MODIS 1640 nm band

avmehta · by **avmehta** » Mon Feb 08, 2021 1:17 pm America/New_York

Hello,

I am processing MODIS L1 to L2 at 1) 1 km and at 2) 250 m. Please see the attached images - in 1 km image I see stripes. In my par file I did not specify any resolution -- considering that 1 km would be default. Can you please help with this?

https://oceancolor.gsfc.nasa.gov/forumd ... s_1640.png and https://oceancolor.gsfc.nasa.gov/forumd ... s_1640.png .

Thank you.

Amita

by **OB SeaDAS - dshea** » Mon Feb 08, 2021 3:05 pm America/New_York

Your picture did not come through, but if you are looking at L1 or L2 MODIS files you will see stripes due to the bowtie effect. For MODIS at 1km you will see stripes every 10 lines, 500m at 20 lines, 250 at 40 lines. It is worse off nadir. See this:

MODIS
https://oceancolor.gsfc.nasa.gov/docs/bowtie/modis/

VIIRS
https://oceancolor.gsfc.nasa.gov/docs/bowtie/viirs/

Hopefully this is the stripping you are seeing, but I can't really tell without more information.

don

avmehta · by **avmehta** » Mon Feb 08, 2021 4:37 pm America/New_York

Thanks Don. But it is not so obvious in other bands -- just 1640 nm! Is that to be expected?
[img][/img]. and [img][/img].
Thanks.
Amita

OB.DAACx - SeanBailey · by **OB.DAACx - SeanBailey** » Fri Feb 12, 2021 3:34 pm America/New_York

Amita,

Yes, it is expected. The 1640nm band (Band 6 in MODIS parlance) on Aqua has some issues. See: https://mcst.gsfc.nasa.gov/calibration/time-dependent-list-non-functional-or-noisy-detector

Sean