MODIS Fog Product

Errors and unexpected results
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weatherextreme
Posts: 11
Joined: Tue Dec 14, 2010 5:48 pm

MODIS Fog Product

Post by weatherextreme »

Hello,
I ordered MODIS hdf format data and view it just fine in McIDAS.
However the data do not contain the Fog product. It also does not contain channel 22 so that I can perform differencing to create the product.
I ordered MOD06.L2 data

Does anyone know where I can obtain the fog product from a past data (i.e., not real-time as I can find these)?

Attached is the list of what came with the data files I ordered.

Thank you!
Elizabeth Austin
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bobc
Posts: 933
Joined: Mon Nov 15, 2010 5:57 pm

Re: MODIS Fog Product

Post by bobc »

Hello Elizabeth -

From NASA LAADS, I was able to order some MOD02 data that contains all 36 bands. From the LAADS page, I clicked on Data and then Search. I used the Satellite/Instrument dropdown to select Aqua MODIS (though you could use Terra MODIS also) and selected MOD021KM. I don't have much experience with the LAADS data ordering interface, but I was able to choose a start/end date/time to match a fog event from May, 2010. Once you have set all of your search parameters, click Search at the bottom of the page. This will list out all of the MODIS granules that fit your request and you can go on to order them.

I set up a local dataset for this MOD02 data, and once the data is added through the Satellite>Imagery chooser, the Field Selector lists out all of the bands by wavelength. For the fog product, I used the Misc>Simple Difference formula to subtract band 22 from 31. When evaluating the formula, I chose 11.0186>Temperature for field a and 3.9719>Temperature for field b. Once I changed the enhancement range for the display, I was able to pick up on fog.

Please let me know if you have any questions.

Thanks -
Bob Carp
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weatherextreme
Posts: 11
Joined: Tue Dec 14, 2010 5:48 pm

Re: MODIS Fog Product

Post by weatherextreme »

Thank you Bob!
It worked like a charm!
Best regards,
Elizabeth
:D
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