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 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. Optical methods are used to monitor many important constituents: OH, HgO, O3, and NO. In addition, a myriad of other constituents, including aerosols are amenable to optical observations. The coupling between chemistry, radiation and dynamics is important and implies necessary close cooperation with other data sources such as the MST radar. 2.1.2 Mesosphere. From the standpoint of optical observations from the ground, most of the mesosphere is an extension of the stratosphere which implies absorption studies at much lower densities. Thus, the chemistry of the mesosphere has not yet received adequate attention and its study will require the development of active techniques such as lidars. Near the mesopause (D region) and below the region of diffusive equilibrium, which characterizes the thermosphere, there is resonance scattering, ionization and dissociation by sunlight resulting in abundant neutral and ionized photochemical activity. Thus, the chemistry and dynamics of this region are observable from the ground in emission. 2.1.3 Thermosphere/Ionosphere. The chemistry, energetics, and dynamics of the thermosphere are dominated by the varying input of energetic particulate and electromagnetic solar radiation. Important trace constituents are created along with ionized, metastable, and vibrationally and electronically excited species. The resulting emissions are observed from the ground during day and night using both active and passive optical techniques. The large variations of these effects in time and space make ground-based optical observations a fundamental means of studying this region. This region is also an important indicator of solar and magnetospheric activity, so coordinated, synoptic observations with support from other disciplines are necessary. 2.1.4 Magnetosphere/Ionosphere. Optical observations yield the only macro scopic evidence for the existence of the magnetosphere. Synoptic images of the aurora provide a nearly continuous indication of the state of the magnetosphere and the solar wind. This is important because the immense size of the magnetosphere precludes adequate coverage by satellite in situ measurements. Many of the magnetospheric processes may also be documented from detailed optical studies of the region of the atmosphere at all lati tudes where the energetic particles from the magnetosphere are precipitated. 2.2 Aurora/Airglow Physics 2.2.1 Introduction. Auroral and airglow physics was founded on ground-based optical observations of the light of the night sky. The airglow is defined as the reradiation of solar energy (excluding the corpuscular component) absorbed by the atmosphere. The aurora is the luminous manifestation of solar corpuscular radiation in the atmosphere. The advent of balloon, rocket and satellite measurements expanded our knowledge of detailed processes but optical observations still account for most of what we know about aurora and airglow, mainly because of a long history, and the inherently high temporal and spatial resolution of optical observations. Traditionally, photographs, emission spectra, and photometric mapping have been used, but recent Improvements in these instruments and the addition of lidar and computerized data-handling has substantially lowered the main barriers to the interpretation ground-based optical observations: 1) Two-dimensional, highly sensitive detectors will lead to vastly Improved resolution in time and space, 2) computer tomography and lidar will aid in the determination of the volume emission rate with altitude, 3) supplemental information from rockets, satellites and radars can provide better information on model atmospheres and, in the case of the aurora, the incoming particle spectrum, 4) laboratory data on reaction rates, transition probabilities, etc. may be more easily incorporated into the analysis. The ultimate goal of describing the entire process of distributing solar energy in the atmosphere will be achieved by assembling Information from a wide variety of experiments. In addition to the chemical reactions of airglow aeronomy, the atmosphere at high latitudes undergoes a highly variable bombardment by electrons and heavier ions. This leads to the view of the high-latitude atmosphere as a large, gaseous collisions laboratory. Studies of atomic metastable states, molecules in highly developed vibrational states, the relation between various emissions and excitation and de-excitation processes all are subjects of optical aeronoiny. The following is an attempt to outline briefly some experiments carried out in auroral and airglow physics (excepting those concerned basically with correlation studies with other types of observations). 2.2.2 Stratosphere. Ground-based optical measurements are needed to improve our understanding of photochemical and transport processes in the lower part of the middle atmosphere. Hydroxyl (OH) emissions, OH absorption, and lidar measurements of OH (resonance fluorescence) are needed to clarify and validate the odd hydrogen chemical models. The OH absorption measurements with high resolution spectrometers (PEPSIOS) use the sun as a source, with the bulk of the absorption occurring in the 25-75 km region and a maximum specific absorption around 35 km. This technique is attractive because it is a relative absorption measurement with no calibration problems. Other species which can be studied by ground-based observations of absorption at lower wavelength resolution include O3, NO2, and NO3. Presently, PEPSIOS spectrometers are in operation or are planned for Fritz Peak, Poker Flat, and Boca Raton. However, at least two more PEPSIOS instruments are needed: one near the equator and a second one in the Southern Hemisphere. An attractive future possibility for PEPSIOS is a CjiO absorption measurement; this would be of interest to modelers studying the stratosphere ozone problem. Lidar observations of aerosol layers are on the upswing because of the strong interest in dust injected into the stratosphere during several volcanic eruptions in recent years. There is now an urgent need for a global network of aerosol lidars to complement the satellite SAGE and SAM measurements of the stratospheric aerosol. Differential absorption lidar (DIAL) measure ments of H2O, SO2, O3, and NO2 are feasible in the troposphere and lower stratosphere, and there is an increasing need for accurate altitude profiles of concentration to be compared with photochemical transport models of these species. 2.2.3 Mesosphere. The least understood region of the atmosphere is the mesosphere which ranges from the upper stratosphere to the ionospheric D region and the well-known metallic ion and neutral vapor layers. There is no dearth of outstanding problems in the chemistry and dynamics of this region, and there is convincing evidence that the stratosphere-mesosphere- thermosphere system must be considered as an interactive one. Key families of constituents include odd nitrogen (NOx), odd oxygen (Ox), and odd hydrogen (HOx) and the alkali metals. Nitric oxide is a major source of ionization for the D region through the photoionization by solar Lyman-a at 1,216A and the source of this NO is predominantly transported from the thermosphere. Temporary increases in D-region absorption of medium and high frequency radio waves (the "winter anomaly") are believed to be primarily to enhanced transport of NO, providing a ground-based indicator of this phenomenon. 02(^a) is a less important source of 0-region ionization. However, the 1.27 m emission is an important one because ground-based measurements at twilight may be used to infer the ozone concentration in the 60 - 90 km 8 region. This information coupled with OH* emission measurements at night can perhaps be be used to deduce nighttime H and O3 concentrations. Infrared remote sensing of the mesosphere includes measurement of OH, O3, Hand 02(^a) emissions. These optical measurements are extremely useful for modellers who need to check models of photochemical processes in the mesosphere and other regions. An important feature of a minor metallic constituent such as sodium vapor is its use as a tracer of atmospheric motions. Lidar measurements of the concentration vs. altitude profile reveal significant wavelike structures Induced by gravity waves and tides present in the background atmosphere. The dissipation of such waves influences the zonal flow and they contribute directly to the dissipation of the larger-scale disturbances. In the future, these effects must be Included in dynamical models of the upper atmosphere. Also, gravity waves probably Influence the transport of trace constituents and heat. With the successful development of sodium lidar systems, it is clear that the small-scale vertical structure of the 80-100 km region can be obtained. Two-wavelength lidar systems have been used to infer neutral atmospheric density and temperature profiles, in the stratosphere and lower mesosphere; and these systems have detected wavelike structures induced by gravity waves. It should be pointed out that a sodium lidar is capable of measuring the thermal structure of the mesopause region. This may be accomplished by stepping the wavelength of the laser across the sodium D-2 resonance line and accurately determining the line shape. Sodium nightglow observations and absorption measurements using PEPSIOS are recommended, as well as a daytime sodium lidar capability. Optical measurements of OH*, 0*, Og and alkali metal emissions are needed to check the photochemical models, and to study the dynamics of the mesosphere and the lower ionosphere. Nitric oxide concentration measurements are needed especially to fill the gap between 40-80 km. A spectroscopic imager to observe OH clouds is highly recommended to improve observations of wave motions in the mesosphere. 2.2.4 Thermosphere. Auroral and airglow emissions in the thermosphere provide measures of a number of quantities which are important to models of thermospheric dynamics and the local photochemistry. The presently increased sensitivity and time resolution in optical instruments allows almost real time airglow data acquisition at medium resolution (0.5A). Complex computation and control systems result in greater accuracy and accessibility for data analysis. Some observations which may seem to be reworking old database will, in fact, be using programs which were proven but untenable as routine monitors before the recent instrumental advances. For the thermosphere, however, the greatest improvement will be in the coordinated efforts of observers at a number of locations. Thermospheric emissions are the most direct indicators of the effects of solar flux on the atmosphere. There are many choices of emissions which result from ionization or dissociation due to solar ultraviolet. For example, if the existing thermospheric dynamics program of 6300A [01] observations with Fabry-Perot interferometers were extended into the twilight they would provide a measure of the solar UV since the dominant production of O^D during nautical twilight (96° to 102® solar zenith angle) is due to photodissociation of O2 in the Schuman-Runge region of the spectrum (1305-1750A). Ameasure of the EUV would result from observations during civil twilight (90°-96® sza) when local photoelectron excitation is 10 predominant. Continuous measurements of 6300A [01] emission with the changing altitude of the earth's shadow would yield the N2/O2 population with altitude and the total electron density in the F-region. This is an example of a proven program which is now practical due to advances in data handling. Atmospheric temperatures at various altitudes may be acquired by choosing species associated with various altitude regions. The doppler width of atomic lines and the rotational intensity distribution of molecular bands both reflect the local kinetic temperature. This method may be used in absorption in the stratosphere, but beginning near the mesopause, a continuous measure of neutral and ion temperatures are available from such species as OH, Na, O2, N2"^ 01 and Oil. Besides thermal studies, changes in temperature at different altitudes with time may be used to infer the effects of tides and waves in the atmosphere. Studies of production and loss mechanisms in either airglow or auroral situations have suffered from lack of simultaneous data from various wavelength regions simultaneously. While this is sometimes a calibration problem, the required number of instruments and detectors of adequate resolution have simply been out of reach for individuals in the past. Thus, the planned construction of high-speed, medium-resolution spectrographic instruments covering the entire atmospheric transmissable wavelength region will allow extensive studies of ratios of populations in various forbidden and allowed states and vibrational distributions. This will permit a more complete assessment of which processes are predominant in the production and loss of a large number of excited states. An example of the need to bring the proposed instrumentation into use may be seen in the fact that the Balmer 11 decrement (Ratio of 6563A to 4861A Hg emission) which has been observed in the aurora for more than 30 years is not known to within a factor of 2, and this may be critical to something so fundamental as the description of the production of hydrogen emission in the aurora. A long-standing problem is the origin of the 5577A oxygen green line in the nightglow. Its source probably involves an excited O2 molecule, but interactions between the three O2 excited states A'^a^, and C^eJ) have not been adequately investigated in the laboratory because of the weakness of the transitions. It is very likely that an Identification can be made by observing the temporal behavior of the 5577A line In relation to that of the three pertinent O2 transitions, particularly in bands originating from high vibrational levels. The spectroscopy of the three O2 UV transitions which have so far been identified in the nightglow are now well understood, so we feel confident that spectra can be simulated at any desired resolution. An unexplored area is the question of production of these O2 states in aurorae. They are certainly produced far less efficiently than the N2 states, but recent auroral spectra suggest that there may be selective production of 02(A'^Au) to the exclusion of the more commonly observed 02{A^Ey'^) state. It is also possible that these auroral spectra show indications of interaction between the O2 metastables and products of auroral chemistry, e.g., nitric oxide. These and many other questions will become amenable to investigation with fast, high-resolution instrumentation. 2.2.5 Interspheric Coupling. A recent result of photochemical modelling reveals that nitric oxide, produced in the thermosphere, may be transported through the mesosphere into the stratosphere were it may influence ozone chemistry through the catalytic destruction process. This most interesting 12 possibility suggests that solar UV and energetic particle effects on NO in the thermosphere may be propagated via the stratosphere. Observations of auroral emissions at high latitude, as well as the NO2 continuum may provide a useful means of studying auroral NO^ production. Concurrent study of the mesospheric emissions (e.g., O2 Ag, OH*) could then be used to gain information about transport and photochemistry in the intervening mesosphere. Metallic species may play an important role in the stratosphere through ion-atom-aerosol interactions; and this suggests another possible link between extra-terrestrial effects and stratospheric composition. It is widely accepted that meteoric ablation is the source of metallic ion and neutral species in the 80-100 km altitude interval which includes the upper D region of the ionosphere. Metallic ions such as Na+, Fe+, Mg+, Ca"*", Sr"**, have been identified. Also, hydrated metallic ions and other metallic cluster ions have been detected. In spite of the fact that much attention has been devoted to the metallic species, particularly atomic sodium, there are major outstanding questions that need to be resolved. In particular, rate constants for the major reactions need to be measured before accurate chemical models can be vali dated. Measurements of metallic ion and neutral atom concentrations need to be made simultaneously at the same location, in order to check models of the neutral and ion chemistry. 2.2.6 Instrumentation. The placement of observing stations at low- and mid- latitudes is not critically dependent on the phenomenon itself and a mobile station should be built there first. This would be good also from the standpoint of testing for the first data collection system. 13 Unlike observations at lower latitudes, placement of observations at high latitudes is critical. The diurnal variation of the auroral precipitation region and winter darkness, combines with geographic, logistic and political limitations to leave but two stations in the Northern Hemisphere for synoptic auroral studies: Poker Flat for nighttime aurora and Svalbard for daytime aurora and polar cap studies. Other stations such as S0ndrestr0m, Greenland and Troms0, Norway may have important roles in their strategic locations associated with the incoherent scatter radars. Most established stations already are instrumented with a scanning photometer, all-sky camera, and even some form of electronic imager. The instruments of interest there would then include the more complex spectro graphic and interferometric devices listed in the Strawman Observatory in Appendix B of this report. A special problem for auroral observations which would impact the design of spectrographic instruments is the fast variation of auroral luminosity in time and space. The proposed spatial resolution in the Strawman is adequate but the readout of the detector should possibly be at a rate of 30 frames per second with an interframe dynamic range of lO^. This may have some impact on the design of the instrument for the high latitude station. Another specialized instrument would be a lidar for resonance scattering studies of the auroral atmosphere. 14 2.3 Atmospheric Dynamics 2.3.1 Stratospheric Dynamics. Stratospheric winds and temperature may be measured by high-resolution absorption interferometry of the shift and width of rotational lines. This sort of observational technique is presently in the developmental stage, but there are certainly no technical barriers to the implementation of this type of observation. 2.3.2 Mesospheric Dynamics. The problem of mesospheric dynamics is one of determining the effect of small-scale motions on the general circulation pattern. In this case, it is the frictional deceleration of the zonal wind by breaking gravity waves which is believed to be important for the simulation of the mean meridional wind and temperature distributions. Gravity waves are thought to be mainly responsible for the vertical transport of momentum. The reasoning behind this is that the drag processes are required in both winter and summer and gravity waves are present in both seasons. Planetary waves, the other leading candidate, are present only in winter. It will be necessary to measure winds, waves and turbulence in the mesosphere and there are several methods for doing this, including optical imaging or photometry of airglow layers, spectroscopy of airglow layers and lidar sounding. Thus, the first attempts should be coordinated multiple optical station observations in connection with an MST radar or other such instrument to determine the occurrence, horizontal wavelength, and horizontal phase velocity of gravity waves in the mesosphere. In the tropics the important parameter is probably long-period equatorial waves. 2.3.3 Thermospheric Dynamics. The study of the upper atmosphere and its dynamics are a necessary part of the understanding of the interaction between the sun and the atmosphere in general. The thermosphere is the first bastion of our atmosphere towards solar activity and it absorbs a 15 great part of both the higher energy particles and radiation from the sun thus becoming a gauge of solar variability. Upon receipt of solar energy the thermosphere redistributes it by creating a weather system which re directs the energy or stores it for later dissipation or transport. As an example, the motions associated with the re-distribution of energy in this region of the atmosphere set up electric fields, which in turn affect thunderstorm activity at lower levels. The absorption of solar energy also involves dissociation and ionization of local atmospheric species. These are later transported downwards and give their energy to other species in the form of heat or chemical energy. Models of atmospheric dynamics are very useful tools to increase our understanding of atmospheric motions. These models are normally used in such a fashion as to try to simulate the few available observations, seldom more than one station at the time, and then interpreting the physical processes included in the model in order to satisfy the observations. At present the (few) available upper atmosphere dynamic observations are divided roughly into two categories: a. Single station with fixed position, but with a long time series of observations. b. Satellite platform observations which provide a short-term coverage of a given region (at some local time). Even though the two types of observations are complementary to each other, there exist not a sufficiently large data base in either to carry more than a few numerical comparisons. At this point it must be noted that, with the upper atmosphere being a plasma, both charged and neutral motions must be measured since they not only affect each other, but their interaction gives rise to some of the heating and forcings of the atmosphere. 16 It should be the goal of a concerted, multi-station optical aeronomy program to provide the following observable quantities (arranged according to latitude, but not restricted to a latitude): High Latitude 1) magnetospheric convection 2) auroral particle flux and energy 3) magnetospheric boundaries and dynamic response Mid Latitude 4) heat and momentum sources 5) small scall structures 6) EXB drift and dynamics Low Latitudes 7) solar forcing versus tides 8) gravity waves and planetary waves 9) penetration of E-field 2.3.4 Dynamics Instrumentation. The atmospheric dynamics program has been identified with interferometry of F-region atomic emissions. This method, providing neutral and ion winds and temperatures, is certainly central to dynamics, but it is by no means the only instrument which should be deployed when the acute problem of lack of stations is solved. Indeed, most of the parameters to be measured according to 2.3.2 above could be extracted from routine observations by imagers, spectrographs, and MST radars. It should be noted, however, that a major contributor to models of atmospheric dynamics would be successful lidar systems. This is especially true in mesospheric dynamics where the measurement of gravity waves, tides and turbulence is restricted to images and spectrographic observations of a relatively high, thin airglow layer. The problem is that high powered lidars for resonance and Rayleigh scattering studies of the upper atmosphere are still a generation away from field use compared to the other instruments proposed in this study. It can only be recommended that some emphasis be placed on the development of this instrument while the major problem of geographic coverage is attached. Specifically, the available observing ground stations at this time are the radar/optical chain at ~ 75 degrees West., and the western optical 17 chain at ~ 110 degrees West. The 75 degree West chain consists of the radars at S^ndrestrom Fjord (Greenland), Millstone Hill (MA), Arecibo (P.R.) and Jicamarca (Peru). Only the Greenland and Arecibo stations have other than a temporary optical program. The Greenland station (in the polar cap) dovetails with the optical stations at Svalbard and Fairbanks, AK., while the latter is the northernmost station of the 110 degree West chain of optical observatories. This chain consist of Fairbanks, as previously mentioned, Calgary, Alberta (~ 52°N) and Fritz Peak, Colorado (~ 40®N). If one desires to obtain the previously described weather map, and one looks at the geography, it is found that some areas necessary for this coverage are devoid of observing stations. For instance, in the polar region, data is necessary between Fairbanks and the Greenland and Spitsbergen stations. Canadian scientists have expressed their interest to fill this void in cooperation with the present stations. Going farther south, there exists a gap between the latitude of Fritz Peak (40 degrees north) and Arecibo (~ 20 degrees north) and between Arecibo and Jicamarca (~ 12 degrees south). That is to say, the mid-latitude equatorial boundary and the Appleton Anomaly are not covered. Also the region between Fritz Peak (~ 105 degrees West) and Arecibo is empty. Thus, in order to obtain the necessary coverage to develop a weather map a number of new optical observing stations become necessary, namely in northern Canada. Millstone Hill, another roughly halfway between Arecibo and Jicamarca in northern South America, one at nominally 30 degrees north in the western chain and another between the latter and Arecibo. These investigations therefore will require a minimum of an additional five ground-based optical observation sites in order to satisfy a weather map approach to the motions of the upper atmosphere. 18 2.4 Space Plasma Physics 2.4.1 Introduction Experimental research in plasma physics and magnetospheric physics has often relied heavily on optical detection. The very existence of plasma physics as a scientific discipline has its roots in the study of glow discharges. Moreover, it was the optical aurora that gave us the first hint that such a thing as the magnetosphere even exists. As the understanding of plasma physics has improved and as more refined techniques of measurement have become available, the emphasis has shifted from the optical emissions to the more fundamental quantities of fields and particles. However, in a number of areas of plasma physics research, optical detection continues to play a key role. Most of the applications depend on the ability to obtain measurements with good temporal and spatial resolution and to observe a large region simultaneously. For these applications, two classes of detectors have been particularly valuable: video imaging systems and scanning photometers. We have identified a number of current problems in ionospheric and magnetospheric plasma physics that can be addressed with the use of optical imagers and scanners. Many of these are already active areas of research, but there is room for considerable expansion. 2.4.2 Airglow This traditional realm of the spectroscopist is usually associated with atmospheric chemistry rather than with plasma physics. However, when the emitting species is an ion, or when the density of a particular ionic species controls the chemistry that ultimately leads to optical emission from a neutral species, the ionospheric plasma can be observed directly by ground-based or airborne optical detectors. The most convenient detector 19 for the purpose is a monochromatic imager. The measureable quantities are the optical intensity, the shapes and scale-sizes of patches, the wavelength of repetitive patterns, and the direction and magnitude of the horizontal velocity. The altitude of the emitting region can be determined by triangulation of data from two sites or can be deduced in some cases from atmospheric models and a knowledge of the chemistry leading to the emissions. Hence for some studies, a monochromatic imager can be an inexpensive and portable substitute for or supplement to an incoherent scatter radar. It also offers the advantage of providing a complete map of the sky in a time span of a few seconds. Airglow structures suitable for such measurements have been observed both at equatorial and mid-latitudes and in the polar cap. In the auroral zone (and to some extent in the polar cap) the technique is less applicable because much of the observed light is controlled by particle precipitation rather than by atmospheric chemical reactions. Although it isn't part of plasma physics, mention should be made here of the observations of large-scale banded structures observed in the OH (neutral) emission. These observations can be made in some cases with the same imaging systems used to observe the ion dynamics. A time-sharing (filter wheel) approach might be very useful to monitor simutaneously the dynamics of the neutral atmosphere at 85-90 km in the OH emission and those of the ionized component at a somewhat higher altitude. 2.4.3 Auroras 2.4.3.1 Magnetospheric topology. The shape of the magnetosphere is continually changing and the optical aurora provides a convenient way of measuring some of the changes. The position and latitudinal extent of the auroral oval and the location of the boundary between discrete and diffuse aurora are useful parameters for a variety of magnetospheric studies. 20 other studies have involved the relationship between the latitudinal move ments of the midnight-sector auroras and those of the cusp auroras. Coor dinated observations in two hemispheres have defined the extent of conjugacy in visible auroras—an important issue in the discussion of open and closed field lines. The location and motions of SAR arcs also help to define the magnetospheric topology. 2.4.3.2 Magnetospheric substorms. Because the manifestations of mag netospheric substorms depend on latitude, local time, and universal time, it is unlikely that the complex pattern would have been perceived without the framework provided by all-sky images of the aurora. This framework is still vital to the interpretation of individual in-situ measurememts. Moreover, video images provide a spatial coverage and temporal and spatial resolution that are difficult to obtain with other techniques. For example, the propagation of the westward traveling surge, the development of large- scale auroral spirals, and the poleward surge of the "breakup arc" are all Important aspects of the substorm that cannot be measured easily except by the use of imaging systems. 2.4.3.3 Plasma instabilities and other specific auroral processes. The magnetospheric and ionospheric plasma support a variety of interesting instabilities. Many of these are most easily recognized by in-situ measure ments or by the detection of electromagnetic radiation in the ELF to HF frequency ranges. Others, however, produce characteristic temporal and spatial patterns in the visible aurora. Optical observations, particularly those made with imaging systems, are essential to the study of these features. For example, auroral curls, observed with video imaging systems, are small-scale (~ 2 km diameter) vortices in the visible aurora. From the side, they appear as field-aligned rays. Their characteristic form led to 21 the realization that many discrete auroral arcs are characterized by velocity- shear. This vorticity is equivalent to excess negative space-charge in the region above the aurora. Because the precipitating electrons must pass through the region of excess charge, the real vorticity in this region is projected onto the atmosphere as an apparent vorticity in the auroral forms. The electric field pattern, consisting of pairs of opposing electric fields associated with individual arc-elements, was deduced from video images of the aurora and was subsequently verified by in-situ measurements from high-altitude satellites. Other auroral features that should eventually be related to specific plasma processes include pulsating auroras (0.01 to 1 Hz), fast auroral waves, and flickering auroras (10 ± 3Hz). The best approach to studying these phenomena is to combine ground-based imaging with other measurements. 2.4.3.4 Global modeling. Several parameters necessary for a quanti tative understanding of the coupling of energy from the magnetosphere to the atmosphere can be obtained easily with optical techniques. The ionization rate can be inferred directly from the intensity of the 3914A emission or any of the 1st N^2"^ bands. The characteristic energy of the precipitating particles and the total input of energy from particle precipitation can be deduced from measurements of the 6300A and 3914A emissions. With some assumptions, the ionospheric conductivity may also be calculated from the optical data. These parameters can also be obtained (also with assumptions) from incoherent scatter radars. Since the radar and optical measurements do not depend on the same assumptions and since the grid of incoherent scatter radars is very coarse, it makes sense to use a blend of the two approaches. It should be noted that only the optical technique can provide a measure of 22 the energy input of precipitating protons. Also, the time needed to map the sky with a radar is long compared to auroral variability. Hence, at the auroral zone, optical imaging systems are essential for the proper interpretation of radar data. 2.4.4 Active Experiments 2.4.4.1 Tracers. A variety of chemicals have been released into the ionosphere to be used as "fluorescent dye" markers for tracing neutral winds, EXB motions and magnetic fields. The injected material is observed from the ground photographically or with optoelectronic imagers. The data are reduced by comparing the cloud positions with the stellar background. By varying the time, location and method of injection, it is possible to trace different features. As one example, a shaped explosive charge can inject barium ions in such a way as to "paint" a long segment of a given field line. This is the only known technique for measuring the dependence on altitude of perpendicular electric fields. Since electron beams and ion beams produce visible streaks when they penetrate the atmosphere, they also can be used with optical detection for traci ng fi^lds in the magnetosphere. 2.4.4.2. Plasma physics experiments using rockets or satellites. In jections of chemicals into the upper atmosphere can also be used in active experiments to study instabilities in an expanding plasma and also the interactions of the plasma with its environment. The possibilities are nearly limitless, but some of the areas that have already been investigated include the formation and collapse of cavities in the earth's magnetic field, the Kelvin-Helmholtz instability in an expanding plasma ring, the formation of ionospheric holes by means of water releases, anomalous ioniza- tion of neutral jets exceeding Alfven's critical velocity, and the stimulation 23 of auroral particle precipitation. In most of these experiments, optical imaging has been an essential diagnostic. Ion and electron beams can also be used for experiments in plasma physics. The beam-plasma-discharge has been studied extensively in the laboratoary using imagers and photometers along with other instruments. This work will continue from Space Shuttle. 2.4.4.3 RF Perturbation Experiments. As with chemical releases and particle beams, RF transmissions can be used either to probe the existing environment or to conduct active experiments. For example, RF can be used to heat the ionosphere or two RF frequencies can be used together to study the non-linear generation of other frequencies. Excitation rates of atmo spheric species are monitored photometrically from the ground. 2.4.5 Instrumentation. Because of the tremendous variety in space plasma physics, it is inappropriate to designate a single instrument as being ideal. Nonetheless, several general points emerged from our discussion. 1) Most of the relevant optical measurements for these areas of research can be made with combinations of images and photometers. For many purposes an all-sky imager combined with a meridian-scanning-photometer is ideal. In other cases a narrow-field imager with a bore-sighted photometer is more appropriate. 2) For many purposes, monochromatic imagers are ideal. In some cases (e.g., some of the studies in auroral morphology) white-light imagers must be used to maintain adequate temporal resolution. 3) Major radar facilities should be supplemented with photometers and imaging systems wherever possible. 4) Instruments must be available for campaign-style programs. 24 5) One or more state-of-the-art solid-state imaging systems should be built for plasma physics studies. Many studies can be undertaken with relatively simple SIT cameras. 6) The key to the use of video data is a suitable digital analysis facility. Thought should be given to making existing facilities available to occasional users of video data. 25 2.5 Theoretical Models It IS the goal of the modelling section of the GBOA program to be able to provide the observing community with consistent, updated modelling prior to and during the observational process. Comparison with the observations which result in changes in the model will occur and be documented immediately. The design of a common computing language will thus speed up this iterative process considerably. 2.5.1 Synthetic Spectra. The production of synthetic emission spectra using modern computing facilities has advanced beyond our average ability to produce comparable observational counterparts. The anticipated advances in optical instrumentation are eagerly awaited by those who carry out the important job of interpretation and analysis of spectral observations by comparison with synthesized spectra. The real need in this area is a common compendium of the latest experimental and theoretical values of the quanities used in the pro duction of synthetic spectra. For example, recent publications on the temperature and intensity of OH and O2 observed in the polar mesopause have been frustrated by differences in "accepted" values for line strengths, lifetimes and Franck- Condon factors. This type of problem should be reduced to a minimum by the proposed program of building an updated library of synthetic spectra accessible to the aeronomy community. 2.5.2 Atmospheric Chemistry. The most important quantities in the modelling of chemical processes in the atmosphere are the time-dependent density and temperature of the constituents and the reaction rate constants. These quantities should be updated both from laboratory studies and from observations. The importance of the relative ease with which this can be done and documented is here emphasized again. 26 2.5.3 Col1isional Chemistry. The interpretation of optical auroral observa tions depends on a thorough knowledge of the effects of precipitating particles on the atmosphere. Such studies have progressed considerably in the last few years with the solution of the electron transport equations to account for low energy electrons and the inclusion of a large number of chemical reactions to document the time-dependent situation. Besides the quantities of importance to atmospheric chemistry (in particular the ion and electron density and temperature), collision and excitation cross-sections are necessary as is some knowledge of the incoming particle spectrum. 2.5.4 Atmospheric Dynamics. The recent emergence of global circulation models has provided the theoretical understanding of some of the processes which give rise to the observed motions. By their very nature these models provide only a broad picture of the dynamical processes which are circumscribed by the necessity to accumulate such diverse parameters as solar euv and uv, auroral heating efficiencies, airglow reradiation, NO, 0 and CO2 cooling, down ward thermal conductivity and upward tides and gravity waves. Certainly this will be the most difficult and complex of the models to update and document. The largest problem at present is the paucity of geographic coverage of measurements of neutral and ion winds and temperature. Historically, the neutral atmospheric motions have been observed optically, while the charged particle motions have been measured by radio techniques, such as backscatter radars. With certain assumptions, it is possible to attempt to derive neutral motions from the radio technique observations or charged particle motions from neutral motion observations. However, at present there is no comprehensive study of the validity of the assumptions for these derivations and just a few incomplete observational comparisons. 27 The available observations are mainly concentrated in the northern hemisphere, over a reasonable latitudinal expanse but rather poorly in the longitudinal extent, however, there exist some glaring gaps as the equatorial regions are approached. The present state of observational data is thus incomplete, which in turn does not allow to use the models to their fullest extent. Therefore, the joint opinion of the participants in the workshop is that a set of observations be obtained simultaneously, or as near as possible, which will provide a "weather map" of the upper atmosphere. This weather map data will then force the models to simulate the observations at all times at all locations, which is at best a severe constraint when compared with the single station simulations available thus far. 28 3. ADVANCES IN OPTICAL TECHNOLOGY 3.1 The Medium Is the Massage There is no doubt that recent advances in optical instrumentation, data handling and computer-modelling will direct the course of optical observations. Indeed, it is these technological advances which provided the impetus for the Ground-Based Optical Aeronomy Workshop and the resulting view that several important problems in upper atmosphere physics could be solved by a concerted coordinated program of ground-based studies of these problems. The develop ments which have lead to this conclusion are the following: 1) The evolution of new detector technology which greatly increases the performance of optical instrumentation. 2) The development of new optical component technologies which permit a variety of new measurements to be made. 3) The evolution of new high technology instrumental design concepts which utilize (1) and (2) above. 4) The evolution of data acquisition and handling systems which can handle the large data rates generated by modern instrumentation. 5) The development of new comprehensive theoretical models and the associated computational power needed to run these models. 6) The realization that a multi-parameter data base acquired via a team approach coordinated at the national level could provide both the experimental data and the theoretical modelling capability needed to significantly advance our understanding of the processes which control the behavior of the upper atmosphere/ionosphere-magnetosphere. 3.2 Detectors Increased sensitivity in nearly all wavelength regions and the development of two-dimensional array detectors has facilitated a number of advances in 29 low light level measurement capabilities. 1) The use of array detectors in spectrographs increases both the effective speed of the system by measuring all wavelengths at once and effective information by imaging the sky along the spectral lines. 2) The use of array detectors in interferometers allows increased wave length information through the use of more fringes or increased spatial resolution by imaging the sky at the detector. 3) Increased sensitivity, particularly in the red and infra-red regions allows significantly shorter integration times. 3.3 Optical Instrumentation 1) Servo-stabilized Fabry-Perot etalons have resulted in new light rejection and filtering levels. 2) Development of holographically ruled gratings has resulted in 2 orders of magnitude improvement in the light scattering properties of these components. 3) Development of superpolished optical surfaces has reduced scattering of light by reflecting surfaces by several orders of magnitude. 4) Development of Tow cost micropnocesses has automated instrumental control and facilitated data acquisition under software control. 5) Development of tunable, dye lasers with output in the megawatt range. These factors have led to the development of a new generation of instru ments which can provide the following kinds of data: 1) Imagers: Good spatial images of relatively weak emissions in narrow wavelength bands over wide fields of view. 2) Spectrographs: Simultaneous measurements of the entire optical spectrum from the near UV to the near IR, with the possibility of a high enough resolution to operate in the daytime. 30 3) Interferometers: Triple etalon filtering of optical emissions at high throughout with the ability to operate in the daytime. 4) Lidars: Optical radar observations of both resonance and Rayleigh- scattered emissions throughout the day and night. 31 4. NEED FOR ORGANIZATIONAL STRUCTURE 4.1 One or Several Sponsoring Institutions? The contributions of aeronomers to the Ground-Based Optical Aeronomy (GBOA) Project must be assembled through some organizational structure. The proposal, instrument design and construction, and scientific data base must be the product of a large cross-section of the aeronomy community. The exact nature of the structure must be broad enough to Include contributions from the largest possible number of people and Institutions but it must be narrow enough to be efficient. Obviously, concessions will have to be made in both directions. Three versions of a possible organizational structure are shown in Figs. 4.1, 4.2 and 4.3. The difference between the three versions revolves about the question of whether the project will be carried out at one university of whether one GBOA program management group will be assembled for each of the five major instrument development programs (spectrograph. Interferometer, imager, lidar, modelling). This should be decided by the aeronomy community and by the financial constraints placed on the projects. The fundlng for the GBOA program would be admi ni stered by one or more universities, each with a responsible program scientist. A project management group would be assembled to Implement the design and construction of each Instrument or system. The system should be designed and fabricated by a dedicated engineering group under the direction of visiting experts. This approach is suggested because the complex part of the system will be in the computer control, data formatting. Instrument characterization, software development, and data communication. These tasks require good organization and close coordination. This engineering group would take responsibility for the design and fabrication of the scientific instrumentation 32 NSF SPONSORING UNIVERSITY PRO SRAM ADMINISTRATIVE SCIENTIST SUPPORT (0 U (U • 6B0A Program Msinagement •H (0 M M-i (d • •H n PL4 4J Instrument Desj Lgn/Fabrication d 0 a d) 4-1 to Science Steering Group •H ca •H a o cC Instrument Chs iracterization CO o. Data Man lagement CO o CO Field Oplerations A A A i A Data P roduct if f Y f o d a U § a o § w •H •H 60 •3 •H M CO a 01 M (3 o ta 4-1 DATA 0) O H O M -H J3 M *J iH CENTER CX CO a* Cl 0) rH 5*ri iH^ 09 *J M 01 n 60 O 4-» o "d 4J M (0 p4 <0 cu II to 1 Figure 4.1 I NSF AERONOMY PROGRAM SPONSORING SPONSORING SPONSORING SPONSORING SPONSORING UNIVERSITY UNIVERSITY UNIVERSITY UNIVERSITY UNIVERSITY MODELLING SPECTROGRAPH IMAGER LIDAR INTERFEROMETER PROGRAM PROGRAMS PROGRAM PROGRAM PROGRAM SCIENTIST SCIENTIST SCIENTIST SCIENTIST SCIENTIST CO SCIENCE STEERING GROUP 7rr-7f M\ PROGRAM PROGRAM PROGRAM PROGRAM PROGRAM MANAGEMENT MANAGEMENT MANAGEMENT MANAGEMENT! MANAGEMENT V t ^ \ ^ \f SCIENCE COMMUNITY A1rglow/Aurora Physics <- DATA Atmospheric Dynamics CENTER Space Plasma Physics -—7 Atmospheric Scattering Model11ng Figure 4.2 NSF AERONOMY PROGRAM I SPONSORING UNIVERSITY I PROJECT SCIENTIST GBOA PROGRAM SCIENCE STEERING GROUP iir- Modelling Spectrograph Imager Program Program Program CO M s: en Management Management Management SCIENCE COMMUNITY Airglow (Auroral Physics Atmospheric Dynamics Interferometer Lidar Space Plasma Physics Program Program Atmospheric Scattering Management Management Model11no i r "TIT 4l JL Distribution DATA CENTER Figure 4.3 but under the supervision of an expert from the science conmunity. This group will also be responsible for field operations and transmittal of the science and instrument data to the data center. They would also be responsible for a data distribution system which will allow the user community to have immediate access to the data. 4.2 Program Scientist. At least the first term of this position should be for three years. This would allow time for the technical organization to be established and begin functioning properly. In succeeding years any member of the community and their sponsoring university should be able to oversee the GBOA with the technical section operating under contract to that sponsor. The program scientist should be prepared to spend half of his time performing the responsibilities of this position. The GBOA program would provide half salary and management support. 4.3 The Science Steering Group (SSG). The SSG will be made up of representatives of subsections of the scientific community. A break-down suggested by the Logan workshop would be: Subject Instrumentation Airglow and Auroral Physics Spectrometry/Photometry Atmospheric Dynamics Fabry-Perot Interferometer Space Plasma Physics Monochromatic Imagery Atmospheric Scattering Lidar Systems Theoretical Models Data Base Organization Campaign Principal Investigators GBOA Stations 36 The community will be divided into five or more groups of coiranon interests. Each group will appoint a member to the SSG who will be their liason. This should be a rotating position with a one or two year term. The GBOA program should compensate SSG members for their time during the first few years when activity will be high. The SSG will meet monthly through the first year. Group meetings should be held in conjunction with the AGU and possibly more often during the first few years. Travel support to special meetings would be provided for some representatives. It is suggested that a Principal Investigator be assigned to each campaign and that person become a member of the SSG. His selection could be related to the scientific objective of the campaign. He would be responsible for the organization and coordination of the campaign through to a specific publication sometimes after the observational period. At the meeting of December 6, 1983, the following provisional SSG was elected from among the attendees: Aurora and Airglow Physics C. S. Deehr G. J. Romick Atmospheric Dynamics T. Killeen J. Meriwether Space Plasma R. Eather T. Hallinan Atmospheric Scattering F. Roessler C. Sechrist Theoretical Models R. Roble S. Sol Oman 4.4 System Implementation The scope of this group will be extensive but will be restricted to preparation and operation of the system. Only proven Instruments will become part of the system; instrument development will remain the 37 responsibility of the individual research program. The instrumentation proposed as part of the system will be reviewed and approved by the SSG. The review process will be supported by the engineering group who will provide definition of cost and schedule. The system implementation will require good engineering management. Detailed design and documentation will be important because we anticipate a number of units may be fabricated and placed into service. Good docu mentation also allows the work to be divided into parts for subcontract support. An implementation organizational structure has been drawn up as a means of demonstrating the scope of this support activity required (see Figure I 4.4). Although the sequence of Interactions is necessary to result in a coordinated system, the complete organization does not need to be at one location. There are several places in this chart where direct supervision by members of the scientific community would be necessary. Several have been indicated by This supervision is required because the techniques we wish to u^se have been developed by individual researchers. The function of the systems implementation group will be to provide engineering definition within the scope of the total system. 38 GBOA Program Management Mechanical Electronic Instrument Data Field Design Design Characterization Management Operations *(Scientific Data Base) *(C^paign P.I.) Fabrication Fabrication Test/Calibration Software Integration Instrument Development Testing * Data Base Definition CJ KD Data Center Distribution User Community Figure 4.4 5. PROGRAM DEFINITION AND IMPLEMENTATION SCHEDULE 5.1 Schedule The approval of this report in its final form by the aeronomy community should provide the basis for a program definition. The community at the Fall 1983 AGU meeting elected a Science Steering Group to guide the initial effort outlined within this report. A proposal will be submitted to NSF requesting funds for a study and implementation period. The product of this phase would be an Implementation Plan covering the first year of activity in detail and a projection through a five year plan. Staff posi tions would be defined but no positions would be filled until the implemen tation plan has been approved for funding. Preliminary schedule for the Implementation Phase is shown in Fig. 5.1. In December 1984 a review of the program and the selection of the operational science steering committee for the implementation phase should take place as well as a reassessment of the program to date. 5.2 Observing Programs Preliminary campaigns would be anticipated as early as fall 1985. Multiple station observations would begin by winter 1985/86. There would be three basic types of observing programs: (1) Synoptic Observations, (2) Coordinated Studies and (3) Campaigns. 5.2.1 Synoptic Observations. Ground based observatories provide a natural vehicle for the acquisition of both long term and short term synoptic measure ments. Having established the observing capability, this valuable function could be readily filled. The measurements could provide continuous coverage of a limited number of key parameters, which could be used to initiate specialized or coordinated studies of special events. 40 FIGURE 5.1 GROUND BASED OPTICAL AERONOMY PROGRAM 1984 1985 1986 1987 1988 JFMAMJJASOND JFMAMJJASOND JFMAMJJASOND JFMAMJJASOND JFMAMJJASOND General Meetings (3 days) Science/Program Review • • • • • Science Section Meetings (AGU) •••••••••• Definition Phase Report • Proposal to NSF • Begin Engineering Staffing • Long Lead Procurement Mid-Latitude Campaign • High Latitude Campaign • GBOA Station #1 Complete • GBOA Station #2 Complete • GBOA Station #3 Complete • 5.2.2 Coordinated Studies. These programs would constitute the primary mode of operation. Coordinated studies would involve the acquisition of data from a number of sites, using instrumentation selected from the systems inventory to solve specific problems. Data acquisition would be coordinated between different instruments and different sites. 5.2.3 Campaigns. The Canadians have used the campaign approach (Appendix C) very successfully. This approach represents a short term coordinated effort involving many kinds of measurements usually to attack transient phenomena associated, for example, with aurora. One of the first possibili ties is to mount a campaign associated with the re-flight of the shuttle EOM mission which is proposed for 1985. Several of the investigators on the shuttle are members of the ground based optical aeronomy community and have suggested this project to NASA. 5.3 Modelling Program Parallel to this development is the development of the data base. This would be the responsibility of the steering committee. They would prepare a plan which would designate the order in which the data base would be developed and balance the development of the data base with the overall system fabrication schedule. Specific sections of the data base would be prepared by members of the scientific community under contract to the sponsoring university and GBOA. The contracted work should result in a reviewed publication which would define the origin of the parameters to be placed in the data base. 5.4 Program Goals The coordinated program will be organized to complement, enhance and re late Independent research programs. The coordinated program will include: 42 a) The collection of parameters for models of our present understanding of aeronomy to provide a consistent scientific data base on which to build. b) The preparation of integrated observational systems which will make optimum use of modern technological developments in detectors, computers and data distribution and management. c) The coordination of measurements will be the important aspect of the observations; the measurements will provide broad spectral coverage, spatial coverage and associated dynamics. d) The distribution results to the scientific community will be easily facilitated because the observational systems will consist of basic instrumentation which will produce data in a standard format con sistent with model input and spectral identification programs. 43 APPENDIX A National Research Council Report: 'Upper Atmosphere Research In the 1980's' The report states that 'Groynd-based remote sensing has, and win continue to have an Important role to play In upper-atmospheric research. Whereas remote sensing from satellites 1s Ideal for obtaining a global though Intermittent view of the earth's atmosphere, ground-based remote sensing Is more effective for making continuous observations and for Intensive observations of phenomena of limited or small scale. The recommendations with respect to ground based optical measurements were extracted from the report, verbatim and are listed below without priority. 1. • We recommend that advances In optical technology recently developed for use on spacecraft be exploited by further development and upgrading of Instrumentation for ground-based studies of the energy sources, chemistry, and dynamics of the upper atmosphere. 2. We recommend that red-line Interferometers be operated In conjunction with 1ncoherent-scatter radars In studies of Frregion dynamics. 3. We recommend that sodium lldar and partial-reflection techniques be further studied and developed to determine their usefulness compared with MST and meteor-wind radars for determining mesospheric winds. 4. We recommend that radar studies of natural and artificially generated irregularities and instabilities In the ionosphere continue to be supported. These studies should be supplemented by sounding-rocket measurements as well as relevant ground-based technique.s A-1 5. We recommend that active experiments be supported to apply the cause-and-effect approach to the study of upper-atmospheric phenomena. 6. We recommend the continuing development of high-resolution spectroscopy for the measurement of trace constituents and physical conditions in the stratosphere and mesosphere. 7. We recommend that studies be made of new microwave and UV techniques for ground-based measurement of total ozone with eventual testing of at least one of these Instruments, including comparison with a Dobson instrument. 8. We recommend that airglow observations be exploited as an effective method of determining the distribution of O3, 0, and H. 9. We recommend that airglow observations be exploited to determine the role of metastable species in thermospheric photochemistry and the distribution of helium and hydrogen in the exosphere. 10. It is recommended that a program of obtaining and archiving Infrared solar spectra obtained within the atmosphere on a routine basis (several times a year) be started for the purpose of monitoring total atmospheric content of minor constituents. 11. It is recommended that NOAA carry out the necessary data- management functions to keep track of what data exist on stratospheric composition and where they are archived. 12. It is further recommended that funding agencies for stratospheric chemical research prescribe that investigators maintain suitable documentation of data sets and cooperate with NOAA data management and services. A-2 13. We recommend that, where practicable, major Installations such as an Incoherent-scatter radar be augmented with a cluster of facilities such as sounding-rocket and balloon launch sites, passive and active optical observatories, and other electromagnetic sounding systems. A-3 APPENDIX B A Strawman A1rg1ow and Auroral Optical Station Introducliion In this report a lot of emphasis is placed on the need for a balanced program: a balance between our ability to analyze data which is comparable to our ability to record data. This concept is different from our more natural techniaue of taking data and then developing the analysis. In this section we will describe briefly a 'Strawman' optical facility which has been organized with the needs of the community in mind. This is suggested as the basis for a proposal for a practical facility based on the latest technology and computing capability which could be assembled and operated in a semi-automatic mode. The objective of the aeronomy observatory is to record simultaneously as much significant data as possible from an atmospheric region of interest. These data will be supplemented with other data describing more general geophysical conditions. The objective of the aeronomy data base will be to allow observations to be correlated with the current understanding of the excitation/emission mechanisms. The Instrument Sets. The instruments and control•computers would be housed in a portable all-weather trailer which would allow it to be moved from site to site. Instruments would be deployed on a pointed scan platform or would be fixed in position to monitor the whole sky. &-1 ^ • There would be two groups of instru ants on the scan platform and they are listed in Table 1. One group wi ?ch would be permanently configured to record supporting data in a common fo; nat is called the Configured < Instruments. The second group of instruments would be user definable, i.e., the user could specify the filters, resolutions, etc. The scan platform would be under computer control. All instruments on the scan platform would be bore-sighted and pointed by azimuth and elevation actuators. Several options would be available for pointing control. A video camera would be the primary tool. Band pass filters and intensity contours could be generated to allow the operator to follow regions of constant brightness, etc. Many other options, including data sampled from the instruments, could be used to control pointing and data collection. The scan platform could be slaved to a radar, a balloon position, an aircraft position, etc. Again, there would be two groups of instruments, configured and user definable. Suggested characteristics are given in Table 2. Visitor Instrument Port. The observatory would provide computing and data collection support to visitors' instruments. This would be an important capability to correlate data from specialized instruments with the observatory data set. Data Rate. The data rate from the optical facility will vary depending on the kind of study being performed. In order to give some idea of the scope of the data collection capability required, estimated data rates are given in Table 3 for the instrument set. Tables 1 and 2. The assumption was made that a data sample would be taken from each instrument every 10 seconds. B-2 TABLE 1 Scan Platform Configured Instruments (Electronically Variable Format) Spatial Resolution Wavelength Resolution F.O.V.* Angular m at 100 km Spectrographs (6 channels) 3,000 A - 1 y 4 A 10® Vert. Slit 0.1° 1.8 Vert Monochromatic Imagers 6300, 5577 10° X 10° 0.1° X 0.1° 70 X 70 Fabry-Perot Interferometers 6300, 5577 0.01 A 0.4° User Defined Instruments CD I OJ Spatial Resolution Wavelength Resolution F.O.V.* Angular m at 100 km 2 Spectrographs Range > 125 A > 0.5 A 10° Vert. Slit 0.1° 1.8 Vert 1 Monochromatic Imager Band Pass Filter User Defined 10° X 10° .04 X .04 70 X 70 1 Monochromatic Imager Band Pass Filter User Defined 1° X 1° .004 X .004 7x7 Fabry-Perot Interferometer 4,000 A- I p User Defined 0.4° *Field of View TABLE 2 Sky Monitors Configured Instruments Wavelength Resolution F.O.V.* Angular Res. Meridian Spectrograph 4000 - 8500 A 3-S/\ 0.5' All Sky Monochromatic Imagers 6300, 5577 All Sky All Sky Spectrograph 4000, 8000 A ±16 A User Defined Instrianents Wavelength Resolution F.O.V,* DO I All Sky Monochromatic Imager Band Pass Filter User Defined All Sky *Field of View TABLE 3 Estimated Data Rates Scan Platform Configured Instruments. Spectrographs 3000 - 10000 A 10 spectra 1® 50 kpbs 2 Monochromatic Imagers 130 kpbs 2 Fabry-Perot Interferometers 50 kbps User Defined Instruments. 2 General purpose Spectrographs 16 kpbs 2 Monochromatic Imagers 130 kbps 1 Fabry-Perot Interferometer 5 kbps Sky Monitors. Configured Instruments. Meri di an Spectrograph 65 kbps All Sky Monochromatic Imagers 30 kbps All Sky Spectrograph 65 kbps User Defined Instruments. All Sky Monochromatic Imagers 65 kbps Visitor Instrument Support 100 kbps Total data rate 706 kbps It will be impractical to keep all of the data that could be recorded. A selection will have to be made of data sets which have specific characteristics. The data will have to be processed and put into a usable format almost in real time, certainly within the day. Preliminary correlation could be done in real time. The data collected during a campaign would be transferred in some form to the data center, possibly NCAR. A reasonable distribution mechanism could be to have the total data set from a campaign written onto a digital (video) disk for distribution. B-5 There is a noteworthy difference be veen the data produced by the optical facility and the normal experime The data set collected by the optical facility will be broad enougl, that all investigators could do their work on data taken simultaneously from the same region of the sky. If an auroral process were described by 50 to 100 related equations, then 50 to 100 time-related signatures could be extracted from the data to provide a solution. B-6 APPENDIX C GROUND-BASED OPTICAL INSTRUMENTATION IN CANADA (Received with thanks from Dr. Gordon Shepherd) HERZBERG INSTITUTE AURORAL GRATING SPECTROMETER EXPEDITIONARY VARIETY OF AURORAL PHOTOMETERS EXPEDITIONARY UNIVERSITY OF CALGARY . AURORAL IMAGER EXPEDITIONARY UNIV. OF MICHIGAN AIRGLOW OBSERVATORY SYNOPTIC UNIVERSITY OF SASKATCHEWAN VARIETY OF PHOTOMETERS EXPEDITIONARY UNIVERSITY OF VICTORIA- BIREFRINGENT PHOTOMETER SYNOPTIC UNIVERSITY OF WESTERN ONTARIO FOURIER SPECTROMETER EXPEDITIONARY YORK UNIVERSITY VISIBLE SCANNING MICHELSON EXPEDITIONARY VARIOUS STEPPING MASK PHOTOMETERS EXPEDITIONARY WIDE ANGLE MICHELSON (dOPPLER) EXPEDITIONARY VARIOUS FABRY-PEROTS SPORADIC *LOW RESOLUTION FABRY-PEROT (PRESTOO SYNOPTIC (manual) CANADA CENTRE FOR SPACE SCIENCE LOW LIGHT LEVEL TV's *0N loan from CCSS C-1 V. OPTICAL AURORA AND AIRGLOW IN CANADA -- INSTITUTIONS AND SCIENTISTS 1. HERZBER6 INSTITUTE OF ASTROPHYSIC^ National Research Council^ Ottawa A. Vallance Jones — auro al spectroscopy and morphology R.L. Gattinger F. CrEUTZBERG AUROfAL photometry F.R, Harris A. YaU CHEMICAL RELEASE PHOTOCHEMISTRY 2. UNIVERSITY OF CALGARY. Calgary, Alberta C.D. Anger SATELLITE AND GROUND-BASED AURORAL IMAGERY, ROCKET PHOTOMETRY, 5577A AIRGLOW, OPTICAL DOPPLER (with UnIV. OF MICHIGAN) J. Haslett CCD DEVICES T.A. Clark MINOR CONSTITUENTS IN THE STRATOSPHERE J.S, Murphree (balloon) R. King 3. UNIVERSITY OF SASKATCHEWAN, Saskatoon, Saskatchewan D.J." McEwen — auroral photometry K.V. Paulson E.J. Llewellyn — atomic and molecular oxygen processes I. McDade UNIVERSITY OF VICTORIA, Victoria, British Columbia H.M. Sullivan — sodium, lithium, potassium in twilight 5. UNIVERSITY OF WESTERN ONTARIO, London, Ontario R.P. Lowe — fourier spectroscopy of oh, minor constituents in the stratosphere 6. YORK UNIVERSITY, Toronto, Ontario J.C. McConnell ground-based, rocket and satellite R.A. Koehler PHOTOMETRY, INTERFEROMETRIC SPECTROSCOPY, G.G. Shepherd optical DOPPLER V.P. Bhatnagar W.A. Gault R. Link B.A. SOLHEIM R.H. WlENS C-2 CANADIAN OPTICAL AURORA AND AIRGLOW MODES OF OPERATION NSERC Grant Support - INDIVIDUAL PROJECTS, DEVELOPMENT OF CAMPAIGN INSTRUMENTS, CAMPAIGN COLLABORATIONS, SYNOPTIC MEASUREMENTS CCSS Campaigns - generally organized around ROCKET LAUNCHES - ONE MAJOR CAMPAIGN ABOUT EVERY TWO YEARS - PULSATING AURORA, SOUTHEND, SASKATCHEWAN Jan/Feb 1980 - CLEFT CAMPAIGN (CENTAUR), Cape Parry, N.W.T. Dec 1931' - ARIES, Churchill, Manitoba Jan/Feb 198it - HADES (harang discontinuity electrodynamics) WINTER 85/85 - THE CCSS PROVIDES LOGISTIC GROUND-BASED SUPPORT IN THE FORM OF TRAILERS IN REMOTE LOCATIONS, POWER, LIVING ACCOMMODATIONS AND, IN CERTAIN CASES, SPECIALIZED INSTRUMENTATION - HILAT -A GROUND STATION IS BEING PROVIDED FOR TELEMETRY CCSS Space Projects - VIKING - a Canadian auroral u.v. imager will be launched ON THE Swedish Viking satellite in May, 1984 - C.D. Anger, principal investigator - WISP (waves in space plasmas) - Spacelab 6, space plasma physics mission - H.G. James, principal investigator - if/AMDII (wide angle michelson doppler imaging interferometer) - G.G. Shepherd, principal investigator - EIMS (energetic ion mass spectrometer) - B.A. Whalen, principal investigator - CANOPUS (Canadian open programme unified study) a ground-based (synoptic) project that is based on collaboration with the OPEN programme - A. Vallance Jones, principal investigator C-3 CANOPUS A ground-based array 60-75® invuriant in central Canada, comprising BARS - bistatic auroral radar system STARE type 50 MHz 20 km resolution 20 X 20 elements in electric field map. MARIA - Magnetometer and riometer array 12 magnetometers, riometers and telluric stations MPS - Meridian photometer array - 6 meridian scanning photometers - 4278 N2'^, He, 01 5577 + 6300 - one minute scans - 0.5® latitude resolution ASI - All sky monochromatic imager - originally planned for BARS resolution - higher resolution now under consideration - 4278, 5577, 6300A DCN - data collection network DAN - data analysis network - Interface to the OPEN data network - Campaign modes - Viking support from May, 1985 C-4 Geographic Coordinates DATA RATE MAP Site * in baud ID STATION LAT(N) LATCW) Instruments BASELINE (preferred) CL Contwoyto Lake, NWT 65®45' iimA • M, P 30 (70) FS Fort Smith, NWT ec^oi' 111®58' M, P 30 (70) ME Mcanook, Alta. 5A®37' 113®20» P 20 (20) RA Rabbit Lake, Sask. 58®12' 113®40^ M 10 (30) TL Tadoule Lake, Man. 58®36' 98*20' M 10 (50) RI Rankin Inlet, NWT 62®A9' 92»07» M, P 30 (70) 94004. EP Eskimo Point, NWT 61®06» M 10 (50) CH Churchill, Man. 58®A4' 9A®0A» M,- I 190 (2A0) BA Back, Man. 57°40' 9A®0A* M 10 (50) GI Gillam, Man. 5b®22' 9A"A2' M. P. I 210 (250) IL Island Lake, Man. 53®51» 9A®A0' M 10 (50) 95053, PI Pin.iwa, Man. 50®09» M, P 30 (70) SE Fort Severn, Ont. 56®00» 87®38' M 10 (50) 53025. N1 Ni p a wi n, Sask. 10A''02' R 3A0 (680) KL Red Lake, Ont. 50'54» 93®28' R 3A0 (680) *M =•• Magnc t oni« t e r, rioineter, tellurics P = Meridian photometer I AJ 1-s ky J raa^-c r K i i; L ii L 1 r «i u r o r a 1 r a il a r 1 - cANui'us srn: cooudi>!ati-:.s, instruments and data ratios C-5 i ./ FtG. i CANOPUSINSTRUMENTSITES \ o c? OS. %n o LL V- ui 3 X 0^ S 0£ u) I Z U/ af X «c. «J i 'wT- X. y c-7