Monitoring and modeling of volcanic plumes are important for understanding the impact of volcanic activity on climate and for practical concerns, such as aviation safety or public health. Here, we apply the Lagrangian transport model Massive-Parallel Trajectory Calculations (MPTRAC) to estimate the SO₂ injections into the upper troposphere and lower stratosphere by the eruption of the Raikoke volcano (48.29^∘ N, 153.25^∘ E) in June 2019 and its subsequent long-range transport and dispersion. First, we used SO₂ retrievals from the AIRS (Atmospheric Infrared Sounder) and TROPOMI (TROPOspheric Monitoring Instrument) satellite instruments together with a backward trajectory approach to estimate the altitude-resolved SO₂ injection time series. Second, we applied a scaling factor to the initial estimate of the SO₂ mass and added an exponential decay to simulate the time evolution of the total SO₂ mass. By comparing the estimated SO₂ mass and the mass from TROPOMI retrievals, we show that the volcano injected 2.1 ± 0.2 Tg SO₂, and the e-folding lifetime of the SO₂ was about 13 to 17 d. The reconstructed SO₂ injection time series are consistent between using the AIRS nighttime and the TROPOMI daytime products. Further, we compared forward transport simulations that were initialized by AIRS and TROPOMI SO₂ products with a constant SO₂ injection rate. The results show that the modeled SO₂ change, driven by chemical reactions, captures the SO₂ mass variations from TROPOMI retrievals. In addition, the forward simulations reproduce the SO₂ distributions in the first ∼10 d after the eruption. However, diffusion in the forward simulations is too strong to capture the internal structure of the SO₂ clouds, which is further quantified in the simulation of the compact SO₂ cloud from late July to early August. Our study demonstrates the potential of using combined nadir satellite retrievals and Lagrangian transport simulations to further improve SO₂ time- and height-resolved injection estimates of volcanic eruptions.
Monitoring and modeling of volcanic plumes are important for understanding the impact of volcanic activity on climate and for practical concerns, such as aviation safety or public health. Here, we apply the Lagrangian transport model Massive-Parallel Trajectory Calculations (MPTRAC) to estimate the SO₂ injections into the upper troposphere and lower stratosphere by the eruption of the Raikoke volcano (48.29^∘ N, 153.25^∘ E) in June 2019 and its subsequent long-range transport and dispersion. First, we used SO₂ retrievals from the AIRS (Atmospheric Infrared Sounder) and TROPOMI (TROPOspheric Monitoring Instrument) satellite instruments together with a backward trajectory approach to estimate the altitude-resolved SO₂ injection time series. Second, we applied a scaling factor to the initial estimate of the SO₂ mass and added an exponential decay to simulate the time evolution of the total SO₂ mass. By comparing the estimated SO₂ mass and the mass from TROPOMI retrievals, we show that the volcano injected 2.1 ± 0.2 Tg SO₂, and the e-folding lifetime of the SO₂ was about 13 to 17 d. The reconstructed SO₂ injection time series are consistent between using the AIRS nighttime and the TROPOMI daytime products. Further, we compared forward transport simulations that were initialized by AIRS and TROPOMI SO₂ products with a constant SO₂ injection rate. The results show that the modeled SO₂ change, driven by chemical reactions, captures the SO₂ mass variations from TROPOMI retrievals. In addition, the forward simulations reproduce the SO₂ distributions in the first ∼10 d after the eruption. However, diffusion in the forward simulations is too strong to capture the internal structure of the SO₂ clouds, which is further quantified in the simulation of the compact SO₂ cloud from late July to early August. Our study demonstrates the potential of using combined nadir satellite retrievals and Lagrangian transport simulations to further improve SO₂ time- and height-resolved injection estimates of volcanic eruptions.

volcanic SO2,Lagrangian transport simulations