Model Assessment of the Impact on Ozone of Subsonic and Supersonic Aircraft


Book Description

This is the final report for work performed between June 1999 through May 2000. The work represents continuation of the previous contract which encompasses five areas: (1) continued refinements and applications of the 2-D chemistry-transport model (CTM) to assess the ozone effects from aircraft operation in the stratosphere; (2) studying the mechanisms that determine the evolution of the sulfur species in the aircraft plume and how such mechanisms affect the way aircraft sulfur emissions should be introduced into global models; (3) the development of diagnostics in the AER 3-wave interactive model to assess the importance of the dynamics feedback and zonal asymmetry in model prediction of ozone response to aircraft operation; (4) the development of a chemistry parameterization scheme in support of the global modeling initiative (GMI); and (5) providing assessment results for preparation of national and international reports which include the "Aviation and the Global Atmosphere" prepared by the Intergovernmental Panel on Climate Change, "Assessment of the effects of high-speed aircraft in the stratosphere: 1998" by NASA, and the "Model and Measurements Intercomparison II" by NASA. Part of the work was reported in the final report. We participated in the SAGE III Ozone Loss and Validation Experiment (SOLVE) campaign and we continue with our analyses of the data.Ko, Malcolm and Weisenstein, Debra and Danilin, Michael and Scott, Courtney and Shia, Run-LieGoddard Space Flight CenterCLIMATE CHANGE; DIAGNOSIS; MATHEMATICAL MODELS; OZONE; PARAMETERIZATION; TWO DIMENSIONAL MODELS; ASYMMETRY; FEEDBACK; FLIGHT OPERATIONS; LOSSES; PLUMES; STRATOSPHERE; SULFUR; SUPERSONIC AIRCRAFT










Potential Environmental Effects of Aircraft Emissions


Book Description

An assessment is provided of the potential environmental effects of fleets of subsonic, supersonic, and hypersonic aircraft. A general discussion of photochemical and transport modeling techniques is included along with a description of the LLL one-dimensional transport-kinetics model that was used in the assessment. Model simulations of the natural and perturbed stratosphere are used to compare theory with observations as a means of verification of model processes. A review is provided of engine emission indexes and 1990 fleet projections. Assessments of the potential effects of subsonic and supersonic aircraft fleets indicate a small increase in total ozone. However, the change in total ozone is the net difference between regions of ozone increase (in the lower stratosphere and upper troposphere) and ozone decrease (in the upper stratosphere). The percent change in the local ozone concentration is much larger than the change in total ozone. The effect of a proposed hydrogen fueled hypersonic transport fleet is a small reduction in total ozone. A study is made of the effect on these results of uncertainties in chemical rate coefficients, speculative chemical reactions, temperature feedback, hydrostatic adjustment, and various model parameters. The potential effect on ozone of aircraft emissions is compared with potential changes due to other anthropogenic perturbations. (Author).







A Review of NASA's 'Atmospheric Effects of Stratospheric Aircraft' Project


Book Description

The NRC Panel on the Atmospheric Effects of Aviation (PAEAN) was established to provide guidance to NASA's Atmospheric Effects of Aviation Program (AEAP) by evaluating the appropriateness of the program's research plan, appraising the project-sponsored results relative to the current state of scientific knowledge, identifying key scientific uncertainties, and suggesting research activities likely to reduce those uncertainties. Over the last few years, the panel has written periodic reviews of both the subsonic aviation (Subsonic Assessment-SASS) and the supersonic aviation (Atmospheric Effects of Stratospheric Aircraft-AESA) components of AEAP, including: An Interim Review of the Subsonic Assessment Project (1997); An Interim Assessment of AEAP's Emissions Characterization and Near-Field Interactions Elements (1997); An Interim Review of the AESA Project: Science and Progress (1998); Atmospheric Effects of Aviation: A Review of NASA's Subsonic Assessment Project (1998). This report constitutes the final review of AESA and will be the last report written by this panel. The primary audience for these reports is the program managers and scientists affiliated with AEAP, although in some cases the topics discussed are of interest to a wider audience.




Atmospheric Effects of Aviation


Book Description

Aviation is an integral part of the global transportation network, and the number of flights worldwide is expected to grow rapidly in the coming decades. Yet, the effects that subsonic aircraft emissions may be having upon atmospheric composition and climate are not fully understood. To study such issues, NASA sponsors the Atmospheric Effects of Aviation Program (AEAP). The NRC Panel on Atmospheric Effects of Aviation is charged to evaluate AEAP, and in this report, the panel is focusing on the subsonic assessment (SASS) component of the program. This evaluation of SASS/AEAP was based on the report Atmospheric Effects of Subsonic Aircraft: Interim Assessment Report of the Advanced Sub-sonic Technology Program, on a strategic plan developed by SASS managers, and on other relevant documents.










Plume to Global-scale Atmospheric Impacts of Aviation Emissions


Book Description

High-altitude emissions from current subsonic aviation or from potentially future supersonic aircraft modify the total column ozone, thus leading to either increases in tropospheric ozone or a decrease in stratospheric ozone, with the latter causing larger UV flux at the ground. Both changes affect human health and, in this thesis, I identify a column ozone-neutral altitude for subsonic and supersonic aviation. Adjoint models of CTMs have been developed to quantify receptor-oriented sensitivities of environmental metrics (e.g. population-weighted ozone exposure) to emissions. Adjoint modeling overcomes the numerical cost of source-oriented sensitivity analysis, as performed by forward models. However, adjoint models of atmospheric chemistry have historically been limited to the troposphere. In this thesis, I build upon previous work and extend the GEOS-Chem Adjoint to further include stratospheric processes, and then validate the sensitivities with multi-year scenarios. I then present adjoint-derived sensitivities to identify column ozone-neutral altitudes for subsonic and supersonic aviation, based on their respective emission characteristics. I find that the 12 - 15 km altitude band is approximately column ozone-neutral for aviation emissions. Neglecting the effects of plume-scale processes introduces a positive bias in the column ozone-neutral altitude that varies between 0.3 up to 1 km.