update RTQC

I implemented here the revision proposed in #102 by @vracape @catsch and @cgourcuf. This pull request also closed #62 raised by @ptestor

sections/oxygen_rtqc.md

@@ -1,8 +1,10 @@
-# Real Time Data Processing & Quality Control
+# Required Metadata, Real Time Data Processing & Quality Control
 
-## Real Time data processing
+## Required Metadata and Real Time Data Processing
 
-Prior to deployment, oxygen sensor metadata (i.e. sensor model, sensor serial number and calibration coefficients) should be sent ahead of the mission to the Data Assembly Center. It is important that the glider is well configured, intermediate parameters (phase measurements) should be sent in real time (RT) as well. This will allow first to check if dissolved oxygen values computed inside the glider are appropriate and then this adds the possibility to recompute the dissolved oxygen concentration using the up to date method associated with the sensor model, intermediate parameters and calibration coefficients. 
+Configurations for the calculation of DOXY are function of the sensor model, sensor serial number, set of calibration coefficients and intermediate parameters. The recommended configurations (e.g. salinity compensation of MOLAR_DOXY, pressure correction for pressure effect on quenching, temperature compensation) and thus the required metadata are available in the Processing Argo oxygen data at the DAC level (https://archimer.ifremer.fr/doc/00287/39795).
+
+Prior to deployment, all the required metadata should be sent ahead of the mission to the Data Assembly Center. It is important that the glider is well configured, intermediate parameters (phase measurements) should be sent in real time (RT) as well. This will allow first to check if dissolved oxygen values computed inside the glider are appropriate {numref}`RTQC_check_Doxy` and then this adds the possibility to recompute the dissolved oxygen concentration using the up to date method associated with the sensor model, intermediate parameters and calibration coefficients. 
 
 <!--
 ![Difference between oxygen concentration computed by the glider (DOXY) and those computed by the Data Assembly Center (DAC) from intermediate parameters and associated calibration coefficient (DOXY2).](/images/RTQC_check_Doxy_combined.png)
@@ -14,7 +16,7 @@ Prior to deployment, oxygen sensor metadata (i.e. sensor model, sensor serial nu
 Difference between oxygen concentration computed by the glider (DOXY) and those computed by the Data Assembly Center (DAC) from intermediate parameters and associated calibration coefficient (DOXY2).
 :::
 
-Configurations for the calculation of DOXY are in fact function of the sensor model and intermediate parameters. The recommended configurations (e.g. salinity compensation of MOLAR_DOXY, pressure correction for pressure effect on quenching, temperature compensation) are available in the [Processing Argo oxygen data at the DAC level](https://archimer.ifremer.fr/doc/00287/39795/). For some optode models, it may be appropriate to apply a time lag correction in RT, taking into account the sensor time response, using either the manufacturer value or any value defined from previous deployments with the specific sensor. A real time lag correction might improve the useability of the real time data significantly.The method is described in {cite}`Bittig2014`.
+For some optode models with large time response (e.g. 3835), it may be appropriate to apply a first time lag correction in RT, taking into account the sensor time response, using either the manufacturer value or any value defined from previous deployments with the specific sensor. A real time lag correction (see methods for such corrections in section (7.x add link)) might improve the usability of the real time data significantly.
 
 There is no unique procedure for Real time data and metadata sending. Protocols, format and file naming convention should be discussed with DACs before deployment. OceanOPS and DACs requirements on data and metadata are described in the OceanGliders Best Practices document in the data and metadata management section, paragraph 6  (link to be added when overview paper is in review).