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 & = -6.24097e-3 \\ Gb_1 & = -6.93498e-3 \\ Gb_2 & = -6.90358e-3 \\ Gb_3 & = -4.29155e-3 \\ Gc_0 & = -3.11680e-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 = doxy23
Confirm the channel type.
<< 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.