Joan Amini, Mehri Akbari, Zahra Hejazizadeh, Ali Akbar Shamsipur,
Volume 0, Issue 0 (3-1921)
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.
Farzad Shirzad, Mr Bohlol Alijani, Mehry Akbary, Mohammad Saligheh,
Volume 0, Issue 0 (3-1921)
Abstract
Climate change and global warming are very important issues of the present century. Climate change process, especially temperature and precipitation changes, the most important issue is environmental science. Climate change means a change in the long-term average. Iran is located in the subtropical high pressure zone in arid and semi-arid regions and the Hyrcanian forest is a green area between the Caspian Sea and the Alborz mountain range. At the 43rd UNESCO Summit, the Hyrcanian forests were registered as the second natural heritage of Iran. Beech is one of the most important tree species and the most industrial species of Hyrcanian forests It accounts for about 18 percent of the northern forest volume (from Astara to Gorgan with a life span of about 250 years). The study area is located in the Shanderman basin in western Guilan province. In this research using tree dendroclimatology, Use of vegetative width of beech tree rings, Weather station statistics located in the study area, And Mann-Kendall nonparametric statistical method, To Investigate Climate Change Trend on Growth Time Series and Pearson Statistical Method, in order to evaluate the correlation of diameter growth of beech tree rings with climate variables in the region, an attempt was made. Results of time series of beech tree growth rings over 202 years. Using the nonparametric method Mann- Kendall showed, Changes in growth rings of beech trees have a downward and negative trend, at level 5 %, it was significant. Temperature Minimum, Average, Maximum, and Evaporation during the growing season, there was an upward trend and Annual precipitation there was a downward trend. Using the Pearson method Fit correlation of growth ring diameter with temperature, For the average monthly in February and the average minimum temperature in July, August and September and Negative correlation, for average maximum temperature in February, July, August and September at 95% level, it was significant and precipitation in June, the correlation was 95% positive and significant.
Hamzeh Alizadeh, Mehry Akbary, Zahra Hejazizadeh, Mohamad Ahmadi,
Volume 0, Issue 0 (3-1921)
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 (3-1921)
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 (3-1921)
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 (3-1921)
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.
Shahram Emamgholi, Gholamrezaa Janbaz Ghobadi, Parviz Rezaei, Sadroddin Motevali,
Volume 0, Issue 0 (3-1921)
Abstract
Temperature is one of the basic elements of climate, so its sudden or short-term and long-term changes can change the climate structure of any place. Intense heat waves are one of the most important climatic disasters that have far-reaching effects on various human activities and when they are of high intensity and frequency, they can produce major problems. In this study, to investigate the trend of 49-year frequency series (1970-1970) of hot wave events in Tehran, from two indices of hot days and hot waves (hot days lasting 2 days or more), non-parametric statistics of Sens trend analysis were used. All stations indicate an increasing trend both in the number of hot days in Tehran and in the frequency of hot wave events in 5 stations in Tehran. In this study, two hot waves were identified in Tehran, the first wave in 2010 covered a large part of the central and western parts of the country and the second wave in 2013, which was in all stations of Tehran and even many provinces. Are registered in the country. The results of spatial analysis of hot wave temperature in the statistical blocks of Tehran showed that generally the central areas of Tehran, including areas 6, 7, 8, 10, 11, 12, 14, 15, 4, 7, and 19 significantly It has been affected by the critical temperatures caused by the warm wave rule, while the northern parts of Tehran have been affected by the lower intensities of the hot wave.
Miss Sorayya Derikvand, Dr Behrooz Nasiri, Dr Hooshang Ghaemi, Dr Mostafa Karampoor, Dr Mohammad Moradi,
Volume 0, Issue 0 (3-1921)
Abstract
sudden stratospheric warming has an obvious effect on the Earth's surface climate. In this research, the changes in precipitation during the occurrence of this phenomenon have been investigated. For this purpose, after revealing the warmings that occurred during the studied period (1986-2020), 18 warmings were identified. The 5th decile and 9th decile of precipitation were calculated for the precipitation data of 117 stations. And the size of the difference from the normal rainfall was checked in two ways. First, the precipitation at the time of warming was compared with the long-term average, and then the trend of changes in precipitation at three times before thewarming, at the same time as the warming, and after the warming was finished. Finally, these results were obtained. Warmings according to the month in which they occur; They have a different effect on the amount of precipitation. In the sudden stratospheric warming that occurred in December, January and February, the northwest experiences the most rainfall changes and is above normal, and the probability of rainfall above the 9th decile increases up to 65%. Western and southwestern regions also have higher than average rainfall and the probability of heavy rainfall is high. Precipitation on the shores of the Caspian Sea shows an inverse relationship with sudden stratospheric warming, so in all the investigations of this research, the lack of precipitation at the time of warming in these areas is significant. Southern regions have less than normal rainfall in all sudden stratospheric warming events. The center of Iran has higher than average rainfall in the sudden stratospheric warming months of March. Eastern Iran also has heavy rains compared to normal during the sudden stratospheric warming months of March.
Dr Mohammad Hossein Nasserzadeh, Dr Alireza Karbalai Derai, Mr Mohammad Siah Kamari,
Volume 0, Issue 0 (3-1921)
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.
Hossein Asakereh, Mansureh Taheri,
Volume 0, Issue 0 (3-1921)
Abstract
One of the climatic characteristics of temperature is the occurrence of extreme temperature. In the present study, the trend of hot days with extreme temperature associated with the coastal plains of the Persian Gulf was investigated. Two environmental and atmospheric databases were used. Environmental data include the average of daily maximum temperature reported from 12 synoptic stations in Persian Gulf coastline (Khuzestan, Bushehr, and Bandar Abbas Provinces) from 1961 to the end of 2018. The extreme temperature for each day temperature was defined to be higher than the average of 75th percentile of the observations at each station and on the same day. Also, the ‘day with extreme temperature’ was applied to a day when the extreme temperature occurred in at least 50% of the stations. The number of hot days with extreme temperature in the study is 554 days, of which 291 days occurred in the warm season and 263 days in the cold season. These days were classified into six groups by performing cluster analysis on sea-level pressure in hot days. Then, for each group, the trend of hot days was examined. In general, it can be concluded that the slope of the line in all groups except the fourth and sixth groups were positive and, as a result, hot days with extreme temperature were increasing.
Mohammad Radman, Mohammad Saligheh, Mohammad Hossein Naserzadeh,
Volume 0, Issue 0 (3-1921)
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 (3-1921)
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 (3-1921)
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.
Dr. Vahab Amiri, Dr. Nassim Sohrabi, Dr. Seyed Mohammadali Moosavizadeh,
Volume 0, Issue 0 (3-1921)
Abstract
This study investigates the impact of natural and anthropogenic factors on the physicochemical composition of groundwater in the Qazvin aquifer. Based on the optimized Gibbs diagram, the concentration of samples at the end of the freshwater interaction path with silicate units results from geochemical evolution due to the dissolution of these geological units and an increase in the Na/(Na+Ca) ratio. The ion exchange mechanism was assessed using bivariate diagrams of Ca+Mg vs. SO4+HCO3 and Schoeller's chloro-alkaline indices CAI-1 and CAI-2. The results indicate that in 68% of the samples, direct ion exchange, and in 32%, reverse ion exchange control the groundwater chemistry. The changes in Ca vs. SO4 indicate that gypsum dissolution alone is not the source of these ions. These changes could be due to ion mobility and transport during pedogenic processes (sulfur biogeochemical cycle) and anthropogenic factors. The study also examined the role of factors such as agricultural input, atmospheric input, soil nitrogen, sewage input, manure input, chemical fertilizers, and the denitrification process in groundwater pollution using NO3/Na vs. Cl/Na and the NO3/Cl vs. Cl diagrams. The results reveal that agricultural and sewage inputs significantly impact the NO3 and Cl content. Furthermore, in some locations, especially in the southeast of the aquifer, the denitrification process causes a decrease in NO3 concentration. These findings can contribute to effective water resource management in this strategic aquifer by understanding the controlling mechanisms of physicochemical composition and identifying potential groundwater pollution sources.
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.
, ,
Volume 17, Issue 47 (12-2017)
Abstract
Suspended particles management is one of the important issues in controlling the air pollution of cities. These particles cause and develop heart and respiratory diseases in people. Mashhad is considered as one of the main and populous cities of Iran. Because of its climatic conditions and its tourism, the city is at the highest risk of this type of pollution. We attempted to use the multi-layer perceptron (MLP) artificial neural network and a Markov chain model to predict PM10 concentrations the city. We applied hourly data of CO, SO2, PM2.5 and temperature in late March and April 2015. Out of 1488 data series, 1300 data were used for network training and 188 data were used for validation. The results indicated the optimal performance of these methods in predicting of the amount of pollutants and also the probability of occurrence of hours with different quality of contamination. The best MLP artificial neural network model predicted the amount of pollutant particles with a coefficient of determination (R2) 0.88, index of agreement of 0.91 and a mean square error of 2.26. Also, the Markov model with average absolute error predicted about 0.1 percent of the probability of transferring the condition and the continuation of different states of air pollution caused by suspended particles.
Professor Ghasem Azizi, , Leyla Sharifi,
Volume 17, Issue 47 (12-2017)
Abstract
Thunderstorms are major climatic events due to the significant effects and catastrophic consequences on humans and the natural environment. The researches have shown that the elevation and latitude factors are two variables that can affect the occurrence of this phenomenon. Therefore, the main aim of this study is to investigate the spatial analysis of the effects of lightning and its effects on the components such as elevation and geographic extent in Iran. Apart from this fact, firstly, the monthly data of thunderstorms occurrence in 118 synoptic stations of Iran, from 1991 to 2010 on a basis from the country's meteorological organization were obtained and GIS software was produced by the annual and seasonal maps of Iran. Then, for the spatial analysis of this climatic phenomenon, the method of landing statistics of the Kriging (Universal) method was to examine its seasonal and annual status. In order to better understand the effect of Thunder hurricanes from altitude and latitude using Curve Expert software, seasonal and annual charts, along with the correlation of each production, were analyzed. The results show that the highest annual thunderstorms occur in the northwest of Iran, and the least amount is consistent with the central and eastern parts of the country. In addition, according to seasonal analysis, although the station has the highest rate at 800 to 1,300 meters, the maximum occurrence of this phenomenon varies from 0 to 2200 meters in different seasons of the stations. The overall result shows that the factor of height is slightly correlated with the occurrence of the Thunder storm phenomenon and the highest correlation is due to the latitude factor.
