Data Crunch And Rotor Speed

If, the sonic boom at the region on the blade closer to where they connect to the rotor mast of a helicopter, is responsible for its lift,

then, at higher altitudes where the air is thin and water has a lower density value (humility) and a reduced boom velocity, a decrease in rotor speed may just maintain lifts.

Intuitively, the normal reaction to a lost in lift is to increase rotor speed.

However, it is not altitude per se that requires a reduced rotor speed, in cold regions a reduction in water density may also require a similar reduction in rotor speed to take flight.

Good night...