© Crown copyright Met Office WMO Lead-centres for verification and archiving Richard Graham (Met Office Hadley Centre) and Won-Tae Yun (KMA) acknowledgements to all GPCs and members of the WMO Expert Team on Extended and Long-range Forecasting (ET-ELRF) WMO workshop on Sub-seasonal to Seasonal Prediction, Met Office, Exeter, 1-3 December 2010

Context Forecasters like to compare output from different models, this is helped by: easy access to products; same map projections, contour conventions etc; digital data for ‘user’ processing. Multi-model combinations also important Verification diagnostics also easier to use if presented uniformly Need for international coordination ECMWF JMA 2m temperature forecasts for DJF2010/11

© Crown copyright Met Office WMO CBS coordination of centres producing long-range forecasts: Global Producing Centres (GPCs) First step: agree standard forecast and verification output: Designate GPCs: centres adhering to agreed procedures/standards in LRF – there are now 12 GPCs, forming an integral part of the WMO GDPFS Next step: increase coordination 2 Lead Centres, facilitating user access to GPC products Lead Centre for Long-range Forecast Multi-model Ensembles (LC- LRFMME) Lead Centre for the Standard Verification System for Long-range Forecasts (LC-SVSLRF) Aim: improve access and usability of global LRF products to aid production of regional/national climate services

© Crown copyright Met Office GPC designation criteria have fixed production cycles and time of issuance; provide an agreed minimum set of long-range forecast products, 2m temp, precipitation, SST (averages of at least 1-month); any lead-time between 0 and 4 months. provide an agreed set of forecast quality measures (WMO Standard Verification System for LRF); provide up-to-date information on forecast methodology used; make products accessible to users (through website and Lead Centres)

GPC nameCentreSystem Configurati on (ensemble size of forecast) Resolution (atmosphere) Hindcast period used BeijingBeijing Climate CentreCoupled (48)T63/L CPTECCentre for Weather Forecasts and Climate Studies 2-tier (15)T62/L ECMWFEuropean Centre for Medium Range Weather Forecasts Coupled (41)T159/L ExeterMet Office Hadley Centre Coupled (42)1.25°x1.85°/L MelbourneAustralian Bureau of Meteorology Coupled (30)T47/L MontrealMeteorological Service of Canada 2-tier (40)T32/T63/T95/2.0 °x2.0° (4- model combination) SeoulKorean Meteorological Agency 2-tier (20)T106/L TokyoJapan Meteorological Agency Coupled (51)T95/L ToulouseMétéo-FranceCoupled (41)T63/L WashingtonNational Centres for Environmental Prediction Coupled (40)T62/L MoscowHydromet Centre of Russia 2-tier (10)1.1°x1.4°/L PretoriaSouth African Weather Service 2-tier (6)T42/L The 12 WMO- designated GPCs

© Crown copyright Met Office WMO Lead Centre for LRF Multi- model Ensembles (LC-LRFMME) Jointly operated by Korean Met Agency & NOAA NCEP Won-Tae Yun, Arun Kumar collect LRF data from GPCs core data: monthly pre-calculated anomalies (EM + members) active additional data: hindcast and forecast started but not active display GPC forecasts in standard formats (next 3-months only at present) generate and display an agreed set of MME products distribute GPC data (for those GPCs that allow it) promote research into MME techniques Primary functions:

GPC forecasts for DJF 2010/11: ensemble mean pmsl anomaly (from LC-LRFMME web) Exeter ECMWF Toulouse Beijing Washington TokyoMelbourne Seoul Montreal Coupled systems Un-coupled systems Pretoria ‘Dynamic’ user- selectable domain

Multi-model GPC pmsl forecasts, DJF 2010/11 from LC-LRFMME website Ensemble mean of 10 GPCs Ensemble mean of 7 GPCs (coupled systems) Ensemble mean of 3 GPCs (un- coupled systems) multi-model subsets produced interactively from LC-LRFMME website Presented at South East Europe Regional Climate Outlook Forum (SEECOF), November 2010

What about last year? pmsl anomalies: observed & GPC predictions from Nov09 for DJF2009/10 anomaly sign ‘consistency’ Observed pmsl anomalies (wrt 61-90) 10-model multi-model EM

Other products/activities Other variables: Nino3.4 region plumes 2m temperature; precipitation; 850 hPa temperature; 500hPa height; SST Methods of multi-model combining: Operational: simple equal weights Research: skill weighted combination; linear and non-linear methods Sub-seasonal: 1-month means available in addition to 3-month means Note: ET-ELRF: last meeting recommended pilot projects on potential for monthly-range prediction for (e.g. rains onset)

© Crown copyright Met Office Priority prediction needs Africa: rainfall DFID-Hadley Climate Science Research Partnership Poll of 9 African Regional Centres and National Meteorological Services Highest priority: predictions of the temporal distribution of seasonal rainfall (e.g. onset, duration, dry spells) Less clear at what lead-time onset prediction is needed to be useful Question: what next beyond standard 3-month means and terciles?

Lead Centre for Standard Verification of Long-range forecasts (LC-SVSLRF) repository of global SVSLRF scores for GPC forecasts Core of SVS: ROC maps and diagrams, reliability diagrams, MSSS documentation on verification scores (Attachment II-8 of the WMO manual on the GDPFS) observation datasets for verification, and code for calculating the SVSLRF scores Jointly operated by Bureau of Met. BoM) & Met. Service of Canada (MSC) David Jones, Normand Gagnon

Examples of submitted data ROC curves ROC score maps Reliability/sharpness diagrams Courtesy: David Jones (BoM)

Use of Lead Centre products at African Regional Climate Outlook Forums (RCOFs)

GPC forecasts for E. Africa ‘short-rains’ SON 2010: ensemble mean rainfall anomaly ExeterECMWFToulouse Beijing Washington TokyoMelbourne Seoul Moscow Montreal Coupled systems Un-coupled systems

Sample verification: ROC scores for SON precipitation, 1-month lead Toulouse WashingtonTokyoMelbourne above below 0.6

WMO Lead Centre information and final consensus, SON 2010 Ensemble mean of 10 GPCs Ensemble mean of 7 GPCs (coupled systems) Ensemble mean of 3 GPCs (un- coupled systems) Model consistency Forecaster judgement Final consensus Verification

WMO Lead Centres in context of GFCS

GPCs: role in the Climate Services Information System (CSIS) GPCs and their LCs Other Centres Monitoring Centres obs/research users GFCS CSIS

WMO Global Seasonal Climate Updates (GSCUs) International consensus on global-scale seasonal monitoring and outlook (will extend the WMO El Niño/La Niña updates); Other climate indices (Indian Ocean Dipole, NAO) Temperature, precipitation Intended users: RCCs, RCOFs, NMHSs, but also ‘globally acting users’ (e.g. UN, Red Cross); Scoping meeting and first meeting of GSCU Task Team took place October 2010; identified work needed before Pilot Phase can be begin requirements of GSCUs on the Lead Centres are feeding into work plans, e.g.: probability forecast products, extension of forecast range verification of the multi-model products

Summary WMO CBS (working with CCl) has designated GPCs and associated Lead Centres for multi-modelling and verification - strengthening coordination of LRF Forecast and verification products are available to RCCs /NMHSs / RCOFs - active use is being made Lead Centres will play a key role in WMO Global Seasonal Climate Updates (monitoring and outlook) – part of GFCS vision. Key plans for the WMO Lead Centres (guided by the Expert Team for Extended and Long-range Forecasts) include: development of probability forecast products extension prediction range (to ~6 months) verification of multi-model products possible centralisation of the verification process Issue of length of hindcast – but also of consistency of choice of the hindcast period across the GPCs

Thank you! Any questions?