5:15 PM - 7:15 PM
[AAS11-P12] Time variation of stratospheric aerosol layer observed by lidar at Fukuoka in 2022 and 2024
~ Observation of the volcanic aerosol from Tonga volcanic eruption
Stratospheric aerosols are long-lived and affect not only climate change through radiation processes, but also chemical processes in the stratosphere due to heterogeneous reactions on the particle surface. In particular, volcanic aerosols that were injected directly into the stratosphere due to major volcanic eruptions have a significant impact on the disturbance of stratospheric aerosols, so information on their spatial and temporal distribution is important.
In January 2022, the Hunga Tonga-Hunga Ha'apai submarine volcano (20.54°S, 175.38°W, hereafter referred to as Tonga Volcano) erupted violently (VEI 6). Large amounts of water vapor and sulfur dioxide were injected into the stratosphere, and sulfuric acid aerosols were formed in the lower stratosphere and spread widely on a global scale. Therefore, there is growing interest in the spatial and temporal distribution of the volcanic aerosols loading by the Tonga volcano eruption, and their impact on chemical processes and radiation balance in the stratosphere.
We have performed long-term monitoring of stratospheric aerosols using lidar at Fukuoka since 1991. The volcanic aerosol layers originating by Tonga volcanic eruption had been observed since April 2022. On April 4, 2022, the first volcanic aerosol layer was observed. Very strong and sharp scattering layers (532nm scattering ratio of ~1.7) were observed around 23 km, where the particle depolarization ratio showed a low value (0.15%), indicating that the aerosol layer was composed of droplet particles. Such droplet aerosol layers with an enhancement of scattering ratio were frequently observed from April to May 2022 in the height range of 20-26 km. Since June 2022, although clear peaks were rarely observed, a broad increase in the scattering ratio was observed in a wide height range of 20-26 km. From the time variation of the integrated backscatter coefficient (IBC) of stratospheric aerosols, it was found that an increase in IBC by Tonga volcanic aerosol was observed from April 2022. The IBC showed a maximum in December 2022, then it decreased and transitioned to the background state in June 2023.
In our presentation, we will report the time variation of the height distribution of the observed volcanic aerosols, and seasonal variations of stratospheric aerosols observed from 2022 to 2024.
In January 2022, the Hunga Tonga-Hunga Ha'apai submarine volcano (20.54°S, 175.38°W, hereafter referred to as Tonga Volcano) erupted violently (VEI 6). Large amounts of water vapor and sulfur dioxide were injected into the stratosphere, and sulfuric acid aerosols were formed in the lower stratosphere and spread widely on a global scale. Therefore, there is growing interest in the spatial and temporal distribution of the volcanic aerosols loading by the Tonga volcano eruption, and their impact on chemical processes and radiation balance in the stratosphere.
We have performed long-term monitoring of stratospheric aerosols using lidar at Fukuoka since 1991. The volcanic aerosol layers originating by Tonga volcanic eruption had been observed since April 2022. On April 4, 2022, the first volcanic aerosol layer was observed. Very strong and sharp scattering layers (532nm scattering ratio of ~1.7) were observed around 23 km, where the particle depolarization ratio showed a low value (0.15%), indicating that the aerosol layer was composed of droplet particles. Such droplet aerosol layers with an enhancement of scattering ratio were frequently observed from April to May 2022 in the height range of 20-26 km. Since June 2022, although clear peaks were rarely observed, a broad increase in the scattering ratio was observed in a wide height range of 20-26 km. From the time variation of the integrated backscatter coefficient (IBC) of stratospheric aerosols, it was found that an increase in IBC by Tonga volcanic aerosol was observed from April 2022. The IBC showed a maximum in December 2022, then it decreased and transitioned to the background state in June 2023.
In our presentation, we will report the time variation of the height distribution of the observed volcanic aerosols, and seasonal variations of stratospheric aerosols observed from 2022 to 2024.