IRI Climate Predictability Tool (CPT) • Simon Mason
What is CPT? Climate Predictability Tool (CPT) is an easy-to-use Windows-based software package for making downscaled seasonal climate forecasts. It runs on Windows 95+. A source code version, which has no GUI or any of the graphics capabilities, is available for other platforms.
What is CPT? Specifically, CPT is designed to produce statistical forecasts of seasonal climate using either the output from a GCM, or fields of sea-surface temperatures. The program provides extensive tests indicating forecast performance.
Comparison of Coupled and Uncoupled Simulations on Simulation of Indian Monsoon Precipitation • Andrew Robertson • Vincent Moron • David DeWitt
Effect of Coupling on Simulated Indian Summer Monsoon coupled uncoupled correlations (%) with CPC GSOD daily rainfall amount 1980–2003
Effect of Coupling on Simulated Indian Summer Monsoon obs daily rainfall frequency coupled uncoupled correlations (%) with CPC GSOD 1980–2003
AGCM-Based Coupled Modeling at IRI • Initial Coupled System: • ECHAM4.5-MOM3 Fully Coupled COLA (Kirtman, Min) Provides ODA Documented in: Schneider et al. (2004) DeWitt (2004) DeWitt (2005) DeWitt, Goddard, Li (In Preparation)
Issues with Initial Forecast System • ODA and OGCM are run at 2 different resolutions • ODA has large salinity drift due to mistreatment of fresh water flux • ODA system not parallel and historic records are not set up for operational usage. • Not apparent that direct coupling is best approach despite fact that it is methodology employed by all operational centers • Open question whether OGCM based systems are best tool to use for S/I forecasting • Computationally Expensive • Large systematic errors even in ocean only integrations (diffuse thermocline)
Development Path for Next Coupled Models AGCM- ECHAM4.5 Ocean Models: MOM4 – Postdoc (Galanti) New postdoc (to be hired) KKZ – Multi-mode reduced gravity model LDEO (State Dependent Bias Corrected Models) CZ(K) ocean INC ocean MOM4 Thermodynamic Ocean Models (Donna Lee)
Enhanced Predictive Skill by Selective Coupling • Dong Eun Lee • David DeWitt
Feedback Parameters Ensemble mean ECHAM 1st month lead forecast NCEP/NCAR Reanalysis (Wm-2K-1)
Off-line SST prediction model ECHAM forecast 24 ensemble surface wind velocity, cloud fraction wind stresses for Ekman effects Seager ATM Latent, sensible heat fluxes and long wave radiation SST Ocean Mixed Layer Fixed MLD at mean annual cycle (Levitus94) Climatological dynamics through flux correction
Seager heat flux 1st mon Lead 1st mon Lead