The coupling of mixed Rossby-gravity waves with diabatic heating during the TRMM-KWAJEX field campaign

Abstract

Composite dynamic and thermodynamic structures of mixed Rossby-gravity (MRG) waves are presented with their coupling with diabatic heating and moisture sources/sinks, using Tropical Rainfall Measuring Mission-Kwajalein Experiment (TRMM-KWAJEX) field campaign data. A significant departure of convectively coupled waves from dry waves exists in the phases of wave component: maximum low-level wind convergence is accompanied by midtropospheric divergence and upper tropospheric convergence that is preceded by increase of moisture in the boundary layer. These phases correspond to surface turbulent transport, shallow and midlevel convections that cause moistening and heating of the lower and middle troposphere. They are followed by deep convection with maximum heating centered in the upper troposphere. The deep convective heating evolves to stratiform-like upper tropospheric heating and lower tropospheric cooling that precedes the quick demise of convection. Such a structure on convectively coupled MRG waves is summarized by four phases, which sheds lights on how tropical waves are coupled with convective processes in all their phases. Key Points Significant convectively coupled MRG waves are disclosed from TRMM-KWAJEX field campaign data Composite structures of dynamic and thermodynamic fields of MRG waves are presented The coupling between wave dynamics and diabatic heating is explored