With more and more hazy days, the sky in Nanjing is getting darker and the vision of the city is getting more and more blurred.

The haze is a great detriment to travel and the health of the public. How do we monitor when the haze comes? Before the haze comes, can we give early warning?

Wang Chengfang, an undergraduate student of the School of Atmospheric Physics at Nanjing University of Information Science and Technology, recently developed a smart detector for hazy weather. It not only accurately “reads” the “vision” situation of the people in Nanjing, but also can distinguish a fog. When skimming comes, the rapid decline in visibility, how much is the role of the particles in the fog, how much is the role of helium particles. This provides feasibility for a wide range of real-time monitoring of hazy weather.

Haze monitoring is difficult

In the field of weather forecasting, haze forecasting has always been a difficult problem. Meteorologists said that the haze is very different in meteorology. Although they all contribute to the state of low visibility, the actual composition of the haze is other than the humidity conditions. Very complicated, for example, due to the high concentration of aerosol contaminants can cause defects, and its composition is very complex. In the sky above our heads, the main chemical components of aerosols include organics, sulfates, nitrates, and ammonium. Salt, black carbon, heavy metals, and some other elements. At the same time, there are many conditions and factors that need to be considered in numerical forecasting, including visibility monitoring and forecasting.

Experts from Nanjing University of Information and Technology told the reporter that in fact, the research on the visibility monitor was only applied in recent years. In the past, the monitoring of the visibility of the smog in China was not based on instruments but on the eyes of weather forecasters. According to experience, they generally use the iconic buildings or mountains far away from the meteorological observatory as the subject matter, relying on the sight of what can be seen in distant weather to roughly “estimate” the visibility, so there are still some Artificial error, and there is no way to detect the visibility of a region in a wide range, full coverage.

Two infrared eyes measure visibility

After several years of development, Wang Chengfang successfully developed the visibility detector. The reporter saw that there was a relative “eye” in sight detection equipment. Wang Chengfang told reporters that both eyes had “infrared” devices installed, and they collectively captured the air between the two infrared “eyes” and then used it. The infrared device “sees through” the particle size and composition of the contaminant particles therein, and accurately measures the extinction coefficient of the contaminant particles in the air, so that accurate visibility that we can see with the naked eye can be accurately calculated.

Wang Chengfang said that one of the benefits of this visibility detector is that it not only can replace the human eye directly to detect how far the grey sky can look, but more importantly, it can distinguish between what kind of particulate matter is Play a decisive role.

The reporter learned that currently developed real-time monitoring equipment for visibility can display visibility information and visibility-time curves in real time at the terminal, which will provide weather experts with clear and detailed forecast information.