The angle between the zenith and the centre of the sun’s disc.
Solar Zenith Angle (SZA)
The angle between the local zenith (i.e. directly above the point on the ground) and the line of sight from that point to the sun
Spatial resolution
The area on the ground that an imaging system, such as a satellite sensor, can distinguish.
Spectral response
The ratio of the relative amplitude of the response of a detector and the frequency of incident electromagnetic radiation.
Spectrometer
An optical instrument that splits the light received from an object into its component wavelengths by means of a diffraction grating, and then measures the amplitudes of the individual wavelengths.
Sun-synchronous orbit
An orbit in which a satellite is always in the same position with respect to the rotating Earth at the same time of day.
Surface reflectance
Surface reflectance is defined as the fraction of incoming solar radiation that is reflected from Earth's surface for specific incident or viewing cases (directional, conical, and hemispherical cases).
Synthetic Aperture Radar (SAR)
A synthetic-aperture radar is an imaging radar mounted on an instant moving platform. The signal is responsive to surface characteristics like structure and moisture.
A multi-decadal summary of landscape wetness that can be used to identify wetlands and groundwater ecosystems.
Telemetry
The science and technology of automatic measurement and transmission of data by wire, radio or other means from remote sources (e.g. space vehicles) to receiving stations for recording and analysis.
