Diurnal Cycle Effects over the Maritime Continent on Tropical Waves Using a Simple Linear Model

The diurnal cycle plays a large role in convective activity in the tropical atmosphere. It is estimated that the diurnal cycle contributes as large as 70% of the tropical variability and spans across multiple scales in time and space. A challenge to modeling is incorporating interactions between the diurnal cycle and the various convectively coupled atmospheric waves. These interactions can be complex especially over the Maritime Continent. This paper aims to model these interactions using a simple unified model of the tropical power spectrum from Stechmann & Hottovy 2017. In this model a simple source/sink of lower tropospheric moisture captures the diurnal cycle effects over two islands in the Maritime Continent (Sumatra and Borneo). Using this model, theoretical results are presented to show all modes of the model are excited by the diurnal forcing, the strongest effects are the resonant effect to the small scale Kelvin and Western Inertial Gravity waves, and the effects on each mode depend on how big of a factor lower tropospheric moisture is in an individual mode.