Will google AdSense punish me for refreshing the page if the user resizes the browser below a certain point?
It violates Adsense Program Policies.
Source : Link
When you refresh the page, it falls under artificially generating impressions.
As far as I know, there is no way to change the size of the ad unit when the user resizes his browser. Even responsive ad units adapt to the screen size only on the first load and browser resizing has no effect.
As a side note, refreshing a page when the user resizes the window isn't a good thing to do unless it is extremely essential. Consider using responsive design or you can display a message asking if the user wants to reload the page. This way, the adsense policy stated above won't be violated.