Reanalysis data sets are widely used to understand many atmospheric processes. Different reanalysis data sets can give very different results for the same diagnostics. S-RIP (https://s-rip.github.io/) is a coordinated activity aimed at comparing key diagnostics between available reanalyses, identifying differences between reanalyses and their underlying causes, providing guidance on the appropriate use of reanalyses in scientific studies, and contributing to future improvements in reanalysis products through collaborations with reanalysis centers and data users. Phase 1 of S-RIP (completed in early 2022; SPARC Report No. 10) focused primarily on the upper troposphere through the middle atmosphere and the processes linking these regions to the troposphere and surface. We look forward to expanding our efforts in phase 2 (S-RIP2), with new foci including studies of tropospheric circulation, extreme weather events and their links to the stratosphere, and focusing on the evaluation of chemical reanalyses, both those focused on the stratosphere and upper troposphere and those focusing on air quality applications. Finally, we would like to extend and enhance climate model(CCMI, CMIP)-reanalysis intercomparison activities.

We welcome abstracts assessing new and forthcoming reanalyses (e.g. ERA5, JRA-3Q), including studies of monsoon circulations (e.g., the Asian summer,African, and North American monsoons) analyses of upper troposphere/lower stratosphere composition, the Brewer Dobson Circulation, and in-depth comparisons of the upper stratosphere and mesosphere including new high-top reanalysis datasets. We particularly welcome new studies assessing tropospheric circulation (e.g., blocking, Rossby wave breaking, jets and storm tracks) and their links to stratospheric influences and extreme weather events; and evaluation of existing and plans for future composition reanalysis data sets (e.g. BRAM-2/3, TCR-2/3, M2-SCREAM), both those focusing on upper tropospheric and stratospheric processes and those focusing on air quality applications. Finally, we invite anyone interested in any aspect of planning or participating in S-RIP2 to get in touch and get involved.