NASA I Reference Publication 1272 I The Atmospheric Effects Stratospheric Aircraft: Erst program Report I M. J. Prather, H. L. Wesoky, R. C. Miake-Lye, A. R. Douglass, R. P. Turco, D. J. Wuebbles, M. K. W. Ko, and A. L. Schmeltekopf ,,rJIS&-RP-$272> THE ATMQSF,.ZRIC .EFFECTS OF +rn %., %., s~wrr.,mswarc ~PRGRW'TZ A FIRST. ,PIZCSRAH 'ftEPDRf' $fi &!$A3 227 p CSGL 43s . F 4 ! - - ,- t NASA NASA Reference PLIblication 1272 The Atmospheric Effects of Stratospheric Aircraft: A First Program Report M. J. Prather, H. L. Wesoky, R. C. Miake-Lye, A. R. Douglass, R. P. Turco, D. J. Wuebbles, M. K. W. KO, and A. L. Schmeltekopf NASA Office of Space Science and Applications Washington, D.6. National Aeronautics and Space Administration Office of Management Scientific and Technical Information Program Contents 1 The Atmospheric Effects of Stratospheric Aircraft: A First Program Report Michael J. Prather and Howard L. Wesoky, Eds. .................................. 1, 2 High-speed Civil Transport Aircraft Emissions Richard C. Miake-Lye, et al. ............................................................ 13:s:: 3A Natural Cycles, Gases Anne R. Douglass, et al. ................................................................ 33 .. ;;-. 3B Upper Atmosphere Aerosols: Properties and Natural Cycles Richard P. Turco ......................................................................... 63,: ', 4 Designing a Methodology for Future Air Travel Scenarios Donald J. Wuebbles, et al. ............................................................ 93 5 Ozone Response to Aircraft Emissions: Sensitivity Studies with 2-D Models Malcolm K. W. KO, et al. .............................................................. 115.. ;. 6 Lower Stratospheric Measurement Issues Workshop Report Arthur L. Schmeltekopf ................................................................. 15!2'->,.). '7 High-Speed Research Program/Atmospheric Effects of Stratospheric Aircraft Research Summaries .................................................................... 187 A Appendix: List of Reviewers .................................................................... A-l / PRECEBOSdG PAGE BLAH:# NOT FiLMED Chapter 1 The Atmospheric Effects of Stratospheric Aircraft: A First Program Report Introduction Michael J. Prather National Aeronautics and Space Administration Goddard Institute for Space Studies New York, NY Howard L. Wesoky National Aeronautics and Space Administration Office of Aeronautics and Space Technology Washington, DC Editors ABSTRACT This document presents a first report from the Atmospheric Effects of Stratosphefic Aircraft (AESA) component of NASA's High-Speed Research Program (HSFW). Stu&es have indicated that, with sufficient technology development, future high-speed civil transport abcrafi could be economically competitive with long-haul subsonic aircraft. However, uncerbainty about atmospheric pollution, along with community noise and sonic boom, continues to be a major concern; and this is addressed in the planned 6-year HSRP begun in 1990. Building on NASA's research in atmospheric science and emissions reduction, the AESA studies are guided by a panel of international scientists, with particular emphasis on stratospheric ozone effects. Because it will not be possible to directly measure the impact of an HSCT aircraft :fleet on the atmosphere, the only means of assessment will be prediction. The process of establishing credibility for the predicted effects will likely be complex and involve continued m'odel devel- opment and testing against climatological patterns. In particular, laboratory simulation sf het- erogeneous chemistry and other effects, and direct measurements of well-understood tracers in the troposphere and stratosphere, will continue to be used to improve the current models. INTRODUCTION The desire for faster civil aircraft has long been recognized. A supersonic fleet and the impact of its exhaust products in the upper atmosphere were the subject of intense study during the early 1970s (e.g., Climatic Impact Assessment Program in the U.S.) (1-6). Emissions from aircraft perturb the chemical and physical environment in which they are emitted: exhaust prod- ucts such as odd-nitrogen compounds (e.g., NOx = NO + NO2) and water vapor acc:umulate in the atmosphere and can lead to photochemical depletion of the stratospheric ozone layer. Scientific assessment of the environmental effects of the proposed fleet ended rapidly with the recognition that a large fleet of supersonic transports (SSTs) was not economically pracdcal. The Anglo-French Concorde was placed in commercial service about 15 years ago, bsut it serves only first-class passengers with a very small fleet of 13 SSTs, and is not considered econorni- cally competitive with existing subsonic aircraft. Recent NASA-sponsored studies (7-9) show that, with sufficient technology develop- ment, future high-speed civil transport (HSCT) aircraft could be economically competiGve with long-haul subsonic aircraft. Table 1 compares Concorde and projected HSCT characterastics. Given the expected range of HSCTs, they could serve an important role in the rapidly gowing international travel market for flights of 9000 km or more. Table 1. Current Outlook: Concorde versus HSCT Coneorde (SST) Projected HSCT 6,600 Range (km) 9,300- 12,000 100 Payload (passengers) 250-300 180,000 Takeoff weight (kg) 340,000 Exempt Community noise standard Far 36, Stage 3 Premium Fare levels Standard Global atmospheric pollution, community noise, and sonic boom still persist as major environrnental roadblwks to HSCTs; and these three concerns are the focus of NASA's HSRP (10). The WSRP began funding research in 1990 and plans to continue funding through 1995. The general course of the 6-year program is first to understand basic phenomena (e.g., strato- spheriG ozone, combustor emissions, sonic boom propagation, etc.), to prepare computer mod- els CIH other engineering design tools, and finally to verify these tools with experiments. The atmosphere presents a special case, since the possible global effects cannot be empirically tested without building and flying a large WSCT fleet. Furthermore, the atmosphere is inherently neither conprollable nor deterministic on a long-term meteorological scale, and thus our predic- tive malels, the keystone of an assessment, cannot be easily validated as in "laboratory con- rsofid" experiments. AESA is the component of HSRP responsible for assessing the effects of WSCTs on stratospheric ozone, atmospheric chemistry, and climate. It builds on the strong research com- munity developed and currently supported by NASA's Upper Atmosphere Programs. AESA stu&es a= directed at improving our basic understanding of the circulation and chemistry of the srsatosphene and upper troposphere. The structure and history of HSRPIAESA are outlined in this chal~ter.The Program has asked several scientists to put together papers that either sum- marize our current knowledge of key elements in atmospheric science or lay the foundation for succeediing assessments. These monographs have been reviewed by the atmospheric science and engineering community and form the basis of this first HSRPIAESA Program Report. AESA OVERVIEW The HSRPIAESA Program was founded in 1988 by an agreement between the NASA Office o:F Aeronautics and Space Technology and the Office of Space Science and Applications. The primary goal of the AESA studies is to prepare the scientific basis for a critically reviewed assessment of the impact of a fleet of HSCTs on the atmosphere, particularly on perturbations to stratospheric ozone. It was recognized that such an assessment must be built on open scientific search,, including communications with the international science community. The WSRPIAESA studies were initiated with the guidance of an advisory panel consist- ing of prominent members from the international atmospheric sciences community; it also includes members from a public interest group, regulatory agencies, and the aircraft industry. The cument membership is given in Table 2. The AESA Advisory Panel helps review research prcpposalls, analyzes the current status of atmospheric science (with respect to AESA Program needs), and develops the overall strategy for AESA studies. It does not advocate specific recommlendations for research; this task is the responsibility of the NASA Program managers. The fist panel meeting was convened in December 1988 and defined the scientific issues critical to the assessment of an HSCT fleet. This workshop led to the draft of a call for research in suppor~of WSFWIAESA studies. The advisory panel continues to review the Program and overall strategy for the HSCT assessment. CONNECTION WITH OZONE ASSESSMENTS In 1975 Congress directed NASA to "develop and carry out a comprehensive program of research, technology, and monitoring of the phenomena of the upper atmosphere so as to provide for an uinderstanding of and to maintain the chemical and physical integrity of the Earth's upper atmosphere." Since then, the Upper Atmosphere Research Program (UAFW) has directed this research, focusing on the effects of increasing stratospheric chlorine caused by the manufacture of chlorofliuorocarbons (CFCs). The UARP has reported biennially to Congress (11) and has led Table 2. Atmospheric Effects of Stratospheric Aircraft: Advisory Panel (a) Scientific Panel Members Dr. R. A. Cox Natural Environment Research Council, United Kingdom Prof. Frederick L. Dryer Princeton University Prof. Dieter H. Ehhalt Institute for Atmospheric