A New Technique For Remote Sensing Of O-2 Density From 140 To 180 Km

Observations of molecular oxygen are difficult to make in the Earth's atmosphere between 140 and 200 km altitude. Perhaps the most accurate measurements to date have been obtained from satellite instruments that measure solar occultations of the limb. These do provide height-resolved O-2 density measurements, but the nature of this technique is such that the temporal/spatial distribution of the measurements is uneven. Here a new space-based technique is described that utilizes two bright dayglow emissions, the (0,0) transition of the O-2 atmospheric band and the O I (630 nm), to derive the height-resolved O-2 density from 140 to 180 km. Data from the Remote Atmospheric and Ionospheric Detection System, which was placed on the International Space Station in late 2009, are used to illustrate this technique. The O-2 density results for periods in May 2010 that were geomagnetically quiet and disturbed are compared to model predictions.