There is in fact a product (over priced) sold for sweeping off the slide topper from the ground
If you want to home brew I would start with a common push broom lay a couple of 1x3s up about a foot,,angle it slightly (1 foot one one end perhaps 10 inches on the other or 8 Angle to match your roof
Another 1x out to your broom handle, which is also a 1x
Hing the handle to theflat top so you you can fold it.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times