Influence of Convective Momentum Transport on Tropical Waves IV. Influence of CMT on the mixed Rossby gravity waves 1. Unstable mixed Rossby gravity waves due to CMT Lei Zhou State Key Lab of Satellite Ocean Environment Dynamics, SIO, Hangzhou, China In-sik Kang School of Earth and Environmental Science, Seoul National University, Seoul, Korea Overview Motivation: The influence of the sub-grid process, i.e., the convective momentum transport, on tropical waves. Method: A two-layer model and the analytical solutions Data for verification: NCEP/NCAR reanalysis, OLR, TRMM precipitation Conclusions: Three influences of the CMT on tropical waves, especially on the mixed Rossby gravity waves 1. It is important for determining the meridional scale of the tropical wave guide; 2. It can lead to the instability of the mixed Rossby gravity waves 3. It can induce upscale momentum and energy transfer from the planetary-wave scale to the large scale. I. Introduction Tropical waves are influenced by many factors, such as: 1. Zonal winds 4. Tropical convection 2. Vertical shear of zonal winds 5. Boundary layer processes 3. Large-scale dynamic field 6. Atmosphere-ocean interaction The factor that is focused on and our intention: Convective momentum transport (CMT), a sub-grid process II. Two layer model 2. Upscale momentum transfer due to CMT Parameterization for latent heat release: (Wang and Xie 1996) V. Indications of the CMT-induced unstable mixed Rossby gravity waves The thermal dynamic equation becomes where 1. Tropical two-day waves 2. Madden-Julian Oscillations The gravity wave speed is III. Analytical solutions to the two layer model The equation with one unknown variable: Assume a wave-like solution: Dispersion relation: where Contact: Lei Zhou Email: lzhou@sio.org.cn