The INGV-CMCC Seasonal Prediction System: improved ocean initial conditions

ALESSANDRI A., A. BORELLI, S. MASINA, A. CHERCHI, S. GUALDI, A. NAVARRA, P. DI PIETRO AND A. F. CARRIL

MONTHLY ENERGY REVIEW

AMER METEOROLOGICAL SOC

Lugar: Boston; Año: 2010 vol. 138 p. 2930 - 2952

0027-0644

The development of the INGV (Istituto Nazionale di Geofisica e Vulcanologia)-CMCC (CentroEuro-Mediterraneo per i Cambiamenti Climatici) Seasonal Prediction System (SPS) isdocumented. In this SPS the ocean initial conditions estimation includes a Reduced OrderOptimal Interpolation procedure for the assimilation of temperature and salinity profilesat the global scale. Nine member ensemble forecasts have been produced for the period1991-2003 for two starting dates per year in order to assess the impact of the subsurfaceassimilation in the ocean for initialization.Comparing the results with control simulations (i.e.: without assimilation of subsurfaceprofiles during ocean initialization), we showed that the improved ocean initialization increasesthe skill in the prediction of tropical Pacific SSTs in our system for boreal winterforecasts. Considering the forecast of the El Ni˜no 1997-1998, the data assimilation in theocean initial conditions leads to a considerable improvement in the representation of its onsetand development.Our results indicate a better prediction of global scale surface climate anomalies for theforecasts started in November, probably due to the improvement in the tropical Pacific. Forboreal winter, in both tropics and extra tropics, we show significant increases in the capabilityof the system to discriminate above normal and below normal temperature anomalies.