Changes in economic activity and emission control policies have led to substantial shifts in anthropogenic emissions worldwide, while climate change has intensified natural sources such as wildfires. Long-term records of tropospheric composition are essential for understanding the evolving patterns of air pollution and their impacts on climate, ecosystems, and human health. Satellite measurements, together with in situ observations, have provided valuable insights into these global changes. However, attributing observed trends to specific emission sources and underlying chemical and physical processes remains challenging because of the complexity of atmospheric chemistry and the integration of diverse observational datasets.
To address these challenges, we developed the Multi-mOdel Multi-cOnstituent Chemical (MOMO-Chem) data assimilation (DA) framework, which integrates a wide range of satellite observations with multiple chemical transport models. MOMO-Chem has been used to produce the Tropospheric Chemistry Reanalysis version 2 (TCR-2), providing globally consistent estimates of tropospheric composition and precursor emissions by assimilating extensive satellite observations from NASA and international missions, including Aura, Aqua, and Terra. The MOMO-Chem framework is now being extended to incorporate multi-sensor data from new-generation satellite instruments, including CrIS and VIIRS (Suomi-NPP and JPSS) as well as Sentinel-5P TROPOMI, using the stretched-grid GEOS-Chem High Performance (GCHP) system. This enables seamless analyses of trace gas and aerosol interactions from city to global scales.
These advancements enhance the attribution of variability in short-lived climate pollutants (SLCPs) to both short- and long-term changes in anthropogenic and natural activities (e.g., biomass burning, biogenic processes) and improve understanding of their roles in air quality, oxidation capacity, and climate. MOMO-Chem has recently been applied to the ASIA-AQ analysis and supports NASA’s Earth Science to Action (ES2A) Air Quality initiative and multiple programs within NASA’s Atmospheric Composition focus area. The MOMO-Chem framework also contributes to international research efforts, including studies relevant to the IPCC and the IGAC Project under Future Earth.
