I am working on the realism of a fictional planet which has an average temperature lower than that of the Last Glacial Maximum (LGM), and possesses a single large supercontinent rather than distributed landmasses.
My research has indicated that Hadley Cells retreated equator-ward during the LGM, which would place the Subtropical Ridges closer to the Equator. I am curious what is likely to occur on a planet that is even colder than that? Would the Hadley Cells disappear entirely? What happens to the Subtropical Ridges and their accompanying deserts in such a case?
For reference: Hadley Cell Retreat - https://journals.ametsoc.org/doi/10.1175/JCLI3766.1