Atmotspäärikorrigeerimine

Atmotspäärikorrigeerimine, also known as atmospheric correction, is a process used in remote sensing to remove the effects of the Earth's atmosphere from satellite or aerial imagery. The atmosphere contains gases, aerosols, and water vapor that scatter and absorb electromagnetic radiation, altering the spectral signature of the ground surface as it is observed by sensors. This distortion can lead to inaccuracies in quantitative analysis of remotely sensed data, such as calculating vegetation indices or identifying different land cover types.

The primary goal of atmotspäärikorrigeerimine is to retrieve the surface reflectance, which is the inherent property of the Earth's surface without atmospheric interference. This is typically achieved by modeling the atmospheric radiative transfer process. Various algorithms exist, ranging from simple empirical methods to more complex physical models. These algorithms often require ancillary data, such as atmospheric water vapor content, ozone concentration, and aerosol optical depth, which can be obtained from ground-based measurements, meteorological data, or specific atmospheric correction algorithms.

Common techniques include dark object subtraction, which assumes that some pixels in an image correspond to surfaces that are completely dark (zero reflectance) in certain spectral bands, and radiative transfer models like MODTRAN or 6S. The outcome of successful atmotspäärikorrigeerimine is corrected imagery that more accurately represents the true reflectance of the land surface, enabling more reliable scientific interpretations and applications in fields like environmental monitoring, agriculture, and geology.