the Siberian high-pressure cyclonic circulation every year. In this regard, an attempt was made to investigate the variability of the intensity of the Siberian high pressure in relation to the abnormal winter circulation of the atmosphere. For this purpose, gridded data of sea level pressure, geopotential height, orbital and meridional wind components of Center for Environmental Prediction/Atmospheric Sciences (NCEP/NCAR) between the years until 2020 (December to February) were used. After applying the Siberian high pressure intensity index, the extreme periods of this high pressure in winter were extracted. Next, the development of this system and the systems affecting the Siberian high pressure were investigated using the quantity of relative Vorticity advection. The results showed that during the winter period, the high pressure center of Siberia has undergone changes and has taken on a growing trend between 4 and 6 hectopascals. On the other hand, it was observed that the role of atmospheric systems such as dynamic ridges on the Siberian region along with advection The negative relative humidity, the location of the Siberian region in the east of the ridge, and the formation of omega bands play an important role in strengthening this system, which has caused this high pressure to develop from east to west or north to south. On the other hand, the role of the polar vortex in the cold advections of the region and the displacement towards the equator has caused the Siberian high pressure to sometimes increase by more than 11 hectopascals compared to its long-term average. Finally, it was observed that the atmospheric circulation in mid-latitudes plays a transitional role in the high pressure changes in Siberia and the polar and subpolar currents.

Mahdi Frotan, Majid Rezaei Banafsheh Daragh ‎,
Volume 0, Issue 0 (3-2007)
Abstract

Climate change is a significant threat to water resources, potentially altering precipitation patterns and increasing the likelihood of droughts in certain regions. This study aims to project future drought conditions in the Aras Downstream Watershed for the period 2025-2050, employing CMIP6 climate models (NorESM2-LM, CanESM5, and MPI-ESM1-2-HR) and the CMhyd software. Historical daily precipitation data from the selected models were compared with data from five stations (Parsabad, Aslan Duz, Jafarabad, Dasht, and Shorgol) within the study watershed. The comparison was conducted using statistical metrics (R2, MAE, MSE, and RMSE), and the results indicated the superior performance of the MPI-ESM1-2-HR model in precipitation estimation. This model was bias-corrected using the LS method in the CMhyd software, and future precipitation was projected based on the outputs of three scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). The Standardized Precipitation Index (SPI) was employed on a three-month timescale to assess drought conditions. The findings revealed that the overall region will experience normal conditions based on SPI classifications. However, there will be a relatively higher potential for drought in the southern part of the watershed under the SSP2-4.5 and SSP5-8.5 scenarios compared to SSP1-2.6. The analysis of the network station averages indicated that the optimistic scenario suggests favorable conditions for the watershed, while the intermediate and pessimistic scenarios suggest‎ a contrasting picture, with drought becoming prevalent across the entire region in the coming decades.

Hamidreza Karimi, Shariar Khaledi, Reza Borna,
Volume 0, Issue 0 (3-2007)
Abstract

Goods and currency smuggling is a widespread issue in Iran, disrupting economic, political, and social planning. While not limited to border regions, these areas are particularly vulnerable due to their unique geographical conditions. This research focuses on the natural factors influencing smuggling in border areas, examining the roles of topography, vegetation, climate, and water resources.

The study aims to determine the extent and mechanisms by which each of these natural factors affects the control of goods and currency smuggling in the country's border regions. This is a fundamental-applied study using descriptive-analytical and quantitative methods. Data were collected through surveys of military and border guard personnel stationed in border regions and analyzed using Pearson correlation coefficient, regression analysis, and path analysis modeling.

The results indicate that topography, vegetation, and climate have the most significant impact on hindering the operations of military and border guard forces in combating smuggling. The Pearson correlation coefficient (0.620) demonstrates a strong relationship between natural geography and the military geography of anti-smuggling efforts. In regression analysis, the "climate" variable shows the highest impact with a beta coefficient of 0.350, while "water resources" has the lowest impact with a beta coefficient of 0.124. Furthermore, the path analysis model shows that vegetation, topography, and water resources, influenced by climatic conditions, affect the quality of anti-smuggling efforts in the country's border regions, thereby creating challenges for military and border guard forces in controlling, monitoring, and combating smuggling.

Masoud Minaei, Sylvia Tramberend, Mohammad Kamangar, Ali Reza Karbalaee, Emilio Politti,
Volume 0, Issue 0 (3-2007)
Abstract

“The global water crisis is exacerbated by significant spatial data gaps in key water stress indicators such as Baseline Water Stress (BWS), posing serious challenges for policy-making and water resource management. This study leverages the XGBoost algorithm one of the most efficient machine learning methods for regression modeling to estimate missing BWS values at the global scale. Key predictor variables include soil moisture, climatic factors (precipitation, temperature, and evapotranspiration), land use/land cover, and elevation, derived from the Aqueduct Water Risk Atlas 4.0 and remote sensing datasets. Through comprehensive data preprocessing and hyperparameter optimization, the model explains approximately 71% of the variance in observed BWS values (R² = 0.711), achieving a Mean Absolute Error (MAE) of 0.727 and a Root Mean Square Error (RMSE) of 1.143 on the standardized 0–5 BWS scale—demonstrating competitive performance compared to prior studies (R² range: 0.60–0.75). Feature importance analysis reveals soil moisture as the dominant hydrological integrator (35.41%), followed by climate variables as the primary driver of the hydrological cycle (24.58%), land use/land cover (18.30%) and population density as key anthropogenic factors (16.04%), and elevation as a topographic modulator (5.67%). The reconstructed global BWS map highlights pronounced spatial heterogeneity in water stress: critical hotspots emerge across the Middle East, North Africa, and South Asia, while higher water security is observed in tropical and temperate regions. This model provides a practical tool for policymakers to identify high-risk areas, develop early-warning systems, and support sustainable water planning. The unexplained variance (29%) underscores the need to integrate socioeconomic data and implement local-scale calibration representing a pivotal step toward addressing the global water crisis.

Gholamreza Barati, Isaa Dehghan,
Volume 0, Issue 0 (3-2007)
Abstract

The Siberian High-pressure (HP) has various effects on Iran’s climate. Climate warming, especially in the last century, has raised the possibility of changes in the Outbreaks of the Siberian High-pressure extending toward Iran (OSH). In this study, to test the mentioned hypothesis, daily sea level pressure maps for 50 years (1972 to 2021) during the month in which the SH appeared more strongly in the monthly composite maps were downloaded from the NCEP/NCAR atmospheric data reanalysis database. The selection of this month was based on the highest central pressure intensity of the high (intensity index) and its greatest spatial extent (spatial index) compared to the other six months. The axes of the OSHs extending toward Iran were classified into four categories: “continuous and reaching,” “continuous and non-reaching,” “discontinuous and reaching,” and “discontinuous and non-reaching.” The design of their synoptic patterns showed a clear decrease in the frequency of “continuous and reaching” OSHs. Continuity refers to the directness of the OSH, and a reaching OSH is one that extends to the borders of Iran or penetrates into the country. Using two criteria— “the integrated advance of cold and dry air from the high-pressure center toward Iran” and “verification of the OSH entering or reaching Iran’s borders”—it was found that cold and dry air travels from Central Asia toward Iran through three main pathways: 1. The pathway of cold and dry air transfer from the western slopes of the Altai Mountains, then across the Turan Plain, and finally into central Iran. 2. The pathway of air transfer from the Dzungarian Plain in western China, then along the Tian Shan Mountains, through Afghanistan, and finally into the north of Sistan-va-Baloochestan Province. 3. The pathway of air transfer from the Kazakh steppes, through the Caucasus corridor (west of the Caspian Sea), reaching Azerbaijan, and extending along the Zagros Mountains. The frequency of OSHs has indicated a decline in five separated decades along all three pathways during the past half century. This decrease is more evident in the third pathway, namely the Caucasus corridor, which already had a lower frequency from the beginning.

Phd Student Farahnaz Khoramabadi, Master Seyyed Abolfazl Masoudian, Assistant Professor Mohammad Sadeq Keykhosravi Kiani,
Volume 0, Issue 0 (3-2007)
Abstract

Global warming is one of the most challenging climatic phenomena of the current era, accompanied by a rise in the average temperature of the Earth's oceans and land over the past few decades. This study provides a comprehensive analysis of the temporal and spatial changes in Iran's maximum temperature over the last four decades, using ERA5 reanalysis data.
Daily maximum temperature data was extracted from ERA5 products in HDF5 file format and processed using the Python programming language. For data analysis, Principal Component Analysis (PCA) was used for dimensionality reduction, and Ward's clustering method was employed to determine homogeneous climatic regions based on the similarity of weather elements. The long-term mean maximum temperature for the country during this period was estimated at 24.2C, with a range of variation from −0.4C to 53.7C. The results from smoothing the data's time series showed a significant temperature jump around the year 1998, which led to an increase in the mean maximum temperature from 23C to 25C. In the spatial dimension, the maximum temperature was directly influenced by topography, altitude, and latitude. The southern and southeastern regions were identified as the warmest, while the high-altitude areas of the west, north, and northeast were the coolest. The results of the PCA showed that the first two components explained more than 78% of the spatial variance and 93% of the temporal variance, respectively. This indicates the existence of consistent and interpretable climatic patterns. Additionally, the Ward's clustering analysis, which divided the data into five distinct clusters, reflected the diversity of temporal behavior of the maximum temperature across the country.
 

Dr Taghi Tavousi,
Volume 0, Issue 0 (3-2007)
Abstract

This study aims to evaluate the indoor environmental quality of urban buildings and their compatibility with the local climate of Zahedan. To this end, faculty housing units at the University of Sistan and Baluchestan were selected as case samples. Climatic data—including temperature, relative humidity, wind, and solar radiation—were analyzed over the period from 1982 to 2024. Solar angle, altitude, and intensity were calculated using mathematical functions, forming the basis for a monthly bioclimatic calendar of Zahedan, developed according to three criteria: air circulation within buildings, physical activity, and clothing type. The findings indicate that by adjusting factors such as window position and clothing, thermal comfort can be achieved throughout the year. In colder months, solar radiation and warm clothing contribute to indoor comfort, while in warmer months, gentle airflow through open windows enhances livability. Designing residential interiors in harmony with the local climate not only improves occupant comfort and health but also offers economic benefits by reducing energy consumption.
Fatemeh Nami Fard, Alireza Entezari, Abdolreza Kashki, Mohammad Baaghideh, Malihe Zaferanie,
Volume 0, Issue 0 (3-2007)
Abstract

This study was conducted to examine the relationship between specific climatic parameters, namely ambient temperature and air pollution, and behavioral abnormalities—including aggression and impulsive behaviors—among children diagnosed with Autism Spectrum Disorder (ASD). The research was carried out in Khorasan Razavi Province, Iran, and the statistical population comprised children with ASD aged 4 to 13 years who attended daily educational–rehabilitation centers dedicated to individuals with ASD. From this population, a total of 186 children were selected through convenience sampling. Data on behavioral variables were collected using three standardized instruments: the Shaheem Children’s Aggression Questionnaire (2006) to assess levels and dimensions of aggressive behavior; the Hirschfield Impulsivity Scale (1965) to measure impulsivity traits; and the Gilliam Autism Rating Scale (1994) for confirming ASD diagnosis and severity. Simultaneously, climatic and air quality information—covering daily ambient temperature and concentrations of key air pollutants—was obtained from reliable local meteorological and environmental monitoring stations. The results demonstrated statistically significant relationships between both temperature and air pollution levels with the severity of aggression and impulsive behaviors in children with ASD. Higher temperatures and increased air pollutant concentrations were associated with elevated behavioral abnormalities. These findings underscore the importance of incorporating environmental and climatic considerations into the clinical management, educational planning, and rehabilitation program design for children with autism. Furthermore, they highlight the need for interdisciplinary collaboration  to develop strategies aimed at mitigating the adverse behavioral impacts of climatic and environmental stressors on vulnerable pediatric populations.

Nazok Hossein Asad, Dariush Yarahmadi, Hamid Mirhashemi,
Volume 0, Issue 0 (3-2007)
Abstract

The ENSO phenomenon is considered one of the most important interannual oscillations in the Earth–atmosphere system and plays a significant role in precipitation variability across different regions of the world. In this study, to identify the multiscale relationship between different ENSO phases and monthly precipitation variability in Iraq, the monthly Niño3.4 index, the Maximum Overlap Discrete Wavelet Transform (MODWT), and the Continuous Morlet Wavelet Transform were employed. First, using multiresolution decomposition of the monthly precipitation signal from 16 stations across Iraq (1990-2020) into six (6) frequency levels (from monthly to multi-year scales), it was revealed that the precipitation signals at all stations follow a relatively similar pattern, although with different oscillation amplitudes. The amplitude of precipitation fluctuations at monthly and seasonal scales was found to be stronger at northern and foothill stations (Kirkuk, Mosul, and Khanaqin) compared to other regions of Iraq, indicating a shorter transition between wet and dry months in northern Iraq. Furthermore, the overall trend of the A6 component at all stations exhibited a decreasing pattern during 1995–2010, with this downward trend being more pronounced in the central and southern regions than in the north. The results of correlation analysis and multiscale wavelet coherence demonstrated a positive and multiscale relationship between ENSO and monthly precipitation in Iraq. Surrogate significance testing indicated that this relationship is not significant at wavelet levels 1 to 3 but becomes significant at 1.5–3-year and 2.5–5.5-year scales (wavelet levels 4 and 5). Overall, precipitation in Iraq tends to increase during El Niño (warm ENSO phase) events and decrease during La Niña (cold ENSO phase) events.

Malihe Izadi, Hamid Reza Varesi, Mahmod Mahmodzadeh,
Volume 15, Issue 37 (9-2015)
Abstract

Attention to housing and planning in line with sustainable development in the framework for planning national and regional is to our use of the knowledge and techniques of programming, existing situation and issues related to it is made clear that. To the main goal this research study and the analysis of the most tiresome effective in planning housing classification level and province of the country based on.This is a descriptive method of research-analysis. collecting data with the use of the results of the census and public housing in 1390 and resources library and documents and evidence have been done. The index of the study, 27 indicators inclusive of housing is a little bit you returned home Models based on regional planning(Multi-criteria decision analysis Vikor) Has beenanalyzed. Using a factor analysis technique, These four factors were  total 91/18 % of the variance explained Calculation of productivity. The provinces have indices using vikor. Based on this classification level, Esfahan(Zero coefficient),Golestan(Zero), Tehran(zero), East Azerbaijan(0/079 coefficient) in first to fourth levels are very Brkhordar And Semnan provinces(0/87),­­Ardabil(0/88), Sistan and Baluchistan(0/90)          ,Bushehr(0/90), Lorestan(0/91), Hormozgan(0/91),Mahal­­   Bakhtiari (0/92), Kohkiluyeh &Bourahmd(0/94),Qom(0/94),North Khorasan (0/96) and Elam(1), Respectively, and thelastlevelsvery brkhordar havetheleast.
Nader Parvin,
Volume 17, Issue 46 (9-2017)
Abstract

studying and identifying the middle levels change affecting the formation of a circular pattern creation is inevitable. In this study, the annual rainfall data for selected stations Zab River Basin during the period 2015-1986 were the standard time. After indexing and spatial-temporal threshold, 184 days without rainfall were selected in the wet period of three severe drought in the region. Level 500 HP height data located in the range of 0 to 80 degrees northern latitude and eastern longitude on dry days as a matrix S_Mode were used and these data using principal component analysis were processed using modern statistical methods. Based on the correlation matrix, the main focus of the 500 HP topography of the basin dry days were identified and analyzed. The results show that, in the happening time of dry days, twelve atmospheric middle levels of height change focus have been effective. In this regard, the following two centers having the highest anomalies (R≥0.7) are detected according to the high levels of the atmosphere: 1) the center of Eurasia-Africa, 2) the center of West Africa, respectively, 48% and 10% of the total area of the study. Such changes in middle atmospheric levels cause to strengthen and deepen the traffic axis and on the ridges. In the meantime, the change of first center has the highest impact on creation of stability and domination of dryness in days of Zab River Basin.

Dr Zahra Hejazizadeh, Mr Meysam Toulabi Nejad, Mr Alireza Rahimi, Mrs Nasrin Bazmi, Mrs Atefeh Bosak,
Volume 17, Issue 47 (12-2017)
Abstract

The aim of this study is modeling spatiotemporal variations of albedo. This study was conducted using simultaneous effects of several components, such as wetness of surface layer of soil, cloudiness, topography and vegetation density (NDVI), using MEERA2 model with a resolution of 50 in 50 km during 2000-2010 in Iran. The results of spatial analysis of albedo values in Iran showed that the highest value is in 44 to 45 degrees of east longitude about 2.8 to 3.3 and the lowest value of albedo is also in 52 to 53 degrees of east longitude, that is, the eastern slopes of the Zagros Mountains, have been recorded at 1 to 1.5 units. In terms of provincial rank, the largest albedo is about 0.25 units in Ilam province and the Fars province is ranked next about 0.24 units. The lowest amount of albedo also in the Gilan provinces and in next Mazandaran province are about 0.19 and 0.18 respectively. In addition, the results of temporal analysis in seasonal scale showed that the highest albedo in Iran in winter was 0.26 and its lowest amount was recorded in spring with 0.23 units. In general, according to the factors used, it can be said that the western and central parts of the country have a highest albedo, and the north and northwest regions of the country have a lowest albedo.
 

Ali Reza Karbalaee Doree, Sayyed Mohammad Hosseini, ,
Volume 17, Issue 47 (12-2017)
Abstract

Air pollution is one of the most important natural hazards in cities that is one of the priorities of climate research.  In this research, synoptic situation of days polluted by ozone in Tehran have been studied and by environmental to circulation approach and cluster analysis. At first, was formed a matrix in 2417*41. Rows are indicated days and columns represent the number of stations. by cluster analysis and Ward method eight different clusters were identified. The results showed that the frequency of the ozone days have a seasonal trend and more can be seen in the first half of year in these cases the establishment subtropical high pressure in Iran. Therefore, cause the persistency of pollution in Tehran.
 


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