Unique Views of Scintillation and Density Structures from the CORISS GPS Sensor

After eight years in orbit the Communication/Navigation Outage Forecasting System (C/NOFS) satellite is scheduled to re-enter in the fall of 2015. During the last year of its life, the orbit often brought the satellite to altitudes below the F-peak. The C/NOFS Occultation Receiver for Ionospheric Sensing (CORISS) GPS sensor provided TEC and scintillation observations via GPS occultation for most of the C/NOFS mission. Once the C/NOFS orbit is lower than the F-peak, radio occultation observations cannot be used to probe the ionosphere. However, CORISS also tracks signals above the horizon that can provide TEC and scintillation observations. The low C/NOFS orbit provides a unique vantage point for CORISS to look up into regions of scintillation. This presentation explores scintillation as observed below the low F-region, its occurrence, intensity variations, and its distribution. We compare statistically the measurements to occulting scintillation measurements.