Hi Ray,
Thank you so much for replying. Hope you are doing fine.
For the other minerals I processed CRISM images in CAT following the steps advised in workshop ppts (ATP corrections, georeferencing, summar parameter calculation).
For sulfates, as you must be aware, an issue regarding artifacts at 2.1micron has been raised. So I used radiance data for them specifically. And no correction was done on them. But in the end, I ratioed the radiance data (for representation purpose basically) but still I got triple absorption of CO2. That problem was observed in 1-2 datasets only. The feature was nullified in other CRISM images upon ratioing.
Since it has been suggested that a step during atmospheric correction may be responsible for thus artifact, I did not carry out volcano scan correction in radiance data. Are you suggesting I should perhaps try that?
Beacuse of the spikes at that wavelength, it has become very difficult for me to correctly identify if the absorptions are real or not. I am willing to share the images of ratioed radiance if that is helpful.
Thank you again for your time.