Meteorological targets that can scatter radar electromagnetic waves mainly include ().

Meteorological targets that can scatter radar electromagnetic waves mainly include atmosphere, clouds and raindrops.

1, on radar meteorology

Radar meteorology is a new branch of meteorology due to the development and wide application of meteorological radar. Radar was invented on the eve of World War II, when it was mainly used to locate military targets.

Later, in the process of detection, it was found that meteorological targets such as clouds and rain can also produce echoes, so from the 1940s, people began to use radar to detect and study meteorological targets. Radar meteorology came into being.

The weather radar emits electromagnetic waves in the form of pulses. When electromagnetic waves encounter precipitation substances (raindrops, snowflakes, hail, etc.). ), most of the energy will continue to move forward, while a small part of the energy will be scattered in all directions by precipitation materials, and the backscattered energy will return to the radar antenna and be received by the radar to form radar echoes.

According to the characteristics of radar echo, we can distinguish the intensity of precipitation, whether there is hail, tornado or strong wind. The new generation Doppler weather radar can not only measure the echo intensity, but also measure the moving speed of the target along the radial direction of the radar (called radial speed) and the width of the speed spectrum (the degree of speed fluctuation).

The main contents of radar meteorology include three parts: the basic theory includes the scattering of radar waves by clouds and precipitation particles (see microwave scattering of clouds and precipitation particles); Attenuation of microwave passing through atmosphere, clouds and precipitation particles (see microwave attenuation in clouds and precipitation); The influence of meteorological conditions on radar wave propagation, such as atmospheric refraction and scattering of atmospheric inhomogeneous structures.

2. Radar meteorology theory

Cloud and precipitation particles will be polarized and polarized under the action of microwave radiation, and will oscillate according to the frequency of incident waves. The oscillating electrodes and magnetic poles will scatter electromagnetic waves with the same frequency as the incident waves around.

The scattering intensity of particles to incident wave energy is not only related to the intensity, wavelength and polarization of incident wave, but also related to the dielectric properties, shape, size and orientation of particles (for aspheric particles). The echo intensity received by radar is related to the backscattering intensity of clouds and precipitation particles.