Comment on egusphere-2026-1681

Abstract

Abstract. The integration of satellite aerosol optical depth (AOD) and trace gas observations using data assimilation has the potential to improve our understanding of aerosol composition. This study evaluates these synergistic effects through combined constraints on total aerosols by AOD and on secondary aerosol formation by trace gases. The simultaneous data assimilation (DA) of NO2, SO2, CO, and HNO3 from OMI, TROPOMI, MOPITT, and MLS, together with AOD from MODIS and VIIRS, improved aerosol analyses in most cases compared to conventional DA runs that separately assimilate AOD or trace gases satellite observations. Validation against independent surface observations of sulfate, nitrate, and ammonium (SNA), and PM2.5 showed improved agreements by 6–98 % compared to the conventional DA runs and the control simulation without any data assimilation. Notably, the reduction in PM2.5 model biases exceeded that achieved by the conventional DA of AOD by 56 % in Northeast Asia. These improvements were achieved by reduced SO2 and soil dust emissions by 30 % and 60 % globally and increased NOx and carbonaceous aerosol emissions by 30 % and 15 %. The simultaneous DA provides even larger reductions in SNA and AOD biases by up to 25 % and 48 % respectively, when the current generation instruments (TROPOMI and VIIRS) is used, instead of the previous generation instruments (OMI and MODIS). This coupled aerosol and trace gas DA framework offers significant advantages for improving global aerosol composition analyses, informing policy decisions with co-benefits for air quality and climate, and optimizing the use of the current satellite observing network.

Authors 6

1. Takashi Sekiya corresponding

   Japan Agency for Marine-Earth Science and Technology

   Affiliation as printed

   Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan

2. Kazuyuki Miyazaki

   Jet Propulsion Laboratory

   Affiliation as printed

   Jet Propulsion Laboratory/California Institute for Technology, Pasadena, CA, USA

3. Henk J. Eskes

   Royal Netherlands Meteorological Institute

   Affiliation as printed

   Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands

4. Pieter Rijsdijk Aachen Space Research Organisation Netherlands

   Royal Netherlands Meteorological Institute · Space Research Organisation Netherlands · Vrije Universiteit Amsterdam

   Affiliation as printed

   Department of Earth Sciences, Vrije Universiteit, Amsterdam, the Netherlands

   Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands

   Space Research Organisation Netherlands (SRON), Leiden, Netherlands

5. Kengo Sudo

   Nagoya University

   Affiliation as printed

   Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan

6. Yugo Kanaya

   Japan Agency for Marine-Earth Science and Technology

   Affiliation as printed

   Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan