Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time
Large explosive volcanic eruptions are capable of injecting considerable amounts of particles and sulfur gases above the tropopause, causing large increases in stratospheric aerosols. Five major volcanic eruptions after 1960 (i.e., Agung, St. Helens, El Chichón, Nevado del Ruiz and Pinatubo) have be...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-05-01
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| Series: | Atmosphere |
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| Online Access: | http://www.mdpi.com/2073-4433/7/6/75 |
| _version_ | 1818606063212036096 |
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| author | Giovanni Pitari Glauco Di Genova Eva Mancini Daniele Visioni Ilaria Gandolfi Irene Cionni |
| author_facet | Giovanni Pitari Glauco Di Genova Eva Mancini Daniele Visioni Ilaria Gandolfi Irene Cionni |
| author_sort | Giovanni Pitari |
| collection | DOAJ |
| description | Large explosive volcanic eruptions are capable of injecting considerable amounts of particles and sulfur gases above the tropopause, causing large increases in stratospheric aerosols. Five major volcanic eruptions after 1960 (i.e., Agung, St. Helens, El Chichón, Nevado del Ruiz and Pinatubo) have been considered in a numerical study conducted with a composition-climate coupled model including an aerosol microphysics code for aerosol formation and growth. Model results are compared between an ensemble of numerical simulations including volcanic aerosols and their radiative effects (VE) and a reference simulations ensemble (REF) with no radiative impact of the volcanic aerosols. Differences of VE-REF show enhanced diabatic heating rates; increased stratospheric temperatures and mean zonal westerly winds; increased planetary wave amplitude; and tropical upwelling. The impact on stratospheric upwelling is found to be larger when the volcanically perturbed stratospheric aerosol is confined to the tropics, as tends to be the case for eruptions which were followed by several months with easterly shear of the quasi-biennial oscillation (QBO), e.g., the Pinatubo case. Compared to an eruption followed by a period of westerly QBO, such easterly QBO eruptions are quite different, with meridional transport to mid- and high-latitudes occurring later, and at higher altitude, with a consequent decrease in cross-tropopause removal from the stratosphere, and therefore longer decay timescale. Comparing the model-calculated e-folding time of the volcanic aerosol mass during the first year after the eruptions, an increase is found from 8.1 and 10.3 months for El Chichón and Agung (QBO westerly shear), to 14.6 and 30.7 months for Pinatubo and Ruiz (QBO easterly shear). The corresponding e-folding time of the global-mean radiative flux changes goes from 9.1 and 8.0 months for El Chichón and Agung, to 28.7 and 24.5 months for Pinatubo and Ruiz. |
| first_indexed | 2024-12-16T14:04:54Z |
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| id | doaj.art-b6009911a7bc4f5590ff73b5c98dcbdb |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-12-16T14:04:54Z |
| publishDate | 2016-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-b6009911a7bc4f5590ff73b5c98dcbdb2022-12-21T22:28:57ZengMDPI AGAtmosphere2073-44332016-05-01767510.3390/atmos7060075atmos7060075Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding TimeGiovanni Pitari0Glauco Di Genova1Eva Mancini2Daniele Visioni3Ilaria Gandolfi4Irene Cionni5Department of Physical and Chemical Sciences, Università degli Studi dell’Aquila, L’Aquila 67100, ItalyDepartment of Physical and Chemical Sciences, Università degli Studi dell’Aquila, L’Aquila 67100, ItalyDepartment of Physical and Chemical Sciences, Università degli Studi dell’Aquila, L’Aquila 67100, ItalyDepartment of Physical and Chemical Sciences, Università degli Studi dell’Aquila, L’Aquila 67100, ItalyDepartment of Physical and Chemical Sciences, Università degli Studi dell’Aquila, L’Aquila 67100, ItalyEnea, Ente per le Nuove Tecnologie, l’Energia e l’Ambiente, Roma 00123, ItalyLarge explosive volcanic eruptions are capable of injecting considerable amounts of particles and sulfur gases above the tropopause, causing large increases in stratospheric aerosols. Five major volcanic eruptions after 1960 (i.e., Agung, St. Helens, El Chichón, Nevado del Ruiz and Pinatubo) have been considered in a numerical study conducted with a composition-climate coupled model including an aerosol microphysics code for aerosol formation and growth. Model results are compared between an ensemble of numerical simulations including volcanic aerosols and their radiative effects (VE) and a reference simulations ensemble (REF) with no radiative impact of the volcanic aerosols. Differences of VE-REF show enhanced diabatic heating rates; increased stratospheric temperatures and mean zonal westerly winds; increased planetary wave amplitude; and tropical upwelling. The impact on stratospheric upwelling is found to be larger when the volcanically perturbed stratospheric aerosol is confined to the tropics, as tends to be the case for eruptions which were followed by several months with easterly shear of the quasi-biennial oscillation (QBO), e.g., the Pinatubo case. Compared to an eruption followed by a period of westerly QBO, such easterly QBO eruptions are quite different, with meridional transport to mid- and high-latitudes occurring later, and at higher altitude, with a consequent decrease in cross-tropopause removal from the stratosphere, and therefore longer decay timescale. Comparing the model-calculated e-folding time of the volcanic aerosol mass during the first year after the eruptions, an increase is found from 8.1 and 10.3 months for El Chichón and Agung (QBO westerly shear), to 14.6 and 30.7 months for Pinatubo and Ruiz (QBO easterly shear). The corresponding e-folding time of the global-mean radiative flux changes goes from 9.1 and 8.0 months for El Chichón and Agung, to 28.7 and 24.5 months for Pinatubo and Ruiz.http://www.mdpi.com/2073-4433/7/6/75composition-climate modelexplosive volcanic eruptionssulfate aerosolsaerosol radiative efficiencystratospheric dynamicsquasi-biennial oscillation |
| spellingShingle | Giovanni Pitari Glauco Di Genova Eva Mancini Daniele Visioni Ilaria Gandolfi Irene Cionni Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time Atmosphere composition-climate model explosive volcanic eruptions sulfate aerosols aerosol radiative efficiency stratospheric dynamics quasi-biennial oscillation |
| title | Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time |
| title_full | Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time |
| title_fullStr | Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time |
| title_full_unstemmed | Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time |
| title_short | Stratospheric Aerosols from Major Volcanic Eruptions: A Composition-Climate Model Study of the Aerosol Cloud Dispersal and e-folding Time |
| title_sort | stratospheric aerosols from major volcanic eruptions a composition climate model study of the aerosol cloud dispersal and e folding time |
| topic | composition-climate model explosive volcanic eruptions sulfate aerosols aerosol radiative efficiency stratospheric dynamics quasi-biennial oscillation |
| url | http://www.mdpi.com/2073-4433/7/6/75 |
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