The 15th National Postgraduate Environmental Forum was held in TongJi University from October 31 to November 1, 2020. The academic paper Retrieval of Global Carbon Dioxide Total Column and XCO2 from TanSat Satellite based on IMAP-DOAS Algorithm” won the first prize.

Professor Liu Cheng from the School of Engineering Science guided this research. The first author is a PhD student called Hong Xinhua. The research completed the inversion of global CO₂ concentration distribution based on the first-level spectral data of TanSat (the first greenhouse gas satellite in China). This research developed the hyperspectral on-orbit secondary calibration technology to solve the problems caused in the operation of TanSat such as instrumental performance degradation, flight instability, calibration parameter deviation, low spectral signal-to-noise ratio, spectral shift and so on, successfully reversed the global CO₂ total column concentration and dry air mixing ratio X_CO2 product in the solar flare observation mode. After comparison with similar satellites and terrestrial TCCON sites in the United States and Japan, the measurement accuracy reached 1.75 ppm which is close to the quality of foreign benchmark products. The Forum Jury commented this research as  It started from a national strategic point of view and has played a major role in getting rid of our country’s dependence on foreign satellite carbon products. Meantime, it supported a scientific basis for the improvement and effective application of our country’s satellite monitoring data.

According to Professor Liu Cheng, the background value of CO₂ in the atmosphere is relatively high (~400 ppm) and stable among many greenhouse gases so that the accuracy of space-based measurement for CO₂ has a strict requirement by even  reaching 2.5~3.0 ppm in a good inversion case. At present, the most popular satellite CO₂ products mainly come from Japan’s GOSAT satellite and the United States’ OCO-2 satellite. Along with the successful launch of TanSat satellite, China is expected to become the third country that can provide global CO₂ independently. The awarded research lasted for two years by overcoming lots of key technical difficulties, and can provide completely independent domestic satellite data support for a much deeper study of surface carbon sources and sinks.

The current National Postgraduate Environmental Forum with the theme of New period, New Direction and New Technology lasted for ten months. About 41 universities (such as Tsinghua University, Zhejiang University) together with 143 high-quality papers in the environmental field participated in this forum. After a preliminary unknown review by nearly a hundred experts and a final face-to-face defense, five first-class prizes and several other prizes were awarded.