What is the reason why radar can detect the internal structure of precipitation weather system?

Radar can detect weather changes, just as we can see clouds, except that visible light is replaced by radio waves.

The weather radar directionally emits intermittent radio waves (called pulse waves or radio pulses) into the sky. When radio waves meet clouds, tiny water droplets in the clouds will scatter radio waves in all directions like sunlight, and some of them will be reflected in the emission direction (called backscattering). This part of the radio waves will be detected by the radar receiving device, and the spatial position distribution and intensity of meteorological targets will be displayed on the radar display.

According to the time difference between pulse transmission and reception, azimuth error, cloud position and size, etc. According to the intensity (attenuation degree) of the echo, various parameters in the cloud system can be known, and the internal structure of the cloud system will be clear at a glance after computer processing.

At different times, radio waves are transmitted and received to the same target. Through the sequential superposition of images, we can know the movement state and internal structure changes of the cloud system, so as to make weather forecast.