Earthdata Forum

Hello,

I have a question regarding the historical naming convention of MODIS product short names.

In the MODIS product identifiers, Terra products use the prefix “MOD” while Aqua products use “MYD”, and combined products use “MCD”.

I understand that these prefixes distinguish the platform and product type. However, I have not been able to find documentation explaining why the letter “O” was assigned to Terra and “Y” to Aqua.

From an intuitive perspective, one might expect Terra and Aqua to be designated using something like “MTD” and “MAD” instead. I am therefore curious about the reasoning behind choosing “MOD” and “MYD” specifically.

Was this decision related to the original EOS data system architecture, legacy system constraints, database naming conflicts, or internal platform coding conventions?

I am particularly interested in the historical or system-design reasoning behind this designation.

Thank you very much for your time and assistance.

Best regards,

Hello,
In February of 2000 we began ingesting derived products from the MODIS sensor on board the TERRA (AM) satellite. Sometime before that, in the planning stages, the MODIS science team had to decide the naming convention for the various products, and they decided on really the only obvious choice to begin them with and that was MOD. They did not take into account future MODIS products and really why would they have. So when AQUA (PM) went up in 2002, they were not going to go back and change all the TERRA MODIS granules short names and meta data to something else like MTD, but they had to differentiate between granules collected from TERRA and AQUA so they choose MYD. We never really heard why they choose Y, I think it was just random, they probably did not want it referred to as MAD or MED or MID. We have added LAADS to this post as they may be able to shed more light on this as MODAPS and Goddard are where many of the science team members are,

For the AQUA and MODIS combined product MCD was the obvious and practical choice. the C stands for combined.
Thanks,
Brett