جستجوی مقالات مرتبط با کلیدواژه « وارونگی دمایی » در نشریات گروه « جغرافیا »

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 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.

In issues related to air pollution, the thickness of the boundary layer is known as the depth of the mixed layer because the pollution on the ground surface is mixed in this entire layer through turbulence processes. In most cases, the boundary of the area is clearly visible on big industrial cities. The depth of the mixed layer has an important effect in the concentration of air pollution which is dependent on the intensity and duration of solar radiation and wind speed. Usually after 2 to 3 hours from the time of maximum solar radiation, air temperature near the earth's surface reaches its maximum value. At this time convection of heat is formed in the air near the earth surface and transfers the heat from the surface to higher altitudes. These vertical movements will cause atmospheric turbulence and increase in instability. This is when the growth of the mixed layer reaches to its highest level. After sunset, night temperature inversion occurs near the surface. This temperature inversion is due to the rapid cooling of the Earth's surface. In such condition, the cold air layer is near the earth's surface and the warm air layer sits on top of it and air is in a stable condition. As a result, the accumulation of contamination, if there are sources of pollutants, will increase in the earth's near-surface layer. If the conditions remain steady during the day, the mixed layer will not have much growth and as a result, contamination in the shallow layer near the surface of the Earth reduces solar radiation.
Each year, thousands of gaseous pollutants and particulate matter are emitted in the metropolitan area of Tehran and due to the geographical and climatic conditions of Tehran, temperature inversion phenomenon is not something unexpected. By formation of the inversion layer, these pollutants will remain near the earth's surface for a long time which in turn will be the cause of a lot of heart and respiratory problems. Therefore, identifying the characteristics of this layer on polluted days is of particular importance to the health of the residents of this city.
In this research, the study area is Tehran which is in the foothills of the southern Alborz and between longitudes 51 ° 2 'to 51 degrees 36' east and latitude 35 degrees 34 minutes and 35 degrees 50 minutes northern. The height of the northernmost point of this city is 1800 and up to 1200 meters in the center and 1050 meters in the south.
To conduct this research, inversion data including temperature, wind, atmospheric pressure and humidity and vertical navigation radiosonde data at the Mehrabad weather station from January to 29 December 2013, were taken from the Meteorological Organization of country. Then the statistics of daily vertical scroll of atmosphere above the Mehrabad synoptic station was received from the University of Wyoming. Also, the hourly data of air pollutants including gaseous pollutants CO, N2O, O3, SO2 and particulate matter (PM10) were prepared from the air quality control center (AQCC) for the stations Aghdasiyeh, Geophysics, Poonak, Rey and District 11.
After receiving information about the vertical scroll of the atmosphere in Mehrabad station, in order to have a closer examination of the vertical profiles of potential temperature changes in the lower atmosphere, using daily data from the radiosonde to obtain potential temperature changes in height were measured. Then, in order to identify the days with high pollution levels (the unhealthy condition for sensitive groups) and days with good conditions, so that all stations under study were the same, based on a standard index of air pollution Table 1 was developed. In the end, 4 days with critical inversion of potential temperature, including two polluted days (February 6th and August 16th) and two clean days (9 February and 5 June) were detected. Then according to the proposed method of Hefter, the approximate height of the boundary layer was calculated for these 4 days.
In this study, it was observed that the boundary layer height in contaminated cold season of the year reached 1,200 meters in the morning hours while in the afternoon in the cold samples, it grew to 1900 meters. In the warmer months based on the height of critical inversion layer in the selected days it reached more than 6,000 meters. In pure samples of warm and cold seasons, the boundary layer height had significant growth to the extent that in the cold sample of the year it reached to 2,100 meters in the morning and 2,600 meters in the afternoon. On June 5, which is intended to represent the clean and pure heating season, boundary layer height was of 5300 meters in the morning hours which shows a 4,000-meters increase in comparison to its polluted counterpart. The point to be noted is that since the active track of potential temperature can be considered as a measure of air stability, in the critical inversion, for the case of polluted samples of morning hours that were irradiated with inversion, active track of the potential temperature was very high in them. Thus on days with radiated inversion (polluted days) we can say that border of boundary layer was based on the inverted layer. Also the methods used in these types of inversions are more efficient for the determining height of the boundary layer.

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.

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.