Category: Optical and atmosphere
Atmospheric Correction
Atmospheric correction removes or reduces atmospheric effects so scenes are more comparable across time and space.
Also known as: AC, surface correction
Expanded definition
Atmospheric correction attempts to convert what the sensor sees into an estimate of the surface signal. It accounts for aerosols, water vapor, and scattering effects that otherwise change pixel values even when the surface does not change.
Most surface reflectance products rely on atmospheric correction. Accuracy depends on assumptions and auxiliary data, and it can struggle under haze, smoke, or thin clouds.
When using atmospherically corrected data for time series, consistency often matters more than perfection. A stable, repeatable correction can be more useful than a “best effort” correction that varies between processing versions.
Related terms
Surface Reflectance (BOA)
Surface reflectance estimates what reflectance would be at the ground after removing atmospheric effects.
TOA (Top-of-Atmosphere)
TOA reflectance is reflectance at the top of the atmosphere, before full atmospheric correction to the surface.
Haze
Haze is atmospheric scattering from aerosols that reduces contrast and shifts reflectance, especially in blue bands.
Cloud Mask
A cloud mask labels pixels likely affected by clouds so they can be excluded or handled differently.