User Meeting 15 June 2005 Monthly Forecasting Frederic Vitart ECMWF, Reading, UK

User Meeting 15 June 2005 Monthly Forecasting System Real-time forecast: Coupled ocean-atmosphere integrations: a 51-member ensemble is integrated for 32 days every Thursday. Atmospheric component: IFS with the latest operational cycle and with a TL159L40 resolution Oceanic component: HOPE (from Max-Planck Institute) with a zonal resolution of 1.4 degrees and 29 vertical levels Coupling: OASIS (CERFACS). Coupling every ocean time step (1 hour) Background statistics: 5-member ensemble integrated at the same day and same month as the real-time time forecast over the past 12 years

User Meeting 15 June 2005 Model Changes during the past year New versions of IFS : Cycle 28R2 in June 2004 Cycle 28R3 in October 2004 (contains a new physic package) Cycle 29R1 in April 2005 (contains a new moist boundary layer scheme) Operational suite (October 2004): The frequency of the monthly forecast is once a week instead of once every two weeks. Starting date is Thursday instead of Wednesday Product dissemination on Fridays Hindcast and real-time forecast are archived under different streams (mnfc and mnfh) Model climatology and anomalies relative to the model climate are archived

User Meeting 15 June 2005 Performance over the Northern Extratropics Monthly Forecast Persistence of previous week probabilities ROC area of probability of 2-meter temperature in upper tercile Day Day DJF05 DJF04DJF03 DJF04 DJF05

User Meeting 15 June 2005 Verification: Week 10/01/ /01/2005

User Meeting 15 June 2005 Verification: Week 24/01/ /01/2005

User Meeting 15 June 2005 Verification: Week 21/02/ /02/2005

User Meeting 15 June 2005 Verification: Week 07/03/ /03/2005

User Meeting 15 June 2005 Verification: Week 21/03/ /03/2005

User Meeting 15 June 2005 Monthly Forecast 13/01/2005 Day 5-11 Day 12-18

User Meeting 15 June 2005 Future developments (1) End of June : Cycle 29R2 New sea-ice treatment: Current scheme: The sea-ice cover is a diagnostic of the ocean model. There is sea ice if SST is lower than a certain threshold (about -1.7C) New scheme (Magdalena Balmaseda and Tim Stockdale) During the first 10 days, sea-ice is persisted from the atmospheric initial conditions. - After 1 month, we impose climatological sea-ice (from ERA40) - Between day 10 and month 1, interpolation between persisted sea-ice and climatological sea-ice.

User Meeting 15 June 2005 Example: Sea-ice cover on 1/1/2005 Current Scheme: NEW Scheme:

User Meeting 15 June 2005 Future developments (2) -Archiving of probabilities: 1) Probability of weekly mean precipitation and temperature anomalies to be above or below a threshold 2) Terciles, quintiles, 10% and 90% distributions of weekly mean precipitation and temperature relative to the model climatology. The boundaries will also be archived.

User Meeting 15 June 2005 Future developments (3) Verification plots on the web site (under development): - Verification of anomaly maps of 2-meter temperature, Z500, precipitation…. - Some probabilistic scores - Some deterministic scores The verification plots will be updated every week

User Meeting 15 June 2005 Examples of verification Anomaly maps: Temperature Z500

User Meeting 15 June 2005 Examples of verification Examples of probabilistic scores: ROC scores

User Meeting 15 June 2005 Examples of verification Example of deterministic scores:

User Meeting 15 June 2005 Future developments (4) SYSTEM changes Autumn 2005: CY30R1. The resolution of the monthly forecasting system will change from TL159L40 to TL159L62. The additional vertical levels will be in the mid-troposphere. 2006: Merging the monthly forecasting system with VAREPS.

User Meeting 15 June 2005 Future developments (5) Merging the monthly forecasting system with VAREPS Present situation: 2 separate systems EPS: Day 0 Day 10 TL255L40 twice a day uncoupled MOFC: Day 0 Day 32 TL159L40 once a week Ocean model

User Meeting 15 June 2005 Future developments (6) Merging the monthly forecasting system with VAREPS End of 2005: 2 separate systems VAREPS: Day 0Day 7 twice a day uncoupled MOFC: Day 0 Day 32 TL159L62 once a week Ocean model Day 15 TL399L62 TL255L62

User Meeting 15 June 2005 Future developments (7) Merging the monthly forecasting system with VAREPS 2006: single system VAREPS: Day 0Day 7 twice a day MOFC: Day 0 Day 32 Ocean model (once a week) Day 15 TL399L62 TL255L62 TL255L62 (*) Once a week * To be confirmed

User Meeting 15 June 2005 Future developments (8) SYSTEM changes 2006 : Merging the monthly forecasting system with VAREPS. New MARS archiving for this system. For example stream mnfc will become enfo Hindcasts will still be produced with the same resolution as the full VAREPS system. This could also be useful for calibrating medium-range weather forecasts.

User Meeting 15 June 2005 Madden Julian Oscillation Experiments: 15/12/92-31/01/93 ERA40 Analysis: U850Velocity Potential 200 hPaOLR

User Meeting 15 June 2005 MJO Experiments Velocity Potential correlation Persisted SSTsCoupledObserved SSTs Persistence of atmos. initial conditions

User Meeting 15 June 2005 MJO Experiments Velocity Potential correlation Mixed-layer model Coupled Mixed-layer model 10-meter vertical resolution

User Meeting 15 June 2005 Real-time monthly forecasts (81 cases) Loss of Variance PC1 FcstPC2 FcstPC1 AnalysisPC2 Analysis