Ground-based Platforms Research Articles

Satellite, airborne and radar observations of auroral arcs

Multipoint measurements are necessary to address many pressing problems in space physics. The combination of satellite, airborne, and ground-based platforms for in-situ and remote sensors is a powerful approach to meeting these needs. The AFGL Airborne Ionospheric Observatory (AIO) has solved problems in this manner by operating in concert with VIKING, DE-B, AE-E, POLAR BEAR, HiLat, DMSP, WIDEBAND, and other satellites, and with Sondrestromfjord, EISCAT, Millstone Hill, Arecibo, and Jicamarca incoherent scatter radars. The aircraft platform has “parked” in satellite orbital planes for up to five consecutive passes, “parked” in the dark moon auroral oval for hours tracing plasma flow through the cusp into the polar cap, and traced detailed plasma boundaries by flying “racetrack orbits” under persistent boundaries. We illustrate here some of the potential of such a combination of sensor platforms by presenting findings associated with auroral arcs, polar cap F-region stable sun-aligned arcs, theta auroras, and other auroral features.

A Versatile Radiometer for Infrared Emission Measurements Of the Atmosphere and Targets

The development of a very versatile, reliable, and sensitive radiometer has provided a tool for performing a variety of significant infrared measurements from ground-based and aircraft platforms in the .8 to 7 pm spectral region. The development techniques of the radiometer, the capabilities of the developed instrument, and some typical target and atmospheric emission measurements are presented in the paper. The instrument design incorporates various techniques to eliminate the need for cooling of the optics and structural parts which avoid the inconveniences and difficulties associated with the operation of cryogenically cooled instruments without significantly sacrificing sensitivity. The radiometer may be used in a selectable spectral wavelength and bandwidth mode, a limited spectral scanning mode, or a tuneable spectral wavelength mode. The various modes of operation are accomplished through the use of interference filters whose spectral characteristics are somewhat adjustable by properly controlling or setting their angular orientation. The simplicity of operation of the instrument has provided a means of measuring atmospheric airglow emissions and aurorally enhanced emissions in the .8 to 1.75 um region on a routine basis. Also, through the use of a reticle chopper and background suppression technique, the same radiometer has been adapted for measurements of low energy target emissions in the .8 to 7 um region.