نتایج جستجو برای: ozone layer
تعداد نتایج: 301828 فیلتر نتایج به سال:
The Tropospheric Emission Spectrometer (TES), a hyperspectral infrared instrument on the Aura satellite, retrieves a vertical profile of tropospheric ozone. However, polar-orbiting instruments like TES provide limited nadirview coverage. This work illustrates the value of these observations when taken in context with geostationary imagery describing synoptic-scale weather patterns. The goal of ...
Urban ozone concentrations are determined by the balance between ozone destruction, chemical production and supply through advection and turbulent down-mixing from higher levels. At high latitudes, low levels of solar insolation and high horizontal advection speeds reduce photochemical production and the spatial ozone concentration patterns are largely determined by the reaction of ozone with n...
Stratospheric ozone depletion through catalytic chemistry involving man-made chlorofluorocarbons is an area of focus in the study of geophysics and one of the global environmental issues of the twentieth century. This review presents a brief history of the science of ozone depletion and describes a conceptual framework to explain the key processes involved, with a focus on chemistry. Observatio...
[1] Measurements of ozone and carbon monoxide (CO) from the INDOEX 1999 experiment show large differences in concentrations of ozone and CO between the Northern Hemisphere and the Southern Hemisphere. These measurements confirm the theory that the Intertropical Convergence Zone (ITCZ) serves as a barrier to mixing over the Indian Ocean, effectively separating the polluted air in the Northern He...
Monitoring tropospheric ozone from space is of critical importance in order to gain more thorough knowledge on phenomena affecting air quality and the greenhouse effect. Deriving information on tropospheric ozone from UV/VIS nadir satellite spectrometers is difficult owing to the weak sensitivity of the measured radiance spectra to variations of ozone in the troposphere. Here we propose an alte...
UV-B radiation is a driving factor for the chemistry of the polluted boundary layer. It is involved in the formation of radicals and consequently influences the formation and concentration of photo-oxidants. The 3-D mesoscale photochemical Metphomod model was employed to study the effect of changes in UV-B radiation on the concentration of photo-oxidants in the boundary layer over the Swiss Pla...
Ozone pollution in the Southeast US involves complex chemistry driven by emissions of anthropogenic nitrogen oxide radicals (NOx ≡NO+NO2) and biogenic isoprene. Model estimates of surface ozone concentrations tend to be biased high in the region and this is of concern for designing effective emission control strategies to meet air quality standards. We use detailed chemical observations from th...
The ozone variability observed by tropospheric ozone lidars during the ESCOMPTE campaign is analyzed by means of a hybrid-Lagrangian modeling study. Transport processes responsible for the formation of ozone-rich layers are identified using a semi-Lagrangian analysis of mesoscale simulations to identify the planetary boundary layer (PBL) footprint in the free troposphere. High ozone concentrati...
High concentrations of both ozone and aerosols are observed in the eastern United States during stagnant weather conditions associated with transport from the W or NW; they show similar spatial and temporal patterns. We discuss a causal mechanism that may contribute to this correlation-the radiative eeects of aerosols on photolysis rates. We measured j(NO 2), the rate coeecient for nitrogen dio...
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