MSC Introductory Weather Radar Course

An electron tube used as a high power oscillator in the microwave bands. This produces pulse to pulse variations that make it unstable for Doppler radar use.

The envelop of electromagnetic energy along the main axis of the beam.

The greatest distance a pulse can travel and return before the next pulse is transmitted.

R_u = C / (2*PRF)

Description

2D map containing the maximum reflectivity present in the vertical column over each surface point (ground view). In addition and optionally, the maximum reflectivity taken along a set of horizontal planes at different altitudes and along specified directions can be given (side-walls).

Notes

• It is assumed that the level slicing used for the side-walls intensity is the same than for the ground map.
• For side-walls, if the height increment is constant then the vertical spacing is given instead of specifying the sequence of height values.
• If side-walls are present, then their number, orientation and height sequence are omitted.

Example image

Reflectivity weighted average velocity of targets in a given volume sampled. Usually determined from a large number of successive pulses. Also called mean radial velocity.

A.K.A: MDS. In a receiver, the smallest input signal that will produce a detectable signal at the output. This value is a measure of receiver sensitivity.

Miscalibration influences compositing and produces biases in the rainfall rate estimates. It is difficult to correct precipitation attenuation because of it. An overestimate of Z produces an exponentially increasing error.

Example Image

A radar system in which the same antenna is used for transmission and reception of energy.

Description

2D-array of horizontal wind vectors, based on measurements of two doppler radars located typically less than 100 km from each other. .

Parameters

Product data quantity: array of speed (tenths of m/s and direction (degrees) of wind
Image size: number of arrays per row (# of columns) and per column (# of rows)
Coordinates of central point of the image
Array spacing: km
Upper limit altitude: m a.s.l.
Lower limit altitude: m a.s.l.
Maximum unambigious speed
Unfolding method used
Fallspeed correction method used if any

Notes

• The barbs cannot be used at area where the beams of the two radars are almost parallel. From this and other reasons, a quality indicator is essential.

Signal returns from a pulse other than the most recent. See also Range Folding.