Abstract's details
Assessing DORIS as an Alternative Source for Ionospheric Correction in Satellite Altimetry
Event: 2026 IDS Workshop
Session: Earth Rotation, Atmosphere, and Clock Products
Presentation type: Oral
The Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) system provides dual-frequency observations that can be used to estimate ionospheric delay in addition to its primary role in precise orbit determination (POD). In this study, DORIS observations from the Jason-3 satellite are used to derive ionospheric delays at altimetry ionospheric pierce points (IPPs) for the period 2016–2024. DORIS observations located less than 1000 km from an altimetry IPP are combined using inverse distance weighting (IDW) interpolation to estimate vertical total electron content (VTEC), providing spatial coverage for approximately 90% of the altimetry IPPs.
The DORIS-based ionospheric delays are validated by comparing it with dual-frequency altimetry measurements as reference, as well as with GNSS-based Global Ionospheric Maps (GIM). The comparison is performed using RMS differences with respect to the reference.
The results reveal distinct characteristics at different temporal scales. At the scale of individual satellite passes, DORIS-derived estimates capture more small-scale variations of VTEC, while GIM produces smoother corrections. At longer temporal scales, the performance of DORIS varies with the observation geometry: when the distance between the observation points and the nearest DORIS station is within about 1600 km, DORIS-based corrections show smaller RMS differences than GIM-based ones, whereas the latter show smaller RMS differences beyond approximately 1900 km. DORIS estimates also vary with ionospheric activity. During the relatively quiet conditions of 2018, DORIS shows smaller RMS differences in 62.17% of satellite passes, while this proportion is 33.41% during the more ionospherically active conditions of 2024.
Back to the list of abstractThe DORIS-based ionospheric delays are validated by comparing it with dual-frequency altimetry measurements as reference, as well as with GNSS-based Global Ionospheric Maps (GIM). The comparison is performed using RMS differences with respect to the reference.
The results reveal distinct characteristics at different temporal scales. At the scale of individual satellite passes, DORIS-derived estimates capture more small-scale variations of VTEC, while GIM produces smoother corrections. At longer temporal scales, the performance of DORIS varies with the observation geometry: when the distance between the observation points and the nearest DORIS station is within about 1600 km, DORIS-based corrections show smaller RMS differences than GIM-based ones, whereas the latter show smaller RMS differences beyond approximately 1900 km. DORIS estimates also vary with ionospheric activity. During the relatively quiet conditions of 2018, DORIS shows smaller RMS differences in 62.17% of satellite passes, while this proportion is 33.41% during the more ionospherically active conditions of 2024.