Earthdata Forum

Dear staff
When using L2GEN to process VIIRS images in SEADAS, I generated L2 files using L1B and GEO files, with the suite set to OC, and selected all bands in the products option. However, the generated file only contains five bands such as 410nm-671nm.How to solve this issue? Thank you very much for your help.


Best regards,
Wei

Please send us exactly what is in your l2prod parameter ... or a screenshot of the GUI so we can know your processing parameters.

This is my l2gen parameters:
PRIMARY INPUT OUTPUT FIELDS
ifile=/mnt/hgfs/VIIRS/1/SNPP_VIIRS.20231106T043000.L1B.nc
geofile=/mnt/hgfs/VIIRS/1/SNPP_VIIRS.20231106T043000.GEO.nc
ofile=/mnt/hgfs/VIIRS/1/SNPP_VIIRS.20231106T043000.L2.OC.nc

# SUITE
suite=OC

# PRODUCTS
l2prod=Rrs_vvv

# PROCESSING OPTIONS
# absaer_opt=0
# absaer=0.0
# aer_angstrom=-999.0
# aer_iter_max=10
# aermodels=[r30f95v01,r30f80v01,r30f50v01,r30f30v01,r30f20v01,r30f10v01,r30f05v01,r30f02v01,r30f01v01,r30f00v01,r50f95v01,r50f80v01,r50f50v01,r50f30v01,r50f20v01,r50f10v01,r50f05v01,r50f02v01,r50f01v01,r50f00v01,r70f95v01,r70f80v01,r70f50v01,r70f30v01,r70f20v01,r70f10v01,r70f05v01,r70f02v01,r70f01v01,r70f00v01,r75f95v01,r75f80v01,r75f50v01,r75f30v01,r75f20v01,r75f10v01,r75f05v01,r75f02v01,r75f01v01,r75f00v01,r80f95v01,r80f80v01,r80f50v01,r80f30v01,r80f20v01,r80f10v01,r80f05v01,r80f02v01,r80f01v01,r80f00v01,r85f95v01,r85f80v01,r85f50v01,r85f30v01,r85f20v01,r85f10v01,r85f05v01,r85f02v01,r85f01v01,r85f00v01,r90f95v01,r90f80v01,r90f50v01,r90f30v01,r90f20v01,r90f10v01,r90f05v01,r90f02v01,r90f01v01,r90f00v01,r95f95v01,r95f80v01,r95f50v01,r95f30v01,r95f20v01,r95f10v01,r95f05v01,r95f02v01,r95f01v01,r95f00v01]
# aermodmax=-1
# aermodmin=-1
# aermodrat=0.0
# aer_opt=-17
# aer_rrs_long=-1.0
# aer_rrs_short=-1.0
# aer_swir_long=-1
# aer_swir_short=-1
# aer_wave_long=862
# aer_wave_short=745
# atmocor=1
# brdf_opt=7
# cirrus_opt=0
# filter_file=/home/dxz/SeaDAS/ocssw/share/viirs/msl12_filter.dat
# filter_opt=1
# gain=[0.96571,0.95267,0.98339,0.98540,0.99177,0.97731,1.0,1.02789,0.998379,1.0]
# gas_opt=495
# glint_opt=1
# maskbath=0
# maskcloud=1
# maskglint=0
# maskhilt=1
# maskland=1
# masksatzen=0
# maskstlight=0
# masksunzen=0
# mumm_alpha=1.945
# mumm_epsilon=1.00
# mumm_gamma=1.00
# offset=[0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0]
# outband_opt=2
# oxaband_opt=0
# polfile=/home/dxz/SeaDAS/ocssw/share/viirs/npp/cal/polcor_viirsn
# pol_opt=3
# proc_land=1
# proc_ocean=1
# proc_sst=0
# rad_opt=0
# sl_frac=0.25
# sl_pixl=-1
# atrem_opt=0


I guess this might be the reason for the atmospheric correction method. I chose -17. Which atmospheric correction method should I choose to preserve the Rrs of visible and near-infrared bands?

It is not the atmospheric correction option, it is: "_vvv" tells l2gen to expand the products to the list of visible wavelengths - which to not include the NIR bands.
You will need to explicitly define the NIR bands for l2gen to return them. Keep in mind, if you request a band that was used in the atmospheric correction process, the Rrs returned was is not a "measured" quantity.

Sean

To add NIR, here's the specific l2prod list for VIIRS SNPP (uses the "vvv" shortcut):
l2prod=Rrs_vvv Rrs_745 Rrs_862

... or everything (without using the "vvv" shortcut):
l2prod=Rrs_410 Rrs_443 Rrs_486 Rrs_551 Rrs_671 Rrs_745 Rrs_862

Also the cautionary note (as Sean mentioned in the previous post, the same wavelengths are being used by default for atmospheric correction).
aer_wave_long=862
aer_wave_short=745

Danny