Articles | Volume 6, issue 4
https://doi.org/10.5194/wcd-6-1683-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-6-1683-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
04 Dec 2025
Research article |
| 04 Dec 2025
| 04 Dec 2025
The potential of GNSS radio occultation data for the analysis of the tropical width: a comparison with reanalyses
Annika Reiter
Wegener Center for Climate and Global Change, University of Graz, Graz, 8010, Austria
Wegener Center for Climate and Global Change, University of Graz, Graz, 8010, Austria
Andrea K. Steiner
Wegener Center for Climate and Global Change, University of Graz, Graz, 8010, Austria
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This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Independent and long‑term stable observations are central for robust climate wind‑trend monitoring. We explore tropospheric and stratospheric wind trends over recent decades using a new global upper‑air wind record derived from radio occultation observations, together with ERA5, MERRA‑2, JRA‑3Q reanalyses and IGRA v2.2 radiosondes. Overall, the datasets show coherent zonal and meridional wind trends, including changes of the jet streams and geopotential height fields.
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Independent and long‑term stable observations are central for robust climate wind‑trend monitoring. We explore tropospheric and stratospheric wind trends over recent decades using a new global upper‑air wind record derived from radio occultation observations, together with ERA5, MERRA‑2, JRA‑3Q reanalyses and IGRA v2.2 radiosondes. Overall, the datasets show coherent zonal and meridional wind trends, including changes of the jet streams and geopotential height fields.
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This study evaluates how three reanalysis datasets represent precipitable water vapor (PWV) during more than 100 typhoons from 2020 to 2024 using multi-source observations. The fifth-generation European Centre for Medium-Range Weather Forecasts Reanalysis (ERA5) performs best, the Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) improves during typhoons, and the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) is less stable
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The tropopause, the boundary between the lower and upper atmosphere, is a sensitive marker of climate change. We studied changes in tropopause height and temperature over the past two decades using precise satellite observations. We found warming in the tropics and rising tropopause heights in many regions, especially over Asia and the Middle East. These changes reflect how both atmospheric layers are responding to climate change and highlight the need for continued satellite monitoring.
Irena Nimac, Julia Danzer, and Gottfried Kirchengast
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Due to the shortcomings of available observations, having accurate global 3D wind fields remains a challenge. A promising option is radio occultation (RO) satellite data, which enable the derivation of winds based on wind approximations. We test how well RO winds describe the ERA5 winds. We separate the total wind difference into the approximation bias and the systematic difference between the two datasets. The results show the utility of RO winds for climate monitoring and analyses.
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Major sudden stratospheric warmings (SSWs) and atmospheric blocking can markedly influence winter extratropical surface weather. To study the relationship between SSWs and blocking, we examine dynamic stratosphere–troposphere coupling using vertically highly resolved observations from global navigation satellite system radio occultation for 2007–2019. Our results provide a purely observational view of the evolution of major SSWs, their link to blocking, and their effect on the polar tropopause.
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We investigated the potential of radio occultation (RO) data for climate-oriented wind field monitoring, focusing on the equatorial band within ±5° latitude. In this region, the geostrophic balance breaks down, and the equatorial balance approximation takes over. The study encourages the use of RO wind fields for mesoscale climate monitoring for the equatorial region, showing a small improvement in the troposphere when including the meridional wind in the zonal-mean total wind speed.
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Preprint archived
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A single tropopause separates the troposphere below from the stratosphere above. In regions of strong vertical wind shear, a second tropopause layer may be associated to complex weather patterns. From GNSS radio occultation data, the distribution of multiple tropopause and its possible relation to the variability of climate indices is explored. A cluster analysis is applied to geographically associate the DT occurrences with the climate indices and a multivariate linear regression is constructed
Irena Nimac, Julia Danzer, and Gottfried Kirchengast
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-100, https://doi.org/10.5194/amt-2023-100, 2023
Revised manuscript not accepted
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As global wind measurements are limited by low spatial coverage or lack of vertical profile information, radio occultation (RO) satellite data might be of help. Wind fields are indirectly retrieved using the geostrophic approximation. We first test how well the method performs, finding agreement better than 2 m/s in wind speed. In a second step, we investigate how good RO and reanalysis data compare. The results suggest that RO-derived wind fields provide added value for climate monitoring.
Karina von Schuckmann, Audrey Minière, Flora Gues, Francisco José Cuesta-Valero, Gottfried Kirchengast, Susheel Adusumilli, Fiammetta Straneo, Michaël Ablain, Richard P. Allan, Paul M. Barker, Hugo Beltrami, Alejandro Blazquez, Tim Boyer, Lijing Cheng, John Church, Damien Desbruyeres, Han Dolman, Catia M. Domingues, Almudena García-García, Donata Giglio, John E. Gilson, Maximilian Gorfer, Leopold Haimberger, Maria Z. Hakuba, Stefan Hendricks, Shigeki Hosoda, Gregory C. Johnson, Rachel Killick, Brian King, Nicolas Kolodziejczyk, Anton Korosov, Gerhard Krinner, Mikael Kuusela, Felix W. Landerer, Moritz Langer, Thomas Lavergne, Isobel Lawrence, Yuehua Li, John Lyman, Florence Marti, Ben Marzeion, Michael Mayer, Andrew H. MacDougall, Trevor McDougall, Didier Paolo Monselesan, Jan Nitzbon, Inès Otosaka, Jian Peng, Sarah Purkey, Dean Roemmich, Kanako Sato, Katsunari Sato, Abhishek Savita, Axel Schweiger, Andrew Shepherd, Sonia I. Seneviratne, Leon Simons, Donald A. Slater, Thomas Slater, Andrea K. Steiner, Toshio Suga, Tanguy Szekely, Wim Thiery, Mary-Louise Timmermans, Inne Vanderkelen, Susan E. Wjiffels, Tonghua Wu, and Michael Zemp
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Earth's climate is out of energy balance, and this study quantifies how much heat has consequently accumulated over the past decades (ocean: 89 %, land: 6 %, cryosphere: 4 %, atmosphere: 1 %). Since 1971, this accumulated heat reached record values at an increasing pace. The Earth heat inventory provides a comprehensive view on the status and expectation of global warming, and we call for an implementation of this global climate indicator into the Paris Agreement’s Global Stocktake.
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Short summary
Observational Global navigation satellite system (GNSS) radio occultation (RO) temperature and wind data show high potential to study the tropical width. Comparisons of RO data with state-of-the-art reanalyses demonstrate their feasibility to study the tropopause break and jet stream metrics for zonal-mean and longitudinally-resolved studies. The RO data record provides observations in regions where other methods fall short, such as over oceans and in the Southern Hemisphere.
Observational Global navigation satellite system (GNSS) radio occultation (RO) temperature and...
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