Météo-France EUROSIP contribution: present, future and sensitivity experiments Jean-François Guérémy Michel Déqué, Jean-Philippe Piedelievre, Lauriane Batté

Outlook Present: EUROPSIP Syst3 - Components - Some products Future: EUROPSIP Syst4 - Components and first tests Sensitivity experiments and specific studies - l91 versus l31 in the frame of EUROPSIP Syst3 - Predictability of regimes and heavy precipitation events - Skill sore over Africa

EUROPSIP Syst3 Operational international project: Multi-model seasonal forecast; (CNRM, ECMWF, UKMO) model: ARPEGE-Climat V4 Tl63l91 + OASIS V2.4 + OPA V8.2 (ORCA 2° grid) Since May 2008 forecast set-up: - Ocean ICs: MERCATOR, Kalman filter analysis including altimetry, SST and (T,S) in situ data Atmospheric ICs: ECMWF analyses - 41 members (8 lagged atmospheric ICs combined to 5 lagged ocean ICs), each month (starting the first) for 7month run - Hindcasts from 1979 (11 members)

EUROPSIP Syst3; product examples Hydrology: reservoir management in Mali Energy: heating management in western Europe JFM forecast

Manantali Dam Water release management in September-October function of the August seasonal forecast

heating management in western Europe Seasonal cumulation: 18°C – (Tn + Tx)

JFM forecast

Toward EUROPSIP Syst4 operational mid 2012 Model: ARPEGE-Climat V5 Tl127l31 + OASIS V3 + NEMO V3.2 (GELATO ice, ORCA 1°) (new radiation and soil schemes - SURFEX) IPCC set-up (climate projections and decadal forecasts) Preliminary tests without SURFEX and GELATO: Similar scores compared to EUROSIP Syst3 44 years (NDJF and MJJA) 9 members Month 2-4 seasonal average Anomaly correlations

Toward EUROPSIP Syst4 operational mid 2012 Initial Conditions: Possibly, nudging or anomaly nudging in coupled mode toward atmospheric analyses (ECMWF), ocean analyses (MERCATOR, from a ¼° analysis) and possibly soil analyses (MF). Initial and/or in-run perturbations taken from analysis departure terms (stochastic term).

l91 versus l31 in the frame of EUROPSIP Syst3 Time period: , EUROPSIP Syst3 l31 and l91

Predictability of regimes and heavy precipitation events (MEDUP french project) National research project: Seasonal forecast of weather regime and heavy precipitation event occurrence (from 01/2008 to 12/2010); (CNRM, IPSL, LTHE) Time period: ENSEMBLES EU project (42 years) Sensitivity tests: 3 # models: ENS_MF, ENS_CEP and Pro_Tl127l62 (CNRM model with a new atmospheric physics – turbulence, convection and microphysics)

Precipitation biases (/CMAP), coupled simulations DJF JJA Standard Tl63l31 Pronostique (convection Guérémy) Tl127l62 Guérémy 2011, accepted in Tellus

Teleconnections SON (similar to Guérémy et al. 2005, Tellus) Composites of T2m anomalies for the years during which the occurrence of Heavy Precipitating Events (HPE) over South-East of France was greater than the mean + 1 standard deviation ( ). ERA40 ENS_MFENS_CEP Pro_ Tl127l62 Years: 1960, 1963, 1964, 1968, 1977, 1994, 1995 >= 7 HPE per year

Teleconnections SON ERA40 Pro_ Tl127l62 Composites of 200 hPa Velocity Potential anomalies for the years during which the occurrence of Heavy Precipitating Events (HPE) over South-East of France was greater than the mean + 1 standard deviation ( ). ENS_MFENS_CEP

Teleconnections SON ERA40 Pro_ Tl127l62 Composites of Z500 anomalies for the years during which the occurrence of Heavy Precipitating Events (HPE) over South-East of France was greater than the mean + 1 standard deviation ( ). ENS_MFENS_CEP

Regimes (stream function , velocity potential  ) 200hPa ERA40, SON 

Predictability of ( ,  )200 regime occurrence relationship to heavy precipitation events, SON ENS_MFENS_CEPPro_Tl127l62 Regime Regime Regime Regime Regime Regime Association HPE (177 over 42 years) / regimes ( ,  )200 Correlation regime occurrence / ERA40

Predictability of Z500 regime occurrence relationship to heavy precipitation events, SON NAO- Atlantic trough NAO+ Atlantic ridge Association HPE (177 over 42 years) / regimes Z500 Correlation regime occurrence / ERA40 ENS_MFENS_CEPPro_Tl127 l62 Regime Regime Regime Regime

Predictability of heavy precipitation events (HPE) from analogues, SON Following Clark and Déqué (2003, QJRMS), analogues (for each member of the ensemble) are chosen in the model hindcasts according to a minimum distance in terms of ( ,  )200 regime occurrence. The result is a distribution of analogue years. From this distribution, forecasted HPE occurrence (larger than mean + 1 std) is calculated and compared to the observed occurrence of the considered year. ENS_MFENS_CEPPro_Tl127l62 Occurrence correlation ENS_MFENS_CEPPro_Tl127l62 Occurrence correlation From the analogues Model forcasted HPE occurrence

Skill sore over Africa RPSS (Ranked probability skill score) computed for precipitation deciles over the period (ENSEMBLES), for West Africa in JJA and South Africa in DJF; GPCC is the reference. Results from a multi-model (5 out of 9); this muti-model provides greater scores than 0, where most of individual model gives no information. Batte 2010, accepted in Tellus

Bathymetry ORCA2 and ORCA1 ORCA2 (182*149) ORCA1 (362*292)

Scores over DJF, observed SST mode Std phys (Tl63l31)Pro phys (Tl63l31)Pro phys(Tl63l91) ACC T850 Trop ACC T850 NH ACC Z500 NH Standard physics, left Prognostic physics, right (31 levels top, 91 levels bottom)  Pro91 > Pro31> Std31