Question about Lt results of Landsat8 OLI

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roxani2018
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Question about Lt results of Landsat8 OLI

by roxani2018 » Mon Nov 08, 2021 11:03 pm America/New_York

Dear all,
Hi!
I used SeaDAS(v8.0) l2gen (oli module) to process with Landsat8 Collection1 data and obtained Lt data successfully. However, when I compared Lt from SeaDAS with Lt calculated directly from DN data, I found they were obviously different (pleased see the attached image). The original data I downloaded from USGS is : LC08_L1GT_122048_20130521_20170504_01_T2, and the results shown in the attached image is based on band5.
I am not sure what caused this kind of difference, so I write to find help.
I am looking forward to your reply and appreciate your kindly help.
Best wishes,
Roxani
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OB.DAAC - SeanBailey
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Re: Question about Lt results of Landsat8 OLI

by OB.DAAC - SeanBailey » Wed Nov 17, 2021 4:14 pm America/New_York

Roxani,

The l2gen code uses the reflectance formula and computes Lt from that. Similar to the approach described here:
https://www.usgs.gov/core-science-syste ... ta-product

There is also a correction applied for the various focal plane modules and an overall vicarious calibration applied.

The result is consistent with the Lt generated by other sensors we support (e.g. a coincident MODIS scene provides comparable Lts)

Sean

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