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. WWRP/WCRP S2S project 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

3. Sub-seasonal to Seasonal (S2S) Prediction Project
Teleconnections (C. Stan and H. Lin)
Madden-Julian Oscillation (D. Waliser and S. Woolnough)
Monsoons (H. Hendon)
Sub-Projects
Africa (A. Robertson and R. Graham)
Extremes (F. Vitart)
Verification and Products (C. Coelho)
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

4. Key highlights in the last year
Development of the S2S database:
10 models available
CMA data portal opened
Subset of S2S data available from IRI data library
BAMS paper on S2S database (to appear in Jan 2017)
Usage: more than 600 registered users at ECMWF, 150 at CMA
Side event for S2S at the WMO executive council in June 2016 to raise community awareness of the value of S2S to WMO member countries (introductory talk by F. Rabier followed by three exemplars of use of S2S forecasts for applications)
Started assessment of S2S models (sub-project activities, MAPP research projects, other WWRP/WCRP groups e.g. SPARC/SNAP)
S2S near real product websites
2-week training school on S2S (23 Nov – 4 Dec. 2015, Trieste Italy) for 45 research scientists from developing countries
S2S sessions at AGU, EMS, RMetSoc Conferences
Workshop on Maritime Continent with WGNE/MJO TF (Singapore, April 2016)

5. US National Academy of Science book on Sub-seasonal to seasonal prediction

6. S2S Prediction Task Force (US)
The OAR Climate Program Office’s Modeling, Analysis, Predictions and Projections (MAPP) Program has organized the Subseasonal to Seasonal (S2S) Prediction Task Force to advance NOAA’s and the Nation’s capability to model and predict sources of S2S predictability. The ultimate goal of this initiative is to help close the gap in prediction skill and products between traditional weather and seasonal lead times.
Elizabeth Barnes (Lead), Colorado State University
Edmund Chang (Co-Lead), Stony Brook University
Paul Dirmeyer (Co-Lead), George Mason University/COLA
Andrea Lang (Co-Lead), University at Albany
14 research projects have been awarded
SubX project (NASA, the National Weather Service, and the Department
of Defense’s Office of Naval Research) : a new interagency prediction system
experiment to test sub-seasonal ensemble prediction systems for
possible operational use by the National Weather Service.
Important contribution to S2S research activities

7. WWRP implementation Plan S2S Contribution to Action Areas

8. AA1: Continue to develop the S2S database and use it to assess state-of-the art models and their skill at predicting high-impact weather events such as tropical cyclones, heat/cold waves and their socio- economic impacts
Proposed activities
Part of S2S sub-project on Extremes science plan (
NOAA/MAPP projects (e.g. MAPP project on Tropical cyclones in S2S database)
Workshop on Sub-Seasonal to Seasonal Predictability of Extreme Weather and Climate (6-7 Dec. 2016, IRI, New York)
Discussion with WMO/WHO joint office regarding prediction of heat waves in South Asia.

9. http://www.ecmwf.int/en/research/projects/s2s/charts/s2s/ Ncep Ecmwf
Extreme Weather Sub-project: 2m temp Extreme Forecast Index (EFI)
forecast range:12-18days verifying 8-14 August 2016
Ncep Ecmwf
JMA Ukmo

10. EFI skill assessment Preliminary results based on ECMWF system:
From L. Ferranti

11. Ongoing case studies in S2S Extreme subproject
AA1: Carry out case studies to demonstrate the capability of S2S models to predict high-impact weather events, and the usefulness of S2S forecasts from improved decision making
Ongoing case studies in S2S Extreme subproject
Two regional pilots have been submitted to the GFCS:
- Advancing Flood Early Warning on sub-seasonal to seasonal time scale over India with coupled hydrologic and atmospheric modelling
- Reservoir management for optimization of energy production in South America

12. Integrating Water and Energy Management over South America Using Sub-seasonal to Seasonal Forecasts
Goals: To develop S2S integrated climate services for the water and energy sectors over SE South America, based on recent developments in S2S forecasting, with the goal of reducing vulnerability of populations to weather-climate variability and change, and reducing carbon emissions.
Partners: The project will be led by scientists at Unversidad de la Republica, Uruguay, in partnership with the Regional Centre for Climate of Southern South America , ADME (Administrator of the Electric Energy Market in Uruguay), and the S2S project.
Advancing Flood Early Warning on sub-seasonal-to-seasonal time scale over India with coupled hydrologic and atmospheric Modelling.
Goal: To support India for the improvement of their water cycle forecasts, it is proposed to extend the water cycle forecast range over a chosen Indian catchment to the sub-seasonal scale and to evaluate the benefit of the early warning system.
Partners: Indian Meteorological Department (IMD), Indian Institute for Tropical Meteorology (IITM),WMO – Technical Commission on Atmospheric Science, GLOFAS, S2S

13. Extreme weather sub-project Case Study Drought prediction over Acre regions
Project led by C. Castro (CEMADEN)
Motivation: The Acre River is currently at the lowest level in the last 11 years, even lower than during the “famous” droughts of 2005 and 2010.
Skill assessment and predictability of drought, using the S2S database
Tight collaboration with the local decision makers in the Acre's Government. Opportunity to learn with them on the problems and challenges, managing and mitigating the impacts of disaster.

14. AA2:Explore the predictability and reliability of sub-seasonal to seasonal forecasts and use of ensembles, through use of the S2S database
Part of S2S sub-projects science plans, most especially sub-project on verification and products
S2S verification session at the 7th International Verification Methods Workshop (IVMW) in coordination with JWGFVR, Berlin, 8-11 May 2017
Year of Midlatitudes-Tropics Interactions to assess sources of predictability
Topic of several MAPP funded projects
Development of pilot real-time sub-seasonal MME predictions: WMO LCLRFMME developed a pilot system for real-time multi-model sub-seasonal forecasts using real-time forecasts (and hindcasts) from a subset of models contributing to the S2S project accessible via ECMWF S2S data archive.

15. Boreal Summer Intraseasonal Oscillation (BSISO) Index (May to October during 1999-2000)
EOF1
EOF2
EOF analysis
of U850/OLR
EOF3
EOF4
BSISO1 index shows the predictability of summer MJO is in range of 7 and 24 days
BSISO2 index indicates the predictability of Asian Monsoon is between 7 and 14 days
W. Jie (CMA)

16. AA3: Study the impact of air-sea interaction on organized convection
Part of the MJO sub-project science plan in collaboration with WGNE/MJO-TF
Collaboration with Year of Maritime Continent
MAPP project (DeMott and Klingaman) on impact of air-sea interaction on organized convection in the S2S database
Proposed field campaign PISTON
AA3: Study the impact of air-sea interaction on organized convection

17. Propagation of Intra-Seasonal Tropical Oscillations (PISTON)
Office of Naval Research Departmental Research Initiative (DRI)
SCIENCE and IMPLEMENTATION PLANNING UNDERWAY
Maloney, Alford, Gordon, Moum, Rutledge, Waliser and rest of PISTON Science Team
Field Campaign Planned for Aug-Sep 2018
TENTATIVE Science Objectives and Hypotheses A. Large scale atmospheric circulation variability over the South China Sea related to the monsoon, intraseasonal oscillations, and convectively coupled waves modifies the local diurnal cycle and air sea interaction in the coastal regions and nearby open seas.
B. SST during BSISO events is modulated by a variety of 3-dimensional ocean processes, including a) breaking internal waves of near-inertial and tidal frequency, b) shear instability of low-frequency flows, and c) lateral mixed layer instabilities such as slumping. Modulation of SST by ocean processes influences BSISO propagation and provides ‘oceanic memory’ influencing the strength of subsequent BSISO events.
C. Local and mesoscale processes related to the presence of land and topography, atmosphere-ocean interactions, and atmosphere-land interactions influence the development and propagation of the BSISO. These processes include land-sea breezes, the diurnal cycle, gravity waves, convective variability, and upper-ocean dynamics.
Roxy and Tanimoto (2012). Composite surface wind vector and SST anomalies boreal summer intraseasonal events.

18. the Asean Specialized Meteorological Centre in Singapore is proposing a 4-5 year program (SEA-S2S) of workshops/training course aimed at ASEAN national meteorological services.
Proposal for a South American training course in 2017 to be held in Paraguay or Columbia
Proposal for training and mentoring at U. Reading
Liaison with Red Cross Climate Centre for use of S2S forecast for disaster risk reduction
AA4:Promote applications of S2S forecasts to disaster risk reduction communities, including food security in developing countries and humanitarian aid, for early warning and early action, such as forecast-based financing

19. Main goal of sub-project on Teleconnections
AA6: Improve understanding of linkages between tropical regions and higher latitudes and assess skill of models representing these linkages, to help elicit the influence of tropical climate change and variability on higher latitude weather
Main goal of sub-project on Teleconnections
June 2017: S2S teleconnection session at WGNE meeting (Montreal)
Oct 2017: 2 week training course on S2S teleconnections and workshop (ICTP, Trieste)
Relaxation type experiments in collaboration with YOPP
Collaboration between S2S and PDE to assess the impact of the MJO on recurving tropical storms and associated Rossby Waves in the west Pacific

20. Composites of Z500 3 pentads after an MJO in Phase 3 - NDJFMEI
NAO Index: mean=0, std=1.02
BoM 0.15
CMA 0.14
HMCR 0.13
NCEP 0.32
ISAC 0.25
CNRM 0.15
UKMO 0.28
JMA 0.22
ECCC 0.21
ECMWF 0.31

21. S2S Product Websites (3 weeks behind real-time)
AA14: Conduct forecast post-processing methodology research in the S2S Verification and products sub-project, including computation of forecast probabilities and comparison of different ensemble forecasting systems configurations to evaluate the benefits of the multi-model ensemble approach
S2S Product Websites (3 weeks behind real-time)
S2S product website at ECMWF: Contains near real-time products (2mtm precip, Z500 anomaly maps, MJO forecasts, EFI…) from S2S models from 1st January
“S2S museum” at university of Tsukuba, Japan: Contains near real time indices (MJO, AO, NAO. SSW…)
SSW Index
ECMWF
NCEP
JMA
BoM

22. 2015/2016 Real-time Forecast verification

23. 11th S2S model (KMA) to be added by end of 2016
AA14 Continue development of the S2S database. Facilitate the sharing of forecast analysis and verification codes for S2S forecasts using a GitHub type mechanism
11th S2S model (KMA) to be added by end of 2016
Add new ocean/sea ice variables in netcdf
Compute and archive indices such as MJO RMMs, SSW index, Weather regimes, Tropical storm tracks, Monsoon indices to be available for the research community from ECMWF and IRI servers
Development of a Github repository joint with NOAA MAPP

24. "THE GAP BETWEEN WEATHER AND CLIMATE FORECASTING: SUB-SEASONAL TO SEASONAL PREDICTION” to be published by Elsevier in 2018 and co-edited by Andrew Robertson and Frédéric Vitart Part I: Setting the scene 1. Introduction: Why S2S? – co-editors AWR+FV 2. Weather forecasting: What sets the forecast horizon? - Zoltan Toth 3. Sub-seasonal variability in climate models and prediction of daily weather characteristics – Vincent Moron 4. The weather and climate predictability continuum – G. Brunet Part II: Sources of S2S Predictability 5. Tropical Intraseasonal Oscillations (MJO, BSISO) – Duane Waliser 6. Extratropical waves, oscillations, regimes, low-order models – Michael Ghil 7. Tropical-Extratropical Teleconnections – Hai Lin 8. Land surface processes relevant to S2S prediction - Paul Dirmeyer 9. Ocean-atmosphere interaction on S2S scales (tropics vs extratropics) – Ping Chang and Saravanan 10. Polar processes: Sea ice, snow cover– Matthieu Chevallier 11. The stratosphere - Andrew Charlton 12. Atmospheric chemistry and aerosol interactions on S2S scales - Steven Pawson Part III: S2S Modelling and Forecasting 13. Forecast system design, configuration, complexity – Yuhei Takaya 14. Data assimilation, initialization and ensemble generation - Roberto Buizza 15. High-resolution and cloud-resolving models - In-Sik Kang 16. Forecast calibration and multi-model combination - Michael Tippett 17. Forecast verification – Caio Coelho Part IV: S2S Applications 18. S2S prediction of weather extremes: Tropical cyclones, extratropical storms, atmospheric rivers, heat and cold waves – Frederic Vitart 19. Ready-Set-Go: From disaster early warning to early action (eg forecast-based financing) - Erin Coughlin 20. Communication/dissemination of forecasts and engaging user communities – Brian Mills/Joanne Robbins 21. Seamless prediction of monsoon onset and active/break phases – A. K. Sahai 22. Hydrologic and agricultural management applications (reservoir management, irrigation scheduling, forecast-informed cropping calendars for planting, fertilizer and pesticide application) - Walter Beathgen 23. Health applications (e.g. malaria, meningitis, cholera, influenza) - Adrian Tompkins & Tetsuo Nakasawa 24. Energy applications (supply and demand management, scheduling, renewables) – Upmanu Lall 25. Epilogue – co-editors

25. S2S Membership