There are two ways to read AMSR/AMSR-E data constructed as an HDF4 file. One is to use only the HDF4 library, and the other is to use the AMSR Data Input Toolkit (ADIT) which uses the HDF4 library as internal routine, for reading AMSR/AMSR-E data in your own C program or Fortran program.
ADIT provides functions for reading and storing AMSR/AMSR-E data into local structured variables of one-scan size.
Some data will be converted with a scale factor and saved into the HDF4 file. ADIT will recognize the scale factor for its conversion and calculate its original value.
If you use ADIT to handle AMSR/AMSR-E data in your program codes, you can easily get the correct data.
Note: ADIT does not support AMSR-E Level 1 version4 product (HDF5 format, released in 2018).
Please substitute AMSR2 Product I/O Toolkit (AMTK) for ADIT.