Respective roles of shallow convection and stratiform rainfall on the simulation of Madden-Julian Oscillation.

Journal Article · Mon Mar 15 04:00:00 EDT 2010 · J. Climate

OSTI ID:1107812

Fu, Joshua Xiouhua ^[1]; Wang, Bin ^[2]; Yeh, Hsi-Chyi

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1. IPRC/SOEST/UH; IPRC, SOEST, University of Hawaii
2. IPRC&DM/SOEST/UH

Respective Roles of Shallow Convection and Stratiform Rainfall on the Simulation of Madden Julian Oscillation Joshua Xiouhua Fu IPRC, SOEST, University of Hawaii The IPRC/UH Hybrid-coupled GCM (HcGCM), which combined ECHAM-4 AGCM with UH intermediate ocean model, produces robust Tropical Intra-Seasonal Oscillations including the boreal-winter MJO and boreal-summer Monsoon Intra-Seasonal Oscillation. In this study, two sets of sensitivity experiments (i.e., short-term retrospective forecast of one MJO event observed during TOGA COARE and long-term free integrations) have been carried out to understand the respective roles of shallow-convection and stratiform rainfall on the simulations and predictions of the MJO. Major findings are summarized as following: Shallow-convection ahead of MJO deep convection moistens the lower-troposphere and preconditions the movement of the MJO. Present study shows that this process is very important to the eastward propagating speed of the MJO. A significant fraction of stratiform rainfall (~30%; stratiform part vs. total rainfall) is needed for ECHAM-4 to have a robust MJO. The above findings suggest that in addition to deep convection, shallow convection and stratiform rainfall needs to be well represented in conventional GCMs to ensure a robust model MJO.

• Research Organization: University of Hawaii, Honolulu, HI
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: SC0002134
• OSTI ID: 1107812
• Report Number(s): DOE-HAWAII-2134
• Journal Information: J. Climate, Journal Name: J. Climate
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
Madden-Julian Oscillation
parameterization and TWP-ICE.
shallow and stratiform clouds