Remote Sensing
Atmospheric correction
The processing step that removes scattering and absorption by the atmosphere so surface reflectance can be compared over time.
Satellites measure light at the top of the atmosphere, which includes haze, water vapour and aerosol effects. Without correction, a hazy day looks different from a clear one, and the difference can mimic vegetation change.
Consistent correction across dates is a prerequisite for time-series analysis. Mixing imagery processed with different correction schemes introduces artefacts that are easy to mistake for real trends.
Frequently asked questions
Is surface reflectance always better?
For multi-date comparison, yes. For single-scene visual inspection the difference is minor.
Who provides corrected products?
Most space agencies now distribute analysis-ready surface reflectance, removing this burden from users.