SASCOF 2010 Météo-France GCM forecasts JP. Céron – Météo-France

SASCOF 2010Météo-France GCM forecasts

JP. Céron – Météo-FranceJean-Pierre.Ceron@meteo.fr

Outline

Météo-France forecasting suiteSSTs Seasonal ForecastsGeneral Circulation ForecastsRainfall Seasonal ForecastsSummary

The Meteo-France Operationnal Suite« Mercator » version of Arpège (v 4) :

Toulouse

Reading

DClim

Météo-France WMO Global Bulletin Users

Euro-SIP (Multi-Models)

The Meteo-France Operationnal Suite

Coupled Model version 3Atmosphere : Arpege 4.4, t63l91 (same levels than ECMWF analysis),Ocean : OPA & Orca grid (31 vertical levels ~10m close to the surface and ~500 m below 3000 m, 2° resolution with 0.5° meridional resolution in the tropics),Coupling : Oasis v2.4,Mercator reanalysis : 1979 – 2007, new assimilation scheme using insitu data and altimetry,Hindcast : over the 1979-2007 period, 11 members, 7 month range run,Operationnal : 41 membres, 7 month range run,Availability : end of the year, beginning of 2008

Outline

Météo-France forecasting suiteSSTs Seasonal ForecastsGeneral Circulation ForecastsRainfall Seasonal ForecastsSummary

SSTs Seasonal Forecast – GlobalMJJ 2010

SST anomaly (ensemble mean)

SSTs Seasonal Forecast – JJA & JAS Global

SST anomaly (ensemble mean)

SSTs Seasonal Forecast

Niño3.4Pacific : Niño boxes

SSTs Seasonal Forecast

Indian Ocean : OOPC boxes

Recap

SSTs Seasonal Forecast

Pacific :

• evolution toward colder condition in the Central and Eastern Pacific

• La Niña event later ?

Indian Ocean :

• Quite warm conditions everywhere (notably in Western part)

• DMI close to neutral

Good stability of the SST forecast over the MJJ to JAS period

Outline

Météo-France forecasting suiteSSTs Seasonal ForecastsGeneral Circulation ForecastsRainfall Seasonal ForecastsSummary

Probabilistic forecasts for MJJ 2010General Circulation

Stream Function 200hPa

Velocity Potential 200hPa

Khi200

JJA

Khi200

JAS

Consistent signal leading to less favourable convective conditions on the half northern part of India and South-East Asia

Monsoon onset delayed (notably in North India) ?

Probabilistic forecasts for MJJ 2010General Circulation

V 850hPa

U 850hPa

Circulation in the low troposphere

• Zonal circulation weakened in the South Hemisphere (Indian Ocean) and strengthenned in the Northern hemisphere (East IO and Pacific)

Meridional circulation strengthenned (West IO)

Outline

Météo-France forecasting suiteSSTs Seasonal ForecastsGeneral Circulation ForecastsRainfall Seasonal ForecastsSummary

Probabilistic forecasts of precipitationMJJ – JJA – JAS 2010

MJJ JJA

JAS

Indian region : Rainfall enhanced on the southern part (GCM discrepancy ?)

South-East Asia : Rainfall enhanced notably in JJA

Probability of extreme rainfall scenariosMJJ – JJA – JAS 2010

MJJ JJA JAS

Below – 1 std

Above + 1 std

Summary

• The forecast for the MJJ 2010 indicates : - an evolution toward cold SST anomalies over the Equatorial tropical Pacific (which should persists during all the summer season) - a relatively warm SST over the Indian Ocean (notably Western part) for all the summer season - Above normal Rainfall in the southern part of the Indian continent and in South-East Asia.Enhanced probability of “extreme” rainfall scenario over these regions - Indian monsoon onset possibly delayed in the Northern part

The Meteo-France Operationnal Suite

Probabilistic forecasts of T2mMJJ – JJA – JAS 2010

MJJ JJA

JAS

Indian region : T2m warmer than normal notably on West cost and Northern part of India

South-East Asia : T2m above normal in MJJ

SST ROC skill : MJJ

tercile categoriesFcst prob. Skill (1987-2001)

Fcst prob. Skill (1987-2001)

outer-quintile categories

Lower Tercile Upper Tercile

Rainfall ROC skill : MJJ

tercile categoriesFcst prob. Skill (1987-2001)

Fcst prob. Skill (1987-2001)

outer-quintile categories

Lower Tercile Upper Tercile

T2m ROC skill : MJJ

tercile categoriesFcst prob. Skill (1987-2001)

Fcst prob. Skill (1987-2001)

outer-quintile categories

Lower Tercile Upper Tercile