Research about Tropical Large-Scale Atmospheric Dynamics

Zonal temporal dispersion relations of the equatorially confined wave solutions with (black) and without (red) the nontraditional Coriolis terms (NCTs). Except the last frame of the animation, sound of piano is played at a sound frequency proportional to the effective buoyancy frequency used to plot every frame. (From Ong and Roundy 2020)

NCTs represent components of Coriolis force that turn eastward motion upward and upward motion westward, and vice versa.

Motivation

Tropical large-scale atmospheric dynamics are known to impact global weather and climate. Traditional atmospheric models often neglect the nontraditional Coriolis terms (NCTs) due to scale analyses of extratropical atmospheric motion. However, the omission of NCTs in tropical large-scale atmospheric dynamics has been a subject of concern.

Modeling approaches

To address this, I developed a model hierarchy incorporating NCTs into the modeling framework. The hierarchy, from simple to complex, included models with linearized physics that are 1D vertical (Ong & Roundy 2020a), 2D meridional vertical (Ong & Roundy 2019), 2D zonal vertical (Ong & Roundy 2020b), and 3D Model for Prediction Across Scales (MPAS) (Skamarock, Ong, & Klemp 2021). I have also explored the effects of NCTs with full physics in a 2D zonal vertical setting using the System for Atmospheric Modeling (SAM) (Ong & Yang 2022). Main findings: My research revealed that omitting NCTs results in a noticeable westerly wind bias in the intertropical convergence zone (ITCZ) (Ong & Roundy 2019) and errors in the height of pressure levels in the tropical atmosphere (Ong & Roundy 2020a). Furthermore, incorporating NCTs in models can affect the speed and behavior of convective systems (Ong & Roundy 2020b; Ong & Yang 2022).

Main findings

My research revealed that omitting NCTs results in a noticeable westerly wind bias in the intertropical convergence zone (ITCZ) (Ong & Roundy 2019) and errors in the height of pressure levels in the tropical atmosphere (Ong & Roundy 2020a). Furthermore, incorporating NCTs in models can affect the speed and behavior of convective systems (Ong & Roundy 2020b; Ong & Yang 2022).

Models evolved

My work has directly contributed to the advancement of MPAS (Skamarock, Ong, & Klemp 2021) and SAM (Ong & Yang 2022), integrating NCTs into their frameworks.

Modeling peers inspired

My research has inspired other scientists to explore the effects of NCTs in atmospheric models, as evidenced by their work on models like the Regional Atmospheric Modeling System (RAMS, Igel & Biello 2020) and the weak temperature gradient framework (Marsico et al. 2023; 2024).

Broader Impact and Prospects

The significance of NCTs in tropical large-scale atmospheric dynamics with full physics for global atmospheric circulation remain unexplored. My ongoing commitment is to collaborate with modeling peers to further investigate the effects of NCTs on global atmospheric circulation and expand their inclusion in models.