Level 1D DLR files contain a combined thumbnail image that contains 4 images: 1356 Angstrom, LBH Short (denoted LBH1),
LBH Long (denoted LBH2), and solar zenith angle. Separate files are created for Channel A and Channel B data. A new L1D file
is generated for each new L1C file. These can correspond to either the Northern or Southern hemisphere.
Combined file definition (image size = 1024 x 1024 pixels)

• Header information (at the top of the set of 4 images)
• Date of image
• Time of image
• File name
• 1356 brightness map (in Rayleighs) integrates the signal from 133 to 137 nm.
• LBH band 1 brightness map (in Rayleighs) integrates the signal from 140 to 148 nm.
• LBH band 2 brightness map (in Rayleighs) integrates the signal from 150 to 160 nm.
• SZA solar zenith angle map is at the reference altitude of 150 km.

The 1356 Angstrom spectral radiance at each grid position.

The spectral radiance at each grid position.

The 1493 Angstrom spectral radiance at each grid position.

Pixel solar zenith angle.

Pixel latitude.

Pixel longitude.