Harsh and dry around top of crater (5)
I believe the answer is:
acrid
'harsh' is the definition.
(thesaurus)
'dry around top of crater' is the wordplay.
'dry' becomes 'arid' (similar in meaning).
'around' is an insertion indicator.
'top of' suggests taking the first letters.
The first letter of 'crater' is 'c'.
'arid' going around 'c' is 'ACRID'.
'and' is the link.
(Other definitions for acrid that I've seen before include "Sharp-smelling like smoke" , "Direly pungent" , "Bitter - caustic" , "Having a bitter smell or taste" , "Astringent" .)