Weather radar is an atmospheric detection tool based on the principle that electromagnetic waves can be captured by clouds and rain particles.

Weather radar uses the principle that electromagnetic waves will be scattered and absorbed by clouds and rain particles.

The weather radar emits pulse waves with a short duration (0.25 ~ 4 microseconds) at a certain repetition frequency, and then receives echo pulses scattered by precipitation particles.

The scattering and absorption of radar waves by water are related to the characteristics of raindrop spectrum, rainfall intensity, the phase state of precipitation particles and the shape and orientation of ice crystal particles. Therefore, through the analysis and judgment of precipitation echo, we can determine various macro and micro physical characteristics of precipitation.

Extended data:

The radar echo chart, from blue to purple, indicates the echo intensity from small to large (10-70dBz). From the echoes of different colors, we can judge the rainfall intensity, rain area range, future rainfall intensity and movement.

1, to determine the rain area.

On the radar echo map, the area surrounded by green echo generally corresponds to the expected rainfall. Generally speaking, it may rain in light green, and it will definitely rain in dark green.

2. Determine the rainfall intensity

The radar echo changed from blue to purple, and the rainfall intensity gradually increased. Generally, the bright yellow area generally corresponds to the rainfall intensity of about 10 mm/h, and the warm red radar echo generally corresponds to the rainfall intensity of about 20 mm/h, and there may be strong convective weather such as short-term thunderstorms, strong winds and hail.

Baidu Encyclopedia-Weather Radar