1. The Sub-seasonal to Seasonal (S2S) Prediction Project
“Bridging the gap between weather and climate”
Co-chairs:
Frédéric Vitart (ECMWF)
Andrew Robertson (IRI) 1

2. WMO/WWRP International Legacy Projects
PPP
S2S
HIW
Tropics
Poles
Minutes
Seasonal
2 weeks
From Sharan Majumdar

3. Mission Statement
“To improve forecast skill and understanding on the sub-seasonal to seasonal timescale with special emphasis on high-impact weather events”
“To promote the initiative’s uptake by operational centres and exploitation by the applications community”
“To capitalize on the expertise of the weather and climate research communities to address issues of importance to the Global Framework for Climate Services”

4. S2S project Implementation plan finalized & printed
5-year project, started in Nov 2013.
Project office: KMA/NIMR hosts the project office in Jeju island.
Trust Fund: Contributions from Australia, USA and UK

5. S2S Steering Group Co-Chairs: Frédéric Vitart (ECMWF) Liaison group:
Andrew Robertson (IRI)
In-Sik Kang (WCRP JSC Liaison)
Members:
Richard Graham (UKMO, CBS)
Arun Kumar (NCEP)
Jean-Pierre Ceron (Météo-France, CCL)
Harry Hendon (CAWCR)
Caio Coehlo (JWVGR)
Yuhei Takaya (JMA)
Steve Woolnough (GEWEX/GASS)
Hai Lin (EC)
Paul Dirmeyer (GLASS)
Anca Brookshaw (UKMO)
Joanne Robbins (SERA)
June-Yi Lee (U. Hawaii)
Duane Waliser (JPL NASA)
Ben Kirtman (UM RSMAS)
Tongwen WU (CMA)
ICO manager: Tetsuo Nakazawa

8. Conferences/Education outreach
Nov 2013: S2S workshop organized by the S2S ICO (Jeju, Republic of Korea)
Feb 2014: International conference on sub-seasonal to seasonal prediction (NCEP)
June 2015: Monsoons workshop (Jeju, Republic of Korea)
Dec 2015: AGU session
April 2016: S2S/MJO-TF/YOMC workshop on convection over the Maritime Continent (Singapore)
: S2S/WGNE Teleconnection workshop
Education:
Oct 2014: Training course was co-organized with APCC in Busan (Republic of Korea)
Nov, 2015: 2 week training course at ICTP (Trieste, Italy) for young scientists from developing countries

9. S2S Database 11 data providers and 2 archiving centres Data provider
ECMWF
UKMO
HMCR EC
Météo
France
KMA
NCEP
CMA
JMA
CNR
BoM

10. Database Description Daily real-time forecasts + re-forecasts
3 weeks behind real-time
Common grid (1.5x1.5 degree)
Variables archived: about 80 variables including ocean variables, stratospheric levels and soil moisture/temperature
Archived in GRIB2 – NETCDF conversion available

11. S2S partners Time-range Resol. Ens. Size Freq. Hcsts Hcst length
Hcst Freq
Hcst Size
ECMWF
D 0-46
T639/319L91 51
2/week
On the fly
Past 20y
2/weekly 11
UKMO
D 0-60
N216L85 4
daily
4/month 3
NCEP
D 0-44
N126L64 16
Fix EC
D 0-35
0.6x0.6L40 21
weekly
Past 15y
BoM
T47L17 33
6/month
JMA
D 0-34
T319L60 50
3/month 5
KMA
CMA
D 0-45
T106L40
Met.Fr
T255L91
monthly
2/month 15
ISA-CNR
D 0-32
0.75x0.56 L54 40 1
HMCR
D 0-63
1.1x1.4 L28 20 10

12. S2S Current Status ECMWF
Database opened since 6 May 2015, initially with 4 models:
ECMWF
Real-time and “on the fly” reforecast from 1st January 2015
NCEP
Real-time from 1st January 2015, reforecast will be complete after 1 year
JMA
Real-time from 1st January 2015, fixed reforecast
BoM
Real-time from 1st January 2015, fixed reforecast
CMA, Meteo-France and HMCR also now available
All the models available by end of 2015

13. By end of June 2015, 94 users, 20K requests, 16TB of data.

14. Research areas Service-oriented research Underpinning research
Societal and economic
research applications (SERA)
Verification
Underpinning research
Sources of predictability Teleconnections
MJO, Monsoon, Stratosphere, Snow/sea-ice/soil moisture …
Modelling
Resolution, Initial conditions, ensemble generation, ocean-atmosphere coupling, systematic errors

15. Sub-Projects S2S Database
Sub-seasonal to Seasonal (S2S) Prediction Project
Interactions and teleconnections between midlatitudes and tropics
Madden-Julian Oscillation
Monsoons
Sub-Projects
Africa
Extremes
Verification
Research Issues
Predictability
Teleconnection
O-A Coupling
Scale interactions
Physical processes
Modelling Issues
Initialisation
Ensemble generation
Resolution
O-A Coupling
Systematic errors
Multi-model combination
Needs & Applications
Liaison with SERA
(Working Group on Societal and Economic Research Applications)
S2S Database

16. Subproject Goals
Monsoons – Develop a set of scientifically and societally relevant intra-seasonal forecast products and metrics that are applicable to all the major monsoon systems which can be monitored with operational real-time forecast systems. Case studies of monsoon onsets.
MJO – Evaluate state of art & characterize shortcomings of MJO - Maritime Continent interactions. Better understand roles of multi-scale interactions, topography and land- sea contrast, and ocean/land-atmosphere coupling .In collaboration with the WGNE MJO Task Force.
Africa – Develop skilful forecasts on the S2S time scale over Africa and to encourage their uptake by national meteorological services and other stakeholder groups. Link to CBS & SERA; weather-within-climate; rainfed agriculture; capacity building.

17. Subproject Goals
Extreme Weather – Evaluate the predictive skill and predictability of weather regimes and extreme events (droughts, floodings, head and cold waves). Assess the benefit of multi-model forecasting for extreme events. Improve understanding of the modulation of extreme weather events by climate modes. Sub-seasonal prediction of tropical storms (link with TIGGE-GIFS and SWFDP). Case studies selected for the strong societal impact
Verification – Recommend verification metrics and datasets for assessing the forecast quality of S2S forecasts. Provide guidance for a potential centralized effort for comparing forecast quality of different S2S forecast systems, including the comparison of multi-model and individual forecast systems and consider linkages with users and applications.
Interactions & teleconnections between midlatitudes and tropics (New!) – Better understand sub-seasonal tropical-extratropical interaction pathways. Identify periods and regions of increased predictability (“forecasts of opportunity”). Improve sub- seasonal to seasonal forecasts of weather and climate for applications.

18. Products/Diagnostics

19. 2-m temperature anomalies - Day 12-18
Forecast start date is 22 Jan 2015
VERIFICATION
NCEP
JMA
ECMWF

20. MJO forecast – 26/02/2015
S2S Database
CAWCR
ECMWF
JMA
NCEP

21. Analysis
ECMWF
JMA
NCEP
CAWCR
MJO Teleconnections
(re-forecasts)
Z500 anomalies 10 days after an MJO in Phase 3

22. Topics for WGSIP-S2S coordination discussed at WGSIP-16
Teleconnections – “stationary” (ENSO) vs transient (MJO), eg with blocking & NAO
Drift/initial shock and verification of the first month – many S2S models are coupled
Data dissemination – sharing between groups, dissemination to users in similar formats
Verification – reference datasets, minimum hindcast lengths, ensemble sizes, MME approaches, spatial methods
GFCS – eg support on NMHSs, RCCs, capacity building workshops