Polar Topside TEC Enhancement Revealed by Jason‐2 Measurements

• Published in: Earth and space science (Hoboken, N.J.) Vol. 8; no. 3; pp. e2020EA001429 - n/a
• Main Authors: Pi, Xiaoqing, Mannucci, Anthony J., Verkhoglyadova, Olga
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.03.2021; John Wiley and Sons Inc; American Geophysical Union (AGU)
• Subjects: Altitude; Bias; Coronal Mass Ejections; coupling of the magnetosphere and ionosphere in the cusp and polar cap regions; Cusp; Data processing; Estimates; Global positioning systems; GPS; Interplanetary Physics; Ionization; Ionosphere; Magnetic Storms; Magnetic Storms and Substorms; Magnetospheric Physics; NASA's Jason‐2 Satellite Zenith‐viewing GPS TEC measurements; Natural Hazards; Polar CaP Ionosphere; Polar environments; polar topside TEC enhancement; polar wind; Receivers & amplifiers; Research Letter; Solar Physics, Astrophysics, and Astronomy; Space Weather; Statistical analysis; Storms; tongue of ionization; Topside Ionosphere; polar wind; NASA's Jason‐2 Satellite Zenith‐viewing GPS TEC measurements; polar topside TEC enhancement; tongue of ionization; coupling of the magnetosphere and ionosphere in the cusp and polar cap regions
• ISSN: 2333-5084; 2333-5084
• DOI: 10.1029/2020EA001429

Significant polar topside total electron content (topTEC) enhancement (PTTE) above 1,336 km altitude is reported for the first time. The results are based on GPS measurements during 2008–2019 from NASA's Jason‐2 satellite with zenith‐oriented antennas. The observations show increasing topTEC toward the southern polar cap at geomagnetic latitudes poleward of 65°S, where TEC values are normally very low. A case study for the 2013 St. Patrick's Day storm indicates that the enhancement can exceed 5.5 TEC units above the dayside ambient state, corresponding to 78% increase. Comparisons with COSMIC/FORMOSAT‐3 topTEC measurements above 800 km altitude confirm that PTTE events are observed from both Jason‐2 and COSMIC on the same day. Our statistical analysis of the Jason‐2 data in the southern polar region reveals that PTTE mostly occurs on the dayside, with a seasonal preference of southern summer, and preferentially during geomagnetically disturbed days but can also occur during quiet days. PTTE during storm days shows increased occurrence, magnitude, and deviation from the mean in the cusp region compared with quiet days. Our case analysis indicates that PTTE is observed simultaneously with the effect of tongue of ionization. This suggests that the during storms, dayside F region plasma moving poleward following the antisunward plasma convection may also be part of the PTTE source, and the plasma upflow driven by the polar wind may act to cause PTTE. Plain Language Summary Significant polar topside total electron content (topTEC) enhancement (PTTE) above 1,336 km altitude is reported for the first time. The results are based on GPS measurements from NASA's Jason‐2 satellite during 2008–2018. The observations show increasing topside TEC toward the southern polar cap where TEC values are normally very low. Comparisons with COSMIC/FORMOSAT‐3 topside TEC measurements confirm that PTTE events are observed from both Jason‐2 and COSMIC on the same day. Our statistical analysis reveals that PTTE mostly occurs in the southern cusp and dayside polar cap, with a seasonal preference of summer, and preferentially during geomagnetically disturbed days but can also occur during quiet days. PTTE during storm days shows increased occurrence, magnitude, and deviation from the mean in the cusp region compared with quiet days. Our case analysis indicates that PTTE is observed simultaneously with the effect of tongue of ionization. This suggests that the during storms, dayside F region plasma moving poleward following the antisunward plasma convection may also be part of the PTTE source, and the plasma upflow driven by the polar wind may act to cause PTTE. Key Points NASA's Jason‐2 satellite zenith‐viewing GPS total electron content (TEC) measurements spanning 2008–2018 are analyzed Significant increases of TEC above 1,336 km altitude in the southern polar region are reported for the first time The polar topside TEC enhancement (PTTE) appears preferentially during geomagnetic storms and during summer