Barometric (Air) Pressure
Barometric Pressure measures the weight of the air. When using pressure transducers to calculate depth of water, the pressure sensor experiences the sum of all the pressure above it - this includes both the pressure of the water column and the pressure of the air column above it. To accurately calculate the water depth, it is, therefore, very important to subtract the barometric pressure from the total pressure reading.
Vented (Guaged) pressure transducers use a special cable to allow the instrument to simultaneously measure barometric pressure along with any other measurements, with the advantage that no additional instruments or calculations are needed - the single instrument can do all your work for you!
Non-Vented (Absolute) pressure transducers do not have any way to measure barometric pressure. When using non-vented units, you will need to use a seperate instrument to log the air pressure and then combine those readings with the data from the transducer for accurate results.
The following products are available to test for Barometric Pressure:
AquaTROLL 200
The Aqua TROLL 200, the first in a new line of water quality instruments from In-Situ® Inc., monitors and logs conductivity, level/pressure and temperature in the harshest environments.
BaroTROLL
The BaroTROLL is a low-cost, self-contained logger that measures barometric pressure. It contains highly precise barometric and temperature sensors, a data logger, and internal power in a 18.3mm (0.72 in) diameter housing.
BaroTROLL 100
The BaroTROLL® 100 instrument measures and logs barometric pressure data, which is used to compensate for changes in water level due to barometric fluctuations. Use the self-contained, economical BaroTROLL 100 with a Level TROLL® 100 or 200 instrument.
