دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Philosophical Foundation of environmental hazards 1 15 FA bohloul alijani Y Environmental hazards include all kinds of hazards in the environment such as natural and technological or natural and man-made. The natural phenomena such as rains or floods are the normal behaviors of the nature which only when they cause damage to the human life, are considered as hazard. The technological events such as road accidents, air pollution and chemical pesticides are always dangerous to human life. Both kinds of two hazards are produced in the context of human- nature relation. For example if human beings avoid flood prone areas there will be no harm or damage. And if human beings control their waste in the urban areas they will never pollute the city. Thus, this is the human who causes risk and damage to his life. The relation between human and the nature is governed by the thoughts and beliefs of human or in general terms his world perspective and philosophy. It is the human perspective and belief which controls his action at any circumstances. A person who believes in the nature as his mother and supporter of life differs from the one who thinks of nature as a sole source to use and enjoy. The first one gets only his basic needs from the environment, but the second person tries his best to exploit the nature for his benefits. Therefore to understand the intensity and frequency of environmental hazards, we should investigate the mental beliefs of people living in different places. A brief discussion of the historical development of hazards will help us to have a better understanding of the philosophical basis of the environmental hazards. From the ancient times up to around nineteenth century life was very simple and man had been using nature only for his basic needs, there was no consideration of environmental hazards. Hazards were considered only as diseases threatening the human life. But later, especially after the industrial revolution, due to the increase of human population and demands, the use of natural resources was exponentially increased far above the production and recovery of the nature. This process triggered the occurrence and expansion of environmental hazards.  The human- nature relation is studied by different scientific fields such ecology, anthropology, and geography from different aspects. The ecologists mostly emphasize on the relationship of individuals with his environment, as the characteristics of environment controls his life. While geography studies the spatial relations between human population and environmental assets. As a result, the philosophical stances of these fields differ substantially. Ecologists want to see whether this relation is dominated by the needs and intentions of man or by the capacity and potentials of the nature. From this point of view three kinds of philosophies were developed including anthropocentrism, biocentrism and ecocentrism. On the other side, geography emphasizes on the spatial distribution of human population on the basis of environmental resources. This spatial relation between human and natural resources is believed to be controlled by the nature or human conducing to the development of two philosophies of environmental determinism and possiblism. Ecological philosophy of anthropocentrism was dominated in the earlier centuries, focusing on the will of human to use and enjoy the nature. In this view, the nature has the instrumental value for human. The result of this philosophy was depletion and destruction of the environment in favor of the human development. But during the twentieth century some philosophers stated that the human does not have the right to harm and damage all living creatures including animals and plants. This view ended with the biocentrism approach.  During the second half of the 20th century due to the over exploitation of nature by human, the philosophers and ecologists realized that the human kind in order to possess a sustainable living should not harm any members of the environmental system including even rocks, rivers, soil and etc. This approach developed the ecocentrism philosophy. The main controlling force in these philosophies is the ethical stance of humans. On the other hand, the older geographers believed that it is the nature that controls the human distribution and living conditions. The humans cannot change the natural arrangement of the environment and should limit their activities to the natural allowances. The development of the technology after the Second World War changed this view. Some geographers believed that human can change the environment by his techniques and developed the possiblism. The adoption of this philosophy and the growth of industrial development ended with the deployment and damage of the natural resources. It is clear from the aforementioned discussion that in all cases, the main reason for the depletion and destroy of the environment was lack of ethical considerations in human behavior toward the nature. If the ecologists have come with the ecocentrism, geographers developed the geocentrism philosophy. That is, to save the nature and prevent environmental hazards we, as human beings, should preserve the natural arrangement of resources. We should not disrupt the spatial order of any resources, because it will cause harmful results in the environment. For example eroding the soil will deteriorate the vegetation and cause floods and other hazards. The alteration of spatial order of surface temperature has caused the thermal imbalance and hence global disorder and warming. There is no doubt that the relation of each human should be controlled and put in the moral contexts, but to prevent the environmental hazards an overall effort is needed over the environment which is possible only through the preservation of spatial order of natural resources. Spatial management of land resources is the outstanding example of this philosophy and ethic. Environmental hazards , Spatial analysis , Land ethics , Philosophical bases of Environmental hazards , Human ecology , http://jsaeh.khu.ac.ir/article-1-2311-en.html http://jsaeh.khu.ac.ir/article-1-2311-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Study of Daily and Seasonal Variations of Wind, Temperature, CO and PM10 in the Atmospheric Surface Layer over Tehran 17 34 FA Mohammad Ali Saghafi Y Abbas Ali Aliakbari Bidokhti N Nowadays air pollution in large cities such as Tehran have dramatic effects on public health, hence study of the way air pollutions varies with meteorological parameters appears to be important. One important aspect of sustainability of large cities such as Tehran, is controlling the emissions of pollutants as the meteorological (climatic) conditions are becoming more acute in terms of air pollution and temperature rise. In this paper some recent records of near surface meteorological parameters as well as some pollutants records are examine to observe how they change daily, monthly and annually and how they are correlated. Considering the variations of winds and temperature (extracted from a 2D sonic anemometer at 10 m at the Institute of Geophysics, Tehran University in the northern part of central Tehran, with one minute intervals) and hurly data of CO and PM10 concentrations for the same station for 2007, their relations were investigated. Also using upper air meteorological data (at 00.00 and 12.00 UTC) from Mehrabad Airport station, the stability of the atmosphere during this period was analysed. Here the buoyancy frequencies that are measure of stability of air column were calculated. For averaging of winds two methods based on the real wind vectors and wind unit vectors were used. By correlations between the pollutants concentrations and meteorological parameters, their relationships were considered. Based on the probability distributions of winds for 2007, it was found that most of the time wind speeds were in the range of 0.5 and 2 m/s. Hence most of the time due to this weak wind there was a condition of air pollution accumulations over the city and only local winds could move the polluted air over the area. Annual cycle of variations of mean surface winds had small amplitude that appears to be due to high mountain ranges that surround the city from north and east. The annual cycle of CO variations showed a peak in autumn and winter while PM10 amounts showed a trough in winter and spring. The higher values of CO in winter seems to be due to the surface temperature inversions and improper burnings of the fuel of vehicles as well as the domestic heating systems. This was indicated in the correlations between temperature and CO concentration.  In annual cycle the correlation between CO and PM10 concentrations was about 0.4 which increased to 0.7 for spring time. This may indicate that in this season the sources of these two are similar and one of them may be used to estimate the others is the sources are not changed. There are two maxima in the daily variations of CO which coincides with minima of wind in morning and evening transition times. In this study it was found that due to calm meteorological conditions (often od local origin, called mountain breezes) over the city air pollution problem is a serious problem requiring more emission control. Also trend factors as the pollutant sources (traffic) and the depth of the atmospheric surface layer are important. It is particularly noticeable that during the midday as the depth of the mixed layer increases, the air pollution concentration is reduced substantially. At night surface drainage flow from north of the city and surface radiation cooling creates near surface inversions that can limit mixing and ventilation of the polluted air from the area leading to higher values of gaseous pollutant over the city.  Also lager stability in the air over the city at higher levels in autumn and winter is due to subsidence inversions as a result of the prevailing meteorological conditions of high pressure systems over this area in these months. Such conditions seem to have increased the creation of more acute conditions for air pollution over the city. For a more resilient city in terms of air pollution, some mitigation need to be undertaken in the face of climate change effects that are deteriorating the atmosphere of the city.   daily variations , seasonal variations , wind , temperature , CO , PM10 , Tehran , http://jsaeh.khu.ac.ir/article-1-2312-en.html http://jsaeh.khu.ac.ir/article-1-2312-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Infrastructures and Resiliency to Natural Disasters With Emphasis on Flood The Case: Typical Tourism Regions in North of Iran (Cheshmekile & Sardabrud) 35 52 FA Mehdi Ramezanzadeh Lasboei N Ali ASgari N Seyed Ali Badri Y Natural disasters are investigated of various dimensions and consequences of natural hazards. As well, they can become as a repeatable phenomenon in the absence of mitigation systems, and could be caused devastating consequences. Resiliency approach as a basis for reducing the negative effects is taken into account to reduce the impact of natural disasters. Today, the two tourist areas of Cheshmekile (Tonkabon County) and Sardabrud (Kelardasht County) as typical feature of regional tourism planning have important potentials for development of tourism. But in recent years they have repeatedly been invaded by floods so that in some cases the impact of economic, environmental, socio-cultural and physical environment is followed. In economic dimension, flash flood destroyed agricultural fields and rural houses and in socio-cultural dimension it has increased insecurity. And finally, in terms of the physical and environmental aspect, it has created the most damage such as adverse changes in the appearance of the landscape, loss of trees, and destruction of public infrastructure (roads and bridges network). It is an approved hypothesis that rural settlements cannot be moved to the riverbank, but have created a situation that endangered abiding rural settlement. Various aspects such as socio-cultural, economic and administrative highly effect on resiliency. Among them, the role of infrastructures such networks, the location of health care facilities, police stations, fire stations and disaster management offices, communication networks (telephone, Internet) are more important to improve resiliency. This paper seeks to answer the key question that is the infrastructure in promoting resiliency after flooding in the two areas satisfactory?  The methodology of the study is objective and analytical analysis is based on the nature and method. The main variables are infrastructures and resiliency. Resiliency as the dependent variable consists of two main components of individual and community resiliency. Required information on the objectives, data integrity and availability has been developed in both library and field methods. In previous studies, library and documentation center is studied. Questions are sorted in the distance range, rated and ranked based on the needs and nature of the research and the knowledge and the education level of the local community. Questions are tested initially and after a measurement of the level of reliability (0.812), which is obtained using Cronbach's alpha. First, to determine the total sample size of villages located in flood risk areas in the two basins 9 villages (50%) were selected. Cochran formula is used to determine sample size. According to Cochran formula for the total population 296 households that included 129 head of households for Sardabrud basin and 167 head of households for Cheshmekileh basin. After the initial survey the collected information is encoded using a statistical software SPSS and then has been processed according to the assumptions formulated. Based on the results of the questionnaire analysis, some indicators, same as access to aid agencies (Crescent) and disaster management center, there were no significant differences between rural settlements such as the two basins distance to the city center is short. The nearest major communication route roads - Branch is located at a distance of 5 km from the city of Kelardasht, but in Cheshmekileh basin there are less than 5 kilometers distance to the main road of the Caspian Sea. That is why the average satisfaction of the local authorities in these areas is much higher than Sardabrood basin. Check out the highlights of each area residents is showed more satisfaction on facilities and services infrastructure in Cheshmekile. Result. To understand the relationship between resiliency and infrastructure used is the correlation coefficient between these two measures 003/0 there is level. This relationship of mutual relations, the improvement of infrastructure in the area with 99% probability of increasing population resiliency against natural disasters (floods) within it. The average calculated for the physical aspects - infrastructure represents the position of the component. Ring roads in northern cities, near airports such as Ramsar Branch, and there are several large medical centers, access to police stations in both basins are made ​​from the perspective of the respondents favored the status of this criterion is to be evaluated. However, among the subset of infrastructure, the roads are better than others. The reason can be attributed to the investment and construction of new networks of communication. In the case of energy network, although the topography of the area is caused that part of the basin, some of villages such as Gavpol, Letak, Drazlat in Cheshmekile basin and Lush, Krdychal and Roudbarak in Sardabrood basin was still stay deprived of the gas network but have favorable drink water and electricity network. However, keeping the population in the rural area is largely dependent on the infrastructure. Resiliency in relation to rural and infrastructural facilities, access to places of temporary accommodation is very important but in this particular field in any of the villages still planning has been done. Natural hazards , Floods , Resiliency , Cheshmekile Basin , Sardabrood Basin , Mazandaran province , http://jsaeh.khu.ac.ir/article-1-2313-en.html http://jsaeh.khu.ac.ir/article-1-2313-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Spatial Analysis of Natural Hazards Resulting from the Over- Exploration of Ground Water in the Coastal Aquifer of Urmia Region 53 65 FA Mohammad Nakhaei Y Meysam Vadiati N Coastal aquifers comparing noncoastal aquifers, are faced to natural hazards more rapidly due to incorrect managements (Bear et al. 1999). Aquifer’s vulnerability to various pollutants or intrusion of saline water to coastal aquifers have been studied by several researchers so far (Chachadi et al., 2002 Cardona et al., 2004). Overlay models are produced to overlay physical indicator maps and weight them (NRC, 1993). There is a high potential in applying methods based on spatial analysis, in hydrogeological studies. Assessment of natural hazards due to over-extraction of groundwater in Urmia coastal aquifer is the aim of this study which can leadto evaluating of groundwater quality fluctuations in coastal aquifer and also salt water intrusion in coastal aquifer. Study area is Urmia plain coastal aquifer. This plain is bounded from North, East, South and West by Zola chai and Kherkhere chai watersheds, Urmia Lake, Gadar Chai watershed and boundary mountains of Iran and Turkey respectively. Present study focused on, utilization of overlaid natural hazards substantial evaluation groundwater over extraction indices spatial models method, using Geographical Information System (GIS). Flow chart of the Methodology of present study is depicted in figure   Fig 1. Methodology flowchart of present study Drawdawn is meaningless?? “Counductivit “is wrong “conductivity” is true. Six parameters that have crucial importance in hazards caused by groundwater over-extraction and groundwater quality depletion subsequently, have chosen upon to literature review, various studies and authors expertise (Nobr et al, 2007 Hammouri and El-Naqa 2008). Weights and ranks were indicated base on experimental results or authors judgment and experts knowledge in similar studies and statistical methods. Used indices final weights were determined as below: Total dissolved solid (TDS) (1), discharge of water wells (2), hydraulic conductivity (1), Aquifer thickness (1.5), Water table depletion (3), Distance from lake shore (1.5). Weight of every layer is given to layers ranks. Final map was determined and areas with low, moderate, high and very high vulnerability was ranked eventually considering the vulnerability amounts importance.     Fig 2. Final map of Spatial Analysis of Natural Hazards in the aquifer of Urmia region   The results of this study revealed that natural hazard’s rates in Urmia Lake coastline due to salt water intrusion and also in aquifer central part is very high, which caused by groundwater over-extraction. Final map shows the areas with low vulnerability has covered 191 square kilometer (about 20 percent of the study area). In these areas groundwater extraction is low and the thickness of aquifer is also negligible. Areas with moderate and high vulnerability contain 353 (37 percent) and 119 (13 percent) square kilometer respectively. In the coastal and central parts of the plain, groundwater extraction is so high and of course features the very high vulnerability that covers 30 percent and 280 square kilometer of the study area. http://jsaeh.khu.ac.ir/article-1-2314-en.html http://jsaeh.khu.ac.ir/article-1-2314-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 The Role of Social Stratification in the Spatial Distribution of Vulnerability to Environmental Hazards in the City of Tehran 67 83 FA Tajeddin Karami karami_ta@yahoo.com Y Although environmental hazards occur because of natural factors, however, political economy, controlling the sociospatial relations and conditions, also affect centrally the increase or decrease of physical and social vulnerability caused by hazards. In this regard, present paper has put the spotlight on “explaining the role of spatial distribution of social stratification in vulnerability to environmental hazards in the city of Tehran”. This is based on Political Ecology Approach which emphasizes the domination of prosperous social strata on the urban natural-ecological endowments and utilities and marginalizes low-income and inferior social strata. So, the recognition of social strata inhabitation across the city is significant for the analysis of social inequalities and their effects on the vulnerability of environmental and human hazards. The concentration of middle to high class and working and inferior classes has also caused the range of social inequality to increase in the metropolitan of Tehran and this trend per se has transformed Tehran to the spatial reflection of the contrast between poverty and wealth to the greatest extent in the country. Hence, regarding the fundamental role of social stratification and class structure and its evolution in explaining the dynamics of socio-economical relations in the dominant society and the process of urban space production and reproduction, explaining the role of spatial distribution of social stratification in vulnerability to environmental hazards in the city of Tehran is significant and necessary. Vulnerability to environmental hazards has been studied from the physical, biological perspectives, social construction perspective and contingency perspective. The present paper emphasizes the effects of social construction on the production of vulnerability. Scientists think radical and critical geography of space is a kind of social production. They believe that not only urban space, but also the entire space has a social structure and nobody can analyze it thoroughly regardless to the society’s work on the space. Thus in a world under the Capitalist System, urban space represents a reflection of the control and domination of superior social strata (owners of power, wealth and high status, or the owners of political, economic and socio-cultural assets) in its functional zones.  This has been appeared in the recent decades, within the literature of hazards and catastrophes and based on “an approach of vulnerability” which has been rested on Political Ecology. The mentioned approach has been concentrated on a series of socio-spatial conditions and political economy which shapes the hazards and catastrophes. Some of the effective social conditions in shaping the hazards and catastrophes and their amounts of vulnerability depend on the racial, ethnic and class characteristics. Racial, class, ethnic and political economy analyses, which dominate their social ties, are considered as part of understanding knowledge system of hazards and catastrophes. Since this causes detecting the role of political economy of inequalities and racial, class and ethical processes and the marginalization caused by it, in the emergence of hazards and exacerbation of catastrophes and crises impacts. To use job structure means to emphasize concrete class structures, according to which an image of social inequality can be offered. Thus in present study, for structure determination and main composition of social stratification in Iran and Tehran “Structure Determination and Composition of Social Strata Model” was used. According to this model and with the use of data from matrix tables, major occupational groups and occupational situation have been classified in 5 classes superior strata, traditional middle strata, new middle strata, working and inferior strata and farmers. The data were prepared and analyzed by ArcGIS and Ms Excel softwaares.   During the last century, uneven development process of the country was in favor of the Tehran and superior strata and powerful institutions located in this city. Regarding the processes and relations emerged from political economy of space and political ecology of Tehran, social strata inhabitation of Tehran has been in compliance with environmental capacities raised from topographic and microclimatic distinctions and ecological endowments. The findings of present paper also indicate physical and social vulnerability changes caused by probable hazards related to the general pattern of social strata inhabitation in north-south geographical direction. Spatial distribution of populated blocks in 1996, for which more than 30% of their inhabitants were “senior managers and experts” and “manufacturing jobs employees and laborers”, indicates the above mentioned issue and clearly show the poverty (old poor neighborhoods) and wealth (expensive and rich neighborhoods) spatial centers. In addition, according to the supporting studies on Tehran Comprehensive Plan, most of old urban tissues are in central and southern regions. Also according to the International Seismological Research Agency (JICA), the mentioned regions would be the most vulnerable in the Tehran probable earthquakes. Therefore, it can be said that findings and results of the present study indicate the determining place of political economy of space and urban political ecology and also the fundamental role of social stratification and class structure for recognition, analysis, explanation and understanding of the urban development challenges and problems. Hence, this is impossible to reduce social and physical vulnerabilities caused by natural and human hazards, particularly in the poor neighborhoods, regardless of political economy of space mechanisms and reduction of the gap and even urban development.  Vulnerability to Environmental Hazards , Social Stratification , Urban Political Ecology , Social Inequality and Tehran , http://jsaeh.khu.ac.ir/article-1-2315-en.html http://jsaeh.khu.ac.ir/article-1-2315-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Circulation Patterns of Heavy Rains in the North West of Iran 85 96 FA Hossien Asakereh Y Fatemeh Tarkarani N Soghra Soltani N Climatic extremes are the special status (high or low) of climatic elements. In spite of the unique definition, there are a lot of thresholds which have been illustrated for extremes. For example, Bonneted (2006) has defined the climatic extremes as intensive and abnormal events that include the lowest and highest values in a time series. Becker et al. (2007) have referred to the extremes of climate as events in every given point that exceeds a special threshold in that place. High extremes and the upper tail of precipitation distribution of frequency have attracted a lot of attention of experts. The thresholds of extremes have been chosen based on geographic situations. The Joint World Meteorological Organization Commission (CCL) for Climatology on Climate Variability and Predictability (CLIVAR) Expert Team on Climatic Change Detection, Monitoring and Indices (ETCCDMI) have been established in 1998 in order to study and determine the indices of climatic extremes. They have introduced quintile indices. Due to consequences of extreme precipitation characters e.g. frequency, duration and intensity, the precipitation extremes have been in the center of attentions of many branches of science. Some experts call these events as social challenges that can determine economic sustainable development.  Extremes analyses are based on investigating the tails of statistical distribution of daily observations, because the longest time scale couldn’t show what it should have shown for extremes. Heavy precipitation for each day is defined as precipitation which is more than normal precipitation of that day in every given place. For this amount of precipitation absolute and relative thresholds have been defined. In present research, heavy precipitation is defined based on relative index and percentile parameter. By using 90th percentile, some characters of tempo-special distribution of extreme precipitation in Northwest of Iran are analyzed based on 729 stations. Northwest of Iran includes four province East and west Azerbaijan, Ardabil and Zanjan. This part of country has 126544.4 and occupied 7.2% of the entire country mainland. Geographic location of Northwest of Iran is located between the following coordinates:    The averages of sea level pressure (SLP) and 500 hp level patterns have been examined. Therefore, two data groups, station based and atmospheric based, have been used. Station based data include precipitation measurements during 1968-2007 synoptic , climatology and rain gauge stations related to Islamic Republic of Iran Meteorology Organization (IRIMO), rain gauge stations of Ministry of Power. Kriging Method is used as optimum interpolation method in order to provide maps of 14975 days. The pixel size of interpolation is chosen with 33× 33 kilometers dimension (approximately 116 pixel). Thus, data set of northwest precipitation with 14975 × 116 dimension and S-mode have been arranged. Atmospheric data include SLP and 500 hp data have been derived from NCEP/NCAR. The area experiencing heavy precipitation from 10-20 to 60-70 percent have been investigated. The map average and precipitation and precipitation center for all of these cases have been estimated. Some characters, for instance tempo-spatial presentation of heavy precipitation has determined by using Geostatistics Methods. A 14975  116 pixel data network was defined. According to 6 categories of extreme precipitation have been recognized. These categories are based on the extent of the area under extreme precipitation. It has been discovered 6 categories 10-20 percent to 60-70 percent of space under investigation. With the average increase of extreme precipitation amounts, the central mean of precipitation has centralized and the isohyets have become irregular. The small change in central mean of precipitation, a serious change had happened in precipitation distribution.   Mean of SLP pattern showed Siberian high pressure system that extended from east to west and indicated positives anomalies. low pressure system in the Red sea which is extended to Europe region and its extension to eastern of Mediterranean sea, south and north of Saudi Arabia as well as its extension to northwest and sometimes the whole west parts of Iran, formed an area with negative anomalies. The low pressure system which was close to European high, formed extreme pressure gradients. In the 500 hp level, the northwest of Iran is in front of the trough which is located in the east of Mediterranean Sea. As the depth of the trough increased, the area where experiencing heavy precipitation increased and the axis of the trough changed from vertical into horizontal shape. The occurrence of the trough formed negative anomalies in the area. In all cases, there are two ridges immediately in west and east of the trough  of the Mediterranean Sea. The occurrence of the western ridge caused cold air mass flowing in the trough where the Mediterranean’s warmer air mass exists and made the front’s formation possible. As the eastern ridge moved eastward, the area where experiencing heavy precipitation increased. http://jsaeh.khu.ac.ir/article-1-2316-en.html http://jsaeh.khu.ac.ir/article-1-2316-en.pdf

دانشگاه خوارزمی Journal of Spatial Analysis Environmental hazarts 2423-7892 2588-5146 1 1 2014 4 1 Classification of Atmospheric Circulation Patterns related to heavy snowfall in west of Iran. 97 107 FA Ebrahim Fattahi ebfat2002@yahoo.com Y Hengameh Shiravand N Heavy snowfall in the cold period will cause a lot of damages and troubles for society such as collapse of building installations, and confusions in road network and fuel distributions.  Freezing event will also make worse the intensity of damages. Therefore, identifying the mechanisms of Atmospheric Circulation Pattern (ACP) which form the heavy snowfall and freezing events will certainly help to manage the risk and mitigate the impacts of the crisis.  The main objective of this research was identification of Circulations Patterns (CP) related to snowy days in the basins located in the west and southwest parts of Iran.  In this study, the geographical location of the study area is  West of Iran in 30- 37degree  North latitude and 45 57  - 51 40  East longitude. The region consists of provinces of Kurdistan, Kermanshah, Hamedan, Lorestan, Ilam, Zanjan, Markazi, Chahar Mahal Bakhtiari, Kohgiloye Boyer and parts of West Azerbaijan. In this study, the days which have at least 15 cm of snow in 24 hours, are known as days with heavy snowfall.To choose widespread snowy days, the days that were reported in three stations at least, 3 adjacent provinces and the amounts of the snow were more than 15 cm, are known as heavy snow days. In this research, to analyze the synoptic patterns of heavy snowfall days, daily data of 500 hp level and sea level pressure in 2/5 degree from reanalysis data of NCEP were extracted. All effective systems covered the studied region. The region consisted of 408 point of (20-60) degree in north and (20-80 ) degree  in east altitude .To classify and analysis the synoptic patterns of heavy snowfall days Cluster  Methods  Analysis and Principal Component Analysis were used. To draw average maps of air circulation patterns, pressure data and daily resulted geopotential height of factor analysis and cluster analysis were used. Then four circulation patterns were obtained. Frequency of days with heavy snow – in fourth patterns - showed patterns of CP1 (13 days), CP2 (17 days), CP3 (39 days), and CP4 (12 days). During the under study period, the most frequency belonged to CP3 pattern – 39 day- and the least is belonged to CP4 pattern -12 days. The results obtained of researching synoptic patterns of heavy snowfall in west and south-west of Iran: On days with heavy snowfall in the South West and West of Iran usually Siberian  high pressure system extended widely and one toungue towerd east of Aral lake and other toungue developed to south till Tibetan also some times its toungue extend on the Caspian sea and north part of Iran to Europa. Azores high pressure center is usually reinforced and its tongue extends to the Mediterranean Sea, central europa and africa and other tongue semi- west Iran and Mesopotamia. Extension of Siberian high pressure in north part of Iran with cold high pressure in east Europe created Azore high pressure belt.the system turning clockwise will cause falling the cold air. While it is snowing heaviling,the blocking system create  between  azore  - Siberian high pressure in the east europa and its tongue covers western north and west of Iran. Sudan tongue of low pressure is active.this low pressure with orient east northern or north extened to north of Iran and create a partly strong tongue. Low pressure and high pressure tongues, to other hand warm air and cold air, hit together in west of Iran. Most strong ridge in east Europe was located .this ridge mostly extened tiltly from east north of Moscow to south of Red sea. -subtropical High height center in west Mediterranean and  Tibetan Plateau reinforced then moved to upper latitudes and caused strong ridges in Asia and europe with axis northern-southern These ridges and low height centers in west of Iran and region of Mesopotamia reinforce ridge in east of Mediterranean and extend to lower latitudes. The ridge cause cold advection the region. In these situation,Polar wandering  with axis of northern- southern or eastern north- western south extended to lower  such as nourth of caspean sea and west of Iran and in the rigon  caused falling cold weather. Ridges of Mediterranean (western-east) in europe and Tibet (northen-southern) in Asia is leaded to tilt in axis of ridge towerd lower latitudes. In such days, studied stations have intense tempreture lapse rate. http://jsaeh.khu.ac.ir/article-1-2317-en.html http://jsaeh.khu.ac.ir/article-1-2317-en.pdf