Raster Analysis tasks that have the outSR property in their Context parameter will save results in the specified spatial reference.
Spatial Reference syntax:
"outSR": {"wkid": <wkid>}The spatial reference is specified with a WKID (well-known ID). Each WKID number is unique to a specific spatial reference. For a list of all the WKID numbers and their corresponding spatial references, see Using spatial references.
Spatial Reference example (GCS_WGS_1984)
"outSR": {"wkid": 4326}