wavelengths when specifying taua

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
Posts: 19
Joined: Tue Jun 06, 2017 11:42 am America/New_York
Answers: 0

wavelengths when specifying taua

by cmitchell » Thu Jan 09, 2020 9:32 am America/New_York


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.



OB.DAAC - SeanBailey
User Services
User Services
Posts: 1483
Joined: Wed Sep 18, 2019 6:15 pm America/New_York
Answers: 1
Been thanked: 5 times

wavelengths when specifying taua

by OB.DAAC - SeanBailey » Sat Jan 18, 2020 7:47 pm America/New_York


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=[] .


Post Reply