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Up Topic SeaDAS / SeaDAS - General Questions / The atmospheric correction of GOCI and VIIRS
- By liugers11 Date 2016-12-23 09:38 Edited 2016-12-23 22:38
Hi,
     When using "aer_opt=-8" and "taua=[]"  to do the atmospheric correction of  GOCI and VIIRS, The Rrs longer than 700 nm (e.g. Rrs_745) does not have values for these two sensors.  Can you tell me how to solve this problem? I need the Rrs products in the NIR bands.
     I have checked this method (Multi-scattering with fixed aerosol optical thickness) using the GUI of SeaDAS. It also has the same prblem with VIIRS or GOCI. Thank you very much.
      Merry Christmas
       Best Wishes
        Ge
- By liugers11 Date 2016-12-28 12:14
Hi,

      In my opinion, the atmospheric correction method (aer_opt=-8" and "taua=[]) does not need the assumptions of water (like the water-leaving reflectance of NIR band is zero). However, I find that when I set "ave_short=745 aer_wave_long=862", these two bands do not have Rrs value. Can you tell me the reason? Thank you very much.
    Best
   Wishes
    Ge
- By seanbailey Date 2016-12-29 01:00
By default, the l2gen code does not report Rrs above 720nm, except in the case of aer_opt conditions that run a NIR iteration.  For such options, the Rrs returned for the bands used in the NIR correction are the modeled values.  This is a diagnostic output, not intended for general use.

But given aer_opt=-8 (user input taua), you can make l2gen generate Rrs for all but the longest wavelength if you set (e.g. MODIS):
aer_wave_short=2130
aer_wave_long=2130


The code doesn't use these values when aer_opt=-8 is selected, but by setting them the code will output Rrs for the default bands (for MODIS, 748 and 869nm).
In fact, you can set it to any band above 600nm that you do not desire Rrs output.

Sean
- By liugers11 Date 2016-12-29 02:35
Hi, SeanBailey
           Thank you very much.  It really helps. In the next step, I will test the performance of the atmospheric correction of VIIRS using SeaDAS in several inland waters.
     Best
     Wishes
      Ge
Up Topic SeaDAS / SeaDAS - General Questions / The atmospheric correction of GOCI and VIIRS

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