What improvements have Fengyun-4 meteorological satellite brought to China's meteorological observation after its launch?

The satellite will realize the hyperspectral vertical detection of the atmosphere in geostationary orbit for the first time in the world. Together with the imaging radiometer platform, it can jointly carry out multi-channel imaging observation and atmospheric hyperspectral vertical detection, and the performance index of vertical detection has reached the performance index of Europe under study. In addition, the spatial resolution, observation frequency and flexibility of lightning event processing of airborne lightning imager are consistent with similar load performance indexes in Europe and the United States.

It can realize multi-spectral observation of high-resolution visible light, near infrared and medium-long wave infrared, and can realize intensive observation of different ranges in a conventional whole area and a small area, with high frequency and high sensitivity to sudden disaster weather. Multi-channel scanning imaging radiometer uses double scanning mirrors combined with three-reflection optical system and linear array detector to obtain remote sensing data. When imaging, the east-west and north-south scanning mirrors scan linearly and step by step respectively, reflecting the radiation of the earth scenery to the main optical system, and dividing the incident radiation into visible light band, near-infrared band and infrared band through the relay optical system.

The detector converts the scene radiation into electrical signals, which are amplified, A/D converted and buffered. The digital signals are encoded and transmitted to the ground after background and noise suppression, image registration and correction. Time background assessment and background removal, strengthen, measure and locate lightning signals, and realize short-term and imminent forecast and early warning of severe convective weather. Vertical structure observation of atmospheric temperature and humidity parameters The interferometric atmospheric vertical detector detects the vertical temperature and humidity profile of the atmosphere through interferometric imaging, which can obtain the atmospheric temperature and humidity profile and trace gas content in the observation area at high frequency and realize the vertical structure observation of atmospheric temperature and humidity parameters.

Interferometric atmospheric vertical detector uses two-dimensional scanning mirror and off-axis three-reflection main optical system to collect the energy of earth gas, and moving mirror Fourier interferometer is used for detection. The main optical system collects the target radiation and images it in the visible light band; At the same time, the infrared band is split, and the moving mirror moves to form a time-domain infrared interference signal, which is encoded and transmitted to the ground after A/D conversion, interferogram data acquisition and preprocessing.