1. NPP VIIRS M6 Saturation Study Update
Chris Moeller
Univ. Wisconsin
March 22, 2012

2. Background
M6 SDR contains “fold over” events when the signal is pushed into deep saturation under bright illumination (e.g. water clouds). Fold over events are characterized by decreasing digital signal level under increasing detector illumination. See presentation “NPP VIIRS M6 Earth Scene Saturation Moeller ” for further background
SDR radiometric calibration of initial two cases (Jan 9 and Feb 10, 2012) lagged sensor performance due to RTA mirror degradation anomaly. Recent cases (Feb 26 and March 13, 2012) are based upon “current” SDR radiometric calibration.
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3. Today’s Review Summary
“fold over” events continue to trend to higher radiances as expected.
“out of range” radiance is now occurring for some good quality scene data as well as some fold over events. Out of range radiances are replaced with out of range threshold.
Reflectance data not consistent with radiance data for out of range occurrences.
M7 is nearing its out of range radiance threshold.
M8 still has margin in these stressing cases.
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4. Four cases to date in tropical South America: Jan 9, Feb 10, 26, Mar 13,
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5. At-launch out of range thresholdM6
At-launch out of range threshold
Lmax
“At-Launch” F LUT
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6. At-launch out of range thresholdM6
At-launch out of range threshold
Lmax
Dec 13 F LUT
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7. At-launch out of range thresholdM6
At-launch out of range threshold
Lmax
Feb 20 F LUT Delivery
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8. At-launch out of range thresholdM6
At-launch out of range threshold
Lmax
M7 At-launch out of range threshold
March 12 F LUT Delivery
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9. March 12 F LUT Delivery
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10. Radiance “out of range” occurrences
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11. M8 At-launch out of range threshold
March 12 F LUT Delivery
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12. Backup Earth scene imagery for all cases
Within band, each case is digitally stretched to same scale for direct comparison.
Red box defines region within which data is sampled for the plots in this package.
All cases over Tropical South America (~10 deg S latitude; high sun)
Display is a scaled radiance quantity
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13. Band M6 (752 nm)
, – UTC
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14. Band M7 (865 nm)
, – UTC
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15. Band M6 (752 nm)
, – UTC
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16. Band M7 (865 nm)
, – UTC
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17. Band M6 (752 nm)
, – UTC
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18. Band M7 (865 nm)
, – UTC
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19. Band M6 (752 nm)
, – UTC
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20. Band M7 (865 nm)
, – UTC
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