A 2‐Dimensional Data Detrending Technique for Equatorial Plasma Bubble Studies Using GOLD Far Ultraviolet Observations

• Published in: Journal of geophysical research. Space physics Vol. 129; no. 5
• Main Authors: Pradipta, Rezy, Huang, Chaosong, Groves, Keith M.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-05-2024
• Subjects: airglow; Data assimilation; Data collection; data detrending; Depletion; depletions; equatorial plasma bubbles; Global positioning systems; Gold; GPS; Interpolation; Latitude; numerical techniques; Plasma bubbles; Radiance; Satellite navigation systems; space situational awareness; Terrain; Total Electron Content; Valleys
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2023JA031963

We formulate a numerical data detrending technique that can be used to help reveal large‐scale equatorial plasma bubble (EPB) structures in 2‐dimensional data from the Global‐scale Observations of the Limb and Disk (GOLD) mission. This GOLD data detrending technique is inspired by and is a generalization of a previous rolling‐barrel data detrending method for 1‐dimensional total electron content (TEC) observations on individual global positioning system (GPS) satellite passes. This 2‐dimensional GOLD data detrending technique treats the observed 135.6 nm radiance as a function of longitude and latitude as an uneven terrain, where EPBs appear as deep but narrow elongated valleys. The unperturbed background radiance is inferred by rolling a ball on the 2‐dimensional terrain to skip over the EPB valleys. The two degrees‐of‐freedom possessed by the rolling ball allow it to smoothly trace the edges of EPB depletions, without falling into the deep valleys. Surface interpolation of radiance values at the ball's contact points onto the whole domain produces the baseline radiance. Subtracting the baseline from the original radiance data yields the net detrended radiance. As a result of the detrending, sharper contrast is present between EPB depletions and the ambient surroundings. As such, this new 2‐dimensional GOLD data detrending may potentially open the door to the development of other more advanced techniques for automated EPB detection and tracking, or data assimilation into low‐latitude space domain awareness (SDA) information ecosystems.
Key Points
A 2‐dimensional data detrending method based on mechanical analogy of rolling a spherical ball on rough and uneven surface is formulated
The data detrending method may be effective for revealing large‐scale equatorial plasma bubble structures in 135.6 nm GOLD observation data
Enhanced equatorial plasma bubble structures in nighttime GOLD images may be useful for development of more advanced practical applications