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Why can radar penetrate wind, rain and clouds? Uncover the secrets of weather radar operation!
In the process of development of modern science and technology, the operating principle of weather radar has become the focus of people's curiosity. This technology, which focuses on observing precipitation, can penetrate thick clouds and provide us with accurate weather forecasts. This article takes a closer look at how this amazing technology works and reveals the science behind it.
Introduction to weather radar
Weather Radar, also known as Weather Surveillance Radar (WSR) or Doppler weather radar, is a type of weather radar used to detect precipitation, calculate movement, and estimate precipitation types (such as rain, snow, hail, etc.) radar system. Many modern weather radars are pulse Doppler radars that, in addition to detecting precipitation intensity, can also track the movement of raindrops.
The evolution of history
The story of weather radar dates back to World War II, when military radar operators discovered that weather phenomena created noise on the radar screen, obscuring potential enemy targets. This prompted scientists to focus on these echoes and begin to explore their application in weather monitoring. Over time, weather radar technology has rapidly developed and become an indispensable tool for national meteorological agencies and research units.
Basic principles of radar
Weather radar detects precipitation in the atmosphere by emitting microwave pulses and receiving their reflected signals.
Emit radar pulses
Weather radar uses a cavity magnetron or Christon tube to emit microwave pulses, each about one microsecond in length. These pulses are reflected back to the radar station by precipitation droplets or ice particles, giving information about their distance and movement.
Receive return signal
After each pulse is emitted, the radar system enters receive mode, listening for signals returning from airborne particles. The duration of this process is approximately one millisecond, which is much longer compared to the pulse duration. This allows the radar to accurately calculate the distance of precipitation.
Measure height
Since the Earth is round, the propagation of radar waves in a vacuum will gradually rise as altitude increases. Based on the refractive index of the atmosphere, radar waves bend slightly toward the ground. In this case, the radar can obtain height information of precipitation above the ground.
Calibration of echo intensity
The radar calibrates the echo strengths of different targets to obtain more accurate precipitation data.
Since the target within each scanned volume is not unique, the radar needs to consider various parameters to calculate the echo intensity to ensure that the data collected is accurate. This includes a number of technical indicators such as transmit power, receive gain and echo cross section of the monitored target.
Technological progress
In recent years, with the rapid advancement of computer technology, the algorithms of weather radar systems have also been significantly improved. Many media and scientific research institutions are beginning to use these innovative technologies to generate more accurate precipitation forecasts. Nowadays, the use of dual-polarization technology has made a qualitative leap in radar's ability to identify precipitation types.
Conclusion
The development of weather radar not only improves our understanding of meteorological events, but also effectively reduces the threat of natural disasters to life and property. With the continuous advancement of technology, future weather forecasts will be more accurate and timely. Against this background, can we make full use of advances in science and technology to better address the challenges posed by climate change?
