SPARC Report No. 10

SPARC Report N°10 (2021) of The SPARC S-RIP Activity: SPARC Reanalysis Intercomparison Project (S-RIP) Final Report

— Early online release —

Prepared by the SPARC S-RIP Activity, edited by Masatomo Fujiwara, Gloria L. Manney, Lesley J. Gray, and Jonathon S. Wright.

WCRP Report 6/2021

SPARC Report No. 10

DOI 10.17874/800dee57d13*

*NOTE: DOI will be valid upon final release of the report. The doi number will not change, and can be used in citation (see below).

The report, availabe below, is an early online release of the final report of the SPARC S-RIP Activity. This version has been reviewed in a blind peer-review process, and type-setting has been done to produce this early version of the report. To finalise the report, editorial work needs to be completed, which will **not change the contents** of the report.

(Full report will be available upon final release).

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

Chapter 01: Introduction (Early online release)
Lead: Masatomo Fujiwara, Gloria L. Manney, Lesley J. Gray, and Jonathon S. Wright

1.1 Motivation and goals
1.2 Scope
1.3 Outline of this report
1.4 Development of the S-RIP team
1.5 Management and Communication
1.6 Links to other projects

Chapter 02: Description of the Reanalysis Systems (Early online release)
Lead: Jonathon S. Wright, Masatomo Fujiwara, and Craig Long

2.1 Introduction
2.2 Forecast models
2.3 Assimilation Schemes
2.4 Observational Data
2.5 Execution stream
2.6 Archived data

Chapter 03: Overview of Temperature and Winds (Early online release)
Lead: Craig Long and Masatomo Fujiwara

3.1 Introduction
3.2 Improvements from older reanalyses to newer versions
3.3 Reanalysis global mean temperature anomaly variability
3.4 Reanalysis ensemble mean (REM)
3.5 Intercomparisons of the reanalyses
3.6 Amplitude of polar annual temperature cycle
3.7 Comparisons with satellite temperature observations
3.8 Comparisons against Other Observations
3.9 Effects of Volcanic Eruptions and Other Natural Variabilities
3.10 Summary and conclusions
3.11 Key Findings and Recommendations

Chapter 04: Overview of Ozone and Water Vapour (Early online release)
Lead: Sean M. Davis and Michaela I. Hegglin

4.1 Introduction
4.2 Description of ozone and water vapour in reanalyses
4.3 Data
4.4 Evaluation of reanalysis ozone products
4.5 Evaluation of reanalysis water vapour products
4.6 Summary
4.7 Key Findings and Recommendations

Chapter 05: Brewer-Dobson Circulation (Early online release)
Lead: Beatriz M. Monge-Sanz and Thomas Birner

5.1 Introduction
5.2 Diagnostics description
5.3 Offline models description
5.4 Description of tracers observations
5.5 Comparison Results
5.6 Discussion
5.7 Conclusions and Recommendations

Chapter 06: Extratropical Stratosphere–troposphere Coupling (Early online release)
Lead: Edwin P. Gerber and Patrick Martineau

6.1 Introduction
6.2 Context and Background
6.3 Reanalysis Datasets
6.4 Sudden Stratospheric Warming Events
6.5 Annular Modes
6.6 Stratospheric Final Warming Events
6.7 Modulation of Stratosphere-Troposphere Coupling by ENSO and QBO
6.8 Stratosphere-Troposphere Coupling through the Antarctic Ozone Hole
6.9 Outlook, Key Findings, and Recommendations

Chapter 07: Extratropical Upper Troposphere and Lower Stratosphere (ExUTLS) (Early online release)
Lead: Cameron R. Homeyer and Gloria L. Manney

7.1 Introduction
7.2 Reanalyses and General Approach
7.3 The Extratropical Tropopause
7.4 Jet Streams
7.5 Transport and Mixing
7.6 UTLS Ozone
7.7 Summary and Recommendations

Chapter 08: Tropical Tropopause Layer (Early online release)
Lead: Susann Tegtmeier and Kirstin Krüger

8.1 Introduction
8.2 Temperature and tropopause characteristics
8.3 Clouds and convection
8.4 Diabatic heating rates
8.5 Transport
8.6 Wave activity
8.7 Width of the TTL
8.8 South Asian Summer Monsoon
8.9 Summary, Key Findings, and Recommendations

Chapter 09: Quasi-Biennial Oscillation (Early online release)
Lead: James A. Anstey and Lesley J. Gray

9.1 Introduction
9.2 Monthly-mean equatorial variability
9.3 Tropical waves and QBO forcing
9.4 QBO teleconnections
9.5 Summary, Key Findings, and Recommendations

Chapter 10: Polar Processes (Early online release)
Lead: Michelle L. Santee, Alyn Lambert, and Gloria L. Manney

10.1 Introduction
10.2 Description of Atmospheric Measurements
10.3 Overview of Reanalysis Polar Temperature Differences.
10.4 Polar Temperature and Vortex Diagnostics
10.5 Polar Diabatic Heating Rates
10.6 Concordiasi Superpressure Balloon Comparisons
10.7 PSC Thermodynamic-Consistency Diagnostics
10.8 Chemical Modeling Diagnostics
10.9 Summary, Key Findings, and Recommendations

Chapter 11: Upper Stratosphere Lower Mesosphere (Early online release)
Lead: V. Lynn Harvey and John Knox

11.1 Introduction
11.2 Climatology of the USLM
11.3 Tropical Dynamics
11.4 Polar Dynamics
11.5 Tides and Normal Modes
11.6 Summary, Key Findings, and Recommendations

Chapter 12: Synthesis Summary (Early online release)
Lead: Masatomo Fujiwara, Gloria L. Manney, Lesley J. Gray, Jonathon S. Wright, James Anstey, Thomas Birner, Sean Davis, Edwin P. Gerber, V. Lynn Harvey, Michaela I. Hegglin, Cameron R. Homeyer, John A. Knox, Kirstin Krüger, Alyn Lambert, Craig S., Patrick Martineau, Beatriz M. Monge-Sanz, Michelle L. Santee, Susann Tegtmeier, Simon Chabrillat, David G. H. Tan, David R. Jackson, Saroja Polavarapu, Gilbert P. Compo, Rossana Dragani, Wesley Ebisuzaki, Yayoi Harada, Chiaki Kobayashi, Krzysztof Wargan, and Jeffrey S. Whitaker

12.1 Key Findings and Recommendations by Chapter
12.2 Overall Findings and Reanalysis User Recommendations
12.3 Recommendations for Improving Reanalyses and Their Evaluation
12.4 Prospects for the Future