This project consists of two experiments. The first will investigate temporal development in the neutral composition in the E-region in response to auroral heating. The PI will make quantitative measurements at two sites: the first, located in the polar cap at Sondre Stromfjord, will represent an upstream site in the antisunward neutral flow in the midnight to dawn sector associated with southward IMF; the second, located equatorward of the first, represents the downstream site. This experiment simultaneously measures spatial characteristics of compositional changes and aurorally-induced Joule and particle heating inputs into the E-region. Observations of both will allow the investigation of the role of local versus transport processes which govern depletions of atomic oxygen. The second experiment will determine if atmospheric gravity waves cause noctilucent cloud particles to sublimate. The study will use data from a Rayleigh lidar and a Michelson interferometer, currently located at Sondre Stromfjord and from a newly developed UV spectrograph. The PI will measure characteristics of NLC cloud particles and AGWs during a maximum solar depression angle between 6 and 8 degrees below the horizon.
