EAS221 Study Guide - Quiz Guide: Montmorillonite, Chlorophyll, Spectral Signature
24 Feb 2017
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Digital number (dn: unit-less value recorded by sensor, number of bits/levels of greyscale/radiometric resolution determine the precision. Radiance (l: the value of all the energy arriving at the sensor after making the round trip through the atmosphere. Reflectance (p: similar to albedo, the ratio of the radiation leaving a reflector to that striking it (%, best representation of the material characteristics of a surface. Respond to visible spectrum: because reflected sunlight is at maximum intensity. Characteristic energy reflected by or emitted from an object (x = wavelength, y = reflectance if you graph it) Reflectance is affected by suspended matter and depth: phytoplankton, sediment, om. Water is a strong absorber of emr: absorbs blue the least; why water can appear blue, absorbs ir the most. The signature = (signature of reflecting surface) (what is absorbed or scattered by water: high presence of phytoplankton results in a peak at the green wavelengths.
