First ICON-FUV Nighttime NmF2 and hmF2 Comparison to Ground and Space-Based Measurements.

Area of Science:

• Space Physics
• Atmospheric Science
• Geophysics

Background:

• The NASA-ICON mission utilizes a Far Ultra Violet (FUV) imager to study ionosphere dynamics.
• Understanding ionospheric density is crucial for various applications, including radio communication and satellite operations.

Purpose of the Study:

• To validate the ICON FUV instrument's O+ density measurements against established methods.
• To assess the FUV imager's capability in determining key ionospheric parameters like peak electron density and altitude.

Main Methods:

• Comparison of nighttime O+ density profiles from ICON FUV with electron density from COSMIC-2 (C2) and ground-based ionosondes.
• Utilized co-located, simultaneous observations from November 2019 to July 2020.
• Applied manual scaling for ionosonde data and automatic quality control for C2 data; filtered photoelectron contamination.

Main Results:

• FUV observations show consistency with C2 and ionosonde measurements, with a small average positive bias (< 1 × 10^11 e/m^3).
• For high electron density cases (NmF2 > 5 × 10^11 e/m^3), FUV estimates peak electron density with a 10% mean difference compared to C2.
• FUV-derived peak altitude is, on average, 15 km higher than C2 and 38 km higher than ionosonde values.

Conclusions:

• The ICON FUV instrument is a reliable tool for nighttime ionospheric O+ density profiling at mid and low latitudes.
• FUV data provides valuable insights into ionospheric structure, complementing existing measurement techniques.
• Further research can leverage FUV data for a more comprehensive understanding of ionospheric variability.