Tell everyone it's the supercharger.
Have you tried to open the hood and look around to see what is making the noise when it is doing it? Honestly, people could guess all day long on the forums with little to no chance of actually getting ir right.
Open the hood, have someone rev up the engine for you and make sure not to contact any moving parts...get a loooong screwdriver and put the metal end against different stuff like the alternator, idler pulley, steering pump, valve covers, etc until you can locate exactly where the noise is from.
A quick way to find out if it's the belt is to have someone make the noise (you can rev the engine yourself from the throttle body under the hood) -- and spray some brake clean or something briefly on the belt itself -- see if the noise changes.
The best way to find out if it is related to something that is serpentine driven is to obviously take off the serpentine belt and start the engine to see if you can get the noise to reproduce itself. You'll have no water pump, no p/s, no alt, etc so you'd want to do this while the engine is cold and only for a brief time.
02 Ext Cab | 4x4 | 3.0 | M50D-R1 | 3" PA BL | 33x12.50x15 Dynapro M/T's | 15x8 Soft 8's