1.2 Measurement Parameters

1.2.1 Level

All Leveloggers measure total (absolute) pressure. When submerged, the Levelogger is recording the combination of barometric pressure and water pressure. The actual pressure of just water (A) above the sensor is obtained by subtracting barometric pressure (B) from the total pressure (L) (see Figure 1-1).

The best method to compensate for barometric pressure is to employ a Barologger above the water level, to obtain records of barometric pressure. The Levelogger Software includes a Data Compensation Wizard, which guides you through the automated process of barometric compensation. Manual methods can be employed to determine the absolute water level using barometric records collected on-site or available from a local weather station (i.e. airport). Water level readings from Leveloggers are automatically temperature-compensated.

A = Actual water column height
B = Barometric pressure
L = Levelogger total pressure readings
D = Depth to water level, below reference datum