There is a sentence in the Geography of the Great God that explains the cause of the cold pole: "Basin topography, poor airflow, weak turbulent exchange."

Turbulent exchange: the transport and mixing of fluid properties caused by turbulent motion of fluid.

The formation of extremely cold region is due to the topographic difference caused by basin topography.

When the cold air from the north arrives, it merges with the oncoming warm and humid airflow, and rises due to the low density and high temperature, while the cold air from the north is forced to fall due to the high density and low temperature, and collides with the opposite airflow to form turbulent exchange, and the result of turbulent exchange is the formation of turbulence or vortex and other rare bad weather phenomena.

However, due to the terrain, the airflow where the cold pole is formed is not smooth, which makes the turbulent exchange weak (weak is not strong) and makes the cold airflow fall and sink in the basin. Over time, it is like a water basin, constantly receiving cold airflow, and finally forming extremely cold weather.

So the phrase "weak turbulent exchange" means that turbulent exchange is not strong.

I don't know if you understand.