جستجوی مقالات مرتبط با کلیدواژه « temperature inversion » در نشریات گروه « جغرافیا »

Regional recognition and analysis of air pollution is one of the important components in the action plan for environmental sustainability. The present study was conducted to analyze the spatial distribution, the reasons for the persistence of air pollution, and the factors that cause it in the dense population-industrial area of the three metropolitan cities of Tehran, Karaj, and Qazvin. In this regard, the combination of station-satellite and atmospheric data between 2018 and 2023 was used. By using the air quality index (AQI), the days that had an average daily pollution index above 150 and were in an unhealthy condition and continued for at least 6 days or more in the five-year statistical period were extracted. Then, two periods from January 17 to 29, 2023, and December 19 to 28, 2022, when air pollution was the most persistent, were selected for analysis. The results of the synoptic analysis showed that during the duration of the pollution, the blocking pattern has caused the movement of the system to stop or slow down, and with the establishment of a strong ridge, the atmosphere of Iran and the region has been kept in a stable state. With its permanent establishment, the mentioned ridge has caused the stillness of the air. As a result of these conditions, pollution has yet to be discharged daily and accumulated. The average distribution and focus of pollutants with the help of satellite images shows that the highest amount of CO and NO2 is concentrated in the city of Tehran. In contrast, the highest amount of SO2 is concentrated in Qazvin province. It seems that the Shahid Rajaei power plant is responsible for a large share of SO2 pollution. The study of the atmospheric patterns of these 7 periods, when air pollution has been high, indicates the dominance of blocking patterns.

This study was aimed at examining the types of inversion and their severity using the thermodynamic indices of the atmosphere such as SI, LI, KI and TT at Bandar Abbas Station for 2010-2020. In this study, Radioosvand data at the Bandar Abbas Station was obtained and used from the University of Wioming for the last 11 years (3.5 local) during the last 11 years (2010 to 2020). The results of the analysis showed that the average number of inversion phenomenon in Bandar Abbas was 501 cases per year, as in some days several types of inversion were observed at different altitude. Of these inversion, about 31.6 % are related to radiation temperature inversion, 4.3 % front, and another 64.1 % for subsidence inversion. Due to the air session underneath, the share of subsidence inversions is more than other types of inversion. In the meantime, the most severe inversion of subsidence was 1354 and the weakest inversions were with 29 cases and fronts. In general, the long -term average intensity coefficient of inversion of Bandar Abbas station with a coefficient of 0.062 indicates that the intensity of the city's inversion is mostly extremely severe, which can be very destructive effects both environmentally and physical health in the city's residents. Bandar Abbas follow. The correlation between the inversion elements also showed that by reducing the thickness of the inversion layer, the intensity of temperature inversion also increased.

The ambient air temperature in the troposphere usually decreases with increased altitude (per 1000 meters increases the height of 5 to 6 degrees Celsius), but sometimes with increased air temperature, which is called temperature or inversion inversion. Temperature inversion occurs when a layer of hot air is above cold air adjacent to the Earth. In this case, air stability is created and instead of increasing temperature height to a few hundred meters above Earth with increased height. We will increase temperature. The importance of temperature inversion phenomenon is doubled when examining the effects of temperature inversion phenomenon. The phenomenon of temperature inversion is important because it causes fumation. This phenomenon occurs when the sun's radiation is unstable in the vicinity of the surface for a short time after sunrise, then combined with the scattered material in the nightly layer, causing the scattered material to return to the surface. . As a result, the concentration of pollutants increases sharply and the phenomenon of fiomia is created.

In this study, the daily data of the radio atmosphere above the Birjand Synoptic Station (Table 1) for 00 Greenwich (3.5 local) over the last 11 years (2010 to 2020) to 11 km high from Earth from Vioming University He got. Indicators used include thermodynamic indices such as SI, LI, KI and TT and potential temperature. Also of other data used in this study, radiosvand transmitted information including inversion height from ground to meter (ZBASE), inversion height from ground to meter (ZTOP), base temperature in base and inversion layer to degree Selicius (TBASE), the temperature difference between the base and the top of the inversion layer to the grade of silicius (DTINV) is the height difference between the base and the apex of inversion to meter (DZINV) and the pressure in the base (PBSE) and the inversion layer (PTOP) from Relationships (1 and 2) are calculated First calculated using the relationship (1) the potential of the ceiling and the floor of the inversion layer of the relationship (1)Θ: Potential temperature to Kelvin grade T: Temperature to Kelvin P: Air pressure to hectopaskal After calculating the potential temperature of the ceiling and floor of the inversion layer using the relationship (1), we have calculated the intensity of temperature inversion using relationship (2) on a monthly, seasonal and annual time scale. Relationship (2):Δθ Difference of the temperature potential and the base of inversion to the grade of Kelvin Δz thick layer of inversion to meter Z station height to hectometry

The results showed that the average annual temperature inversion phenomenon at Birjand Station was about 90 cases per year, as it may not occur in different heights in some days, about 11.1 % of the radiation temperature inversion, front. A 12.4 %, and the other 76.5 % is related to temperature inversion of subsidence. Due to the air session underneath, the share of subsidence inversions is more than other types of inversion. The results showed that the highest average inversion layer in Birjand was formed in 2010 and 2015 at 9 ° C. The highest annual temperature of the inversion is related to the inversion of subsidence, which is due to the subsidence of the air subcutaneous air subcutaneous in the upper layers of the atmosphere and the high temperature on the ground. In terms of annual altitude, the highest height of the inversion layer occurred in 2019 with 4490 meters. In terms of thickness of the inversion, the inversion of the type of subsidence with 207 and the radiation with 145 meters form the thickest and the thinnest layer of inversion. Results of the average inversion layer pressure in Birjand showed that 2014 and 2015 were formed with about 870 miles and 2019 with 592 milligrams. Among the types of inversion, the most severe inversion of the front was 0.044 % and then subsidence with 0.030 %. In terms of the intensity of severe inversion with 0.7 % and poor inversions with 0.92 % were the lowest and the highest in Birjand. In fact, the inversions of the city of Birjand are poor because of their physiographical and geographical properties.

The correlation results also showed that there was a direct and significant relationship between the intensity of inversion and the inversion layer temperature at 99 %. That is, the higher the temperature of the inversion layer, the greater the inversion of inversion and vice versa. But there is a significant relationship between the inversion intensity and the height of the layer at 95 % probability level. This reverse relationship indicates that whenever the inversion layer occurred at the lower altitude, the inversion of inversion has also increased; But the relationship between the thickness and intensity of the inversion layer showed that with the increase in the thickness of the inversion layer, the inversion of inversion in Birjand also increased as the layer temperature was higher as the inversion was more severe. There is also a direct and significant relationship between the intensity and pressure of the inversion layer at 95 % so that with increased pressure, the inversion will increase. In general, the city of Birjand is under the tranquility of the tropical climate because of its specific location, which is also on the roads of 120 -day Sistan, so it will be weak if inversion occurs.

Air pollution, especially in the two pollutants of suspended particles less than 2.5 microns and sulfur dioxide, is one of the important problems of large and industrial cities of Iran, including in Tehran, especially in the cold half of the year, which affects the health and comfort of citizens.

The severity and weakness of air pollution in Tehran is related to climatic patterns and the dominance of air masses over the city of Tehran.

By following the air pollution during the year 2019, this research investigated the pollutant variables on a monthly, daily and hourly basis for 4 districts 2, 5, 9 and 18 of Tehran city in five pollution measurement stations and based on three climate scenarios: effect of stability, instability and inversion, separate clean and polluted days and investigate the role of air masses dominating the city for both conditions. To better understand the relationship between the weather patterns governing the study area, atmospheric conditions at 1000 and 500 millibar levels, as well as the earth's surface map, have been analyzed. Air pressure, temperature, rain and wind are the elements that have been investigated. Pollutant measurement data were obtained from stations located in the four districts of Tehran municipality and from the air quality control company affiliated to Tehran municipality, and meteorological data were obtained from the country's meteorological organization, and finally, radiosonde data from Mehrabad station were used for the inversion study.
Geographical Context: the area of study in this research is Tehran and its 4 municipal zones 2, 5, 9 and 18.

The research results show that the air quality of the study area has a strong dependence on the development of the geopotential ridge in the middle troposphere, the absence of wind blowing at a significant speed on the surface of the earth, the extreme stability of the air and the creation of a dynamic inversion layer or subsidence at high altitude. In other words, periods of air pollution intensity are related to weak pressure gradient, calm wind, air subsidence and temperature inversion.

Finally, during severe and critical pollution, high-pressure air dominates the city surface and the air is stable, and the wind either does not exist or is less than 3 meters per second, which does not have the power to purify the air. In the defined scenarios, the presence of strong wind (over 6 meters per second) is the best solution for having clean air, and rainfall is effective in removing pollution only when it rains heavily and for a long time.

Introduction Today, one of the most important issues in the field of climatology is air pollution and its relationship to the general circulation of the atmosphere. The atmosphere around the planet Earth is made up of gases called fixed atmosphere gases. Humans and all living things are accustomed to this composition of the atmosphere and have adapted to it. Any changes in the quality and quantity of these elements can be considered as air pollution. Therefore, since the main cause of all changes in the characteristics of the human environment is related to changes in atmospheric pressure, so in all climate-related studies, the first step is to identify patterns of air masses. Anti-cyclonic circulation patterns, both at the Earth's surface and in the upper atmosphere, create sunny weather, leading to temperature inversion and subsequent air pollution, especially in densely populated and industrial cities. In winter, when these inversions are stronger, hot air on the cold air acts like a cap that prevents air mixing. Thus, urban areas have a strong potential to face serious problems of air pollution as a result of a combination of limited conditioning of air and emission of pollutants from high atmospheric levels. Atmosphere in terms of temperature inversion is associated with minimum air mixture and stable conditions. So the highest density in the direction of the wind extends from the source of diffusion. Methodology For the recognition and extraction of the synoptic patterns affecting the temperature inversion in Tabriz city, we initially prepared the data records on the temperature inversion for the time period of 2001-2010 by the use of upper atmosphere station data. This was followed by the utilization of digital data on sea surface pressure as daily mean from the reanalyzed data series of NCEP/NCAR in the eastern longitudes of 10°-60° and the latitudes of 10°-90° in 651 pixels of 2.5/2.5 degrees. With the PCA analysis on the data of sea surface data pressure in the days having temperature inversion, we reduced their volume and carrying out cluster analysis on the obtained components we recognized the most important atmospheric patterns and through which the map of each pattern was drawn. Results and discussion Based on the results of cluster analysis on the matrix of factor scores in this study, the occurrence of temperature inversion in the city of Tabriz is due to the domination of four consecutive patterns. The general characteristics of these patterns are as follows. 1- In general, in the hot period of the year, the high-pressure pattern of Migrant Europe is the most important system in the formation of temperature inversions. In this pattern, languages from the highlands to the western shores of the Caspian Sea are advancing, and due to the presence of a mid-level ridge, it is possible to strengthen the anticyclone core at sea level and thus create a stable atmosphere. With the dominance of the downward process of air, the stability of the earth's surface air and the possibility of inversion formation in the warm period of the year intensify. Two summer patterns, which have been associated with the establishment of a high-pressure pattern on the northwest and in some cases with a low pressure on the Persian Gulf, have caused the upheavals of this period of the year.2 - In other patterns that have occurred more in the cold season, the surface stable layer due to the penetration of the tabs of Anti-cyclonic systems including high-pressure Siberian and European Migrant Europe high-pressure is done alone or in combination and in some cases with high-pressure Migrant Europe. North pressure is also present on the map, which is exacerbated by the Convection of cold weather. Despite the process of air fall due to the dominance of the convergence region of the mid-level convergence creates deep inversions and sometimes double-layer. In these patterns, the thickness of the inversion layer is low and the temperature difference between the peak and the base is high, which indicates the acute conditions of inversion to create air pollution. This phenomenon is likely to occur in any season. But its severity, which depends on synoptic factors. Conclusion The most important factor in causing temperature inversion in most cases is how to arrange the dominant pressure patterns, In this Patterns the cold weather due to the presence high pressure system expanded in the surface with the establishment Left side of a deep trough over the region, the cold air has diffused from higher latitudes on Tabriz and strong sustainability has been created in vertical column of the atmosphere. In cases of being cause the Northern low pressure along with pressure-immigrant Europe for the spread of a cold into the region. The warm air of lower latitudes has been placed over the cold air of ground by domination of a deep ridge over the region. Therefore the intensity of stability increased and severe temperature inversion into the air near the surface formed.

Air pollution is one of the major problems in Tabriz, Iran. One of the natural factors involved in air pollution is Temperature inversion which is an effective factor in urban environments therefore the purpose of this study is to investigate the significance relationship between concentration of particulate matter (PM10), carbon monoxide and dioxide sulfur with meteorological parameters such as horizontal vision, pressure, relative humidity, temperature, wind speed, maximum wind speed, KI index, the height of the top of temperature inversion layer, depth and intensity of temperature inversion. Therefore, a 5-year period, from 2008 to 2013 was considered and pollution conditions of Tabriz in the days of inversion were studied using skew-t maps. In order to investigate the relationship between the concentration of pollutants with the properties of temperature inversion layer, climatic parameters and atmospheric stability Pearson correlation was used. Also, multivariate step-wise linear regression was used to indicate the variables which had a greater role in the increase or decrease of the concentration of pollutants. The results showed that the amount of PM10 is significantly related to the intensity of inversion and pressure, CO with inversion intensity, pressure and relative humidity, SO2 with inversion intensity and temperature. Multivariate stepwise regression analysis showed that the intensity of the thermal inversion is the only variable that is positively related to all three pollutants, which indicates the effect of inversion layer’s intensity on the trend of air pollution and intensification of pollutants concentration. Also, relative humidity and temperature after temperature inversion were the most effective elements on the trend of CO and SO2 pollutants. As a result, variables such as inversion intensity, temperature, relative humidity and pressure had greatest impact on the concentration of pollutants.

Atmospheric stability resulting from temperature inversion is one of the main problems of the metropolises such as Tehran especially in cold periods of the year. This article aims to study the temperature inversion in Tehran from 2010 to 2014 in daily, monthly, and seasonal time scales. Some parameters were studied base height and top height, base and top layer temperature, temperature difference between two mentioned layers, layer depth of inversion, and air pressure in base and top layers. Then the days with dynamic and radiation inversions were studied. Using various indicators, the days were classified according to inversion intensity ranging from weak to very intense. The results showed that the number of days with temperature inversion was 231 (206 days of radiation inversion and 25 days of dynamic inversion).Most temperature inversions occurred in summer while the least happened in spring. Very intense inversions, however, occurred in winter and fall. The results indicate that temperature inversion was observable in most of the days especially in summer. Temperature inversions are less frequent and more intense in winter. Studying inversion days showed which can be highly effective in atmospheric stability in closer layers to the Earth surface especially in cold seasons.

Air pollution as one of the most important technological risks of contemporary era is mainly resulted from the emergence of large cities and fast growing industries. One of the main objectives of climatic and environmental studies is to survey atmospheric pollutions. Tabriz is one of the metropolises where air pollution is a problem in it. Of course, what is essential regarding the severity of air pollution in the city of Tabriz is the function of atmospheric processes that act widely, in this case temperature inversion is one of the most important factors. Weather condition of each single day is affected by synoptic conditions therefore; sometimes it can result in stability and tranquility in the atmospheric conditions and due to the concentration of pollutants in lower atmospheric layers and the lack of or poor atmospheric motions, the severity of pollution increases. Given the importance of weather stability in the occurrence of atmospheric problems investigating the synoptic conditions of Tabriz city during critical air pollution periods and providing recommendations and preventive measures in this regard are of very essential importance. For this reason, the present article aims to investigate the cause of severe and periodic air pollutions in Tabriz.
The daily data of Tabriz pollution over a 6 year period (2008-2013) were the data of current study (CO, PM10) that were collected from the Department of Environmental Protection, East Azerbaijan Province. Among these data, four successive pollution periods along with temperature inversion were selected by EXCEL filtering software. Then the situation of pollutants regarding their healthiness and unhealthiness were studied using PSI index. Also in this article due to the direct effect of temperature inversion on intensity of pollutant concentrations and depth of temperature inversion, Skew-T maps used to determine the pollution periods of Tabriz. Then, according to the purpose of this study which was to identify synoptic systems affecting air pollution in Tabriz, to identify synoptic patterns that influence the amount of pollutants in polluted days to suspended particles; daily synoptic maps at ground level and 500 hp of pollutant days received from NCEP/NCAR and finally the synoptic patterns affecting sustainable and long-term periods of air pollution in Tabriz were investigated.
The study area is often influenced by synoptic patterns of mid-latitudes. The most important seasonal thermal systems that affects large sections of the country are Siberian high pressure and low pressure summer heat. During the cold season, Siberian high pressure is strengthened which can affect the frequency of large areas of Iran including Tabriz. In the most days of the year especially in cold season, due to shortness of the length of day and cold radiation at night, temperature inversion including radiation and subsidence can occur in cold seasons of the year. Also the local characteristics of area especially lack of high speed winds in seasons i.e. autumn and winter to reduce the intensity of inversion layer and concentration of pollutants has provided the situation for air pollution. When a high-pressure system constantly during successive days focuses on a special area the intensity of temperature inversion reaches its peak. Then with the arrival of a low pressure systems inversion fades away. In general, the main factor that reinforcing inversion in high temperature is due to the continuity of high- pressure systems which can cause long-term pollutions.
In present study investigated the atmospheric patterns affecting air pollution in Tabriz during the statistical period of (2008-2013). The main objective of this study was to investigate the relationship between sea level and 500 hPa synoptic patterns with temperature inversion and prolonged periods of pollution. The results showed that the concentration of pollutants in most days was due to the intensity inversion layer in a way that when the intensity of temperature inversion reaches more than 5°C has the greatest impact on increasing the concentration of pollutants in all investigated periods. The findings also indicated a strong correlation between the function of strong and weak inversion layers with low pressure and high pressure systems in a way that strong inversion layer is always associated with high pressure systems. Results indicates that the Siberian high pressure has a significant role in the occurrence of pollutions in Tabriz city of and the mentioned circulation system in more than half of the studied days can cause the formation of high concentration of pollution in Tabriz. This synoptic system due to the establishment of cold weather on the Zagros and the combination of high pressure developed in the Zagros Mountains has created strong pressure. Of course, this system is more powerful when in middle levels of atmosphere in all phases the high altitude was 500 hPa level along with the stack system stack and stack based in the region have developed and intensified the high pressure on the ground and caused the stability of clear weather and also caused the formation of a strong inversion layer and increase the concentration of suspended particles in the atmosphere of the city of Tabriz.

Increase of temperature with height in the troposphere is called temperature inversion. Parameters such as strength and depth are characteristics of temperature inversion. Inversion strength is defined as the temperature difference between the surface and the top of the inversion and the depth of inversion is defined as the height of the inversion from the surface. The common approach in determination of these parameters is field measurements by Radiosonde. On the other hand the Radiosonde data are too sparse, so using satellite images is essential for modeling the temperature inversion. Necessary condition for the temperature inversion modeling using satellite images, examine the relationship between the brightness temperature difference with the temperature inversion strength and depth of the resulting data is Radiosonde. Temperature inversion phenomenon is common in Tehran. So Mehrabad airport weather station was selected as the 1st study area. Then correlation coefficients between Brightness temperature differences of different band pairs and the inversion depth and strength collected by Radiosonde were calculated. The results showed weak linear correlation. This could be due to the change of the atmospheric water vapor content and the relatively weak temperature inversion strength and depth occurred in Tehran. Proving this hypothesis is an innovation in the present work, in continuation of this research, the factors increasing the linear correlation coefficient was investigated. Due to the presence of deeper and stronger temperature inversion in Kermanshah, this region was chosen as the second studied region. The calculated correlation coefficients increased for Kermanshah all due to increase in the strength and depth of the temperature inversion in this region. Knowing that the amount of water vapor in the atmosphere in winter is less than warm seasons, Tehran and Kermanshah data were divided into two all seasons and cold seasons.Increase of correlation coefficients for both Tehran and Kermanshah in the cold season verifies the effect of atmospheric water content. For instance, the correlation coefficient between BT7.2-BT11 with strength and depth of inversion for Kermanshah for all season are 0.51 and 0.70 respectively. This for cold season was boosted to 0.78 and 0.85.

In this research we have studied Tabriz temperature inversion using radio-sound information، Skew-t maps and synoptic maps during the 2004-2008 period in daily and monthly scales. After reviewing the information and data at first days with weak، medium، and intense and very intense temperature inversion conditions were specified. Thereafter، the synoptic pattern of very intense and weak samples relating to three earlier days and two days after the peak of temperature inversion were analyzed using ground surface synoptic maps of 850 and 700 hp. The results indicate that there is a strong correlation between the occurrence of high pressure systems and the intense and very intense temperature inversion. In such a way that the intensity of temperature inversion has a straight relationship with synoptic pattern conditions especially the entrance of high pressure systems in the area. When the high pressure system in a stable condition is coming to the area in few-days scale، the intensity of temperature inversion is maximized. After the entrance of the low pressure cells، the temperature inversion is eliminated. Findings of this research have shown that with analyzing the synoptic systems that lead to the occurrence of temperature inversion and through the recognition of the patterns dominating over it، one can predict extreme temperature inversion. In addition، we can distinguish the patterns leading to the air pollution

Parameters such as strength and depth are characteristics of temperature inversion. Inversion strength is defined as the temperature difference between the surface and the top of the inversion and the depth of inversion is defined as the height of the inversion from the surface. The common approach in determination of these parameters is field measurements by Radiosonde. On the other hand the Radiosonde data are too sparse, so the main objective of this study is modeling the temperature inversion using MODIS thermal infrared data. There are more than 200 days per year in which the temperature inversion conditions are present Tehran. Mehrabad airport weather station was selected as the study area. 120 inversion days was selected from 2007 to 2010 where the sky was clear and the Radiosonde data were available. Brightness temperature in bands 27, 28, 31, 32, 33 and 34 of MODIS was calculated for these days. Then brightness temperature difference between the paired bands BT6.7-BT11, BT7.2-BT11, BT13.3-BT11, and BT13.6-BT11 were calculated and the correlation coefficients between these pairs and the inversion depth and strength calculated from Radiosonde were calculated. The results showed poor linear correlation. This could be due to the change of the atmospheric water vapor content. The polynomial mathematical models were used for modeling the temperature inversion. In order to calculate polynomial coefficients brightness temperature differences and the depth and strength of the temperature inversion obtained from of Radiosonde data, were entered in equations. Due to the large search space for finding the optimal model, Genetic algorithms were deployed. A model with the lowest terms and highest possible accuracy was obtained. The Model was built upon the differences between brightness temperatures in thermal bands. This for inversion strength resulted in as:Comparison with the Radiosonde measured data indicate that the inversion strength can be estimated with RMSE of 0.6o C and R2 of 0.84. Also depth of inversion can be estimated with RMSE of 45.59 m and R2 of 0.82. In this study, the methods of estimation of strength and depth of atmospheric temperature inversion using MODIS images were investigated. The method applied here consists of relationship between strength and depth of inversion with the differences of brightness temperatures extracted from MODIS thermal bands of 27, 28, 31, 32, 33 and 34. A multi parameter linear regression equation was applied to pairs of temperature differences and the strength and depth of inversions measured by Radiosonde at Mehrabad airport, Tehran. Due to the large searching space, an intelligent algorithm such as Genetic algorithm was deployed. Although the results are not as good as those achieved at polar region, still it is promising.