Earthdata Forum

Hi everyone,

I have a question regarding the availability timing of MODIS and VIIRS products.

Both MOD09A1/MYD09A1 (MODIS) and VNP09A1/VJ109A1 (VIIRS) are 8-day composite products based on similar acquisition periods. However, I’ve noticed that MODIS products are generally made available more quickly than VIIRS products.

For example, the most recent MODIS products covering the acquisition period of 2025-06-02 to 2025-06-09 were released on 2025-06-12. As of today (2025-06-17), the corresponding VIIRS products have not yet been released.

Could you clarify why this difference in delivery time occurs? Is it expected that VIIRS products take longer to be released compared to MODIS? Given that VIIRS is intended to eventually replace MODIS, I would like to understand if this delay is inherent to the VIIRS processing chain or if improvements in timeliness are anticipated in the future.

Thank you in advance for your attention.

Hi Savee,
Sorry for the delay with the VIIRS processing and availability. Actually, there is no inherent difference in the acquiring, processing or ingesting of MODIS and VIIRS that would make a delay for one over the other. There are many times when MODIS is the tardy one. Infact as time goes by, I think we will see it happen more and more to MODIS because Terra is 25 years old and Aqua is 22. I am not looking forward to this but in the not too distant future MODIS will end entirely. When that day comes data acquisition and processing will be cut in half which should translate into VIIRS data being available in a much timelier fashion. Please let me know if you have any questions.
Thanks,
Brett