Satellite-Based Emission Inversion for Air Pollutants and Greenhouse Gases

Satellite-based emission inversions of atmospheric pollutants and greenhouse gases provide indispensable information and data foundation for a comprehensive understanding of the sources of these key atmospheric compositions and for the precise implementation of emission reduction measures. Great advances have been made in the field of emission inversion over the past two decades, with Chinese domestic scholars making substantial contributions, which have provided important scientific support for environmental protection and carbon neutrality in China. In celebrating the 100th anniversary of the Chinese Meteorological Society, this paper systematically reviews the research progress of Chinese scholars in satellite-based emission inversion in the past two decades, based on 85 journal papers. Several widely used inversion methods, including data assimilation, local mass balance, Gaussian models, two-dimensional models and machine learning, are briefly summarized. Emission inversion studies of atmospheric pollutants, including nitrogen oxides (NO_x), ammonia (NH₃), formaldehyde (HCHO), glyoxal (CHOCHO), sulfur dioxide (SO₂) and carbon monoxide (CO), as well as greenhouse gases, including carbon dioxide (CO₂) and methane (CH₄) performed by Chinese scholars are then presented. Finally, the historical evolution of inversion methods and target species, challenges in current satellite-based emission inversion and future research directions are discussed to promote more accurate quantification of atmospheric pollutants and greenhouse gas emissions.