Thermospheric atomic oxygen concentrations from WINDII O+(2P→2D) 732 nm emission: Comparisons with the NRLMSISE-00 and C-IAM models and with GUVI observations

Abstract

Thermospheric atomic oxygen concentrations have been retrieved from observations by the Wind Imaging Interferometer (WINDII) O+(2P→2D) 732 and 733nm emissions and are compared with results obtained by the Global Ultraviolet Imager (GUVI). Although the observations compared were taken ten years apart, the periods were selected on the basis of solar activity, using the Canadian Ionosphere and Atmosphere Model (C-IAM) to bridge the time gap. Results from all of these were compared with those from the Naval Research Laboratory Mass Spectrometer and Incoherent Scatter (NRLMSISE-00) model. Comparisons were made on the basis of F10.7 solar flux, day of year, local time, season, latitude and longitude. The WINDII local time variations showed enhanced values for the Northern spring season. Latitude and longitude plots showed smooth variations for NRLMSISE-00 and large variations for both WINDII and GUVI observations; in particular a depression in atomic oxygen concentration around 40°S latitude and 100°E longitude that is tentatively identified with a longitudinal wave 1 that does not propagate in local time but has an annual variation. The averaged values showed the WINDII values to be 0.75 that of NRLMSISE-00 compared with 0.80 for GUVI. Thus the WINDII values agreed with those of GUVI to within 6%, although taken 10 years apart.