Recent SI Prediction Activities at IRI

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Recent S/I Prediction Activities at IRI
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IRI Climate Predictability Tool (CPT)

• Simon Mason

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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.
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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.
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Comparison of Coupled and Uncoupled Simulations
on Simulation of Indian Monsoon Precipitation

• Andrew Robertson
• Vincent Moron
• David DeWitt

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Effect of Coupling on Simulated Indian Summer
Monsoon
coupled
uncoupled
correlations () with CPC GSOD daily rainfall
amount 19802003
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Effect of Coupling on Simulated Indian Summer
Monsoon
obs daily rainfall frequency
coupled
uncoupled
correlations () with CPC GSOD 19802003
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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)

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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)

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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)

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Enhanced Predictive Skill by Selective Coupling

• Dong Eun Lee
• David DeWitt

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Feedback Parameters
Ensemble mean ECHAM 1st month lead forecast
NCEP/NCAR Reanalysis
(Wm-2K-1)
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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
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Seager heat flux
1st mon Lead
1st mon Lead