This collaborative research, proposed by Computational Physics, Inc. and Southwest Research Institute, will carry out modeling studies of the magnitude of and spatial variation in the upper atmosphere's 1083 airglow emission. The project will build upon the investigator's previous exploratory work in a two-year effort. The investigators will include empirical and analytic descriptions of the attenuation of photoelectron fluxes upon passage through the plasmasphere in the iterative calculation for conjugate photoelectron fluxes. They will also generate comprehensive maps (latitude vs. local time) of helium distributions and resulting 1083 nm and 388.9 nm emission intensities under a variety of geophysical conditions, both for revealing the sensitivities of the airglow emissions to various inputs and for supporting the analysis and interpretation of 1083 nm and 388.9 nm data obtained by others. In the second year, they will assess line profile features for remote sensing of thermospheric temperatures and motions. Helium is a tracer of upper thermospheric dynamics, so that measured line center displacements may offer a unique test of general circulation models of the upper thermosphere. However, since the 1083 emission peak altitude is above 400 km, observed displacements will not constitute a direct wind speed measurement, but rather will reflect the magnitude of lateral (ballistic) fluxes governed by latitudinal and longitudinal gradients in density and temperature as well as by wind patterns.
