Function_cosine_lat6090.py:

Using the ERA5 reanalysis data to describe the variables related to the stratospheric polar vortex, such as zonal wind, temperature, and ozone from 60° to 90° through a cosine weighted average.

Function_EPflux_BD_circulation_ERA5.py:

Using the ERA5 reanalysis data to conduct batch calculations of Eliassen-Palm flux (EP flux) and residual circulation.