In the early morning of June 3, Fengyun 4B was successfully launched on the Long March 3B carrier rocket at the Xichang Satellite Launch Center. As the first operational satellite of China's new generation geostationary orbit meteorological satellite FY-4 series, FY-4B will cooperate with the network of FY-4A in orbit.

The satellite project of FY4B is organized and implemented by the National Space Administration, and the China Meteorological Administration is the user department. How has the technology content of B Star, which undertakes the business mission, improved? How will it forecast the weather more accurately?

Forecaster's "eyes"

"Unlike the test satellite A with a working assessment life of 5 years, FY4B, as a business satellite, has a design and working life of 7 years, and higher requirements for various performance indicators." Dong Yaohai, chief designer of FY-4 of the Eighth Academy of China Aerospace Science and Technology Corporation, said that on the basis of inheriting the advantages of comprehensive exploration capability of A, FY4B has a high frequency, high resolution High sensitivity and other capabilities will be further improved.

It is reported that the newly loaded fast imager of satellite B has the ability of regional high temporal resolution and high spatial resolution monitoring. Combined with advanced geostationary orbit radiation imager, On the basis of imaging China and surrounding areas once every 5 minutes by satellite A, satellite B can achieve 1-minute continuous observation imaging in a million square kilometers area.

"This will help forecasters more flexibly observe the structure and evolution of mesoscale disastrous weather such as typhoon and rainstorm, and also make it easier to identify and capture small-scale, short-lived and destructive severe convective weather such as short-time heavy rainfall, squall line and thunderstorm," said Zhang Zhiqing, deputy chief designer of Fengyun Meteorological Satellite Project.

"Forecasters used to use whatever products meteorological satellites provided before. When Fengyun 4B satellite is put into use, it can become the forecaster's' eye '." Zhang Zhiqing said that demand driven intelligent observation will lead the meteorological satellite business from providing data products to rapidly responding to the demand for forecasting services.

0.05 ℃! Accurately perceive atmospheric changes

In addition to increasing the frequency, FY4B will provide higher detection sensitivity and accuracy than A satellite. It can accurately sense the temperature change of the earth's atmosphere of 0.05 ℃ at a distance of 36000 km, and the deviation between the temperature detection result and the true value is within 0.5 ℃, which is twice as much as that of Star A.

"This will provide more accurate initial field data for regional numerical weather forecasting and improve the accuracy of forecasting sudden weather." Yang Lei, deputy chief designer of the ground system of FY-4 optical star, said that the geostationary orbit radiation imager carried by satellite B this time also added a 7.24 μ m to 7.6 μ m low-level water vapor channel, which is equivalent to installing a high-tech "probe" at the source.

"For forecasters, the rapid change of low-level water vapor has an important indication significance for the occurrence and development of local sudden convection system, and is a powerful assistant for forecasting and early warning," said Yang Lei, The spatial resolution of the geostationary orbit interferometric infrared detector of satellite B has also been improved from 16 km to 12 km. This means that the detected grid points are finer, and more abundant clear sky temperature and humidity profile data can be obtained, which can better assist meteorological decision-making.

In addition, through tackling key problems, the research team has broken through key technologies such as large field of view optical system, sub angular second level high-precision scanning control, and can further provide more precise observation data for analysis and positioning of typhoon observation, typhoon path prediction, severe convective weather system, etc.

Double stars "work together" to make up for the lack of observation range

"The Fengyun family has long been included in the global operational application meteorological satellite series by the World Meteorological Organization, and has become a duty satellite of the international charter mechanism for space and major disasters. The Fengyun meteorological satellite is continuously providing data products and services for 118 countries and regions." Zhuang Guotai, director of the China Meteorological Administration, said that the soon to be "inducted" Fengyun 4B satellite, We will work with Fengyun No.4 A star to expand the "territory" of Fengyun family's global services.

Looking into the starry sky, Fengyun IV A The observation range of binary stars of Star B will reach the Indian Ocean to the west and the Pacific Ocean to the east, which not only covers the land area of China, but also covers a broader area such as the Northwest Pacific Ocean and Oceania.

"After the fixed position of FY4B moved eastward, the observation range was extended to the east of the solar boundary, which greatly made up for the shortcomings of the previous satellite observation range in the eastern side of the Northwest Pacific Ocean. It can fully cover China's responsible sea areas, providing strong support for global typhoon monitoring, especially for the 'Belt and Road' meteorological service." Qian Qifeng, deputy director of the Typhoon and Marine Meteorological Center of the China Meteorological Administration, said.

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