Example 18: deri_o2sat_garcia, derived O2 saturation from concentration

Consider an RBRconcerto³ C.T.D.DO logger, where the DO channel is a RBRcoda ODO. The RBRcoda ODO transfers both the foil temperature and the dissolved oxygen concentration (not compensated for salinity). The RBRconcerto³ calculates the concentration compensated for salinity first, then the air saturation (in %) via the following equation:

where

• Cc is the concentration in uMol/L, compensated for salinity,

• Patm is atmospheric pressure, and

• Pav is air vapour pressure.

Solubility is calculated via Gordon and Garcia as:

where S is the salinity in PSU and Ts is defined as:

with T being the water temperature in °C and:

Air vapour pressure (in dbar) is calculated as:

The corresponding logger coefficients are:

• n0, the index of the concentration channel, already compensated for salinity

• n1, the index of the water temperature channel

• n2, the index of the salinity channel

• n3, the index of the atmospheric pressure channel (set to value in order to use settings atmosphere)
  

The O₂ saturation equation was revised in firmware 1.094 of the RBRconcerto³, RBRmaestro³, RBRduo³, RBRlegato³ and RBRargo³. For the previous implementation of this equation, refer to the version B of this document.

Examples

>> calibration 9 type
<< calibration 9 type = doxy22

Confirm the channel type.

>> calibration 9
<< calibration 9 type = doxy22, datetime = 20171201000000, n0 = 4, n1 = 5, n2 = 8, n3 = value

Request confirmation of all channel indices.