Preprints
https://doi.org/10.5194/amt-2024-80
https://doi.org/10.5194/amt-2024-80
11 Jun 2024
 | 11 Jun 2024
Status: this preprint is currently under review for the journal AMT.

Observed impact of the GNSS clock data rate on Radio Occultation bending angles for Sentinel-6A and COSMIC-2

Sebastiano Padovan, Axel Von Engeln, Saverio Paolella, Yago Andres, Chad R. Galley, Riccardo Notarpietro, Veronica Rivas Boscán, Francisco Sancho, Francisco Martin Alemany, Nicolas Morew, and Christian Marquardt

Abstract. Space-based Radio Occultation (RO) experiments currently require the tracking of signals from the Global Navigation Satellite System (GNSS) by a Low-Earth-Orbit (LEO) satellite as the signals travel through different layers of the atmosphere. The orbit and clock solutions for the GNSS constellations affect these experiments in two ways: They are needed to obtain a zero-differencing GNSS-based orbit and clock solution for the LEO, and they enter directly the processing of each single radio occultation profile, where the orbit and clock information for the transmitter (GNSS satellite) and receiver (LEO) is required. In this work, we investigate how different GLONASS and GPS orbit and clock solutions affect the statistical properties of RO profiles by comparing our results with forward-modelled bending angle profiles obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) short-range forecasts. Given that GNSS orbits are relatively smooth, the focus will be on the effect of different transmitter clock data rates, and we tested the range from 1 to 30 seconds. The analysis is based on the reprocessing of Sentinel-6A data (four months in 2021, or about 110k occultations) and of a smaller sample of recent COSMIC-2/FORMOSAT-7 data (about 9k occultations). We find that at impacts heights above about 35 km GLONASS bending angles statistics markedly improve with the use of high-rate clock information. For GPS, not much is gained by using rates higher than 30 s, and the statistics are better for more recent GPS blocks. These results are likely the manifestation of the different short-timescale behaviour of the atomic clocks onboard the GPS and GLONASS constellations.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Sebastiano Padovan, Axel Von Engeln, Saverio Paolella, Yago Andres, Chad R. Galley, Riccardo Notarpietro, Veronica Rivas Boscán, Francisco Sancho, Francisco Martin Alemany, Nicolas Morew, and Christian Marquardt

Status: open (until 16 Jul 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Sebastiano Padovan, Axel Von Engeln, Saverio Paolella, Yago Andres, Chad R. Galley, Riccardo Notarpietro, Veronica Rivas Boscán, Francisco Sancho, Francisco Martin Alemany, Nicolas Morew, and Christian Marquardt
Sebastiano Padovan, Axel Von Engeln, Saverio Paolella, Yago Andres, Chad R. Galley, Riccardo Notarpietro, Veronica Rivas Boscán, Francisco Sancho, Francisco Martin Alemany, Nicolas Morew, and Christian Marquardt

Viewed

Total article views: 85 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
68 11 6 85 5 5
  • HTML: 68
  • PDF: 11
  • XML: 6
  • Total: 85
  • BibTeX: 5
  • EndNote: 5
Views and downloads (calculated since 11 Jun 2024)
Cumulative views and downloads (calculated since 11 Jun 2024)

Viewed (geographical distribution)

Total article views: 83 (including HTML, PDF, and XML) Thereof 83 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 24 Jun 2024
Download
Short summary
Radio Occultation (RO) measurements are an important contribution to numerical weather predictions and long-term climate studies. Using more than a hundred thousand occultations recorded by instruments onboard the Sentinel-6A and Cosmic-2 satellites, this work studies the effects of the clock data rate of the Global Navigation Satellite System on the RO data quality. GLONASS occultations benefit of high-rate clock data (1 second), GPS occultation have high quality already at 30 seconds.