Office of Naval Research
Coupled Ocean-Atmosphere Dynamics and Predictability of Madden-Julian Oscillations
Arthur J. Miller, Hyodae Seo (Hawaii), Ragu Murtugudde (Maryland), Duane Waliser (JPL/CalTech/UCLA), Markus Jochum (NCAR)
Award: $225,000
Duration: 2010-2012
Project Summary.
We propose to join the DRI MJO team to study the predictability and dynamics of MJO's in the Indo-Pacific sector using a high-resolution regional coupled ocean-atmosphere model (SCOAR) that couples the Regional Spectral Model (RSM) with the Regional Ocean Modeling System (ROMS). Although the MJO is fundamentally an atmospheric phenomenon, its interaction with SST produces significant changes in amplitude, wavelength, propagation speed and structure. Our initial results with modeling MJO's in a high-resolution (0.25 deg atmosphere and ocean) Indian Ocean domain reveal a much better representation of MJO processes than coarser resolution uncoupled atmospheric models. Our previous work with SCOAR in the tropical Atlantic has demonstrated the improvements in precipitation associated with African Easterly Waves when the atmospheric resolution is enhanced. Team members are also involved in theoretical aspects of coupled climate interactions at disparate scales in the ocean and the atmosphere, which is crucial for understanding how small-scale SST anomalies can drive significant MJO-scale responses.
We propose to use SCOAR with high resolution in the Indo-Pacific sector to investigate (a) dynamical and thermodynamical impacts of ocean-atmosphere coupling on MJO, (b) sensitivity to initial conditions in MJO predictability experiments and (c) sensitivity to diurnal cycle mixing processes and background climatic conditions on the model simulations and predictability of MJO. Although a surface wave model is not currently part of SCOAR, we propose to incorporate a wave model into SCOAR for exploring its effects on the surface fluxes of air-wave-sea coupled runs, as well.
Our team features extensive multi-disciplinary and collaborative experience with MJO dynamics, coupled ocean-atmosphere dynamics, ocean-atmosphere modeling, ocean data assimilation, physical-biological interactions, and theoretical ocean-atmosphere predictability. This research will eventually help to identify improvements to the practical framework for real-time operational forecasting of MJO by FNMOC.