PhCor compares the amplitude of each scan with and without atmospheric phase correction. The phase correction is only adopted when it reduces the phase decorrelation within each scan. Note that the spectral units, L01 to L12, do not store information on time scales smaller than a scan, while the continuum units, C01 to C12, do so; two streams of data are so stored at Bure for each L0i and C0i unit, respectively with and without atmospheric phase correction.
A green line on the bottom of the plot produced during the flux calibration (see Figure ) shows, when being above zero, the scans for which the program PhCor activates the atmospheric phase correction.
In addition, this procedure checks for interferences in the WVR channels, if it was not done before (for instance by the pipeline).
Note that the data are not corrected for atmospheric decorrelation if ``let do_atm no'' was selected (see Sect. ).
At the end, a procedure is launched to verify if the phase calibrators are polarized, setting the variable do_avpol accordingly (see Sect. ) to define the amplitude calibration mode.