TRMM VIIRS Level 1A01
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.
TRMM VIIRS
TRMM VIIRS Level 1B01 Calibrated Radiance Product
The TRMM Visible and Infrared Scanner (VIRS) Level 1B Calibrated Radiance Product (1B01) contains calibrated radiances and auxiliary geolocation information from the five channels of the VIRS instrument, for each pixel of each scan. The data are stored in the Hierarchical Data Format (HDF), which includes both core and product specific metadata applicable to the VIRS measurements. A file contains a single orbit of data with a file size of about 95 MB. The EOSDIS "swath" structure is used to accommodate the actual geophysical data arrays.
1B PPS Research
The Level 1B algorithm and software transform Level 0 counts into geolocated and calibrated antenna temperatures (Ta) and brightness temperatures (Tb).