In March, MCST began gradually implementing several calibration algorithm improvements into the Terra and Aqua MODIS Collection 6.1 Level 1B products for the reflective solar bands. The algorithm changes, which were previously developed and tested for the upcoming Collection 7 L1B reprocess, will improve the accuracy and stability of the MODIS reflectance and radiance products going forward.
MODIS entered its modified science configuration in preparation for Terra constellation exit maneuvers (CEMs) on 2022/283. CEM #1 was performed on 2022/285 and CEM #2 was performed on 2022/292. MODIS performed an outgas from 2022/293 17:30:25 – 2022/294 19:44:48. MODIS returned to nominal science configuration on 2022/294 19:59:49. Cold focal plane temperatures are expected to reach operating range by 2022/297.
Beginning in October 2022, Terra will exit the spacecraft constellation that has been its home for the last twenty years and continue operations at a lower orbit altitude. To assure instrument health and safety, Terra/MODIS will be commanded to a modified configuration with SMIR and LWIR focal planes turned off, blackbody calibrator turned off, along with space view and nadir doors closed. MODIS will remain in this configuration throughout the duration of the constellation exit maneuvers.
Aqua S/C transitioned to a safe mode on March 31st, 2022 (2022090). Post the S/C recovery, MODIS was brought back to Science Mode on April 14th, 2022 (2022104). Increase in the PV LWIR TEB electronic crosstalk was observed post-safe mode that resulted in increased striping in the L1B imagery. MCST developed a crosstalk correction algorithm and LUTs for the PV LWIR TEB to be applied Aqua MODIS C6.1 for forward production starting 2022208.0000 under version 6.2.3.
As an FYI, MCST continues to monitor the impact of the Aqua safe mode event earlier this year. We have noted changes in the SWIR bands (bands 5-7 and 26).
Band 6 detector 4 (product order) has been marked dead in the QA LUT as of 2022090.1600 (March 31, 2022). This update was delivered for processing on June 15, 2022, so additional processing will be required for this change to be made in historic data.
We are continuing to monitor the remaining SWIR detectors for any further changes in performance.
MODIS Characterization Support Team
The MODIS Characterization Support Team (MCST) is dedicated to the production of a high quality MODIS calibration product. This product is a precursor to every geophysical science product. MCST works for the Science Team Leader and is responsible for developing and maintaining the calibration product (L1B algorithm).
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 methodolgies to handle known issues with the aging MODIS sensors. Summary talks of the proposed Collection 6 changes have been delivered at the MODIS science team meetings over the last few years.
Current L1B LUT Versions:
Terra C6: 18.104.22.168; Terra C6.1: 22.214.171.124; Aqua C6: 126.96.36.199; Aqua C6.1: 188.8.131.52