Solar radiation enters the Earth's atmosphere with a portion being scattered by clouds and aerosols.

Processing, archiving and distributing Earth science data
at the NASA Langley Research Center

What is the difference between L1B2 Ellipsoid and Terrain georectified radiances?

In order to resample the data from the nine MISR cameras to the SOM grid, it is necessary to assign an altitude to each location on the grid. In the Ellipsoid product, this altitude is represented by the WGS84 ellipsoid. In the Terrain product, it is the altitude of Earth's terrain. Both products are broken arranged into 180 blocks measuring 563.2 km (cross-track) x 140.8 km (along-track). The Terrain product does not contain valid data for blocks that are considered to be completely over water.
 

Illustration of Ellipsoid vs Terrain Projection
Objects along a camera line-of-sight. Camera-to-camera co-registration.