I was wondering if there was a mechanism for SeaDAS to output the aerosol model it determines for a given atmospheric correction procedure (i.e. for aer_opt=-2,-3,-9). I was hoping this output would be available when I put the product aerindex into my L2Gen product list, however I just seem to get NaNs in that one. Perhaps i'm misunderstanding what aerindex is/was used for.
Furthermore, if one had access to an array of output aerindex (or whatever) values, then I was thinking it would be cool if the user could modify that array and then use it as an input to a subsequent L2Gen call to force the atmocor to choose the chosen aerosol model.
With the original Gordon and Wang implementation with 12 aerosol models, it was pretty easy...just ask for:
aer_model_min and max are the bounding models that encompassed measured epsilon value, ratio is the weighting between them.
Then we went to 80 models with a relative humidity selection and so we have:
Yeah, a bit complicated. Also, there is no mechanism within the code to read and apply model numbers from an input file. You can do so for a pair of models:
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aer_opt (int) (default=99) = aerosol mode option ... -4: Multi-scattering with fixed model pair (requires aermodmin, aermodmax, aermodrat specification) -5: Multi-scattering with fixed model pair and iterative NIR correction (requires aermodmin, aermodmax, aermodrat specification)
There is also a method that can take an input angstrom coefficient and use it for the model selection:
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... -6: Multi-scattering with fixed angstrom (requires aer_angstrom specification) -7: Multi-scattering with fixed angstrom and iterative NIR correction (requires aer_angstrom specification)
BTW, aerindex is a very ancient attempt at flagging absorbing aerosol in the data (the aerosol models, even today, are non- or weakly absorbing). There is a convoluted polynomial that defines an absorbing aerosol index. I think it only worked for SeaWiFS and MODIS (if you can say what it ever did was "working"). One of those vestigial bits that never seems to get removed...you should ignore it