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

Where do I find the surface altitude of an L1B2 SOM grid location?

The value is stored in the MISR Ancillary Geographic Product (AGP), of which there are 233 unique files, one for each of the World Reference System-2 (WRS-2) paths. Like the L1B2 products, these are divided into blocks, and the fields within the "Standard" grid of the AGP are provided at 1.1-km sampling. The average elevation over a 1.1-km grid sample are provided in the "AveSceneElev" field. AGP files can be obtained from the MISR Order and Customization Tool and through the ASDC Data Pool.