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 CERES FOV or Footprint?

The CERES Field of View (FOV) is synonymous with the term Footprint and is determined by the Point Spread Function (PSF) which is a two-dimensional, bell-shaped function that defines the CERES instrument response to the viewed radiation field. The resolution of the CERES radiometers is usually referenced to the optical FOV which is 1.3° in the along-track direction and 2.6° in the cross-track direction. The CERES FOV or footprint size is referenced to an oval area that represents approximately 95% of the PSF response. Since the PSF is defined in angular space at the instrument, the CERES FOV is a constant in angular space, but grows in surface area from a minimum at nadir to a larger area at shallow viewing angles.