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

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 2012.02.28” for further background https://casanosa.noaa.gov/docman/?group_id=378&open_folder=61027#61027. 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. UWisc, 2012-03-22

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. UWisc, 2012-03-22

Four cases to date in tropical South America: Jan 9, Feb 10, 26, Mar 13, UWisc, 2012-03-22

At-launch out of range threshold M6 At-launch out of range threshold Lmax “At-Launch” F LUT UWisc, 2012-03-22

At-launch out of range threshold M6 At-launch out of range threshold Lmax Dec 13 F LUT UWisc, 2012-03-22

At-launch out of range threshold M6 At-launch out of range threshold Lmax Feb 20 F LUT Delivery UWisc, 2012-03-22

At-launch out of range threshold M6 At-launch out of range threshold Lmax M7 At-launch out of range threshold March 12 F LUT Delivery UWisc, 2012-03-22

March 12 F LUT Delivery UWisc, 2012-03-22

Radiance “out of range” occurrences UWisc, 2012-03-22

M8 At-launch out of range threshold March 12 F LUT Delivery UWisc, 2012-03-22

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 UWisc, 2012-03-22

Band M6 (752 nm) 2012-01-09, 173441 – 173605 UTC UWisc, 2012-03-22

Band M7 (865 nm) 2012-01-09, 173441 – 173605 UTC UWisc, 2012-03-22

Band M6 (752 nm) 2012-02-10, 173219 – 173344 UTC UWisc, 2012-03-22

Band M7 (865 nm) 2012-02-10, 173219 – 173344 UTC UWisc, 2012-03-22

Band M6 (752 nm) 2012-02-26, 173232 – 173357 UTC UWisc, 2012-03-22

Band M7 (865 nm) 2012-02-26, 173232 – 173357 UTC UWisc, 2012-03-22

Band M6 (752 nm) 2012-03-13, 173246 – 173410 UTC UWisc, 2012-03-22

Band M7 (865 nm) 2012-03-13, 173246 – 173410 UTC UWisc, 2012-03-22