The radiometric stability of selected thermal emissive bands (TEBs) of Terra and Aqua MODIS is evaluated via a direct intersensor comparison with SNPP VIIRS. The analysis adapts a “nadir-only” refinement of the simultaneous nadir overpasses (SNOs) analysis to evaluate radiometric deviations in MODIS Collection 6.0 and 6.1 data releases, the latter having been implemented with a version of crosstalk effect mitigation for Terra MODIS Bands 27−30. The comparison time series shows radiometric deviation in Terra MODIS Band 29 (8.55 mm) up to 6%, or 3 K in brightness temperature (BT), in Collection 6.0, and -1.5%, or -0.7 K in BT, in Collection 6.1. In particular, the safe mode event of February 2016 has significantly worsened the effect. This study includes the inter-TEB comparisons of MODIS bands B31 and B32 with SNPP VIIRS, and also describes a procedure using both radiance-to-radiance comparison and BTdifference time series to estimate the BT-difference uncertainty specifications as well as the radiance-to-radiance time series baselines. The Terra MODIS Band 29 result highlights the continual impact of crosstalk effect on numerous TEBs of MODIS Collection 6.1 that is not fully mitigated, which can further impact cloud masks, sea surface temperatures and other product retrievals.
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