Xylem WQ-FDO OPTICAL DISSOLVED OXYGEN TRANSMITTER - Manual (Page 11)

Global Water
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Other Calculations:
Salinity:
Salinity is a unitless number but is generally referred to in PSS (Practical Salinity
Scale or PSU (Practical Salinity Units). Salinity can be calculated from
conductivity by the equation:
Salinity = A+(B*R^0.5)+(C*R)+(D*R^1.5)+(E*R^2)+(F*R^2.5)
Where:
A = 0.0120
B = -0.2174
C = 25.3283
D = 13.7714
E = -6.4788
F = 2.5842
R = Measured conductivity in uS / 53087uS
Altitude:
Calculating the barometric pressure based on altitude is not exact. It can vary with
air temperature, temperature lapse rate, and other atmospheric conditions. The
following is a good approximation.
Elevation
Feet
Pressure
mbar
Elevation
Feet
Pressure
mbar
Elevation
Feet
Pressure
mbar
0 1013 2000 944 4000 878
250 1004 2250 936 4250 870
500 994 2500 926 4500 862
750 985 2750 918 4750 854
1000 977 3000 910 5000 846
1250 969 3250 902 5250 838
1500 960 3500 894 5500 832
1750 952 3750 886 5750 824
P
a
= 1013 - (3.54733E-2*A) + (4.6068714E-7 * A^2)
Where:
P
a
= Atmospheric Pressure in mbar
A = Altitude in feet