Polar Topside TEC Enhancement
Abstract
We address a phenomenon seen in total electron content (TEC) data above low Earth orbit altitudes in the polar region, namely polar topside TEC enhancement (PTTE), which has not been reported before. Topside TEC can be obtained by processing data collected using Global Navigation Satellite System (GNSS) receivers onboard low Earth orbit satellites. Such receivers have been developed at the Jet Propulsion Laboratory for the purpose of precise orbit determination, and have been carried by a series of Earth and Space science satellites. Examples of such missions are ocean altimetry such as TOPEX/Poseidon, Jason series, and COSMIC/FORMOSAT-3. The PTTE events seen in Jason-2 data (above 1330 km altitude) occur exclusively during daytime. Most of them are observed in the southern polar cap, and the latitude features of PTTE show TEC increases at latitudes poleward of the nominal auroral zone. The TEC enhancement can be larger than 50% and is prominent in the polar region where the ambient TEC level is low. To explore the phenomenon further, topside TEC data above 800 km altitude from the COSMIC satellites are also examined and compared to the Jason-2 measurements. The comparisons confirm that the PTTE also appears in the COSMIC upper ionospheric observations. Throughout 10 years of Jason-2 topside TEC data, we have seen many PTTE events under various geophysical and space weather conditions during quiet and storm days. The phenomenon draws our attention because the source of enhanced plasma densities above the orbit altitude in the polar cap is not clear. To assess the mechanism of PTTE, charged particle precipitation, plasma drift, and auroral boundary data from Defense Meteorology Satellite Program (DMSP) satellites are also examined accordingly for case studies. In this report we will present the characteristics of PTTE, comparisons to COSMIC and DMSP data, and our assessment of possible PTTE mechanisms.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSA43B3198P
- Keywords:
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- 0358 Thermosphere: energy deposition;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 2427 Ionosphere/atmosphere interactions;
- IONOSPHERE;
- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHERE;
- 2437 Ionospheric dynamics;
- IONOSPHERE