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Case #:PM_MOD11_22318   Opening date: 11/14/22   Last update: 12/05/22
Status: Closed
The C6 MODIS Terra Day and Night Land Surface Temperature/Emissivity (MOD11*) daily LST products are showing loss of data retrieval in the L2 and L3 daily/CMG products. The issue is under investigation. The two images below show global browse images from C6 and C61 for October 27th, 2022 (2022.300). The image on the left shows a significant loss of LST retrieval in the C6 MOD11B1 product compared to the global browse image of C61 on the right. LDOPE is currently investigating this to determine the root cause of this issue and the impacted periods. This note will be updated as more information becomes available.

MOD11B1-D1 day A2022300 (2022-10-27)
C6 Global Browse Image

MOD11B1-D1, day A2022300 (2022-10-27)
61 Global Browse Image


UPDATE 12.05.22


The C6 MOD11 production has been discontinued starting on A2022319 (11/19/2022) onwards. The Terra PV LWIR bands (27-30) crosstalk issues has significantly degraded the quality in the input MOD07_L2, following the last set of Terra Constellation Exit Maneuvers (CEMs),causing significantly less or no LST retrievals at all for most granules. The MOD07 product is an input to the MOD11 LST product. Specifically, the MOD07 Quality Assurance Bits0 (Retrieved Temperature Profile QA) and Bits1-2 (Retrieved Temperature Profile Confidence QA) are used by LST. Below is an image of the MOD07 QA bit table for reference, where a 'Valid Pixel Count' for LST will include Bit0 = 1 (useful) and Bit1-2 = 1 (Best Quality).

MOD07 QA Bit Table

The MOD07_L2 global valid pixel count for different data days is shown below and is significantly lower starting on DOY 2022.320 and onwards. Hence, users are requested to switch to the C61 version of the Terra LST products.

Day of Year Valid Pixels Total Pixel Count
2022.318 71714 109620*288 = 31570560
2022.319 65544 109620*288 = 31570560
2022.320 2103 109620*288 = 31570560
2022.321 2471 109620*288 = 31570560


UPDATE 11.15.22


The loss of retrieval in C6 MOD11 products has been traced to degraded performance of the input MOD07_L2 Atmospheric Profiles data, because of the Terra PV LWIR bands (27-30) crosstalk effects. Though this crosstalk issue was present from the beginning of the mission, its impact on the product was not significant, and not noticeable until after year-2009. The IR crosstalk effect became more significant following the MODIS Terra safe hold in February 2016. The C6.1 reprocessing implements an approach to correct this crosstalk in the calibration from the beginning of the mission through the safe hold period and into the forward processing period. Hence, users are requested to switch to the C61 version of the Terra LST products for improved performance.

Occurrence: C6 MOD11 L2 and L3 daily/CMG products. Impacted period TBD.

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