Abstract
The Visible Infrared Imaging Radiometer Suite (VIIRS) has been flown on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite, launched in 2011. A number of major changes in the sensor data record (SDR) algorithm and calibration parameters have been made to the NOAA operational processing of S-NPP VIIRS data, which has led to inconsistencies in the long-term data record. This paper presents NOAA STAR’s effort in reprocessing the S-NPP VIIRS SDRs from January 1, 2012 to July 31, 2016. Version 1 reprocessing has been completed. In the reprocessing, reflective solar bands (RSB) are recalibrated using consistent RSBAutoCal based F-factors. In addition, a new radiometric bias correction term was introduced to the SDR products to make the calibration consistent with the ocean color (OC) F-factors for RSB. A constant M5/M7 bias correction to reconcile OC, aerosol, and cloud teams’ concerns was also introduced. An Ltrace algorithm was developed to address the long-lasting calibration anomaly in the sea surface temperature bands (M15 and M16) observed during quarterly warm-up/cool-down (WUCD) events. Warm spikes in the daytime SST time series were successfully minimized. Day/Night band (DNB) SDR is improved using modulated spectral response functions and improved dark offset, gain ratio, and stray light correction parameters. Geolocation products were reprocessed using the latest geometric calibration parameters. In addition, terrain correction was implemented to the entire DNB geolocation data archive. Going forward, Version 2 reprocessing effort is currently in progress. RSB calibration will be further enhanced in version 2 by using Kalman filter based gain coefficients which reconciles calibration results from latest solar calibration parameters with reduced oscillations, lunar, deep convective clouds, and extended simultaneous nadir overpass. In addition, Version 2 reprocessing is being developed with the capability of on-demand SDR reprocessing.
Suomi-NPP VIIRS Sensor Data Record Reprocessing Improvements and Status
The Visible Infrared Imaging Radiometer Suite (VIIRS) has been flown on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite, launched in 2011. A number of major changes in the sensor data record (SDR) algorithm and calibration parameters have been made to the NOAA operational processing of S-NPP VIIRS data, which has led to inconsistencies in the long-term data record. This paper presents NOAA STAR’s effort in reprocessing the S-NPP VIIRS SDRs from January 1, 2012 to July 31, 2016. Version 1 reprocessing has been completed. In the reprocessing, reflective solar bands (RSB) are recalibrated using consistent RSBAutoCal based F-factors. In addition, a new radiometric bias correction term was introduced to the SDR products to make the calibration consistent with the ocean color (OC) F-factors for RSB. A constant M5/M7 bias correction to reconcile OC, aerosol, and cloud teams’ concerns was also introduced. An Ltrace algorithm was developed to address the long-lasting calibration anomaly in the sea surface temperature bands (M15 and M16) observed during quarterly warm-up/cool-down (WUCD) events. Warm spikes in the daytime SST time series were successfully minimized. Day/Night band (DNB) SDR is improved using modulated spectral response functions and improved dark offset, gain ratio, and stray light correction parameters. Geolocation products were reprocessed using the latest geometric calibration parameters. In addition, terrain correction was implemented to the entire DNB geolocation data archive. Going forward, Version 2 reprocessing effort is currently in progress. RSB calibration will be further enhanced in version 2 by using Kalman filter based gain coefficients which reconciles calibration results from latest solar calibration parameters with reduced oscillations, lunar, deep convective clouds, and extended simultaneous nadir overpass. In addition, Version 2 reprocessing is being developed with the capability of on-demand SDR reprocessing.