Showing 16 results for فشار
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Volume 13, Issue 29 (9-2013)
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Volume 14, Issue 32 (6-2014)
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Volume 14, Issue 35 (3-2015)
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Daryosh Yarahmdi, Asadollah Khoshkish, Mustafa Karampour, Ismail Ahmadi,
Volume 16, Issue 40 (3-2016)
Abstract
One of the Siberian high pressure system is the Earth climate system, atmospheric important. The purpose of this study, analysis of core changes Siberian high pressure system in the period mentioned. To identify the core spatial variations in the timeframe mentioned data, daily sea level pressure and temperature of the earth's surface with a resolution of 2.5 degrees within the space of 30 to 65 degrees north latitude and 130 degrees east longitude from the database 45 to NOAA NCEP / NCAR for the cold was extracted. The core of the GIS spatial data analysis system and two separate zones and point to output six decades was ten years old and were analyzed. To study the process of change, determine the direction of the trend, type and timing of changes in temperature and pressure of the core of the system the test of Mann-Kendal is used. Comparison between the first and sixth decades 60-year period showed that the core in January from the East to the West and in October and March from the North East to the South West from the Balkhash Lake to Baikal there has been a significant shift. Results also showed that during the same period the Siberian High central pressure was reduced in January while the land surface temperatures in January showed a significant upward trend. Unlike the months of October and January, in March the central pressure had few mutations but no trend was observed. However, during this month the Earth's surface temperature has increased significantly during thementioned period.
Gholam Hassan Jafari, Asghar Rostamkhani,
Volume 16, Issue 43 (12-2016)
Abstract
One of the unique properties of northern landforms of zanjanrood catchment is having smooth surfaces that have been interrupted by deep valleys. Rivers that don’t have a wide catchment upper their front mount are running in parallel deep valleys that the topographical situations don’t let them to receive around surface runoffs. This situation has made them to move in parallel form and not to join with each other. In some parts of sub basins, the water dividing line had been incorporated with the beach of main river valley (Sohrein River). The extent of catchments upper the mount front is not in a situation that let to dig valleys that sometimes exceeded to hundreds meters deep. These valleys had kept their primary height differences than it’s around. According to these properties, the style of formation and their evolution was considered as a geomorphological point. To get the answer, topographic and geologic maps and satellite images was made, and traced the geomorphologic effects of faults and corrected in different field works. Evaluation of tectonic activity in area, have been estimated by using Morphtectonics indicators of asymmetric factor (Af), integral hypsometric curve (Hi), valley floor width-to-height ratio (Vf) and transverse topographic (T). Relative Active Tectonics Index (LAT) showed the whole basin high activity (class2). Based on the Af index uplift have been attributed to the right bank in Sohrin and Sarmsaqlv basins and in Qracharian sub-basin to the left bank. Which states that the center of Neotectonic power center located in the place between the three sub-basins?
Dr Mohamad Zaheri, Mr Ali Majnouni-Toutakhane,
Volume 19, Issue 53 (6-2019)
Abstract
The increased use of thermal power plants has led to the spread of greenhouse gases in the air and has caused psychological problems for humans. Accordingly, the present study was conducted to measure the pollutants released by Sahand Bonab thermal power plant and to investigate the effects of this pollution on the psychological and psychological pressure of rural residents. The GWP100 method was used to measure the pollutants of the power plant and to measure the mental and emotional pressures of the citizens, a questionnaire was used to assess the psychological stress of Markham. The statistical population of this study is 10254 people over 15 years of age in 7 villages located in the greenhouse of the power plant. Using formulas and simple random sampling, 375 subjects were selected as sample size. The results showed that the most pollutants released are CO2 and NOx, which is 4.17 times the warm seasons in the seasons. Also, analysis of the results by using a Pearson test showed that six variables including neurological and disturbing variables p= 0.272, stress and psychological stress p= 0.325, feeling of energy decrease, p= 0.287, feeling of despair and disappointment in life p = 0.142, feeling Depression in life of p= 0.211 and change in behavior patterns in everyday life p= 0.269 had the most effect on air pollution. Also, mental and psychological stress in nearby villages was higher than in remote villages, more women than young men than older men and elderly people. The results of multivariate regression and path analysis showed that in general, the air pollution caused by the power plant has the ability to explain R2 = 37.42 percent of the changes related to the psychological and psychological pressure of the villagers. Finally, it can be said that thermal power plants have negative mental and psychological effects according to type of activity, type of age and gender of the villagers, which should be considered in the studies of the construction of power plants.
M Masoud Jalali, M Mehdi Doustkamian, A Amin Shiri Karim Vandi,
Volume 19, Issue 55 (12-2019)
Abstract
The aim of this study was to analyze the mechanism is precipitation Comprehensive Iran. For this purpose the daily precipitation data of 483 synoptic and climatology stations arranged. In this study, a comprehensive annual rainfall is said to have a minimum rainfall and above, 50% sequence coverage and have at least two days. Winter surround Iran on the condition of rainy days were extracted and examined. Then, to review and analyze the mechanism of atmospheric precipitation comprehensive synoptic and dynamic parameters such as moisture flux, vortices, ground level pressure, Geopotential, meridional and zonal wind component for the levels of 1000, 850, 700 and 500 HP studied and analyzed was. The results of this study showed that the widespread mechanism of dynamic and synoptic Winter country most affected by the composition of the atmosphere patterns such as the Mediterranean low pressure - low pressure core Persian Gulf, Iran, Central High East Europe closed low pressure, low pressure Urals - the Middle East, high pressure, low pressure Saudi Arabia - High pressure belt Europe and Siberia - Iran's low-pressure center. However most of the winter precipitation of moisture flux feed barley middle-Level interaction, particularly levels of 850 and 700 HP respectively. It was while change 500 hPa atmospheric dynamical mechanism is an important role in Iran's winter inclusive.
Ms Mahboobeh Pouratashi, Dr Mohammad Moradi, Dr Ebrahim Fattahi,
Volume 20, Issue 57 (6-2020)
Abstract
This research aims to study the impact of temperature and wind in the southern low-pressure system and its associated precipitation in the southern regions of Iran. As The southern low pressure system moves eastward, it crosses the southern regions of Iran, causing medium and heavy rainfall in these areas. In this study, two southern low-pressure systems that caused heavy rainfall on March 11, 2015 and January 17, 2000 in southern Iran were selected, analyzed and simulated using the numerical Weather Research and Forecasting (WRF) model. Since the wind and temperature fields play a significant role in the southern low-pressure systems, four experiments were performed for investigating the effects of temperature and wind on the intensification and weakening of the southern system. The simulation results showed that the simulation for the increased (decreased) temperature caused the weakened (intensified) the southern low pressure in the studied area. This result showed that the vertical structure of the southern low-pressure and its physical characteristics are similar to the mid-latitudes cyclones, and these systems were different from the thermal low pressures. The results of wind speed changes showed that the increased (decreased) wind speed simulation caused an increase (decrease) in relative vorticity, thus the southern low pressure was intensified (weakened). In both cases, the rainfall was decreased by the increased temperature simulation, and decreased temperature caused an increase in rainfall. It was also seen that the increase in wind speed caused the special humidity advection to be increased and then the rainfall increased. Also the amount of rainfall decreased when conditions did not provide for the advection of specific humidity or the wind speed reduced.
Mahdi Khazaei,
Volume 21, Issue 63 (12-2021)
Abstract
This study investigates the subtropical anticyclones and summer monsoons of the north hemisphere in the 500 hPa level, effective on Iran in a 38-year period (1975-2012). For this purpose, the data of geopotential heights of 500 hPa at 12 UTC with a spatial resolution of 2 by 2 degrees of the (NCEP/NCAR) were used. Results show that three independent patterns (Azores anticyclone, Saudi anticyclone and North West Africa anticyclone) and four combinatory patterns derived from the independent patterns have controlled the atmosphere of 500 hPa level of Iran. In most cases, the maximum in geopotential heights in above-mentioned anticyclone centers reach to more than 5920 geopotential meters, but often the tongue of these anticyclones control the atmosphere of 500 hPa levels of Iran with the geopotential height of 5880 to 5900 meters. In contrast, at this pressure level, the large-scale monsoon system is very weak and the maximum geopotential height of this system is about 5840 meters. The extent and intensity of the monsoon system has been reduced so that its tongues do not affect the 500 hPa level of Iran at any time. Given that the main factor in the development of large-scale monsoon system is the surface heating (bottom-up formation) and the main factor in the development of subtropical anticyclone is descending of atmospheric dynamics, the main reason for the development of summertime subtropical dynamic anticyclone should be a very strong and unit agent, something other than the summer monsoons.
Mrs Zahra Hejazizadeh, Mr Farshad Pazhoh, Mr Fardin Ghadami, Mrs Haniyeh Shakiba,
Volume 22, Issue 65 (6-2022)
Abstract
The aim of this study is to synoptic analyze of the number of frost days in a year of Khuzestan province. For this purpose, using the minimum daily temperature data of 12 stations during the statistical period of 1992 to 2017, the Meteorological Organization of the country, 54 days of frost was identified. Sea level pressure, Geopotential Height, Zonal and meridian wind and temperature of 500 hPa data with size of 2/5 * 2/5 degree arc from the National Oceanic and Atmospheric United States of America were extracted. On the matrix of the variance of sea level pressure data in 54 days, the analysis of the basic components was performed and 10 components which identified 83% variance of the sea level pressure. Then, by applying the hierarchical cluster analysis method, the integration method was applied to the scores of the 10 components and 5 patterns of sea level pressure were identified. The results showed that frost phenomenon in Khuzestan province occurs from November to march and its trend is decreasing during the statistical period. Also northern and western parts of the province have allocated the most frequency of frost. Also the synoptic condition analysis of troposphere showed that 5 sea level pressure pattern with different make ups lead to pervasive frosts of Khuzestan province. Weak and moderate frosts formed by the influence of Siberian and European cold high pressure systems. But severe frosts occur with spread of Iceland low pressure to Iran, along with strong cold pressures. Meanwhile, the powerful Siberian high pressure is present in most of the patterns, which its interaction with sub polar and Icelandic low pressure, plays the most role in the most severe frost in the province of Khuzestan. Also in the middle level of troposphere penetration of deep troughs from northern latitudes and east European huge blockings has the most role, which has advection of cold air from the side west of troughs on the country and during the intensity of the frost added to its continuity.
Mehdi Salemi, , , , ,
Volume 22, Issue 67 (12-2022)
Abstract
The most important part to be considered is the determination of the carrying capacity of the protected areas, since these areas are able to accommodate a large number of tourists, so if these areas are not planned more accurately, the number of tourists will exceed the cc limit of the area. Resulting in instability and degradation of these areas, and therefore knowledge of the status of the area's cc will greatly help to control the damage. The aim of this study was determine potential, and social-cultural cc with the purpose of the establishment in ecotourism development. Therefore, in order to the determination of the potential of this area, calculation of the social-cultural cc after the identification of the social - cultural pressures using model PSR the social- cultural pressures regarding the calculation of the correction by applying the percentage corrections of the pressures and the relative importance using the techniques ANP and of each of them after the grading layer using the techniques WLC and builder model at Arc GIS10.5 combined. Social - cultural cc in the direction of the development of ecotourism determined. The results 50% of the content that the level region has high cc, 33% of the surface area has an cc and 17 percent of the level region has low cc. Findings of the research show that there is a low range of cc in the central part of the region; finally, based on the findings, suggestions have been made to increase the regional distribution cc.
