GROUND-BASED OPTICAL AERONOMY IN THE 1980's A WORKSHOP REPORT ON THE PRESENT AND FUTURE STUDY OF THE INTERACTION BETWEEN SOLAR RADIATION AND THE ATMOSPHERE Compiled at the Geophysical Institute of The University of Alaska for The Lunar and Planetary Laboratory of The University of Arizona Tucson, Arizona 85721 iS d'CWSSSiCtClHi/^ tfvi 6) 'twere ^{(otnc^Ks ^m<mi^^>diMSCO'U\icCi itcof[iam (i(C/ (j^<L^ UU^ <w 0)t^ <Saurce^ ^ CM/^y^ ^ if{i,j}omrM:k'iomriujir^ Ms}(\ic(i coniro6 ^ dJi6tn^ti^vu(^ a^j>\roUct(by\'^a'V\\/ i^ stu(^ ^ co^Q'X' miirdoiion^j ^Kwwcs <w ^cfUe <ic^-Cuv6i^ aj^cacf\ies inait' or- v" ABSTRACT The objective of Ground-Based Optical Aeronomy (6B0A) is to contribute to the understanding of the interaction between the atmosphere and incident solar radiation. The complexity of the problem is such that a cooperative effort must be made in addition to the present individual projects. This effort should take advantage of recent advances in optical and computing instrumentation and construct at least three optical observing systems, compile a computerized modelling database, and coordinate the observational and analytical projects of the participants. To realize this plan, the GBOA community should submit a proposal to the National Science Foundation to fund the development of an Implementation Plan covering the first year of activity in detail and a projection of activities and funds for the following four years. TABLE OF CONTENTS Page ABSTRACT 1 1. INTRODUCTION 1 1.1 The Ground-Based Airglow and Aurora Optical Facilities Workshop, August 1-4, 1983 1 1.2 Agenda 1 2. GROUND-BASED OPTICAL AERONOMY (GBOA) 4 2.1 Spheres of Interest in Optical Aeronomy 4 2.1.1 Stratosphere 4 2.1.2 Mesosphere 4 2.1.3 Thermosphere/Ionosphere 4 2.1.4 Magnetosphere/Ionosphere 5 2.2 Aurora/Airglow Physics 6 2.2.1 Introduction 6 2.2.2 Stratosphere 7 2.2.3 Mesosphere 8 2.2.4 Thermosphere 10 2.2.5 Interspheric Coupling 12 2.2.6 Instrumentation 13 2.3 Atmospheric Dynamics 15 2.3.1 Stratospheric Dynamics 15 2.3.2 Mesospheric Dynamics 15 2.3.3 Thermospheric Dynamics 15 2.3.4 Dynamics Instrumentation 17 2.4 Space Plasma Physics 19 2.4.1 Introduction 19 2.4.2 Airglow 19 2.4.3 Auroras 20 2.4.3.1 Magnetospheric topology 20 2.4.3.2 Magnetospheric substorms 21 2.4.3.3 Plasma instabilities and other specific auroral processes 21 2.4.3.4 Global modeling 22 Page 2.4.4 Active Experiments 23 2.4.4.1 Tracers 23 2.4.4.2 Plasma physics experiments using rockets or satel1ites 23 2.4.4.3 RF perturbation experiments 24 2.4.5 Instrumentation 24 2.5 Theoretical 26 2.5.1 Synthetic Spectra 26 2.5.2 Atmospheric Chemistry 26 2.5.3 Collisional Chemistry 27 2.5.4 Atmospheric Dynamics 27 3. ADVANCES IN OPTICAL TECHNOLOGY 29 3.1 The Medium is the Massage 29 3.2 Detectors 29 3.3 Optical Instrumentation 30 4. NEED FOR ORGANIZATIONAL STRUCTURE 32 4.1 One or Several Sponsoring Institutions? 32 4.2 Program Scientist 36 4.3 The Science Steering Group (SSG) 36 4.4 System Implementation 37 5. PROGRAM DEFINITION AND IMPLEMENTATION SCHEDULE 40 5.1 Schedule 40 5.2 Observing Programs 40 5.2.1 Synoptic Observations 40 5.2.2 Coordinated Studies 42 5.2.3 Campaigns 42 5.3 Modelling Program 42 5.4 Program Goals 42 APPENDIX A- National Research Council Report: 'Upper Atmosphere Research in the 1980's' A-1 APPENDIX B-A Strawman Airglow and Auroral Optical Station B-1 APPENDIX C- Ground-Based Optical Instrumentation in Canada C-1 APPENDIX D- Attendees List D-1 1. INTRODUCTION 1.1 ^The Ground-Based Airglow and Aurora Optical Facilities Workshop, August 1-4, 1983. Sixty scientists from 31 different U.S. and Canadian universities and government agencies representing perhaps three-quarters of all the active U.S. scientists working in this area of aeronomy gathered on the Utah State University campus to discuss the direction of scientific research in ground-based optical aeronomy. The workshop reviewed the goals of solar-terrestrial and atmospheric research as outlined in the National Academy of Science (NAS) report "Solar Terrestrial Research in the 1980"s" (See Appendix A) and discussed the ground-based facilities required to attain these goals. It became apparent that the introduction of advanced instrumentation and data handling systems combined with large-scale modeling could approach the NAS goals, but it would require a cooperative effort unprecedented in the history of observational optical aeronomy. 1.2 Agenda The agenda for the first two days of the workshop included a review of ongoing independent research projects and gave the attendees a good idea of the overall scope of the present ground-based aeronomy research program. This review demonstrated that the ultimate objective of ground- based optical aeronomy is understanding the interaction between the earth's atmosphere and the incident solar energy. Solar electromagnetic and corpuscular radiation is absorbed and scattered by the atmosphere, initiating convection, conduction, ionization and re-radiation in order to distribute to the biosphere this kilowatt per square meter of incident solar energy. Parts of this natural equilibration process are affected adversely by the increasing scale of human activities. 1 Fortunately, the very complexity of the energy distribution process leads to a flexibility of response and accommodation of the initial levels of the offending pollution, which restores the system to near equilibrium. Continuing and increasing disturbances, however, may not be absorbed without producing large-scale adverse effects. Thus, it is important to understand as fully as possible the myriad interrelated processes involved in the absorption and distribution of solar energy in the atmosphere. With this as a goal, three main topics were identified, both in terms of physical processes and main observing instruments. The relationship of the topics (Atmospheric dynamics, Aurora/Airglow, Space physics) within optical aeronomy and to other types of aeronomy are shown diagrammatically in Figure 1.1 Within each of these main divisions, there exist many individual, apparently unrelated subsets which leads to the impression that the overall field is undirected and without purpose. However, significant scientific advances are often made by isolated, individual investigators on relatively small budgets. Thus the purpose of a Ground-Based Optical Aeronomy (GBOA) program should be not to disturb the present individualistic approach to optical aeronomy; but it should be to 1) provide a forum for establishing overall goals and coordination for GBOA research and 2) provide access to Instruments, computer-based models, and synoptic observing coordination not normally available to Individuals. Fortunately, we are now beginning to understand enough about the overall problem to know some of the major variables and how realistically we can assume constancy for others. This understanding leads to special programs which are devised to study specific combinations of variables. Thus under "Dynamics" an association of stations simultaneously monitoring one or two emissions in conjunction with model calculations can produce SOLAR ENERGY Electromagnetic 10^2 mw Corpuscular 10^-10^ MW Satellite Observations ATMOSPHERIC AURORAL/AIRGLOW J5PACE PHYSICS DYNAMICS Interferometric, Spectrographic, Photographic, Photographic Photometric Photometrlc Observations Observations Observations ro * at Incoherent Scatter Radar Observations Atmospheric Magnetosphere- Circulation Ionosphere Coupling Modelling Model1i ng Emission Particle Atmospheri c Spectra Transport Chemi stry Model11ng Figure 1.1 an F-region weather map which yields the average behavior of the global F- region wind field under the influence of solar radiation, particle input and gravitational effects. Similar coordinated studies in each of the three areas will begin to contribute to the understanding of the overall distribution of solar energy in the atmosphere. On the third day of the workshop the attendees initiated a scheme" to prepare a five year plan of scientific direction for a large-scale assault on the basic problems of aeronomy. Section leaders were charged with the preparation of the workshop report for the community and the National Science Foundation, the sponsor of the workshop. The topics and leaders were as follows: C. Deehr - University of Alaska, Fairbanks - High Latitude Studies (Aurora and Airglow) D. Torr - Utah State University, Logan - Mid-Low Latitude Studies (Auroral and Airglow) G. Hernandez - NOAA, Boulder - Dynamics R. Eather - Boston College, Chestnut Hill - Space Plasma Physics R. Roble - NCAR, Boulder - Central Data Systems The following document is the final report of this conference assembled from these sectional reports by C. S. Deehr and G. Romick, University of Alaska, Fairbanks, L. Broadfoot, University of Arizona, Tucson and T. Hal 11nan (University of Alaska, Fairbanks). A draft was submitted to the aeronomy community for approval and adoption as a proposal for future action. A meeting of this same group was held on Tuesday evening, December 6, 1983 as a part of the American Geophysical Union Fall Meeting in San Francisco. Consents and criticisms as a result of that meeting have been Incorporated In this report. Including more extensive revision and comments by S. Sol Oman and M. H. Rees. 3 2. GROUND-BASED OPTICAL AERONOMY (GBOA) 2.1 Spheres of Interest in Optical Aeronomy 2.1.1 Stratosphere. Optical remote sensing of the stratosphere is usually done in absorption with the sun as a source. Re-radiation of solar energy does take place in the far infrared but re-absorption limits ground-based observations. Stratospheric dynamics (winds and temperature) has been studied using in situ and radar methods, but the problem may be approached using optical techniques. The chemistry of the stratosphere is of major importance and optical observations are central to this problem.