Introduction
The power returning to the radar is processed and displayed to indicate target ‘reflectivity’. Thus, a weather radar system estimates the efficiency with which targets in the atmosphere return the energy transmitted by the radar.
Radar Reflectivity – a measure of the efficiency of a target intercepting and returning transmitted radio wave energy.
Both C- and S-band radars are designed to detect ‘precipitation particles’ in the atmosphere. The efficiency of a target consisting of these particles in backscattering energy to the radar depends upon:
- Particle size (diameter)
- Particle concentration (number per m3)
- State (ice, liquid or mixture)
- Shape (spherical, oblate etc)
- Translates to
- Rainfall rate
- Drop size distribution
- Rainfall rate
Particle size and state are the most significant contributors to wide variations in the reflectivity indicated intensities of precipitation targets observed by weather radar. The most reflective precipitation particles in the atmosphere are large and usually have a liquid surface (water-coated hailstones).
The Radar Equation is used to derive Z from Pr
Reflection
Which of the following options has the higher reflectivity?
Z = Σni(D) Di6 /unit volume (mm6/m3)