1. Reflectivity is a measure of the ability of a surface to reflect radiation, equal to the reflectance of a layer of material sufficiently thick for the reflectance not to depend on the thickness.
2. The reflectance properties of an object depend on the material and its physical and chemical state, the surface roughness as well as the geometric circumstances (e.g. incidence angle of the sunlight). The reflectance of a material also varies with the wavelength of the electromagnetic energy. These differences in reflectance make it possible to identify different earth surface features or materials by analyzing their spectral reflectance signatures.
https://www.collinsdictionary.com/de/worterbuch/englisch/reflectivity (1.); http://gsp.humboldt.edu/olm_2015/Courses/GSP_216_Online/lesson2-1/reflectance.html (2.)
Author: Laura Saupe