SPARC Reanalysis Intercomparison Project

S-RIP Report

SPARC (2022), SPARC Reanalysis Intercomparison Project (S-RIP) Final Report ,edited by Masatomo Fujiwara, Gloria L. Manney, Lesley J. Gray, and Jonathon S. Wright, SPARC Report No. 10, WCRP-6/2021, doi: 10.17874/800dee57d13, available at

(Chapter "2E" (an extended version) is available here.)

The SPARC Reanalysis Intercomparison Project (S-RIP) is a coordinated activity to compare all (or some of the newer) reanalysis data sets for various key diagnostics, to understand the causes of differences among reanalyses, to provide guidance on the appropriate usage of various reanalysis products in scientific studies, and to connect such activities with future improvements in the reanalysis products by establishing collaborative links between the reanalysis centres and the SPARC community.

S-RIP focuses on reanalysis output in the stratosphere, upper troposphere and lower mesosphere. This activity is closely connected with the SPARC Data Assimilation activity and several other SPARC activities (see also SPARC's current activities).

The S-RIP report is structured with two introductory chapters (introduction and reanalysis system descriptions; Chapters 1–2 as listed in the report structure) and two overview chapters summarizing the underlying structure, climatology, and interannual variability of the reanalysis systems (Chapters 3–4). These are followed by seven, more process-oriented or region-specific chapters detailing the performance of each reanalysis with respect to key aspects of the atmospheric structure and circulation (the Brewer–Dobson circulation, extratropical stratosphere–troposphere coupling, the extratropical UTLS, Tropical Tropopause Layer, the quasi-biennial oscillation, polar processes, and USLM), with particular focus on commonly used metrics (Chapters 5–11). The report concludes with a synthesis summary (Chapter 12).

We have encouraged the contributors to use the S-RIP colour definition for each reanalysis data set (see also here & Chapter 1, Appendix A) to enhance the readability of the whole report. Contact Masatomo Fujiwara for more information.

A brief history of S-RIP: The idea for the S-RIP was first discussed in June 2011 at the 8th SPARC Data Assimilation workshop in Brussels, Belgium, and was officially endorsed as an emerging activity by the SPARC Scientific Steering Group in February 2012. The S-RIP working group was formed with 11 members in July 2012. This working group discussed prospective chapter titles, co-leads, and contributors to the report. A kickoff planning meeting was held with 39 participants at the Met Office in Exeter, UK from 29 April to 1 May 2013. The S-RIP was endorsed as a full SPARC activity in January 2014. The 2014 workshop was held at NOAA in Maryland, USA from 10 to 12 September 2014. The 2015 workshop was held at Université Pierre-et-Marie-Curie in Paris, France from 12 to 14 October 2015. The 2016 workshop was held in Victoria, Canada from 19 to 21 October 2016. The 2017 workshop was held at ECMWF, Reading, UK from 23 to 25 October 2017. The S-RIP 2018 Chapter-lead Meeting was held at NWRA, Boulder, USA from 25-29 June 2018. See past events page for more details.