The Level-1A product is a simple concatenation of Level-0 data with a Header, which could easily be reversed back to Level-0. Level-1A remains in a binary format and is not in HDF. The Level-1B format groups like data together.

The Level-1A product consists of two files: the Level-1A Product file and the SFDU header file. The Level-1A Product file, ”1A-01,” is a concatenation of Header record, Spacecraft Attitude packets, VIRS Housekeeping Data packets, VIRS Science Data packets, QACs, and an MDUL. The SFDU header is a separate file whose format is specified in the Interface Control Document Between EOSDIS Core System (ECS) and TRMM Science Data and Information System (TSDIS) for the ECS Project.

Learn more