Mike,

 

I never studied parachutes, but I think round parachutes work primarily from velocity pressure. The formula is pressure = 1/2 * density * v^2. Pressure must be constant at equilibrium, so velocity would vary more or less with the inverse of the square root of density. This ignores viscous and aerodynamic effects, which I would expect to be small.

 

Thus, for standard atmosphere, the speed at sea level would be about the square root of 2.048/2.377, or 92.8% of the velocity at 5000'. Based on the assumed 1500 fpm decent rate at 5000', this would yield a sea level decent of 1392 fpm or 23.2 fps. This is equivalent to stepping of a 8.36 ft ladder.

 

Rob