SPARC Reanalysis Intercomparison Project (S-RIP)

‒ Progress Report ‒Presented by: Michelle L. Santee

Jet Propulsion Laboratory, California Institute of Technology, USA

Masatomo Fujiwara1, Gloria L. Manney2, 3, Lesley J. Gray4, 5, and the S-RIP team

1Hokkaido University, Japan; 2NorthWest Research Associates, USA; 3New Mexico Institute of Mining and Technology, USA; 4University of Oxford, UK; 5NCAS, UK

25th SPARC Scientific Steering Group Meeting, 16 – 18 October 2017, Incheon, South Korea

Contents: S-RIP Progress

1. Introduction to S-RIP 2. Progress 3. Planned Discussion Items in the S-RIP Workshop next week (at

ECMWF, Reading, UK) 4. S-RIP Advanced Chapters Progress 5. Summary

1. Introduction to S-RIP

• The goals of S-RIP are: • to create a communication platform

between SPARC-related researchers and the reanalysis centers

• to better understand the differences among current reanalysis products and their underlying causes

• to provide guidance to reanalysis data users by documenting the results of this reanalysis intercomparison in peer reviewed papers and two SPARC S-RIP reports

• The interim report, under revision • The full report, in 2018/19

• … with these activities … to contribute to future reanalysis improvements

https://s-rip.ees.hokudai.ac.jp/

Reanalysis Center (Contacts for S-RIP)

Name of the Reanalysis Products

ECMWF (R. Dragani) ERA-40, ERA-Interim, (ERA-20C), (CERA-20C)

JMA (Y. Harada) JRA-25, JRA-55

NASA (K. Wargan) MERRA, MERRA-2

NOAA/NCEP (C. Long, W. Ebisuzaki)

NCEP R-1, NCEP R-2, CFSR

NOAA & Univ. Colorado (G. Compo, J. Whitaker)

(20CR)

Table: List of global atmospheric reanalyses currently available.

Notes: • ERA-20C, CERA-20, and 20CR: The “surface-input”

reanalyses (surface obs. only assimilated) • The JRA-55 family also includes

• “JRA-55C” (conventional obs. only assimilated) • “JRA-55AMIP” (no obs. assimilated; SST specified)

Notes on planned new products (will not be covered in the Full Report): ERA5 (1979– (Q2 2018), 1950– (Q1 2019); JRA-3Q (2022); CRA40 (?)

1. Introduction to S-RIP https://s-rip.ees.hokudai.ac.jp/Chapter Title Chapter Co-leads

1 Introduction Masatomo Fujiwara, Gloria Manney, Lesley Gray

2 Description of the Reanalysis Systems

Jonathon Wright, Masatomo Fujiwara, Craig Long

3 Climatology and Interannual Variability of Dynamical Variables

Craig Long, Masatomo Fujiwara

4 Climatology and Interannual Variability of Ozone and Water Vapour

Michaela Hegglin, Sean Davis

5 Brewer-Dobson Circulation Thomas Birner, Beatriz Monge-Sanz

6 Stratosphere-Troposphere Coupling

Edwin Gerber, Patrick Martineau

7 Extratropical UTLS Cameron Homeyer, Gloria Manney8 Tropical Tropopause Layer Susann Tegtmeier, Kirstin Krüger

9 QBO and Tropical Variability James Anstey, Lesley Gray

10 Polar Processes Michelle Santee, Alyn Lambert, Gloria Manney

11 Upper Stratosphere andLower Mesosphere

Lynn Harvey, John Knox

12 Synthesis Summary Fujiwara, Manney, Gray

1. Introduction to S-RIP https://s-rip.ees.hokudai.ac.jp/

• June 2011: Discussion started at 8th SPARC Data Assimilation (DA) workshop (Brussels, Belgium)

• February 2012: S-RIP became an emerging activity of SPARC • June 2012: An S-RIP session at 9th SPARC DA workshop (Socorro, NM, USA)

• April-May 2013: S-RIP Planning Meeting (Exeter, UK) • January 2014: S-RIP officially endorsed by the SSG as a full activity of SPARC • Sep. 2014: S-RIP Workshop with DA WS (College Park, MD, USA) • Oct. 2015: S-RIP Workshop with DA WS (Paris, France) • Oct. 2016: S-RIP Workshop with DA WS (Victoria, Canada) • Oct. 2017: S-RIP Workshop with DA WS (Reading, UK) Next Week!

• 2016 – 2017: • complete “basic” chapters (Chapters 1 – 4) “S-RIP Interim Report”

• 2018: • complete the whole report (Chapters 1 – 12) “S-RIP Full Report” • review S-RIP and decide on future of activity

2. Progress – The Interim Report

• Editors: M. Fujiwara, J. S. Wright, G. L. Manney, L. J. Gray • External Editors: Judith Perlwitz, Seok-Woo Son, and Vincent-Henri

Peuch

• The S-RIP Interim Report manuscript (Chapters 1-4) was completed in December 2016

• The first review report was received in March 2017. • A revised version is in preparation and will very soon be submitted to

the external editors (** October 2017).

2. Progress – The Special Issue • The inter-journal special issue on "The SPARC Reanalysis Intercomparison

Project (S-RIP)" in Atmospheric Chemistry and Physics (ACP) and Earth System Science Data (ESSD)

• https://www.atmos-chem-phys.net/special_issue829.html [Editors: P. Haynes, G. P. Stiller, W. Lahoz]

• https://www.earth-syst-sci-data.net/special_issue10_829.html [Editor: G. P. Stiller]

• 18 papers (including those under review) currently • Key papers: • Chaps. 1 & 2: Fujiwara et al., “Introduction to the SPARC Reanalysis Intercomparison

Project (S-RIP) and overview of the reanalysis systems” (published) • Chap. 3: Long et al., “Climatology and interannual variability of dynamic variables in

multiple reanalyses evaluated by the SPARC Reanalysis Intercomparison Project (S-RIP)” (accepted)

• Chap. 4: Davis et al., “Assessment of upper tropospheric and stratospheric water vapour and ozone in reanalyses as part of S-RIP” (accepted)

2. Progress – Other Activities • Connection with other SPARC activities:

• Data Assimilation WG, SNAP, QBOi, DynVAR, OCTAV-UTLS, CCMI, Data Initiative, and Gravity Wave

• WCRP Task Team for Intercomparison of ReAnalyses (TIRA) • Formed in October 2016; led by Mike Bosilovich of NASA/GMAO • Members: Reanalysis centers, WCRP core projects (Masatomo Fujiwara as SPARC

liaison), intercomp. tool developers, etc. • Regular (~1.5 monthly) teleconferences • A start-up joint activity on the coupling (atmosphere–ocean–land surface–

cryosphere) – the water cycle? (still under discussion)

• 5th International Conference on Reanalysis (ICR5) • Rome, Italy, 13-17 November 2017 • Invited talk on S-RIP (by Masatomo Fujiwara) • Several S-RIP related scientific talks and posters

2. Progress – Notes: The New Colours• New S-RIP colours … for the Full Report

• https://s-rip.ees.hokudai.ac.jp/mediawiki/index.php/Notes_for_Authors

3. Planned Discussion Items in the S-RIP Workshop next week (at ECMWF, Reading, UK) • Progress reports from all chapter co-leads + several scientific talks • Inputs for Chapter 12 (synthesis summary)

• Submission deadline for the full report manuscript [to be determined next week, but would be around mid 2018]

• Activities in 2018 [to be determined next week, but most probably No workshop in 2018 – a side meeting during the GA (Kyoto, Japan, October)]

• Report of the S-RIP surveys ("wish list" and model/pressure level data) • Future of the S-RIP • Others

4. S-RIP Advanced Chapters Progress

• Chap. 05: Brewer–Dobson Circulation • Chap. 06: Stratosphere–Troposphere Coupling • Chap. 07: Extratropical Upper Troposphere and Lower Stratosphere • Chap. 08: Tropical Tropopause Layer • Chap. 09: Quasi-Biennial Oscillation and Tropical Variability • Chap. 10: Polar Processes • Chap. 11: Upper Stratosphere and Lower Mesosphere

Chap. 05: Brewer–Dobson Circulation

Time evolution of modelled AoA from CTM simulations with 5modern reanalyses in the NH mid-latitudes in the lowerstratosphere (left). Thin lines show instantaneous model output.Thick lines are smoothed with a one-year running mean.(Chabrillat et al., to be submitted to ACP, 2017.)

Trend in the net upwelling at 70 hPa in the tropics, from 4 modernreanalyses. The trend value is calculated from the Reanalysis-Ensemble-Mean (REM) by first averaging the time series (not theaverage of the trend value from each reanalysis) (the method hereis as an option to better deal with uncertainties in the reanalyses;see Davis and Birner, 2017). (Birner et al., in prep.)

Mean Age of Air at 40N–50N at 20 km (between the turnaround latitudes)

REM

Chap. 06: Stratosphere–Troposphere Coupling Seasonal occurrence of Sudden Stratospheric Warmings

in the (left) pre-satellite era and (right) satellite era

• Modern reanalyses are nearly indistinguishable in terms of major SSW events (right panel) • Less agreement w/ first generation reanalyses, even in satellite era (e.g., NCEP-NCAR vs. ERA40) • More uncertainty in pre-satellite era, but only one state-of-the-art reanalysis available (left) • Sampling uncertainty is large (not shown), hence there is still value in pre-satellite reanalyses (i.e., to get more events) for

understanding dynamics of SSWs Figure courtesy of B. Ayarzagüena et al. (in preparation)

_REM

Chap. 07: Extratropical UTLS • Regional trends in upper tropospheric jets (DJF, 1980–

2014) using model level data from 5 modern full-input reanalyses and the JETPAC (JEt and Tropopause products for Analysis and Characterization software package; Manney et al, 2011, ACP).

• Bars show the slope of a linear fit to the trend over 1980--2014, thin “error bars” show 1-sigma uncertainty in the slope; triangles show trends that are significant at the 95% confidence level.

• The NH polar (or “eddy-driven”) jet has consistently shifted equatorward, except over eastern North America and the Atlantic, and its altitude has increased

• Similar analysis has also been done for the SH, and for the subtropical jets in each hemisphere.

• While the reanalyses generally show trends of the same sign in the NH, this is not always the case in the SH.

(Manney & Hegglin, J. Clim., in press)

Chap. 08: Tropical Tropopause Layer

• The cold point for the reanalysis (model-level data) is the one for every profile (at every lon, lat on the 6-hourly data), then averaged over each month (calculated by Sean Davis)

• The radiosonde data sets are taken from James S. Wang et al. (JGR, 2012)

TTL Temperature Trends (20S-20N) for 1979-2005

Chap. 09: QBO and Tropical Variability

• Key diagnostics: • Representation of QBO• Mechanisms for Holton-Tan • Analysis of tropical waves and their propagation• Impact of QBO at Earth’s surface• Solar cycle signal in stratosphere

Chap. 10: Polar Processes

(Z. D. Lawrence, paper in preparation)

(poleward of 40S, during Austral winter)

• Minimum T differences from MERRA-2 (left) and standard deviations (SD) of those differences; colored envelopes are 99% confidence intervals

• The reanalyses converge towards much better agreement in the later years at all levels.

• There are step-like changes in agreement among the reanalysesaround 1998 (near the time of TOVS to ATOVS transition)

• The reanalyses typically agree to within about 1K in the most recent decade.

• The SDs of the differences increase with altitude, and show a modest decrease over the time period

• In the NH, the reanalyses agree better throughout the period, so convergence towards better agreement is less obvious.

←↑Toshihiko Hirooka (Kyushu University) and Yoshio Kawatani (JAMSTEC)

Reanalysis Diffs

SAO

SSW

Peter Hitchcock (NCAR)

Polar Vortex

Lynn Harvey (CU/LASP) AGU

Solar Tides

Takatoshi Sakazaki (U. Hawaii)Submitted to ACPD

Solar, ENSO, QBO, Volcanic MLR

Lesley Gray (Oxford)Mitchell et al. (2014)

Inertial Instability

T, U, V, Climo

Planetary WavesJeff France(CU/LASP)

2d & 5d Waves

John McCormack (NRL)

Chap. 11: Upper Stratosphere and Lower Mesosphere

Yoshihiro Tomikawa(NIPR)

5. Summary: S-RIP Progress

• The Interim Report (Chapters 1 – 4): Under revision • The ACP/ESSD inter-journal special issue on "The SPARC Reanalysis

Intercomparison Project (S-RIP)": 18 papers currently, including Chapers 1+2, 3, and 4 papers

• New connections: e.g., WCRP Task Team for Intercomparison of ReAnalyses (TIRA)

• S-RIP 2017 Workshop is planned in the next week (at ECMWF, Reading, UK)

• S-RIP Advanced Chapters Progress

• The Full Report (Chapters 1 – 12): Will be completed in mid 2018 (and then reviewed, revised, and published)

Comments and suggestions at the SSG meetingReport from Michelle Santee: 1. The S-RIP activity report was very well received by the SPARC SSG, with

the project’s progress considered to be impressive2. S-RIP is looked on as the "poster child" for these kinds of activities -- an

example of how such projects can be successfully coordinated3. In particular, the approach S-RIP has taken of having journal articles

published in a dedicated special issue in conjunction with a SPARC Report was viewed as a model that other activities might follow to incentivize contributors

4. One suggestion for future discussion among the project participants: Explore how the tools that have been developed for the current analyses can be applied to subsequent generations of meteorological data sets as they become available

5. Obviously, the current S-RIP project needs to cut off investigation at some point, since new reanalyses are constantly coming online, but those systems will also need to be thoroughly assessed and we should take advantage of the infrastructure that has been developed