the pressure will fluctuate as the temperature fluctuates.
water pressure at 1000 ft depth in 50 degree water
will be higher than
water pressure at 1000 ft depth in 60 degree water.
due to thermal expansion.
the speed at which the probe decends
will be
faster in 60 degree water.
and
slower in 50 degree water.
due to viscosity.
unless they include these two things into their formula it will
be wrong everytime.
also , they would need to take temperature and pressure readings at timed intervals as the probe decends to aquire any accurate or useable data.
taking salinity into consideration would also be a good idea.
however with these two readings alone you could determine how fast the probe decends if the salinity is known.
why not just weight down a probe and attach it to a buoy that stays submerged at 200 ft or so and bobs up to send the data?
the probe could be attached to the bouy by a optical fiber type fishing line of sorts and be reeled in and out as needed.
the data could be sent to the bouy via the optics.
that sounds expensive and if so then they could calibrate the probes with the buoy / probe thingy.
.
