Stratosphere, emissions model

Strain energy, dioxiranes, 1134-5 Stratosphere, emissions model, 605 Structure... 

As shown in Fig. 3, CHEMGL considers 10 major well-mixed compartments air boundary layer, free troposphere, stratosphere, surface water, surface soil, vadose soil, sediment, ground water zone, plant foliage and plant route. In each compartment, several phases are included, for example, air, water and solids (organic matter, mineral matter). A volume fraction is used to express the ratio of the phase volume to the bulk compartment volume. Furthermore, each compartment is assumed to be a completely mixed box, which means all environmental properties and the chemical concentrations are uniform in a compartment. In addition, the environmental properties are assumed to not change with time. Other assumptions made in the model include continuous emissions to the compartments, equilibrium between different phases within each compartment and first-order irreversible loss rate within each compartment [38]. 

The role of biomass in the natural carbon cycle is not well understood, and in the light of predictions of a future atmospheric energy balance crisis caused by carbon dioxide accumulation, in turn the result of an exponential increase in the consumption of carbon fuel, the apparent lack of concern by scientists and policy makers is most troubling. Yet there is no other single issue before us in energy supply which will require action long before the worst effects of excess production will be apparent. The only satisfactory model is the action taken by the R D community with respect to the SST in nitric oxide potential and chloro-halocarbon emissions, when it was realised that the stratospheric ozone layer was vulnerable to interference. Almost all other responses to pollution" have been after definitive effects have become apparent. 

GrooB, J.-U., C. Bruhl, and T. Peter, Impact of Aircraft Emissions on Tropospheric and Stratospheric Ozone. Part I Chemistry and 2-D Model Results, Atmos. Em iron., 32, 3173-3184 (1998). 

As a result, increasing NCI, emissions does not have a significant direct effect at lower altitudes as it does at higher ones but rather has indirect effects on the halogen and HOx cycles, which reduce the ozone destruction due to these species. The net result, then, is interference in these other ozone-destroying cycles, leading to an increase in ozone at these altitudes as seen in the model predictions in Fig. 12.7. (In the very low stratosphere, NOx can also produce 03 through the VOC-NO,. chemistry discussed in Chapter 6.)... 

Jackman, C. H., D. B. Considine, and E. L. Fleming, A Global Modeling Study of Solid Rocket Aluminum Oxide Emission Effects on Stratospheric Ozone, Geophys. Res. Lett., 25, 907-910... 

Stone, R. S., J. R. Key, and E. G. Duton, Properties and Decay of Stratospheric Aerosols in the Arctic Following the 1991 Eruptions of Mount Pinatubo, Geophys. Res. Lett., 20, 2359-2362 (1993). Strand, A, and 0. Hov, The Impact of Man-Made and Natural NOA. Emissions on Upper Tropospheric Ozone A Two-Dimensional Model Study, Atmos. Enriron., 30, 1291-1303 (1996). 

In this study we will present aspects of STE in relation with the budget and concentrations of ozone in the troposphere, specifically in the Northern Hemisphere. Firstly, we present ozone observations in the tropopause region from the measurement campaign MOZAIC, and discuss their correlation with potential vorticity. The results have been used to improve the parameterization of stratospheric ozone in a coupled tropospheric chemistry - general circulation model. We will show examples of the performance of the model regarding the simulation of ozone in the tropopause region, and present the simulated seasonality of cross-tropopause ozone transport in relation to other tropospheric ozone sources and sinks. Finally, we will examine and compare the influence of cross-tropopause transports to surface ozone concentrations for simulations with contemporary, pre-industrial, and future emission scenarios. 

One clear limitation of most of the models is that they have little or no representation of explicit stratospheric chemistry. This could also clearly limit the models ability to predict the full atmospheric impact on ozone of aircraft emissions since it is predicted by the models that approximately 1/3 of the ozone perturbations occur in the lower stratosphere. 

Abstract. The impact of future aircraft emissions on concentrations of reactive nitrogen, water vapour and ozone has been calculated using the 3-dimensional stratospheric chemical transport model SCTM-1. Emissions of NOx (N0+N02) and H20 from both sub- and supersonic aircraft have been considered. 

The model results obtained in this study suggest that future aircraft emissions will have a significant impact on levels of NOx, stratospheric water vapor, and ozone in both the troposphere and the stratosphere. The effect of future supersonic aircraft depends strongly on the cruising altitude assumed for the supersonic fleet. 

ORM assumes that the atmosphere is in local thermodynamic equilibrium this means that the temperature of the Boltzmann distribution is equal to the kinetic temperature and that the source function in Eq. (4) is equal to the Planck function at the local kinetic temperature. This LTE model is expected to be valid at the lower altitudes where kinetic collisions are frequent. In the stratosphere and mesosphere excitation mechanisms such as photochemical processes and solar pumping, combined with the lower collision relaxation rates make possible that many of the vibrational levels of atmospheric constituents responsible for infrared emissions have excitation temperatures which differ from the local kinetic temperature. It has been found [18] that many C02 bands are strongly affected by non-LTE. However, since the handling of Non-LTE would severely increase the retrieval computing time, it was decided to select only microwindows that are in thermodynamic equilibrium to avoid Non-LTE calculations in the forward model. 

Gidel L.T., Crutzen P.J. and Fishman J., A two-dimensional photochemical model of the atmosphere. 1 chlorocarbon emissions and their effect on stratospheric ozone. J. Geophys. Res. , 88, 6622-6640 (1983). 

Carli B., Comparison of current models of OH stratospheric concentration with far-infrared emission measurements. Starnberger See, West Germany, 11-16 January 1984. 

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