The eddy transport and mixing effects on the horizontal distribution of heat, moisture, mass, potential vorticity, and passive tracers in general are generally well resolved by modern atmospheric models. However, simulation should not be equated with understanding. The need to understand and parameterize the atmospheric eddies is still imperative, with applications on the variability of the large-scale features such as westerly jet, Hadley cell, waviness, and their response to external climate perturbations. In this talk, I will review the geophysical fluid dynamics theories behind the scaling of eddy scales and eddy diffusivity, and illustrate their applications in terms of understanding the reduced equator-to-pole temperature gradient and the reduced temperature variance under climate warming. If time permits, I will share some thoughts on fruitful future directions for advancing the theoretical understanding of the atmospheric eddies and their role in shaping the atmospheric circulation and the global climate.

Eddy Diffusivity,Polar Amplification,Eddy closure