Advances in Low-Latitude Ionosphere Observed by FORMOSAT-7/COSMIC-2
Abstract
The Formosa Satellite 7, also named as the Constellation Observing System for Meteorology, Ionosphere, and Climate (abbreviated as FORMOSAT-7/COSMIC-2 or F7/C2 in short), is a constellation of six small satellites, designed to monitor weather and space weather. The constellation was launched into an initial circular low-Earth orbit at an altitude of 720 km and 24-deg inclination angle from the Kennedy Space Center, Florida, at 0630 UTC on 25 June 2019. The six small satellites were close to each other at the initial orbit. It will take about 16 months for the constellation to reach the mission orbit with 24-deg inclination angle at around 550 km altitude. F7/C2 is equipped with a radio occultation (RO) receiver, called TGRS, which receives the GNSS (global navigation satellite system) signal from GPS and GLONASS satellites, and is capable of observing the low-latitude ionospheric electron density three-dimensionally. A scientific payload of Ion Velocity Meter onboard F7/C2 concurrently provide the in-situ observations of ion density, temperature, and drift. Taking advantage of dense low-latitude coverage with more than 2500 soundings of the ionospheric vertical electron density profiles every day and in-situ observations, two significant structures at low-latitudes are observed. For studies of the diurnal variation during equinoxes, electron density images of the low-latitude ionosphere show a clear wave-4 (wavenumber 4, WN4) structure. The four longitudinal F-region enhancements result from a stronger equatorial plasma fountain at each longitude region produced by a stronger F-region eastward electric field. Another interesting feature is the four plasma depletion bays (PDBs) located at different longitudes. These four PDBs show clear asymmetric distributions which may be affected by the summer-to-winter neutral wind. In-situ observations of the daytime WN4 and nighttime PDBs provide an excellent opportunity to find the physical mechanisms.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSA038..04L
- Keywords:
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- 2415 Equatorial ionosphere;
- IONOSPHERE;
- 2437 Ionospheric dynamics;
- IONOSPHERE;
- 2439 Ionospheric irregularities;
- IONOSPHERE;
- 2441 Ionospheric storms;
- IONOSPHERE