Which material has a high reflectivity?

 
Optical properties of ice and snow
The optical properties of a material influence how optical radiation reacts when it hits the material surface. Each material has its own spectral signature, which is due to its ability to reflect, absorb and transmit the incoming radiation at different wavelengths.
 
Ice and snow generally have a high reflectivity at visible wavelengths (VIS; approx. 0.4-0.75 µm), lower in NIR (near infrared, wavelength approx. 0.78-0.90 µm) and lower in SWIR (short-wave infrared, wavelength approx. 1.57 - 1.78 µm) has a very low reflectivity. The low reflectivity of ice and snow in the SWIR has to do with the content of microscopic liquid water (VIS and NIR together are often abbreviated as VNIR). However, the characteristic reflectivity varies with the actual composition of the material and is therefore different for snow, firn, glacier ice and polluted glacier ice.
 
Reflection curves for snow, ice, vegetation and water
 
 
Reflection curves for snow, vegetation, water and rock
 
 
The colored area in the diagram above shows how strongly the earth's atmosphere allows electromagnetic radiation of a certain wavelength to pass through. Areas with high atmospheric transmission are well suited for observing the earth from space. The numbered rectangles indicate in which spectral bands the sensors (here ASTER and Landsat Thematic Mapper) detect radiation.

The reflection curves for firn and glacier ice are interrupted at the longer wavelengths, as they would overlap with the reflection curve for snow. The reflection curve for polluted glacier ice is also interrupted at the longer wavelengths, since the reflectivity there can vary greatly depending on the type and amount of pollution. A general reflection curve for polluted glacier ice at long wavelengths cannot therefore be defined.

See example (right).