VIIRS C2 False Fire from L1 M13

Spurious "arcs" of false fires observed in the C2/SNPP VIIRS L2 fire product (VNP14; Figure 1, Figure 2) for ~40 granules during the mission period. All cases are the result of spurious, high-radiance M13 scans in the Level-1B input product (VNP02MOD). These spurious M13 values are typically confined to an individual scan or scan line, but in extreme cases can span hundreds of adjacent lines (Figure 3). In most instances the bad M13 scans were not flagged in the pixel-level M13 quality flags(QF13) in the VNP02MOD, causing false fires. In rest of the instances, the false fire occurrence is due to the fire code ignoring the M13 pixels flagged with "Temp_not_nominal" condition (Figure 4). In such instances, the science team plans to eliminate the spurious fires by adjusting the handling of different QF13 flag combinations in the VNP14 production software, but raises caution in the overall viability of such a fix due to the dependency of frequency of individual flags. The science team also recommended that the NASA VIIRS Characterization Support Team (VCST) to eliminate the unflagged bad M13 scans in the Level-1B VNP02MOD product.

Occurrence: SNPP VNP14 data and all downstream products.

PGE:

Case Name: TM_NPP_VNP14_24177