Earthdata Forum

Hi,

When setting aer_opt = -8 in l2gen, what wavelengths do I have to specify taua at? The wavelengths of the output Rrs? I've tried:

1. processing an image with taua specified for my chosen Rrs wavelengths, and the image processed successfully
2. processing an image with taua specified for a random selection of my chosen Rrs wavelengths (i.e. less wavelengths than I selected for Rrs), and the image processed successfully.

For both the above runs, the output was identical - so I'm curious as to how the code interprets my taua specification.

Cheers
Catherine

Catherine,

aer_opt=-8 requires one taua per wavelength.  For MODIS, that'd be 16 (IR bands not needed), VIIRS would be 10, SeaWiFS needs 8. 

For example, setting taua to 0.2 for all bands in VIIRS would look like this:
l2gen ifile=V2014316183000.L1B-M_SNPP.nc geofile=V2014316183000.GEO-M_SNPP.nc ofile=t2.aer.nc aer_opt=-8 taua=[.2,.2,.2,.2,.2,.2,.2,.2,.2,.2]


The code should complain if you don't give it enough elements in taua=[] .

Sean