At 12mm, the opacity of the atmosphere can be significant: in mediocre
conditions, the signal loss is can be a 20% at low elevations. With
12-mm data, an opacity correction should be applied to the data during
step. To apply this correction, atlod
model of the atmosphere (using meteorological data contained
within the dataset) to compute a model opacity. Note that this is just
that - a model - and so has its limitation. To apply atmospheric
opacity correction, use
|options=opcorr,birdie,reweight,xycorr||Options for typical 12-mm|
|continuum observation, or|
|options=opcorr,hanning,compress||possible options for spectral|
Please note the following:
options=opcorrcannot be used.
birdieoption for continuum data is used to discard edge channels and every second channel (as noted earlier, successive channels are not independent, and so there is no sensitivity penalty in discarding every second channel).