Dear Maoyi,

I think that is due to polar vortex and Ozone loss.

I think you can contact Mr Khaykin, a researcher at the French laboratory Latmos. He was my teacher in the Master of Arctic Studies.

[email protected].

Good luck 🤞

Regards

Zakia

It is just that the net wind speeds are in the opposite directions in the N and S hemispheres during this time period.

Dear Molulaqhooa Maoyi

Please consult the definition of a stream function provided by the American Meteorological Society

http://glossary.ametsoc.org/wiki/Streamfunction