MODIS Land News
Terra Orbital Drift Information
Terra is scheduled to exit the 'Morning Constellation' of Earth Science satellites by October, 2022. Because of onboard fuel shortage, the last of Terra mission maneuver was done on February 27, 2020 to maintain the mean local time (MLT) of 10:30 AM. Thereafter, Terra has been drifting slowly from its MLT and will reach and exceed 10:15 AM MLT by October 2022, when it will make the constellation exit with a lowered orbit altitude of 694kms. Terra MODIS will remain operational and generate the full suite of products until the end of the mission in December 2025.
More information can be found on the Terra website's orbital drift pages.
Similarly, the Aqua flight operations team completed the final mission manuevers related to maintaining a 1:30 PM MLT equator crossing and 705 km orbit altitude on March 18, 2021. In July 2021, Aqua began drifting to a later MLT. In January 2022, Aqua began its constellation exit; it exceeded a 1:45 PM MLT crossing in February 2023. MLT will continue to drift, reaching 3:50 PM around August 2026. Aqua MODIS will remain operational and generate the full suite of products until the end of the mission in August 2026.
Earlier (later) crossing times for a morning (afternoon) platform like Terra (Aqua) mean lower solar elevations leading to more prevalent shadows. This decrease in orbit altitude alters the spatial coverage of the sensor including possible gaps in spatial sampling, decreased spatial coverage, and higher spatial resolution. Products are mostly expected to be science quality except for reduced grid size (from lower altitude) and without a strict 16-day repeat of observations (from drift and changing orbit).
Details on the impact of the Constellation Exit on the quality of the product are being compiled and will be posted when available.
Other Orbital Drift Resources
- Terra's Lower Orbit Virtual Community Forum
- Orbit Lowering Impacts on MODIS (Audio recording, Land portion begins at 10:30 min)
- View/download the slide deck associated with the above recording (MODIS slides 54-75, Land discipiline slides begin on slide 65)
MODIS Collection News
MODIS C6
MODIS C6 products were decommissioned in summer of 2023.
MODIS C6.1/C6.2
C6.1 reprocessing of Land products was completed for all products by August 2023.
C6.1 DSR/PAR (MCD 18) were fully decommissioned in June of 2024 and all DAACs have now fully switched to C6.2. The new MCD18 C6.2 algorithm includes several improvements and refinements over the previous collections. Observations from shortwave infrared channels are used in addition to those from visible channels when retrieving atmospheric parameters. This change is especially noteworthy for cloudy sky cases and over snow covered surfaces.
MODIS C7
C7 L1 Geolocation and TOA product processing have commenced at MODAPS, once L1 changes were fully vetted and confirmed by the instrument geolocation and calibration teams, and is expected to be completed by late summer. The atmosphere products will not begin C7 reprocessing until mid to late 2025. Land product reprocessing is currently planned to begin in summer of 2025. The C7 reprocessing uses an annual Land/Water Mask (LWM). This new LWM will be incorporated into the geolocation product.
All the products in this collection will be in netCDF4 format.
MODIS News and Information Links
Link to news information from the MODIS web site
Links to additional meeting and publication information from the MODIS web site
