This grant continues ground-based optical studies in support of CEDAR program objectives concerning upper atmosphere and ionosphere coupling and dynamics. These optical observations are made using Fabry-Perot interferometers (FPI), tilting-filter photometers and mapping filter photometers, often in conjunction with incoherent scatter radars or other optical apparatus. The research is a logical continuation of the studies carried out under the present grant at three optical observatories; the Laurel Ridge Airglow Observatory (LRAO) in Pennsylvania, the Arequipa Automated Airglow Observatory (A30) in Peru and Pitt Automated Airglow Observatory (PAAO) at Millstone Hill, Massachusetts, in operation since May 1986. The major emphasis of the work under the present grant has been the development of a capability to make simultaneous, co- located optical measurements (neutral thermosphere dynamics) and radar measurements (ionospheric plasma dynamics) on a continuing basis. The automated airglow observatory at Arequipa, Peru was our first effort in this area, and initial comparisons of the motions of the thermosphere (measured by the Jicamarca radar) indicate the transition from E-region control of the plasma drift to control by the neutral wind. The optical observations at Arequipa using the FPI and its companion tilting filter photometer will continue. Further, the observational capabilities will be improved by the addition of a sky-mapping filter photometer to determine the morphology of equatorial airglow depletions and enhancements.
