Example 17: corr_o2conc_garcia, O2 concentration compensated for salinity and pressure

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 and pressure first:

\[O2corr = (C_0 + C_1 \cdot O2unc) \cdot exp(S \cdot (Gb_0 + Gb_1 \cdot Ts + Gb_2 \cdot Ts^2 + Gb_3 \cdot Ts^3) + Gc_0 \cdot S^2) \cdot (1 + P \cdot C_2)\]

where

O2corr is the corrected O2 concentration, compensated for salinity and pressure,
O2unc is the uncompensated O2 concentration returned by the RBRoptode,
C₀ and C₁ are corrections and scaling factors for the uncompensated O2 concentration,
C₂ is a correction factor for pressure,
S is the salinity in PSU,
P is sea pressure in dbar,

and

\[Ts = ln(\dfrac{298.15 - T}{273.15 + T})\]

where T is the water temperature (in °C), and

\[\begin{equation*} \begin{aligned} Gb_0 & = -6.24523e-3 \\ Gb_1 & = -7.37614e-3 \\ Gb_2 & = -1.03410e-2 \\ Gb_3 & = -8.17083e-3 \\ Gc_0 & = -4.88682e-7 \end{aligned} \end{equation*}\]

which correspond to Garcia and Gordon coefficients.

The corresponding logger coefficients are:

c0 is C₀
c1 is C₁
c2 is C₂
n0 is the index of the water temperature channel
n1 is the index of the salinity channel
n2 is the index of the pressure channel
n3 is the index of the atmospheric pressure channel (set to value in order to use settings atmosphere)

One might change c0 and c1 in order to perform a two-point calibration to the RBRcoda ODO. Please note that those coefficients are used and stored only by the logger, not the RBRcoda ODO.

Examples

>> calibration 4 type
<< calibration 4 type = doxy23

Confirm the channel type.

>> calibration 4
<< calibration 4 type = doxy23, datetime = 20171201000000, c0 = 0,c1 = 1, c2 = 3.25e-5, n0 = 5, n1 = 8, n2 = 3, n3 = value

Request confirmation of all calibration coefficients.