The SPARC Reanalysis Intercomparison Project (S-RIP) Phase 2 (ACP/WCD inter-journal SI)(ACP/WCD inter-journal SI)
The SPARC Reanalysis Intercomparison Project (S-RIP) Phase 2 (ACP/WCD inter-journal SI)(ACP/WCD inter-journal SI)
Editor(s): ACP co-editors | Coordinators: Gabriele Stiller and Peter Haynes | Co-organizers: Gloria Manney, Jonathon Wright, and Masatomo Fujiwara Special issue jointly organized between Atmospheric Chemistry and Physics and Weather and Climate Dynamics

The climate research community uses reanalyses widely to understand atmospheric processes and variability in the middle atmosphere, yet different reanalyses give very different results for the same diagnostics. For example, the global energy budget and hydrological cycle, the Brewer–Dobson circulation, stratospheric vortex weakening and intensification events, and large-scale wave activity at the tropical tropopause are known to differ among reanalyses.

The Stratosphere–troposphere Processes And their Role in Climate (SPARC) Reanalysis Intercomparison Project (S-RIP) began in 2013 as a coordinated activity to compare numerous key diagnostics in reanalysis data sets. The objectives of this project were

  • to understand the causes of differences among reanalyses,
  • to provide guidance on the appropriate usage of various reanalysis products in scientific studies,
  • to contribute to future improvements in the reanalysis products by establishing collaborative links between the reanalysis centres and the SPARC community.

Phase 1 of the S-RIP project culminated with the publication of the S-RIP report ( in January 2022 and a very successful special issue ( in ACP and ESSD with over 50 papers. Phase 1 was very successful in achieving the above objectives, and in doing so it taught us the value and importance of continuing reanalysis intercomparisons and communications between the reanalysis centres and the SPARC community. The above objectives thus remain the primary aims of S-RIP as the project moves into Phase 2.

This special issue was initiated in the early stages of S-RIP Phase 2. The community continues to produce valuable papers including both updates using new reanalyses of diagnostics studied in Phase 1 and evaluation of diagnostics for processes and atmospheric regions that were not emphasized in Phase 1. This special issue comprises papers both during this transitional period and in the following years of Phase 2 and both updates of work on processes studied in Phase 1 and new studies focused on additional processes and/or atmospheric regions.

The S-RIP project focuses primarily on differences among reanalyses, but studies that include operational analyses and studies comparing reanalyses with observations or model outputs are encouraged. Phase 1 of S-RIP emphasized diagnostics in the upper troposphere, stratosphere, and mesosphere. This special issue will collect research relevant to S-RIP, including broadening of the scope to, for example, evaluation of new reanalyses and of chemical reanalyses; more comprehensive evaluation of processes in the upper stratosphere and mesosphere; evaluation of tropospheric processes such as blocking, jet stream variations, and temperature anomalies; and more comprehensive evaluation of links between the stratospheric, upper tropospheric, and near-surface circulation and implications for extreme weather events.

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10 Jul 2024
Climatology of the terms and variables of transformed Eulerian-mean (TEM) equations from multiple reanalyses: MERRA-2, JRA-55, ERA-Interim, and CFSR
Masatomo Fujiwara, Patrick Martineau, Jonathon S. Wright, Marta Abalos, Petr Šácha, Yoshio Kawatani, Sean M. Davis, Thomas Birner, and Beatriz M. Monge-Sanz
Atmos. Chem. Phys., 24, 7873–7898,,, 2024
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31 May 2024
Intercomparison of aerosol optical depths from four reanalyses and their multi-reanalysis consensus
Peng Xian, Jeffrey S. Reid, Melanie Ades, Angela Benedetti, Peter R. Colarco, Arlindo da Silva, Tom F. Eck, Johannes Flemming, Edward J. Hyer, Zak Kipling, Samuel Rémy, Tsuyoshi Thomas Sekiyama, Taichu Tanaka, Keiya Yumimoto, and Jianglong Zhang
Atmos. Chem. Phys., 24, 6385–6411,,, 2024
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23 Feb 2024
Variability and trends in the PV-gradient dynamical tropopause
Katharina Turhal, Felix Plöger, Jan Clemens, Thomas Birner, Franziska Weyland, Paul Konopka, and Peter Hoor
EGUsphere,,, 2024
Preprint under review for ACP (discussion: final response, 4 comments)
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18 Jan 2024
A multi-scenario Lagrangian trajectory analysis to identify source regions of the Asian tropopause aerosol layer on the Indian subcontinent in August 2016
Jan Clemens, Bärbel Vogel, Lars Hoffmann, Sabine Griessbach, Nicole Thomas, Suvarna Fadnavis, Rolf Müller, Thomas Peter, and Felix Ploeger
Atmos. Chem. Phys., 24, 763–787,,, 2024
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11 Jan 2024
Evaluation of vertical transport in ERA5 and ERA-Interim reanalysis using high-altitude aircraft measurements in the Asian summer monsoon 2017
Bärbel Vogel, C. Michael Volk, Johannes Wintel, Valentin Lauther, Jan Clemens, Jens-Uwe Grooß, Gebhard Günther, Lars Hoffmann, Johannes C. Laube, Rolf Müller, Felix Ploeger, and Fred Stroh
Atmos. Chem. Phys., 24, 317–343,,, 2024
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10 Jan 2024
Seasonally dependent increases in subweekly temperature variability over Southern Hemisphere landmasses detected in multiple reanalyses
Patrick Martineau, Swadhin K. Behera, Masami Nonaka, Hisashi Nakamura, and Yu Kosaka
Weather Clim. Dynam., 5, 1–15,,, 2024
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