Long-range transport of volcanic aerosol from the 2010 Merapi tropical eruption to Antarctica
<p>Volcanic sulfate aerosol is an important source of sulfur for Antarctica, where other local sources of sulfur are rare. Midlatitude and high-latitude volcanic eruptions can directly influence the aerosol budget of the polar stratosphere. However, tropical eruptions can also enhance polar...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/15859/2018/acp-18-15859-2018.pdf |
| Summary: | <p>Volcanic sulfate aerosol is an important source of sulfur for
Antarctica, where other local sources of sulfur are rare. Midlatitude and high-latitude volcanic eruptions can directly influence the aerosol budget of the
polar stratosphere. However, tropical eruptions can also enhance polar
aerosol load following long-range transport. In the present work, we analyze
the volcanic plume of a tropical eruption, Mount Merapi in 2010, and
investigate the transport pathway of the volcanic aerosol from the tropical
tropopause layer (TTL) to the lower stratosphere over Antarctica. We use the
Lagrangian particle dispersion model Massive-Parallel Trajectory Calculations
(MPTRAC) and Atmospheric Infrared Sounder (AIRS) SO<sub>2</sub> measurements
to reconstruct the altitude-resolved SO<sub>2</sub> injection time series
during the explosive eruption period and simulate the transport of the
volcanic plume using the MPTRAC model. AIRS SO<sub>2</sub> and aerosol
measurements, the aerosol cloud index values provided by Michelson
Interferometer for Passive Atmospheric Sounding (MIPAS), are used to verify
and complement the simulations. The Lagrangian transport simulation of the
volcanic plume is compared with MIPAS aerosol measurements and shows good
agreement. Both the simulations and the observations presented in this study
suggest that volcanic plumes from the Merapi eruption were transported to the
south of 60° S 1 month after the eruption and even further to
Antarctica in the following months. This relatively fast meridional transport
of volcanic aerosol was mainly driven by quasi-horizontal mixing from the TTL
to the extratropical lower stratosphere, and most of the quasi-horizontal
mixing occurred between the isentropic surfaces of 360 to 430 K. When the
plume went to Southern Hemisphere high latitudes, the polar vortex was
displaced from the South Pole, so that the volcanic plume was carried to the
South Pole without penetrating the polar vortex. Although only 4 % of the
sulfur injected by the Merapi eruption was transported into the lower
stratosphere south of 60° S, the Merapi eruption contributed up to
8800 t of sulfur to the Antarctic lower stratosphere. This indicates that
the long-range transport under favorable meteorological conditions enables a
moderate tropical volcanic eruption to be an important remote source of
sulfur for the Antarctic stratosphere.</p> |
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| ISSN: | 1680-7316 1680-7324 |