Recent S/I Prediction Activities at IRI

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

correlations (%) with CPC GSOD daily rainfall amount

1980–2003

coupled uncoupled

Effect of Coupling on Simulated Indian Summer Monsoon

Effect of Coupling on Simulated Indian Summer Monsoon

correlations (%) with CPC GSOD 1980–2003

coupled uncoupled

obs daily rainfall frequency

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

NCEP/NCAR ReanalysisEnsemble mean ECHAM 1st month lead forecast

Feedback Parameters

(Wm-2K-1)

ECHAM forecast 24 ensemble

Ocean Mixed LayerFixed MLD at mean annual cycle (Levitus94)

Climatological dynamics through flux correction

Seager ATM

SSTLatent, sensible heat fluxesand long wave radiation

surface wind velocity,cloud fraction

Off-line SST prediction model

wind stressesfor Ekman effects

1st mon Lead 1st mon Lead

Seager heat flux