The operation of an extremely-low-frequency/ very-low-frequency radiometer at Arrival Heights, Antarctica. A.C. Fraser-Smith, Stanford University. During the 1997-1998 field season, this project will continue to operate an extremely-low-frequency and very-low-frequency (ELF/VLF) radiometer at McMurdo, Antarctica, to monitor radio noise from natural sources such as thunderstorms. The Arrival Heights site is one of a network of eight such radiometers operated by Stanford University for the Office of Naval Research. Characterizing the possible sources of radio interference is important for operational purposes. Additionally, the variations in global noise reflect variations in global thunderstorm activity and can, therefore, provide information on global climate change. The antarctic site was chosen about 15 years ago because it is unusually free from manmade electromagnetic interference. The ELF/VLF record of data collected by this project now extends unbroken for more than 10 years. (S-100)
Magnetometer data acquisition at McMurdo and AmundsenScott South Pole Stations. Louis Lanzerotti, AT&T Bell Laboratories; Alan Wolfe, New York City Technical College. Magnetometers installed at selected sites in both polar regions continue to measure the magnitude and direction of variations in Earth's magnetic field in the frequency range from 0 to about 0.1 hertz. Our project focuses on measurements of these variations using magnetometers installed at conjugate sites in the Northern and Southern Hemispheres, specifically at McMurdo and AmundsenScott South Pole Stations, Antarctica, and at Iqaluit, Northwest Territories, Canada. We are also analyzing these data in association with similar data acquired from several automatic geophysical observatories that are part of the polar experiment network for geophysical upper-atmosphere investigations (PENGUIN) program (S-112). Using these systems, we gather data on the coupling of the interplanetary medium into the dayside magnetosphere, including the magnetospheric cusp region, as well as the causes and propagation of low-frequency hydromagnetic waves in the magnetosphere. Because of unique climatic conditions at the South Pole, we are also able to correlate optical measurements with particle-precipitation measurements and with hydromagnetic-wave phenomena recorded by the magnetometer. (S-101)
An investigation of magnetospheric boundaries using ground-based induction magnetometers operated at manned stations as part of an extensive ground array. Roger Arnoldy, University of New Hampshire. An array of induction coil magnetometers located at high geomagnetic latitudes in the Arctic and Antarctic is operated, and the data collected are analyzed, by this project. The sites are Sondre Stromfjord, Greenland, and Iqaluit, Northwest Territories, Canada, in the Arctic and at Amundsen-Scott South Pole and McMurdo Stations in the Antarctic. The sites also complement similar magnetometers in the U.S. and British automatic geophysical observatory (AGO) networks and the MACCS array in Canada. The measurements of magnetic pulsations at these high geomagnetic latitudes are used to study the plasma physics of some of the important boundaries of the magnetosphere, particularly those surrounding the area through which the solar wind enters the magnetosphere and where the magnetosphere transfers the solar wind's energy to the Earth's atmosphere in the form of aurora and similar phenomena. This project is jointly supported by the U.S. Arctic and Antarctic Programs. (S-102)
Antarctic auroral imaging. Stephen Mende, Lockheed Palo Alto Research Laboratory. In the past, space satellites have performed detailed exploration of the magnetosphere, and the average distribution of the energetic particle plasma content of the magnetosphere has been mapped. This form of measurement is unsuitable, however, for observing the dynamic behavior of the magnetosphere. Auroral phenomena are produced when particles from the magnetosphere precipitate into the atmosphere causing the atmosphere to fluoresce. Because particles preferentially travel along the magnetic field line, the aurora can be regarded as a two-dimensional projection of the three-dimensional magnetospheric regions. Thus, observing the morphology of the aurora and its dynamics provides an important way to study the dynamics of the three-dimensional magnetosphere. This method requires knowledge of which type of auroras represent which energy of precipitation and their connection to the various regions of the magnetosphere.
AmundsenScott South Pole Station is uniquely situated for optical observations of polar aurora. The specific advantage of South Pole is that during the winter the aurora can be monitored 24 hours a day unlike most other places, where the sky becomes too bright near local mid-day. An intensified optical, all-sky imager, operating in two parallel wavelength channels4,278 and 6,300 Ångstromswill be used to record digital and video images of aurora. These wavelength bands allow us to discriminate between more or less energetic electron auroras and other precipitation. From South Pole Station, we can observe the polar cap and cleft regions by measuring auroral-precipitation patterns and interpreting the results in terms of coordinated observations of magnetic, radio-wave absorption images and high-frequency, coherent-scatter radar measurements. Through this investigation, we hope to learn about the sources and energization mechanisms of auroral particles in the magnetosphere and other forms of energy inputs into the high-latitude atmosphere. (S-104)
A study of very high latitude geomagnetic phenomena: Continued support. Vladimir Papitashvili, University of Michigan. This joint U.S.-Russian project focuses on the structure of very-high-latitude ionospheric current systems, the integrated effect of which is observed at the earth's surface by magnetometers. Correlative data from antarctic and Greenland magnetometer arrays will be used to investigate symmetries and asymmetries in the electrodynamics of the northern and southern polar caps and auroral regions. Two Russian permanent magnetic observatories (Vostok and Mirnyy) and a remote autonomous magnetometer at Sude are operated jointly by the University of Michigan and the Russian Arctic and Antarctic Research Institute in 1997. Scientific objectives for the 1997-1998 field season are as follows:
The principal investigator, V. Papitashvili, and a Russian magnetician, A. Frank-Kamenetsky will be delivered from McMurdo to Vostok in November 1997 by the first flight of LC-130. Dr. Frank- Kamenetsky will stay at Vostok through winter of 1998 and operate digital magnetometer system; he will take a snow traverse to Mirnyy in December of 1998 revisiting Komsomolskaya and Sude. Dr. Papitashvili will return to McMurdo from Vostok in December 1997 upon completion of the project objectives for the field season. (S-105)
Global thunderstorm activity and its effects on the radiation belts and the lower ionosphere. Umran Inan, Stanford University. Very-low-frequency (VLF) radio receivers at Palmer Station, Antarctica, operated by this project, study ionospheric disturbance caused by global lightning. The principal mode of operation is to measure changes in amplitude and phase of signals received from several distant VLF transmitters. These changes occur in the VLF signals following lightning strokes because radio (whistler) waves from the lightning can cause very energetic electrons from the Van Allen radiation belts to precipitate into the upper atmosphere. This particle precipitation in turn causes increased ionization in the ionosphere, thus affecting the propagating VLF radio waves. Because the directions to the VLF transmitters are known, it is possible to track remotely the path of the thunderstorms that cause the changes. The Palmer receivers are operated as a collaboration with the British and Brazilian Antarctic Programs, both of which operate similar receivers. This project contributes to the Global Change Initiative. (S-106)
Extremely-low-frequency/very-low-frequency (ELF/VLF) waves at the South Pole. Umran S. Inan, Stanford University. Advancing our understanding of the electrodynamic coupling of upper atmospheric regions and refining our quantitative understanding of the energy transport between the magnetosphere and the ionosphere are two important objectives of the U.S. Antarctic Program's automatic geophysical observatory program. Particle precipitation driven by extra-low-frequency/very-low-frequency (ELF/VLF) waves have a part in transporting and accelerating magnetospheric and ionospheric plasmas, processes that result from a variety of physically different wave-particle interactions. Because measuring ELF/VLF waves from multiple sites provides a powerful tool for remote observations of magnetosphere processes, we maintain a system at AmundsenScott South Pole Station that measures magnetospheric ELF/VLF phenomena. Data from this system are correlated with data from the automatic geophysical observatory system. During the 1997ñ1998 austral summer, our objectives are:
South Pole Air Shower Experiment 2. Thomas Gaisser, University of Delaware. The South Pole Air Shower Experiment 2 (SPASE-2) consists of a sparsely filled array of scintillation detectors covering several thousand square meters at South Pole. It detects energetic charged particles (mostly electrons), which are produced in the upper atmosphere by cosmic rays. The experiment has several goals, the most important of which is to determine the elemental composition of the primary cosmic rays at energies above approximately 100 teraelectronvolts. To do this, SPASE-2 works in conjunction with the Antarctic Muon and Neutrino Detector Array (AMANDA), which has several hundred optical detectors so deep in the ice sheet that the only products of the cosmic ray interactions that can be seen by AMANDA are muons. The ratio of muons to electrons produced in a cosmic ray shower is a sensitive function of the mass of the original primary cosmic ray. Because SPASE can measure the number of electrons produced by a cosmic ray as well as its total energy and because AMANDA can determine the number of muons, the mass of an incident primary cosmic ray can be determined. The determination of the elemental composition of cosmic rays is one of the most important outstanding questions in cosmic ray physics, and such information will shed light on the origin of energetic cosmic rays. This project is cooperative with the University of Leeds in the United Kingdom. (S-109D)
High-latitude antarctic neutral mesospheric and thermospheric dynamics and thermodynamics. Gonzalo Hernandez, University of Washington. It is possible to deduce the temperature and wind speed of the atmosphere by measuring the emission spectra of certain trace gasses, especially the spectra of those that are confined to fairly narrow altitude regions. This project uses a Fabry-Perot infrared interferometer located at Amundsen-Scott South Pole Station, Antarctica, to look at the band spectra of several trace species, most importantly the hydroxyl radical (OH), in orthogonal directions. By determining the doppler shift of the lines, researchers can measure the winds. The brightness and line ratios within the bands provide density and temperature information. The OH in the atmosphere is primarily found in a narrow band near 90 kilometers altitude. The fact that the measurements are being made at the axis of rotation of Earth significantly limits the types of planetary waves, thus simplifying the study of the large-scale dynamics of the atmosphere. (S-110)
Riometry in Antarctica and conjugate regions. Theodore Rosenberg, University of Maryland. We will use imaging and broadbeam riometers and auroral photometers to study the processes of energy transfer from the solar wind to Earth's magnetosphere and ionosphere at high geomagnetic latitudes. The emphasis will be on understanding the ionospheric signatures of dayside auroral phenomena associated with particle entry into the cusp and boundary layers, as well as the nightside substorm effects associated with the magnetotail and plasma sheet. Three imaging riometers, located at AmundsenScott South Pole Station (Antarctica), Sondre Stromfjord (Greenland), and Iqaluit (Northwest Territories, Canada, the magnetic conjugate to the South Pole) will provide continuous, simultaneous, conjugate measurements of polar auroral phenomena. All of the above data sets will also be used in conjunction with data obtained by automatic geophysical observatories. (S-111)
Correlative medium-frequency radar studies of large-scale middle atmospheric dynamics in the Antarctic. David C. Fritts and Ben B. Balsley, University of Colorado at Boulder. Using two medium-frequency radars, we will measure the dynamics of the mesosphere and lower thermosphere at high time and spatial resolution (2 minutes and 2 kilometers). The first of these systems was installed at McMurdo Station in January 1996; the second is planned for installation at the British base of Rothera (67.5°S) during January and February 1997. Using these instruments, we will be able to study in detail large- and small-scale motion fields and their latitudinal and temporal variability. When the results of these data are compared with similar products from Northern Hemisphere radars, we expect to be able to study interhemispheric differences in the behavior of the mesosphere and lower thermosphere, which preliminary studies indicate are quite substantial. (S-113)
Astrophysical gamma-ray spectroscopy with the high resolution gamma-ray and hard x-ray spectrometer (HIREGS) on long-duration balloon flights. Robert P. Lin, University of California, Berkeley. Our objectives are as:
All-sky-camera measurements of the aurora australis from AmundsenScott South Pole Station. Masaki Ejiri, National Institute of Polar Research, Japan. AmundsenScott South Pole Station, located at the south geographic pole, is a unique platform from which to undertake measurements of the polar ionosphere. Because of the configuration of the geomagnetic field in the Southern Hemisphere, the station is situated in such a way that dayside auroras can be viewed for several hours each day. Research has shown that they are caused by precipitation of low-energy particles, which enter the magnetosphere by means of the solar wind. Since 1965, data have been acquired at the South Pole using a film-based, all-sky-camera system. Using advanced technology, we can now digitize photographic images and process large amounts of information automatically. Besides continuing to acquire 35-millimeter photographic images with all-sky-camera system, U.S. and Japanese researchers will collaborate and use an all-sky-camera processing system developed at Japan's National Institute of Polar Research to analyze data. This system displays data in a geophysical coordinate framework and analyzes images over short and long intervals not possible with individual photographic images. The data will be used to investigate dayside auroral structure, nightside substorm effects, and polar-cap arcs. These studies can also be used to obtain further insight into the physics of the magnetosphere, the convection of plasma in the polar cap, and solar winds in the thermosphere. (S-117)
Solar and heliosphere studies with antarctic cosmic-ray observations. John Bieber, University of Delaware. Neutron monitors in Antarctica provide a vital three-dimensional perspective on the anisotropic flux of cosmic rays that continuously bombards Earth. At McMurdo and AmundsenScott South Pole Stations, year-round observations will continue for cosmic rays with energies in excess of 1 billion electronvolts. These data will advance our understanding of a variety of fundamental plasma processes occurring on the Sun and in interplanetary space. Neutron-monitor records, which began in 1960 at McMurdo Station and 1964 at South Pole Station, will play a crucial role in efforts to understand the nature and causes of cosmic-ray and solar-terrestrial variations occurring over the 11-year sunspot cycle, the 22-year Hale cycle, and even longer time scales. At the other extreme, we will use new methods to study high time-resolution (10-second) cosmic-ray data to determine the three-dimensional structure of turbulence in space and to understand the mechanism by which energetic charged particles scatter in this turbulence. (S-120)
RICERadio Ice Cherenkov Experiment. David Besson, University of Kansas. Electromagnetic radiation (e.g., light, x-rays, gamma rays) cannot escape from inside the most active regions of the Universe, for instance from the nuclei of galaxies, nor can the highest energy gamma rays even propagate through intergalactic space because they will be absorbed by the cosmic background infrared photons. Neutrinos, however, can traverse a considerable amount of material unimpeded, and if they can be detected in such a way that their arrival direction and energy can be determined, they can be used to study high-density regions and highest energy events of the cosmos. When an electron-type neutrino does interact in a dielectric medium (such as the deep glacial ice beneath South Pole), it will produce a shower of electrons and positrons that will cause the energy of the original neutrino to radiate rapidly away as electromagnetic radiation. The probability of such interactions increases with increasing energy, so that a detector's sensitivity increases with energy. Thus, a modest sized (by neutrino detector standards) instrumented volume of ice, say a 100-meter cube, could have an effective volume of a cubic kilometer, a size which is deemed necessary to do astronomy. This project is a pilot to determine the feasibility of the radio detection of neutrino interactions in ice. (S-123)
Rayleigh and sodium lidar studies of the troposphere, stratosphere, and mesosphere at the Amundsen-Scott South Pole Station. Jim Abshire, National Aeronautics and Space Administration, Goddard Space Flight Center. The automated geophysical observatory (AGO) lidar is an ongoing, National Aeronautics and Space Administration (NASA) funded project to develop and demonstrate a compact, low-power, and autonomous atmospheric lidar for operation in the U.S. Antarctic Program's AGOs deployed to various locations in Antarctica. The primary science mission of AGO lidar is detecting, monitoring, and profiling polar stratospheric clouds (PSCs). These clouds form in the extremely cold polar stratosphere during the austral winter, and a particular type of PSC (type 1) has been implicated in the annual springtime destruction of stratospheric ozone. A secondary science mission is long-term continuous monitoring of atmospheric transmission and backscatter from the surface. These data will be compiled into a database that will provide statistics on atmospheric conditions for the Geoscience Laser Altimeter System (GLAS).
The first AGO lidar is scheduled to be deployed to AGO P1 by the AGO servicing crew in November 1997. This instrument will have redundant laser diode transmitters operating at 670 nanometers, producing 500 milliwatt peak power pulses, at 1- or 4-microsecond pulse lengths, and a pulse-repetition frequency of 4 kilohertz. The backscattered laser light will be collected by a 20-centimeter diameter telescope and detected by all-solid-state single-photon counting modules in a cross-polarized detection scheme. Type 1 PSCs will depolarize incident radiation. Because the laser transmitters in AGO lidar produce highly linearly polarized light, we expect to see a depolarization signal (up to several percent) in the backscattered light.
The lidar data will be archived in the lidar instruments' own flash memory as well as the optical drive provided by the AGO platform. The AGO lidar will also contain its own Argos transmitter, which will telemeter at least one atmospheric profile per day back to NASA's Goddard Space Flight Center in Greenbelt, Maryland. (S-126)
Rayleigh and sodium lidar studies of the troposphere, stratosphere, and mesosphere at the Amundsen-Scott South Pole Station. George Papen, University of Illinois. During the 1997-1998 field season, this project will continue the operation of a sodium resonance lidar at the South Pole to study the vertical structure and dynamics of the atmosphere from the lower stratosphere to the mesopause. During this third year of the project, an iron resonance lidar will be added and will extend the measurements of the dynamics and temperature structure to 100 kilometers altitude. Additionally, an airglow imaging camera will be used to study the horizontal structure. When used in conjunction with the normal balloonborne radio sondes, which are flown regularly from South Pole, the final complement of instruments will provide extensive data on
High-latitude electromagnetic wave studies using antarctic automatic geophysical observatories. James LaBelle, Dartmouth College. At radio frequencies between 0.05 and 5.0 megahertz (MHz), three types of radio phenomena related auroral origin can be detected: narrowband near 2.8 and 4.2 MHz, broadband noise bursts in the frequency range of 1.44.0 MHz, and broadband noise at frequencies below 1 MHz. An accepted physical theory explains the third type, called "auroral hiss," but the origin of the other two types is unknown. Although these radio emissions constitute a small fraction of the total energy of the aurora, they may provide important clues to the more energetic processes, analogous to the way in which solar radio emissions are used to infer the processes taking place in the solar corona. Using LF/MF/HF receivers, we hope to collect further clues about these emissions from antarctic auroral zone and polar cap sites, taking advantage of radio-quiet antarctic conditions. The receivers will be installed at Amundsen-Scott South Pole Station, in three U.S. automatic geophysical observatories, and in two British automatic geophysical observatories.(S-128)
Spectroscopic and interferometric studies of middle atmosphere dynamics and particle precipitation patterns over the South Pole. Gulamabas Sivjee, Embry-Riddle Aeronautical University. An infrared spectrophotometer, an eight-channel photon-counting photometer, and an infrared Michelson interferometer are maintained by this project at the South Pole to study the dynamics and chemistry of the upper atmosphere. By measuring the variations in the brightness and temperature of airglow band emissions, researchers can detect planetary, gravity, and tidal waves. Studying the horizontal wave structures by looking in several directions while making these measurements at several wavelengths, which come from different heights in the atmosphere, provides information on the vertical extent of the wave activity. Additionally, viewing the different altitude auroral emissions with the spectrophotometer provides insight into the nature of the sources of the auroral precipitating electrons and how these different sources vary as a function of time. (S-129)
The antarctic muon and neutrino detector array (AMANDA) project: The antarctic ice sheet as a high-energy detector. Robert M. Morse, University of Wisconsin at Madison. The primary objective of AMANDA is to discover sources of very-high-energy neutrinos from galactic and extragalactic sources. These neutrinos could be of diffuse origin coming from the contributions of many active galactic nuclei or point sources coming from super-nova remnants, rapidly rotating pulsars, neutron stars, and individual blazars or other extragalactic point sources. AMANDA consists of photomultiplier tubes imbedded at depths between 1 and 2 kilometers in glacial ice near the South Pole. This array uses natural ice as a Cherenkov detector for high-energy neutrinos of astrophysical origin that have passed through Earth. Recently, new sources of high-energy gamma rays have been discovered, such as the source Mrk-421 discovered by the CGRO and the Mount Hopkins Observatory. These sources, also believed to be copious emitters of high-energy neutrinos, are the type of objects that AMANDA has been designed to study.
To date, neutrino astronomy has been limited to the detection of solar neutrinos and one brief burst from the supernova that appeared in the Large Magellanic cloud in February 1987 (SN-1987a). Only now is building large neutrino telescopes becoming technically feasible, and as one of the first generation detectors, AMANDA promises to be a large contributor to this new branch of neutrino astronomy. The AMANDA project includes plans to install seven additional detector strings to complement the four strings that are already in place at depths of 1,500ñ1,900 meters. These strings, installed during the 1996ñ1997 season, will be positioned at a depth of 2,000 meters in the ice, and will each contain 36 photomultiplier tubes modules. The 2-kilometer-deep holes in the ice will be drilled by the Polar Ice Coring Office. (S-130)
Center for Astrophysical Research in Antarctica. Doyal A. Harper, University of Chicago. Infrared and submillimeter astronomy has the potential for answering major questions about the formation of the Universe:
Because of the cold temperatures and the near absence of water vapor in the atmosphere above the polar plateau, the infrared skies are consistently clearer and darker in Antarctica than anywhere else on Earth. These conditions enable researchers to make measurements that would be extremely difficult or impossible from other sites. To capitalize on these advantages, the University of Chicago and several collaborating institutions have established the Center for Astrophysical Research in Antarctica (CARA), which is one of 24 Science and Technology Centers funded by the National Science Foundation. To support its scientific mission, CARA is working to establish an observatory at the South Pole and to investigate the conditions for astronomy at the South Pole and other sites on the polar plateau. Currently, CARA supports research using three major telescope facilities.
The Astronomical Submillimeter Telescope/ Remote Observatory (AST/RO) project uses a 1.7-meter-diameter telescope to conduct surveys of atomic and molecular line emission from interstellar gas in the galactic plane, the galactic center, and the Magellanic Clouds.
The South Pole Infrared Explorer (SPIREX) project uses a 0.6-meter-diameter telescope to investigate the potential of the site for near-infrared astronomy and to conduct observations of distant galaxies, cool stars, and heavily obscured star-forming regions.
The Cosmic Background Radiation Anisotropy (COBRA) project uses a 0.75-meter-diameter telescope (Python) to map the anisotropy in cosmic microwave background radiation at sufficient sensitivity to test current theories of the origin of the Universe.
In addition to projects using these three telescopes, the Center has undertaken the Advanced Telescopes Project to collect data on the quality of polar plateau sites for astronomical observations and to plan for future telescopes and facilities.
Projects included as part of CARA are
Besides making measurements of "seeing" quality using the SPIREX telescope, the Advanced Telescopes Project also supports a number of other efforts including wide-field cameras, a near-infrared sky brightness monitor (in collaboration with the University of New South Wales), and an instrument for monitoring mid-infrared sky brightness and transmission (in collaboration with the National Aeronautic and Space Administration's Goddard Space Flight Center). (S-132)
Cosmology from Dome C in Antarctica. Lucio Piccirillo, Bartol Research Institute, University of Delaware. The thermal cosmic microwave background radiation (CMBR), left over from the Big Bang, carries the only available information about the distribution of matter in the very early universe. Generally, scientists believe that galaxies and other structures arose from the gravitational amplification of tiny density fluctuations. Detecting high energy cosmic neutrinos represents a unique opportunity to probe the distant universe. While the trajectories of protons, because they are charged particles, are likely to bend in galactic and intergalactic magnetic fields, neutrinos point directly back to their source. Using an array of radio receivers buried in the ice at the South Pole, we hope to detect high energy cosmic neutrinos in order to measure the cosmic neutrino flux at high energies and to determine sources of such a flux. During our first field season we will deploy a small number of dipole receivers and transmitters to measure ice properties and develop the technology needed for the efforts to follow. When completed our array will be complementary to the Antarctic Muon and Neutrino Detector Array (AMANDA). Both use antarctic ice to reconstruct the incident direction and energy of a cosmic neutrino, but AMANDA relies on phototube technology to probe the optical frequency range while our array will be tuned to radio frequencies. (S-140)
Long-duration ballooningLaunch and telemetry support. Steven Peterzen, National Scientific Balloon Facility. Wholly funded by the National Aeronautic and Space Administration, the National Scientific Balloon Facility (NSBF) is operated under contract by New Mexico States' Physical Science Laboratory. The effort in Antarctica, known as the Long-Duration Balloon Program, launches high-altitude balloons carrying scientific payloads into the stratosphere. These large helium-filled balloons (804,199 cubic meters) circumnavigate the continent between 3 and 4 millibars for up to 24 days. For each circumpolar flight, NSBF performs the launch operations, designs and manages the telemetry links, and then terminates and recovers the flight system. (S-145)
Infrared measurements in the Antarctic. Frank J. Murcray, Ronald Blatherwick, and Aaron Goldman, University of Denver. For this project, we will use an infrared (IR) interferometer to monitor selected trace constituents in the atmosphere above AmundsenScott South Pole and McMurdo Stations. The measurements will be made in two modes: absorption and emission. The absorption mode uses the Sun, shining through the atmosphere, as an infrared source of IR radiation and allows us to measure a number of trace constituents, especially during the local springtime when the antarctic ozone hole is forming. The emission mode, using radiation emitted by the atmospheric gases themselves, is less sensitive than the absorption mode but does allow critical measurements during the long, dark polar night, when the chemistry that sets the stage for the springtime ozone depletion is taking place. The compounds we will measure include hydrogen chloride, nitric acid, chlorofluorocarbon-11 and -12, nitrous oxide, methane, ozone, and chlorine nitrate. Each of these gases plays a role in ozone depletion, and several are also important greenhouse gases. This project is a precursor to the establishment of an antarctic Network for the Detection of Stratospheric Change (NDSC) station. When the NDSC station is established (presumably at Dome C), we will extend our project to this site and begin making similar measurements there. This project is jointly funded by the National Science Foundation's Office of Polar Programs and Division of Atmospheric Sciences and also by the National Aeronautic and Space Administration's Office of Earth Sciences and Applications. (S-148)