WCRP Working Group on Seasonal to Interannual Prediction Adam Scaife & Francisco Doblas-Reyes (WGSIP co-chairs)

(1st) International workshop on seasonal to decadal prediction Toulouse May 13-16, special thanks to George Boer and Laurent Terray

http://chfps.cima.fcen.uba.ar/ CIMA CHFP Data Server

CHFP database “CMIP for seasonal forecasting”

Extratropical forecast skill is emerging on seasonal timescales! Slides from Amy et al Northern Annular Mode in winter Sea Level Pressure Signals to noise is small so large ensembles are needed! All models show some skill and the predictability of the NAM is much higher than in previous operational systems Alexey Karpechko & Adam Scaife

Stratosphere Historical Forecast Project a WGSIP-SPARC project Amy Butler, Adam Scaife, Natalia Calvo, Andrew Charlton-Perez + WGSIP members High Top Hindcasts Parallel to WGSIP-CHFP Extended models Initialising extra atmosphere, better represented stratosphere Integrations 4 month lead times (1st November and 1st May start dates) 2 seasons (DJF and JJA) Case study years: 1989 onwards At least 6 members per year, preferably more © Crown copyright Met Office

Extratropical forecast skill is emerging on seasonal timescales! Slides from Amy et al Amy Butler & Adam Scaife

Decadal Prediction (with WGCM) WGSIP WGCM DCPP

Decadal Predictions CMIP-WGCM-WGSIP oversee this framework CMIP5 Protocol Ocean observations will be at the heart of decadal climate prediction systems. Major challenges will, therefore, be to continually assess whether existing and planned ocean observing systems are optimal for decadal predictions and to address any identified deficiencies. As one example, a tremendous advance has been the measurements of temperature and salinity over the upper 2000 m of the global ocean currently provided by ARGO profiling floats. There exists, however, a need to assess whether observations from below 2000 m would be of use in decadal climate predictions by more completely characterizing deep ocean conditions, such as the lower limb of the MOC, and in assessing other changes such as in abyssal ocean heat content. Also, with a lifetime of individual ARGO floats of only a few years, there is a need to evaluate and minimize the impact of instrumentation changes on the quality of the records both for climate analyses and for initializing prediction models. CMIP-WGCM-WGSIP oversee this framework Part of our discussions is to think about ‘What next?’ Working with Veronika Eyring, George Boer and others on CMIP6

CMIP5 decadal predictions Predictions (yr 2-5) from 6 CMIP5 systems Initialized solid, uninitialised dashed Global-mean T and Atlantic multi-decadal variability Correlations and RMSE below BUT Outstanding issues with protocol See proposal for a joint WGCM/WGSIP/CLIVAR for CMIP6…. Forecast time Doblas-Reyes et al. (2013)

Real Time Decadal Forecast Exchange Doug Smith, Adam Scaife and the decadal prediction community…. 15th session of the WMO Commission for Climatology recommended action to start the coordination and exchange of decadal predictions Proposal went out to various groups to exchange decadal prediction information research exercise – we can learn a lot from this prevent over-confidence from a single model equal access, ownership and recognition Uni. Tokyo – Kimoto Masahide , MRI – Masayoshi Ishii, SMHI – Klaus Wyser,Colin Jones, KNMI – Wilco Hazeleger, IC3 – Francisco Doblas- Reyes, Virginie Guemas, MPI – Daniela Matei, Wolfgang Muller, Holger Pohlman, CCCMA – George Boer, Bill Merryfield, UKMO-Hadley – Doug Smith, Adam Scaife, READING UNI – Ed Hawkins, NRL – Judith Lean, David Rind, CERFACS – Christophe Cassou, IPSL – Juliette Mignot

Real Time Decadal Forecasts: 2012-2016 relative to 1971-2000 Effect of initialisation Smith et al, Clim. Dyn., 2012

WGSIP activities summary Growing number of seasonal hindcasts in the CHFP database (CMIP for seasonal) Exciting results for extratropical winter predictability and a clear role for the stratosphere Decadal hindcasts provided to CMIP5 and analyses appearing in literature Real time decadal predictions being exchanged (Smith et al 2012) A draft decadal prediction protocol for CMIP6 is being developed jointly by WGSIP/WGCM/CLIVAR following agreement amongst these groups via the Decadal Climate Prediction Panel