Undergrad Radiation from air burst weapons

[nmsurobert]

I've been trying to read up and understand why a air burst of a nuclear weapon is less catastrophic than a ground burst when speaking about nuclear fallout. I think I understand that intensity of the dangerous radiation falls off quickly because of an inverse square law, but what happens to the rest of the radioactive material (energy)? it just floats away? the atmosphere just eats it up?
if a nuclear weapon explodes when hitting the ground, is the dangerous radiation now embedded in the ground and that is why the fallout of a ground burst is worse?

thanks.

 

[Bandersnatch]

Heave a read through this document:
http://nuclearweaponarchive.org/Nwfaq/Nfaq5.html#nfaq5.2
The sixth paragraph and onwards of pt. 5.2.1 address this question directly.

In short, groudbursts suck in large amounts of particulates, onto which radioactive isotopes are deposited. These large and heavy particles then fall relatively quickly, contaminating the area with high-density radiation.
In airbursts the radioactive bomb products are dispersed, and take a long time to fall to the ground (allowing time for decay processes to settle down).

 

[nmsurobert]

i will read through that. thank you!