Science / Weather / Reflectivity: A measure of the process by which a surface can turn back a portion of incident radiation into the medium through which the radiation approached. It also refers to the degree by which precipitation is able to reflect a radar beam.

Differential Reflectivity (ZDR)

Technology / Radar / Differential Reflectivity (ZDR): Ratio between the reflectivity of a horizontal polarised pulse and the reflectivity of a vertical polarised pulse. Zdr depends on the asymmetry of the shape, the orientation and the falling behaviour MORE

Reflectivity Factor (Z)

Technology / Radar / Reflectivity Factor (Z): Integral over the backscatter cross-section of the particles in a pulse volume. For particles small compared to the wavelength the scatter cross-section is d6, where d is the diameter of the particle. MORE

Hook Echo

Science / Weather / Hook Echo: A radar reflectivity pattern observed in a thunderstorm, appearing like a fish hook and indicating favorable conditions for tornadic development. However, hook echoes and tornadoes do not always accom MORE


Science / Weather / Bwer: Acronym for Bounded Weak Echo Region. Refers to radar echo signatures with low reflectivity in the center, surrounded by higher reflectivity. It is associated with strong updrafts and is found in the MORE

Bright Band

Science / Weather / Bright Band: A narrow, intense radar echo due to water-covered ice particles at the melting level where reflectivity is at its greatest. MORE

Doppler Velocity (V)

Technology / Radar / Doppler Velocity (V): Reflectivity-weighted average velocity of targets in the pulse volume. Determined by phase measurements from a large number of successive pulses. Also called radial velocity. Gives only the radial com MORE