Detailed Description

Color Key Case pending Case closed Case reopened QA note
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Case #:PM_MOD21_17307   Opening date: 11/03/17   Last update: 11/27/18
Status: Closed
The C6 MxD21 products were found to contain incorrect LST values. Emissivities that are too low over many regions and LST values that are too high are also consistently observed globally in the most recent version of the C6 MOD21 L2 data. This issue has been traced to a potential coding error in interpolation of the WVS coefficients. The issue impacts the L2 data and downstream L3 LST daily and 8-day composite products (MxD21A1/ MxD21A2).Users should be aware that the current suite of products has been found to be unusable for science and validation purposes.

Below is a comparison of a C6 processed MOD21 LST granule compared to MOD11 LST. The L2 MOD21 granule over western Africa shows a much larger temperature range than observed in MOD11. The third image shows the absolute difference image (MOD21 - MOD11) the specific differences can be observed.

NOTE: This issue has been addressed in the current operational version of the C6 using the revised suite of PGEs with software fix to address this and several other minor known issues in the product.



Absolute Difference in K = (MOD21 - MOD11)

LST Difference scale in K

Occurrence: C6 Both Terra and Aqua MXD21 LST products as described above.

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