Keynote Speaker - Lei Ding (THKL)

Thank you. Good evening. Thank you all for attending my presentation. Let me first start with a short video of the infrared payloads on both satellite platforms.

Okay, thanks all. This is just a video introducing the satellite of the major meteorological satellite and payloads of China, and out of another screen.

Okay. This conference is held in Shanghai, and I think this is a big and beautiful city. I've lived for 50 years. There have been several typhoons in the last three months. I mention this just because I want to say that China is one of the countries with the most serious disasters in the world. There are many kinds of disasters, the distributions are frequent, and heavy losses in this country. In the last decades or so, the number of global meteorological disasters have increased by 46 percent, and the sustainable development of human economy and society is facing several challenges in China. Losses caused by meteorological and its derivative disasters, including flood, typhoon, drought, storm, snow disasters, freezing, forest fire, etc., account for more than 70 percent of all natural disasters. Earth observation is a powerful method to monitor the occurrences of the disasters. This image shows there were eight tropical cyclones distributed all over the world on the same day, and we can study or forecast routes based on satellite. Satellite platforms are extremely useful tools to deal with the challenges of natural disasters. Various countries make much account of satellite platforms for opposite observations. This is the distribution of satellites with high quantities in orbit by countries according to NOAA, and we can realize global three-dimensional, all-weather, and seamless observations here. The numerical weather prediction, or NWP, proposes the initial value for more of our model prediction. It needs as much monitoring and data as possible to be developed. As ECMWF essentially figured out, in this curve you can see the error reduces quickly in the past 20 years and had a rapid development. Reduction of initial state errors is driven by more accurate and more assessed observations and the improved accuracy and resolution of forecast model and better data simulation and measures. We know the screen can provide data all over the world, and the spatial resolution is very important for NWP, whether visible, infrared, or microwave. We can see in these curves here, each channel has its specific wavelength range, and in the certain spatial band, the same target has different features in different channels. For this, we can design a target like snow, fog, and dust storm. The more narrow the wavelength is, the more accurate the spectral features we can get from the target. Here we can see the observation with high spectral resolution obtains more details, especially for satellite platforms. In order to obtain more accurate data, scientists all over the world are constantly developing high spectral instruments, from experimental and airborne, low orbital spaceborne, to geostationary orbit. It has lasted over 40-45 years from 1969. China is the first and the unique one who has such sounder on board 23, 35, 800 kilometers away. It shows the history of spaceborne sounder and NWP models. In recent years, high spectral resolution infrared sounders with thousands of channels have become a major part of the data assimilation system of many numerical weather predictions, and provide temperature and constituent profiles with a relatively high vertical resolution. AIRS, IASI, and CrIS are the best level of spaceborne sounders. They have thousands of channels: for AIRS more than 2,200, for IASI more than 8,000, and for CrIS more than 1,000 and 2,000 separately. The Chinese high spectral resolution infrared sounder, like the HIRAS which is on board the polar orbit satellite, only three always, just dropped it as FY-3D, started work in 2018. The comparison with IASI and CrIS is very promising. The example of a very uniform signal shows good performance for this payload, and the profiles for temperature and moisture are gained for four years. To get such a high spectral resolution, the Michelson interferometer was used, and it can increase the spectral and spatial resolution of the atmospheric sounding instruments and provide high spatial density temperature, moisture, and trace gas profiles with a high vertical and temporal resolution from geostationary orbit. ECMWF only monitored the number of satellite data products operationally, and the figures show we can get more and more data from space. This comes to a new era for weather prediction. The powerful computation and huge data enhance the accuracy of prediction, and the data from Chinese satellites increase obviously.

What do we need for approach observation resolution? First of all, we want image improvement, which means high spatial resolution. Secondly, we want continuous monitoring, which means high temporal resolution. For quantitative remote sensing and different targets, we certainly need high resolution, a new geometry matrix resolution, and high spectral resolution. There are mainly two types of satellite platforms: the polar orbiting platform, where the satellite rotates around the Earth bypassing the poles and can provide global coverage twice a day, which is better at a bad temporal frequency. On the other hand, polar orbiting satellites have high spatial resolution, so they can be used to monitor land surface and atmosphere spectral structure for more details. The geostationary orbiting platform has higher observation frequency, and it circles with the Earth and can always face the Earth, and can be used for atmospheric vertical detection and lightning detection, but its technical implementation is difficult, such as its pointing accuracy and stability. We have two main types of orbit, but why do we need geostationary orbit hyperspectral infrared sounders? First, observation from a geostationary orbit can get large spatial coverage and higher temporal resolution for regional models. Compared with microwave sounders, it has finer vertical resolution, and high temporal resolution observation means it can provide critical information for forecasting, for example for storm forecasts.

Now we come to the Fengyun platform. Fengyun is the name for Chinese meteorological satellites. The odd numbers like FY-1 and FY-3 are for polar orbit satellites, and the even numbers like FY-2 and FY-4 are for geostationary orbit satellites. There are totally 19 meteorological satellites sent to space, and now three operational ones work here now. These show countries and organizations developing hyperspectral technology. China, for the FY-3 and the HIRAS for FY-3 and the GIIRS for FY-4, both are interferometer sounders. Now China has the hyperspectral atmospheric vertical detection capability in both polar orbit and geosynchronous orbit. We can see all these together. This is the technical properties for the payloads. The US and Japan send imagers in orbit like this, and the ABI and the AHI and also the lightning mapping imager. China has both imagers and sounders on orbit, for the FY-3 04A and 04B, and also has the lightning mapping imager on board. Compared with the first generation satellite FY-2, FY-4 could provide more observation data and useful information in three dimensions: spectral, spatial, and temporal. It is a challenge to effectively dig out the useful information from the big data. This means here comes a new era for big data for weather prediction. This is the first spaceborne interferometer that flies in geostationary orbit to make a measurement of three-dimensional atmospheric structure. It is based on the principle of Fourier transform and located on the first new generation geostationary orbit platform for FY-4. This is the structure of the FY-4 and this is for the GIIRS payload. For the structure, there are many requirements for the platforms. First is the micro-vibration isolation. We can get the structure and handle it with this technology. We can measure the vibration less than 0.1 milligrams and angular vibration less than 5 microradians. This is the measurement results of the satellite. Then we can get the force of frequency of band vibration all day for three-dimensional spectral data. We can see here the micro-vibration network is good. Another requirement for the platform is damping several heat alternating environments. We can see the heat deformation leads to image dissociating in the 24-hour cycle. The sun shines on different surfaces of the satellite, and the temperature will range more than 300 degrees. We can see it will affect the image of the payload. For the optical model, we can get better imaging quality. This is the specification of the payload. We can see these profiles for temperature and humidity. This is the concept of the payloads for one segment. The error estimation is less than usual. This is the chopping of the GIIRS. This is the potential for prediction. This is just assimilating the data gained from the GIIRS. We can see this is the working model and the operational model to observe the Earth. We can see it has important impacts on the recent typhoon analysis and forecasts. It works from west to east and focuses on the same area for forecasting. This is the temporal resolution of three minutes. The results of the minutes and we can see the operational model here. For the temporal resolution, we can see the results of the prediction to obtain enhanced accuracy of the prediction. This is also for the typhoon case. We can see here we use several channels of the spectral resolution. We can see the reality of the result using the data from the GIIRS is closer to the reality. This is also for the forecasting. This is the target of the region using it in another case. Here is the time assimilation of the GIIRS for typhoon forecast. We can see this is the real route of the typhoon, and with the data from the GIIRS, we can see it is really close to the real one. This is also the location. We can see for the first time the temperature and humidity data in the vertical detection. We have another payload, FY-4, launched onboard FY-4B last June, and we can get many models which are enhanced for the new payload. We had detectors, interferometers, and the cold optics and heat control enhanced for this payload. This is the detectors and the cold structure. This is also for the temperature of the interferometer and the performance of the payload on board. It performs better advances, better spectral response for the long wave bands and microwave infrared bands. We also have cooperation with the University of Wisconsin for the first hyperspectral infrared sounder.

Here comes the end of my presentation. The GIIRS, the first one working in geostationary orbit and operating in real-time detection, has better spectral capability and new applications. Thank you all. Here's another, he just comes at the institute. Thank you all, and welcome to our institute.