Collection 6 has been under development for a number of years. MCST, in consultation with representatives of the science disciplines, developed improvements to the calibration algorithms and methodologies to handle known issues with the aging MODIS sensors. Terra and Aqua forward processing and reprocessing using L1B Collection 6 (C6) started in 2012. The following references document the major changes implemented in MODIS Collection 6 LUTs as compared with the Collection 5 (C5) LUTs.
Brian N. Wenny ; Aisheng Wu ; Sriharsha Madhavan ; Zhipeng Wang ; Yonghong Li ; Na Chen ; Kwo-Fu Chiang ; Xiaoxiong Xiong; MODIS TEB calibration approach in collection 6. Proc. SPIE 8533, Sensors, Systems, and Next-Generation Satellites XVI, 85331M (November 19, 2012); doi:10.1117/12.974231.
Junqiang Sun ; Amit Angal ; Xiaoxiong J. Xiong ; Hongda Chen ; Xu Geng ; Aisheng Wu ; Taeyoung J. Choi ; Mike Chu; MODIS RSB calibration improvements in Collection 6. Proc. SPIE 8528, Earth Observing Missions and Sensors: Development, Implementation, and Characterization II, 85280N (November 28, 2012); doi:10.1117/12.979733.
Changes that are either new to C6 or not previously applied to all C5 processing are summarized below.
|Nature of the Change||Description of Upgrades for Both Terra and Aqua|
|Code||New treatment of data from inoperable detector|
|Code||Fixed the sector rotation issue|
|Code||Addressed PCLW electronics issue|
|LUT||RSB correction for SDSM D9 degradation|
|LUT||New m1 tables (includes SDSM D9 degradation correction)|
|LUT||Using EV data at several AOI and lunar data to derive m1 and RVS for Terra bands 1-4, 8-9 and Aqua bands 8-9|
|LUT||Time-dependent RVS for bands 13-16|
|LUT||Detector-dependent RVS for in bands 8 through 12 (plus Terra band 3)|
|Code, LUT||RVS fit using a 4th-order polynomial|
|LUT||Modified derivation of TEB offset and nonlinear calibration coefficients|
|Code||New computation of the uncertainty index (UI)|
|New LUTs||Added 6 RSB and 11 TEB LUTs for improved uncertainty determination|
|Removed LUTs||8 RSB and 5 TEB LUTs no longer needed by new uncertainty algorithm|
|Code, New LUT||Quality assurance flags expanded from a detector basis to a subframe basis|
|Output||Added a product file attribute that indicates noisy subframes|
|Output||Added a noisy subframe list|
|Output||Added a dead subframe list|
|Output||Added a product file attribute that indicates pixels affected by dead subframes|
|Nature of the Change||Description of Other Terra Upgrades|
|LUT||Time-dependent RVS for bands 17-19|
|Nature of the Change||Description of Other Aqua Upgrades|
|LUT||Treatment of RSB MS 2 RVS|
|Code, New LUT||New calibration treatment during WUCD band 33,35,36 saturation. Added 3 new LUTs for determining default band 33,35,36 b1 values|
|LUT||Modified derivation of a0, a2 coefficients to account for cold FPA fluctuations|
The major impacts to the reflective solar band data L1B products are striping reduction, improved reflectance values and Earth-view data quality, and mitigation of long-term trend drifts. The major thermal emissive band improvements include temperature retrievals, uncertainty index assessment, and Terra:Aqua agreement at cold scene temperatures.