Global morphology of ionospheric F-layer scintillations using FS3/COSMIC GPS radio occultation data

We report on the FormoSat-3/Constellation Observing System for Meteorology, Ionosphere and Climate (FS3/COSMIC) limb-viewing observations of GPS L-band scintillations since mid-2006 and propose to study global F-layer irregularity morphology. The FS3/COSMIC has generally performed more than 1000 ionospheric radio occultation (RO) observations per day. We reprocess 1-Hz amplitude data and obtain complete limb-viewing profiles of the undersampling (sampling frequency lower than Fresnel frequency) S4 scintillation index from about 80% of the RO observations. There are a few percent of FS3/COSMIC RO observations having greater than 0.09 undersampling S4max values on average. However, seven identified areas, Central Pacific Area (−20° to 20° dip latitude, 160°E–130°W), South American Area (−20° to 20° dip latitude, 100°W–30°W), African Area (−20° to 20° dip latitude, 30°W–50°E), European Area (30°–55°N, 0°–55°E), Japan Sea Area (35°–55°N, 120°–150°E), Arctic Area (>65° dip latitude), and Antarctic Area (<−65° dip latitude), have been designated to have a much higher percentage of strong limb-viewing L-band scintillations. During the years in most of the last sunspot cycle from mid-2006 to the end 2014, the scintillation climatology, namely, its variations with each identified area, season, local time, magnetic activity, and solar activity, have been documented.