Atmospheric remote sensing using global navigation satellite systems: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

Chu, Chung-Huei; Huang, C. Y.; Fong, Chen-Joe; Chen, Shu-Ya; Chen, Yi-Hsiu; Yeh, Wen-Hao; Kuo, Ying-Hwa

doi:10.3319/tao.2021.11.15.02

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…Following the success of the F3/C program, NSPO and the National Oceanic and Atmospheric Administration (NOAA) of the US launched FORMOSAT-7/COSMIC-2 (F7/C2) satellites on June 25, 2019 (Chu et al 2021). F7/ C2 constellation consists of six small satellites at an altitude of 550 km, with an inclination angle of 24 degrees, and orbiting period of about 97 min.…”

Section: Introductionmentioning

confidence: 99%

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Liu

Lin

et al. 2022

TAO

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FORMOSAT-3/COSMIC (F3/C) constellation of six micro-satellites was launched into the circular low-earth orbit at 800 km altitude with a 72-degree inclination angle on 15 April 2006, uniformly monitoring the ionosphere by the GPS (Global Positioning System) Radio Occultation (RO). Each F3/C satellite is equipped with a TIP (Tiny Ionospheric Photometer) observing 135.6 nm emissions and a TBB (Tri-Band Beacon) for conducting ionospheric tomography. More than 2000 RO profiles per day for the first time allows us globally studying three-dimensional ionospheric electron density structures and formation mechanisms of the equatorial ionization anomaly, middle-latitude trough, Weddell/Okhotsk Sea anomaly, etc. In addition, several new findings, such as plasma caves, plasma depletion bays, etc., have been reported. F3/C electron density profiles together with ground-based GPS total electron contents can be used to monitor, nowcast, and forecast ionospheric space weather. The S4 index of GPS signal scintillations recorded by F3/C is useful for ionospheric irregularities monitoring as well as for positioning, navigation, and communication applications. F3/C was officially decommissioned on 1 May 2020 and replaced by FORMOSAT-7/COSMIC-2 (F7/C2). F7/C2 constellation of six small satellites was launched into the circular low-Earth orbit at 550 km altitude with a 24-degree inclination angle on 25 June 2019. F7/C2 carries an advanced TGRS (Tri Gnss (global navigation satellite system) Radio occultation System) instrument, which tracks more than 4000 RO profiles per day. Each F7/C2 satellite also has a RFB (Radio Reference Beacon) on board for ionospheric tomography and an IVM (Ion Velocity Meter) for measuring ion temperature, velocity, and density. F7/C2 TGRS, IVM, and RFB shall continue to expand the F3/C success in the ionospheric space weather forecasting.

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Section: Introductionmentioning

confidence: 99%

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Liu

Lin

et al. 2022

TAO

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“…Both receive the level 0 downlink data and perform processing to level 1 and 2 products in near real-time (NRT) with the COSMIC Data Analysis and Archive Center (CDAAC) software framework [17]. The CWB additionally runs the TROPS system [18]. The DPCs are configured and maintained to provide automated processing with high availability.…”

Section: Data Processing Centersmentioning

confidence: 99%

COSMIC-2 Mission Summary at Three Years in Orbit

et al. 2022

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We summarize the status of the FORMOSAT-7/COSMIC-2 (COSMIC-2) mission which has completed its first three years in orbit. COSMIC-2 is a joint U.S./Taiwan program consisting of six satellites in low-inclination orbits with the following payloads: Global Navigation Satellite System radio occultation, in-situ ion velocity meter, and tri-band radio frequency beacon. The constellation is in its final orbit configuration and reached mission full operating capability in September 2021. An extensive calibration/validation campaign has to date enabled the release of all baseline neutral atmosphere products and nearly all baseline ionosphere products. The mission is providing usually more than 5000 neutral atmosphere RO profiles per day with a precision better than 2 μrad from 30–60 km altitude. Each day, nearly 12,000 combined total electron content occultations and arcs are generated with absolute accuracy of better than 3 TECU. IVM density precision is at or below the 1% requirement. Neutral atmosphere and ionosphere latency, measured from time of observation to product creation time, is below 30 min median. Data products are delivered in near real-time to operational weather and space weather centers and made available openly to the research community. New ionosphere products specifying the presence and absence of scintillation are under development and planned for future release.

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“…After such dedicated service lasting about 14 years, far exceeding the expected mission lifetime, which saw more than 4.6 million RO profiles, the F3/C mission was officially decommissioned in May 2020. A follow-up mission named FORMOSAT-7/COSMIC-2 (F7/C2) has already been launched on 25 June 2019, which also consists of a cluster of six satellites identical to that of the F3/C, circumnavigating the Earth with a period of about 97 min from low-inclination (24 • ) orbits at an altitude of ~550 km [63]. The Tri-GNSS radio occultation system (TGRS), the main mission payload of F7/C2, receives the refracted signals from GNSS (global navigation satellite system) satellites, including GPS, GLONASS, and Galileo systems, providing many more soundings than its predecessor.…”

Section: Introductionmentioning

confidence: 99%

Advances in Ionospheric Space Weather by Using FORMOSAT-7/COSMIC-2 GNSS Radio Occultations

et al. 2022

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This paper provides an overview of the contributions of the space-based global navigation satellite system (GNSS) radio occultation (RO) measurements from the FORMOSAT-7/COSMIC2 (F7/C2) mission in advancing our understanding of ionospheric plasma physics in the purview of space weather. The global positioning system (GPS) occultation experiment (GOX) onboard FORMOSAT-3/COSMIC (F3/C), with more than four and half million ionospheric RO soundings during April 2006–May 2020, offered a unique three-dimensional (3D) perspective to examine the global electron density distribution and unravel the underlying physical processes. The current F7/C2 carries TGRS (Tri-GNSS radio occultation system) has tracked more than 4000 RO profiles within ±35° latitudes per day since 25 June 2019. Taking advantage of the larger number of low-latitude soundings, the F7/C2 TGRS observations were used here to examine the 3D electron density structures and electrodynamics of the equatorial ionization anomaly, plasma depletion bays, and four-peaked patterns, as well as the S4 index of GNSS signal scintillations in the equatorial and low-latitude ionosphere, which have been previously investigated by using F3/C measurements. The results demonstrated that the denser low-latitude soundings enable the construction of monthly global electron density maps as well the altitude-latitude profiles with higher spatial and temporal resolution windows, and revealed longitudinal and seasonal characteristics in greater detail. The enhanced F7/C2 RO observations were further applied by the Central Weather Bureau/Space Weather Operation Office (CWB/SWOO) in Taiwan and the National Oceanic and Atmospheric Administration/Space Weather Prediction Center (NOAA/SWPC) in the United States to specify the ionospheric conditions for issuing alerts and warnings for positioning, navigation, and communication customers. A brief description of the two models is also provided.

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Atmospheric remote sensing using global navigation satellite systems: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

Abstract: FORMOSAT-3/COSMIC global atmospheric and ionospheric investigation. (2) The rise Of FORMOSAT-7/COSMIC-2 Operational Mission. (3) First results from FORMOSAT-7/COSMIC-2.

Cited by 7 publications

References 18 publications

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

COSMIC-2 Mission Summary at Three Years in Orbit

Advances in Ionospheric Space Weather by Using FORMOSAT-7/COSMIC-2 GNSS Radio Occultations

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