MSC Introductory Weather Radar Course

In radar, indicates the melting point of a snowflake. High intensity return is caused by the water surrounding the ice crystal, hence appearing large.

A radar operating in the 3900 to 6200 megahertz range whose wavelength is generally accepted as 5 centimetres.

Description

2D-map containing the representative reflectivity for the horizontal plane (layer) placed at a predefined altitude. A set of maps for various heights may be given inside of the same product.

Notes

• The parameter filling of cones can optionally be omitted.

Chaff is a radar countermeasure in which aircraft or other targets spread a cloud of small, thin pieces of aluminium, metallised glass fibre or plastic, which either appears as a cluster of secondary targets on radar screens or swamps the screen with multiple returns.

Modern armed forces use chaff (in naval applications, for instance, using short-range SRBOC rockets) to distract radar-guided missiles from their targets. Most military aircraft and warships have chaff dispensing systems for self-defense. An intercontinental ballistic missile may release in its midcourse phase several independent warheads, a large number of decoys, and chaff.

Chaff can also be used to signal distress by an aircraft when communications are not functional. This has the same effect as an SOS, and can be picked up on radar. It is done by dropping chaff every 2 minutes.

Problems caused in weather radar products

Chaff is frequently released by military aircraft during exersices. On the radar display it is usually seen as narrow bands of high reflectivity. Sometimes these chaff echoes may have a distance for hundreds of km. The width of the bands depends on the range from the radar and the amount of diffusion time.

Example Image

Electromagnetic radiation in which the electrical field rotates uniformly about the direction of propagation. The effect is to reduce return signals from spherical targets, which eliminates some precipitation targets from the radarscope. Usually found on Air Traffic control radars.

Radar returns from cloud and precipitation-free (optical clear) air. Clear-air echos are caused by Bragg scatter and insects. Bragg scatter comes from small-scale fluctuations of the refractive index (i.e. turbulent fluctuations of humidity).

A radar, such as a pulse Doppler, in which phase of the transmitted energy is preserved for comparison with the phase of returned energy to determine target motion.

A signal which contains information in both its phase and amplitude.

2D-map containing the representative reflectivity for the horizontal plane (layer) placed at a predefined altitude. A set of maps for various heights may be given inside of the same product.

Notes

• The parameter filling of cones can optionally be omitted.

Process of removing undesirable aliases from the velocity field, i.e. the correction of the process of aliasing.