China News Service, Shanghai, February 20th: What are the "gold-picking" skills of China Fengyun Satellite who have worked hard for more than 50 years in the "meteorological arena"?
Reporter Zheng Yingying
At the Beijing Winter Olympics, a number of China Fengyun satellites "looked" at the earth from space, monitoring surface temperature and changes in wind and clouds, and helping meteorological guarantees.
In the "arena" of space, the Chinese "Fengyun Satellite Family" who have been fighting for more than 50 years is not a player without a story.
Over the years, whether in polar orbit or in geostationary orbit, the "Fengyun Satellite Family" has opened up a new world.
The world's first "three-orbit" country is "sweeped" every 4 hours
The reason why China's "Fengyun Satellite Family" is a "gold-picking" player is because of its "wide coverage".
In 2021, China will launch the world's first civilian Dawn orbit meteorological satellite, the Fengyun-3E satellite (referred to as "Dawnstar"), and with the previously launched Fengyun-3C and D satellites, China will become the world's first satellite. A country that realizes the "dawn track, morning track, afternoon track" Samsung network operation.
Similar to the United States and Europe, China's previous satellite observation time was concentrated around 10:00 am and 2:00 pm. In the observation assimilation time window of every 6 hours, there are always 2 to 3 orbits of the world's satellite observations in the blank area, which cannot be provided. The initial observation of global coverage; and the launch of the FY-3E satellite made up for the shortcomings of satellite observation orbits and the lack of observation data.
Chen Xiaofei, chief designer of the Fengyun-3 satellite of the Eighth Academy of China Aerospace Science and Technology Corporation, introduced in an exclusive interview with a reporter from Chinanews.com that compared with Fengyun-4, which "stares at the earth and produces a picture in 1 minute", Fengyun-3 has only one satellite. It takes 12 hours to "scan" the world once, that is to say, if it appears over China at 10:00 in the morning, it will not appear over China again until 10:00 at night, so the "timeliness" is poor.
Now, with the dawn orbit at 5:30 in the morning, the morning orbit at 10 am, and the afternoon orbit at 2 pm, Fengyun-3 can "scan" the world every 4 hours, and the timeliness of the data Greatly improved.
Chen Xiaojie, Product Assurance Manager of Fengyun-4 Satellite of the Eighth Academy of China Aerospace Science and Technology Corporation and Director of the First Office of the General Department of Meteorological and Environmental Satellites, said that after the launch of "Dawn Star", China's low-orbit observation orbits are the most abundant in the world. The United States has morning and afternoon orbits combined. Among civilian satellites, China is the only one with dawn orbits. "Therefore, meteorological researchers in Europe and the United States and other countries around the world are very much looking forward to some observation data of 'Dawn Star'."
Efficiency increased by more than 20 times, "staring" directly at the earth
Chen Xiaojie said that in the past 10 years, the observation capability of Fengyun Satellite has been greatly improved.
In the field of geostationary meteorological satellites that do not move relative to the earth, from Fengyun-2 to Fengyun-4, China's meteorological satellites have achieved a great leap forward.
"The original Fengyun-2, we called it 'spin-stabilized' because it was spinning all the time; now Fengyun-4, we call it 'three-axis stable' because it has a relatively stable attitude towards the earth." Chen Xiaojie said.
He revealed that, in fact, for the geostationary orbit meteorological satellite, the above-mentioned leap is very large; China, the United States and Europe started to develop the latest generation of "three-axis stabilized" geostationary orbit meteorological satellites, probably from the 1990s. The demonstration began, but so far only China and the United States have successfully developed it independently.
Why is "three-axis stabilization" so important?
Chen Xiaojie explained that it is conceivable that if the earth is ahead, the satellite needs to observe it. If the satellite is in a spinning state and observes as it rotates, the effective time of observation is very short, and it can only observe 4% to 5% of the effective time.
The "three-axis stabilization" is equivalent to the satellite staring directly at the earth, and the efficiency can be increased by more than 20 times at once.
"It is very important to achieve 'gazing' in a stationary orbit. For example, we are fixed over Beijing. If we were spinning, the observation efficiency was not fully utilized; Any dynamic changes in regional weather conditions can be captured by satellites in time."
At present, a number of China Fengyun meteorological satellites have been included in the global operational application meteorological satellite sequence by the World Meteorological Organization, and have become important members of the global integrated earth observation system and duty satellites of the International Disaster Charter Mechanism, contributing to global meteorological disaster observation and weather forecasting.
For example, in January of this year, the Hongaha Apay Island volcano in Tonga, an island country in the South Pacific, erupted, and the FY-3 and FY-4 satellites in orbit observed the volcanic eruption.
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