Coupled and Forced Solutions of MJO: Implication for Prediction

Bin Wang, Xiouhua Fu, Tim LiUniversity of Hawaii

Are MJO or boreal summer ISO reproducible in forced AGCM simulation (AMIP)?

Atmospheric only model may significantly loss of reproducibility and predictability.

Bifurcation of the coupled and forced solutions due to IC and BC errors.

Atmospheric Model: ECHAM4.6 T30 (3.75o).Ocean Model: 2.5-layer Intermediate Model, 2ox1o

Coupling: daily, Full, No flux correctionIntegration 16 years (10 years) (CTL and sensitivity)

Regional Hybrid Coupled Model

Boreal summer ISO (northward propagation over

Indian monsoon region)

Coherent evolutions among convection, surface winds and SST (Observations)

Phase Relationships between Rainfall and SST

Design of four sensitivity experiments

Labels Initial Condition

Boundary Condition

CPL(CTL) ECMWF analysis at January 1, 1988

Direct coupling (Save SST for ECHAMDATM)

ECHAM (BC): Forced

Same as above Truncated SST from CPL

CPL(BC)

Same as above Indirect coupling(Pass truncated SST to atmosphere)

ECHAM (IC)Forced

1-day difference Forced by SST from CPL(I)

CMAP Rainfall

Coupled

Daily Forced

Mean Forced

CPL(CTL)

ECHAM (BC) Forced

CPL(BC)

ECHAM (IC)Forced

Fu and Wang 2003

Regressed Fields from the Control Coupled Run

Thank You !