which bands for water vapour retreival

[rese_support]

 I was wondering which bands (channels) need to be
 selected in Window 1 and Window 2 for water vapour retreival with band
 regression in ATCOR4. The default window 1 890.5 890.5 Channels 53-53
 Water vapour (WV) absorption region 937.0 and 958.0 nm (channels 58 to
 60). or could we just accept the default bands in window 1 and wv
 absorption region but make changes in preference_parameters.dat file
 885.0 1000.0 start/stop for interpolation in 940nm region. (default).

The start/stop interpolation wavelengths are meant if water vapor
retrieval is not very successful (e.g., if the 940nm band calibration is
bad). So, it won't affect the retrieval but rather the interpolation in
case the 940/1130 interpolation flag is set in the preferences. For the
water vapor retrieval, one can use the recommended bands - for AISA,
often the 820 nm band works better than the 940 band, however.

 Should we take this decision based on the data, or are
 there some generic rules on how to choose the wavelengths for water
 vapor estimation?

It depends on the sensor configuration and one has to check out the
water vapor map - if it is smooth everything should be fine. If not, one
should go for another absorption region or use different bands (e.g.
more in the center, broader ranges). Such adjustments require
experience, however.