Automatic geophysical observatories
Automatic geophysical observatories Studying the polar ionosphere and magnetosphere with automatic geophysical observatories: The U.S. program in Antarctica T.J. ROSENBERG, Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2431 J.H. DOOLITTLE, Lockheed Palo Alto Research Laboratory, Palo Alto, California 94304
the polar cap and the response of the atmosphere to the many forms of high-latitude wave and particle-energy inputs. The approach to this problem by countries operating in the Antarctic has been to install radar facilities at several coastal stations (Halley, soon to be followed by Syowa and Sanae) that provide large and overlapping fields of view of the polar cap ionosphere, coupled with the deployment of a network of spaced observatories beneath this canopy. The practical limitations of supporting additional manned observing stations at very high geomagnetic latitudes led to the development of unmanned automatic geophysical observatories (AGOs). The U.S. AGO program is complemented at lower geomagnetic latitudes by AGOs operated by the United Kingdom and Japan. The AGOs (see back cover) provide power and data acquisition as a host to the instruments in a room temperature she!ter. They are powered by propane-fueled thermoelectric generators that use no moving parts and can run for a full year between serosEATh vicing. The AGOs were designed, built, and installed at the field sites by Lockheed Palo Alto Research Laboratory. LOBE REGION The AGO science program is PLASMASPHERE called the polar experiment network for geophysical upperatmosphere investigations (PENGUIN) and is the product of a SOLAR team of U.S. and Japanese investiWIND -gators with long experience in successfully conducting ionospheric and magnetospheric research in \\PIA.MAPAUSE PLASMA SHEET Antarctica. The network, when BOUNDARY LAYER completed, will consist of a suite POLAR CUSP of instruments (optical and radiowave auroral imagers, magnetometers, and narrow- and MAGNETOPAUSE MAGNETOPAIJSE BOUNDARY LAYER wide-band radio receivers) placed BOW SHOCK at six AGO locations on the polar plateau. The instruments, their Figure 1. Regions of geospace.
he vast antarctic plateau, comprising much of East TAntarctica, is situated at very high geomagnetic latitudes. In fact, the geomagnetic polar cap above 800 lies entirely on the continent. By contrast, the region above 80° magnetic latitude in the Northern Hemisphere lies mainly in the Arctic Ocean. Consequently, it is practical only in Antarctica to set up multiple, spaced ground-based facilities to provide nearglobal coverage of the polar upper atmosphere at such high geomagnetic latitudes. Continued progress in understanding the Sun's influence on the structure and dynamics of the Earth's upper atmosphere will depend on knowledge of the electrodynamics of the polar cap region and the key role that this region plays in coupling the solar wind with the Earth's magnetosphere, ionosphere, and thermosphere (see figure 1 for the key regions of the geospace environment). Measurements that are critically needed include the electric field convection pattern across
ANTARCTIC JOURNAL - REVIEW 1994
347
designated AGO sites, the responsible principal investigators, and institutions are given in I Table 1. AGO science program table 1. Descriptions of experimental techniques and the identification of other collaborating scientists and institutions are contained in subsequent papers in this issue T.J. Rosenberg University of Maryland (Detrick and Lutz; Detrick and Rosenberg; Imaging riometer P1-P6 Doolittle and Mende; Fukunishi, Taguchi, and Fluxgate P1-P6 L.J. Lanzerotti AT&T Bell Laboratories Lanzerotti; man, Brown, and Yarbrough; magnetometer Rosenberg and Detrick; Shafer et al.; Weather- Search-coil P1-P6 H. Fukunishi Tohoku University wax, LaBelle, and Trimpi; Wolfe et al.; Antarc- magnetometer tic Journal, in this issue). All-sky auroral P1-P6 S.B. Mende Lockheed Research Laboratory AGOs have been deployed to sites imager labeled in figure 2 as P2 (December 1992), P1, ELFNLF radio P1-P5 U.S. man Stanford University and P4 (both January 1994). Three additional receiver AGOs have been staged at McMurdo Station LF/HF radio P1, P2, J. LaBelle Dartmouth College for deployment to sites P3, P5, and P6 to receiver P4 complete the network over the next couple of Meteorology P1-P6 J.H. Doolittle Lockheed Research Laboratory seasons. Table 2 lists the geographic and geomagnetic coordinates of the present and planned (in italics) AGO sites. For reference, the locations of British and Japanese AGOs U.S. AGO NETWORK are also shown in figure 2 and table 2. The U.S. AGO sites were chosen to form an array (P2, SP, P1, P6) along the geomagnetic meridian that includes South Pole Station and /VN ----------------.---stretches from the latitude of the polar cusp (approximately 70° geomagnetic latitude under highly disturbed conditions) to the - - - 1 I N pole of the dipole magnetic field (P6) located N. I N MA in the vicinity of Dome C. A second meridion_1163 3 al array (P3, P4, P6) is situated about 1.6 hours earlier in magnetic local time to allow comparative observations to distinguish between temporal and spatial effects in the polar cap. AGOs at sites P1, P4, and P5, I together with manned stations Casey, \ I Dumont D'Urville, and McMurdo provide a \ I longitudinally spaced array at 800 geomagA netic latitude to give coverage in the polar cap over the full 24-hour range of magnetic local time. ' The AGOs are designed to be deployed / and serviced by ski-equipped LC-130 Her/ / cules airplanes. Experience gained in 1992 at \ \ / P2 with a very rough landing surface has 600 80° 70° rccA th,'o,-.f A, TI C XT t.-..-.+.,. 1avy aIILa1LI.. Figure 2. Map of Antarctica showing the U.S. AGO network in the context of the geomagflight squadron VXE-6 for the safety of the air- netic coordinate system whose pole is located at P6 near Dome C. Two meridional arrays plane. A new logistical approach was tried in are formed: one (P2, P1, P6) includes South Pole station and the other (P3, P4, P6)is dis1993 in which an advance team was put into placed from the first by about 1.6 hours in magnetic local time. A longitudinal array at each site by a smaller Twin-Otter airplane to about 800 magnetic latitude is formed by AGOs at P1, P4, P5 and the manned stations prepare a smooth ski-way for the Hercules. Casey, Dumont D'Urville, and McMurdo. Ski-way grooming is accomplished in 3-4 speed for takeoff, and open-field aircraft operations were necdays by dragging a small snow plane behind a snowmobile. essary, despite the hazard presented by the sastrugi. A recent Although this technique worked well at P1 and P2, the colder logistics evaluation of the still higher P5 site has led VXE-6 to conditions at the higher altitude P4 site resulted in a groomed conclude that support of that site may exceed the capabilities ski-way that was too soft to allow the LC-130 to gain adequate
ANTARCTIC JOURNAL - REVIEW 1994
348
Table 2. AGO sites. (Boldface indicates future sites.) Geographic Geographic Magnetii Zite Year latitude longitude latitude P2 1992 85.670S 46.38©W 70.00°S P1 1994 83.860S 129.61°E 80.00°S P4 1994 82.010S 96.760E 80.00°S P3 1995 82.500S 30.00°E 72.500S P5 1996 75.700S 89.200E 80.00°S
18.600E 18.600E 43.100E 40.1 0°E 80.00°F
of the rest of the 1993 data, then in further comparisons as the PENGUIN network is fully established. We wish to thank members of the 1992 and 1993 AGO field crews, M.A. Anderson, E.W. Paschal, W.J. Trabucco, M.L. Trimpi, and A.T. Weatherwax. This work was supported by National Science Foundation grants OPP 89-18689 and OPP 93-17621 and contract OPP 88-14294.
References
P6 1995 74.100S 128.800E 90.00°S 0.00 Detrick, D.L., and L.F. Lutz. 1994. The 16-beam, phased-array SP 1956 90.0°S 0.00 74.200S 18.60 OE radiowave imager for studies of cosmic noise absorption Bi 1992 77.500S 23.40°W 63.690S 28.99 'F at U.S. automatic geophysical observatory sites. Antarctic B2 1995 80.750S 20.40°W 66.530S 28.53 'F Journal of the U.S., 29(5). B3 1996 81.500S 3.00°E 68.880S 35.81 'F Detrick, D.L., and T.J. Rosenberg. 1994. Initial results from B4 1997 78.00°S 3.00°E 66.570S 40.25 O E the PENGUIN imaging riometer at AGO-P2. Antarctic 11 1991 -70.0°S -39.50E -68.0°S -74.00F I Journal of the U.S., 29(5).
Doolittle, J.H., and S.B. Mende. 1994. Coordinated auroral observations at South Pole Station and AGO-P2. Antarctic Journal of the U.S., 29(5). Fukunishi, H., M. Taguchi, and L.J. Lanzerotti. 1994. Pcl-2 pulsations observed by a search-coil magnetometer at AGO-P2. Antarctic Journal of the U.S., 29(5). Inan, U.S., A.D. Brown, and J. Yarbrough. 1994. Initial results from the PENGUIN ELF/VLF receiver at AGO-P2. Antarctic Journal of the U.S., 29(5). Rosenberg, T.J., and D.L. Detrick. 1994. Coordinated auroral absorption observations at South Pole Station and AGO-P2. Antarctic Journal of the U.S., 29(5). Shafer, D.C., A.D. Brown, W.J. Trabucco, and U.S. Inan. 1994. A programmable and low-power ELF! VLF receiver for automatic geophysical observatories. Antarctic Journal of the U.S., 29(5). Weatherwax, A.T., J. LaBelle, and M.L. Trimpi. 1994. Auroral radio emissions observed at AGO-P2. Antarctic Journal of the U.S., 29(5). Weatherwax, A.T., I. LaBelle, and M.L. Trimpi. 1994. A comparison of electromagnetic noise at ground-based radio observing sites. Antarctic Journal of the U.S., 29(5). Wolfe, A.J., L.J. Lanzerotti, C.G. Maclennan, and R.L. Arnoldy. 1994. Simultaneous enhancement of Pci, Pc4, Pc5 hydromagnetic waves at AGO-P2. Antarctic Journal of the U.S., 29(5).
_J
of the airplane. Alternate sites at lower elevations are being considered for P5. Data have been returned from the first year of AGO operations at site P2. Observations were obtained by all instruments until 1 June 1993 when a fault in an optical disk drive led to a shutdown of the station. The following series of papers describe some of the initial results obtained from P2 during the interval 23-31 May 1993 selected for preliminary review. In some instances, the data are compared with simultaneous observations from South Pole Station. The 1993 data from AGO site P2 represent the first opportunity to make comparisons between observations made at South Pole Station and an adjacent location, allowing the temporal and spatial continuity or dissimilarity of polar cap phenomena to be studied. The preliminary evaluation of this first week of AGO data clearly shows the promise of a rich prospect for the coordinated investigations to follow, first through the examination
Coordinated auroral observations at South Pole Station and AGO-P2 JOHN H. DOOLITTLE and STEPHEN B. MENDE, Space Science Laboratory, Lockheed Palo Alto Research Laboratory, Palo Alto,
California 94304
Amundsen-Scott South Pole Station is located at a magnetic latitude of about 74.2 0, a location that places it inside the polar cap during magnetic nighttime (that is, when the Sun is located in the direction of the magnetic pole) where field lines map to the magnetospheric tail. During magnetic midday, South Pole Station is situated under the magnetospheric cusp where the field lines are believed to open to the interplanetary magnetic field. Rairden and Mende (1989) summarized the behavior of the cusp aurora based on 630.0-nanometer (nm) O('D2)
tarctica offers some distinct advantages for conducting Onuroral research when compared to the high latitudes in the Northern Hemisphere. The larger offset between the magnetic and geographic poles (approximately 16 0 in the Southern Hemisphere vs. approximately 10° in the Northern Hemisphere) results in the winter polar darkness extending over a larger region of high magnetic latitude. This allows the aurora to be monitored around the clock for diurnal motions and for responses to activity in the geomagnetic and interplanetary magnetic fields.
ANTARCTIC JOURNAL - REVIEW 1994 349
the polar cap and the response of the atmosphere to the many forms of high-latitude wave and particle-energy inputs. The approach to this problem by countries operating in the Antarctic has been to install radar facilities at several coastal stations (Halley, soon to be followed by Syowa and Sanae) that provide large and overlapping fields of view of the polar cap ionosphere, coupled with the deployment of a network of spaced observatories beneath this canopy. The practical limitations of supporting additional manned observing stations at very high geomagnetic latitudes led to the development of unmanned automatic geophysical observatories (AGOs). The U.S. AGO program is complemented at lower geomagnetic latitudes by AGOs operated by the United Kingdom and Japan. The AGOs (see back cover) provide power and data acquisition as a host to the instruments in a room temperature she!ter. They are powered by propane-fueled thermoelectric generators that use no moving parts and can run for a full year between serosEATh vicing. The AGOs were designed, built, and installed at the field sites by Lockheed Palo Alto Research Laboratory. LOBE REGION The AGO science program is PLASMASPHERE called the polar experiment network for geophysical upperatmosphere investigations (PENGUIN) and is the product of a SOLAR team of U.S. and Japanese investiWIND -gators with long experience in successfully conducting ionospheric and magnetospheric research in \\PIA.MAPAUSE PLASMA SHEET Antarctica. The network, when BOUNDARY LAYER completed, will consist of a suite POLAR CUSP of instruments (optical and radiowave auroral imagers, magnetometers, and narrow- and MAGNETOPAUSE MAGNETOPAIJSE BOUNDARY LAYER wide-band radio receivers) placed BOW SHOCK at six AGO locations on the polar plateau. The instruments, their Figure 1. Regions of geospace.
he vast antarctic plateau, comprising much of East TAntarctica, is situated at very high geomagnetic latitudes. In fact, the geomagnetic polar cap above 800 lies entirely on the continent. By contrast, the region above 80° magnetic latitude in the Northern Hemisphere lies mainly in the Arctic Ocean. Consequently, it is practical only in Antarctica to set up multiple, spaced ground-based facilities to provide nearglobal coverage of the polar upper atmosphere at such high geomagnetic latitudes. Continued progress in understanding the Sun's influence on the structure and dynamics of the Earth's upper atmosphere will depend on knowledge of the electrodynamics of the polar cap region and the key role that this region plays in coupling the solar wind with the Earth's magnetosphere, ionosphere, and thermosphere (see figure 1 for the key regions of the geospace environment). Measurements that are critically needed include the electric field convection pattern across
ANTARCTIC JOURNAL - REVIEW 1994
347
designated AGO sites, the responsible principal investigators, and institutions are given in I Table 1. AGO science program table 1. Descriptions of experimental techniques and the identification of other collaborating scientists and institutions are contained in subsequent papers in this issue T.J. Rosenberg University of Maryland (Detrick and Lutz; Detrick and Rosenberg; Imaging riometer P1-P6 Doolittle and Mende; Fukunishi, Taguchi, and Fluxgate P1-P6 L.J. Lanzerotti AT&T Bell Laboratories Lanzerotti; man, Brown, and Yarbrough; magnetometer Rosenberg and Detrick; Shafer et al.; Weather- Search-coil P1-P6 H. Fukunishi Tohoku University wax, LaBelle, and Trimpi; Wolfe et al.; Antarc- magnetometer tic Journal, in this issue). All-sky auroral P1-P6 S.B. Mende Lockheed Research Laboratory AGOs have been deployed to sites imager labeled in figure 2 as P2 (December 1992), P1, ELFNLF radio P1-P5 U.S. man Stanford University and P4 (both January 1994). Three additional receiver AGOs have been staged at McMurdo Station LF/HF radio P1, P2, J. LaBelle Dartmouth College for deployment to sites P3, P5, and P6 to receiver P4 complete the network over the next couple of Meteorology P1-P6 J.H. Doolittle Lockheed Research Laboratory seasons. Table 2 lists the geographic and geomagnetic coordinates of the present and planned (in italics) AGO sites. For reference, the locations of British and Japanese AGOs U.S. AGO NETWORK are also shown in figure 2 and table 2. The U.S. AGO sites were chosen to form an array (P2, SP, P1, P6) along the geomagnetic meridian that includes South Pole Station and /VN ----------------.---stretches from the latitude of the polar cusp (approximately 70° geomagnetic latitude under highly disturbed conditions) to the - - - 1 I N pole of the dipole magnetic field (P6) located N. I N MA in the vicinity of Dome C. A second meridion_1163 3 al array (P3, P4, P6) is situated about 1.6 hours earlier in magnetic local time to allow comparative observations to distinguish between temporal and spatial effects in the polar cap. AGOs at sites P1, P4, and P5, I together with manned stations Casey, \ I Dumont D'Urville, and McMurdo provide a \ I longitudinally spaced array at 800 geomagA netic latitude to give coverage in the polar cap over the full 24-hour range of magnetic local time. ' The AGOs are designed to be deployed / and serviced by ski-equipped LC-130 Her/ / cules airplanes. Experience gained in 1992 at \ \ / P2 with a very rough landing surface has 600 80° 70° rccA th,'o,-.f A, TI C XT t.-..-.+.,. 1avy aIILa1LI.. Figure 2. Map of Antarctica showing the U.S. AGO network in the context of the geomagflight squadron VXE-6 for the safety of the air- netic coordinate system whose pole is located at P6 near Dome C. Two meridional arrays plane. A new logistical approach was tried in are formed: one (P2, P1, P6) includes South Pole station and the other (P3, P4, P6)is dis1993 in which an advance team was put into placed from the first by about 1.6 hours in magnetic local time. A longitudinal array at each site by a smaller Twin-Otter airplane to about 800 magnetic latitude is formed by AGOs at P1, P4, P5 and the manned stations prepare a smooth ski-way for the Hercules. Casey, Dumont D'Urville, and McMurdo. Ski-way grooming is accomplished in 3-4 speed for takeoff, and open-field aircraft operations were necdays by dragging a small snow plane behind a snowmobile. essary, despite the hazard presented by the sastrugi. A recent Although this technique worked well at P1 and P2, the colder logistics evaluation of the still higher P5 site has led VXE-6 to conditions at the higher altitude P4 site resulted in a groomed conclude that support of that site may exceed the capabilities ski-way that was too soft to allow the LC-130 to gain adequate
ANTARCTIC JOURNAL - REVIEW 1994
348
Table 2. AGO sites. (Boldface indicates future sites.) Geographic Geographic Magnetii Zite Year latitude longitude latitude P2 1992 85.670S 46.38©W 70.00°S P1 1994 83.860S 129.61°E 80.00°S P4 1994 82.010S 96.760E 80.00°S P3 1995 82.500S 30.00°E 72.500S P5 1996 75.700S 89.200E 80.00°S
18.600E 18.600E 43.100E 40.1 0°E 80.00°F
of the rest of the 1993 data, then in further comparisons as the PENGUIN network is fully established. We wish to thank members of the 1992 and 1993 AGO field crews, M.A. Anderson, E.W. Paschal, W.J. Trabucco, M.L. Trimpi, and A.T. Weatherwax. This work was supported by National Science Foundation grants OPP 89-18689 and OPP 93-17621 and contract OPP 88-14294.
References
P6 1995 74.100S 128.800E 90.00°S 0.00 Detrick, D.L., and L.F. Lutz. 1994. The 16-beam, phased-array SP 1956 90.0°S 0.00 74.200S 18.60 OE radiowave imager for studies of cosmic noise absorption Bi 1992 77.500S 23.40°W 63.690S 28.99 'F at U.S. automatic geophysical observatory sites. Antarctic B2 1995 80.750S 20.40°W 66.530S 28.53 'F Journal of the U.S., 29(5). B3 1996 81.500S 3.00°E 68.880S 35.81 'F Detrick, D.L., and T.J. Rosenberg. 1994. Initial results from B4 1997 78.00°S 3.00°E 66.570S 40.25 O E the PENGUIN imaging riometer at AGO-P2. Antarctic 11 1991 -70.0°S -39.50E -68.0°S -74.00F I Journal of the U.S., 29(5).
Doolittle, J.H., and S.B. Mende. 1994. Coordinated auroral observations at South Pole Station and AGO-P2. Antarctic Journal of the U.S., 29(5). Fukunishi, H., M. Taguchi, and L.J. Lanzerotti. 1994. Pcl-2 pulsations observed by a search-coil magnetometer at AGO-P2. Antarctic Journal of the U.S., 29(5). Inan, U.S., A.D. Brown, and J. Yarbrough. 1994. Initial results from the PENGUIN ELF/VLF receiver at AGO-P2. Antarctic Journal of the U.S., 29(5). Rosenberg, T.J., and D.L. Detrick. 1994. Coordinated auroral absorption observations at South Pole Station and AGO-P2. Antarctic Journal of the U.S., 29(5). Shafer, D.C., A.D. Brown, W.J. Trabucco, and U.S. Inan. 1994. A programmable and low-power ELF! VLF receiver for automatic geophysical observatories. Antarctic Journal of the U.S., 29(5). Weatherwax, A.T., J. LaBelle, and M.L. Trimpi. 1994. Auroral radio emissions observed at AGO-P2. Antarctic Journal of the U.S., 29(5). Weatherwax, A.T., I. LaBelle, and M.L. Trimpi. 1994. A comparison of electromagnetic noise at ground-based radio observing sites. Antarctic Journal of the U.S., 29(5). Wolfe, A.J., L.J. Lanzerotti, C.G. Maclennan, and R.L. Arnoldy. 1994. Simultaneous enhancement of Pci, Pc4, Pc5 hydromagnetic waves at AGO-P2. Antarctic Journal of the U.S., 29(5).
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of the airplane. Alternate sites at lower elevations are being considered for P5. Data have been returned from the first year of AGO operations at site P2. Observations were obtained by all instruments until 1 June 1993 when a fault in an optical disk drive led to a shutdown of the station. The following series of papers describe some of the initial results obtained from P2 during the interval 23-31 May 1993 selected for preliminary review. In some instances, the data are compared with simultaneous observations from South Pole Station. The 1993 data from AGO site P2 represent the first opportunity to make comparisons between observations made at South Pole Station and an adjacent location, allowing the temporal and spatial continuity or dissimilarity of polar cap phenomena to be studied. The preliminary evaluation of this first week of AGO data clearly shows the promise of a rich prospect for the coordinated investigations to follow, first through the examination
Coordinated auroral observations at South Pole Station and AGO-P2 JOHN H. DOOLITTLE and STEPHEN B. MENDE, Space Science Laboratory, Lockheed Palo Alto Research Laboratory, Palo Alto,
California 94304
Amundsen-Scott South Pole Station is located at a magnetic latitude of about 74.2 0, a location that places it inside the polar cap during magnetic nighttime (that is, when the Sun is located in the direction of the magnetic pole) where field lines map to the magnetospheric tail. During magnetic midday, South Pole Station is situated under the magnetospheric cusp where the field lines are believed to open to the interplanetary magnetic field. Rairden and Mende (1989) summarized the behavior of the cusp aurora based on 630.0-nanometer (nm) O('D2)
tarctica offers some distinct advantages for conducting Onuroral research when compared to the high latitudes in the Northern Hemisphere. The larger offset between the magnetic and geographic poles (approximately 16 0 in the Southern Hemisphere vs. approximately 10° in the Northern Hemisphere) results in the winter polar darkness extending over a larger region of high magnetic latitude. This allows the aurora to be monitored around the clock for diurnal motions and for responses to activity in the geomagnetic and interplanetary magnetic fields.
ANTARCTIC JOURNAL - REVIEW 1994 349
