English abstract
Of all weather conditions, inversion is probably the most important wherever atmospheric pollution is discussed. The inversion layer generally acts as a blanket of air warmer than the air immediately below it, which is a reversal of the normal. The net result of inversions from an air quality perspective is a very stable atmosphere characterized by little mixing which may result in an imbalance between pollution generation and pollution dissipation. As very little vertical mixing of polluted air takes place in an inversion layer, pollutants released become trapped under or within the stable layer of air. Pollutants continue to be emitted into the atmosphere but are not transported away and the air quality will be affected. The objective of this study is to examine the characteristics of the low-level tropospheric temperature inversions to a height of 4 km above a suburban site in different Arabian Gulf Countries by using 10-year records of daily upper-air meteorological data. The temperature profile data included in this study was derived from the radiosonde data collected by the Meteorology Department from different stations in the Arabian Gulf Countries. The study addresses the statistical analysis of inversion parameters and investigates whether changes in these parameters (i.e., depth and strength) have occurred during the last decade. Both surface-based and elevated inversions are investigated. The study is important since it is the first investigation that addresses the statistical analysis of the thermal inversion layers in the Gulf region. The study indicated monthly changes in inversion frequency, height, depth, and strength. The frequency of the occurrence of all inversions seems to be slightly stable through out the period of the study. Since the frequency of the elevated inversions is the complement of the surface-based inversions, the highest frequency of surface-based inversions in some months corresponded to the time of minimum elevated inversions in the others. Overall, most of the inversions tended to be surface-based in all stations of the study areas in the Gulf Countries. The surface-based and elevated inversions vary from winter to summer months depending on the changes of the atmospheric weather parameters in all stations of the study areas. The elevated inversions were generally lower and weaker than the surface-based inversions. The study also indicated annual variations in the thermal inversions associated with inversion depth, height, temperature and strength across both the surface-based and elevated inversions through out the 10-year period at some of the selected stations of the study areas in the Gulf Countries (Saudi Arabia Station No. 41024, Kuwait Station No. 40582, Abu Dhabi Station No. 41217, Salalah Station No. 41316). Most of the relationships between the atmospheric parameters associated with both surface based and elevated inversions showed positive correlation at all stations of the study areas in the Gulf Countries. The results generally showed a positive correlation between all atmospheric parameters, such as temperature, relative humidity, dew temperature, wind direction and speed for both surface-based and elevated inversions. The relationships between the inversion depth and temperature difference across the elevated inversion indicated strong and positive correlation (r> 0.60), but weak and positive correlation (r< 0.60) across the surface-based inversion at all stations of the study areas, except for the State of Kuwait (Station cutanate of iman Salalah Station na 4131 No. 40582) and the sultanate of Oman (Salalah Station No. 41316), which both showed the correlation which hoth showed the correla coefficients of (r = 0.570) and (r = 0.514), respectively across the elevated inversions. The results also indicated that the bottom and top heights across the elevated inversion were associated strongly and positively with each other (r> 0.95) at all stations of the study areas in the Gulf Countries. The outcomes of this research will help the decision makers of different sectors in the Gulf Countries to review and establish rules, regulations, and strategies for the mitigation of climate change and global warming which are projected to compound the pressures on natural resources and the environment, associated with rapid urbanization, industrialization and economic development in the Gulf Countries. Extensive studies should be highlighted for the comparison of the results of the present study areas with the observations of inversion layer in other Middle East countries and other regions in the world to explore the link between the thermal inversions, the phenomenon of larger-scale global warming, climate change, and the causes of cyclones and natural disasters.
