The spaceborne observations of the ISTP/GGS satellites are complemented by ground-based observations that remotely sense the ionospheric base of the magnetosphere, thus providing ground-truth for the spacecraft measurements, and coverage of regions inacc
essible to satellites. Ground-based experiments have helped to fill the gap left by the lack of a low-altitude orbiter in ISTP/GGS. They provide the observational signature of the final link in the Sun-Earth connection chain, the flow of mass and momentum
, and energy dissipation in the Earth’s atmosphere. This capability of continuous monitoring of the flow into the terrestrial atmosphere is an essential contribution.
Four separate investigations constitute the set of ground-based instruments in the GGS program. The Sondrestrom incoherent scatter radar is located in Greenland. The Super Dual Auroral Radar Network (SuperDARN) of high-latitude HF radars has been develop
ed and operated with funding from Britain, Canada, Finland, France, Japan, South Africa, Sweden and the US.
The ISTP/GGS ground system routinely recovers well above 95% of data transmissions from the Deep Space Network.
From August 1996 through March 1997, the ISTP/GGS Ground System created 27,203 data products; 99.73% of these products were error-free and delivered on schedule.
Also included is the Canadian Auroral Network for the Origin of Plasmas in the Earth’s Neighborhood Program Unified Study (CANOPUS), comprised of magnetometers, riometers, meridian photometers and all-sky imagers. Finally, the SESAME project operated by
the British Antarctic Survey, contributes ionospheric sounder, VLF, Fabry-Perot interferometer, magnetometer and riometer measurements from its station in the Antarctic.