The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud
<p>We employ the ECHAM5/MESSy2 atmospheric chemistry general circulation model (EMAC) that incorporates calculations of gas-phase and heterogeneous chemistry coupled with the ozone cycle and aerosol formation, transport, and microphysics to calculate the 1991 Pinatubo volcanic cloud. We consid...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/471/2023/acp-23-471-2023.pdf |
| _version_ | 1797954981402247168 |
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| author | M. Abdelkader G. Stenchikov A. Pozzer H. Tost J. Lelieveld |
| author_facet | M. Abdelkader G. Stenchikov A. Pozzer H. Tost J. Lelieveld |
| author_sort | M. Abdelkader |
| collection | DOAJ |
| description | <p>We employ the ECHAM5/MESSy2 atmospheric chemistry general circulation model (EMAC) that incorporates calculations of gas-phase and heterogeneous chemistry coupled
with the ozone cycle and aerosol formation, transport, and microphysics to calculate the 1991 Pinatubo volcanic cloud. We considered simultaneous
injections of <span class="inline-formula">SO<sub>2</sub></span>, volcanic ash, and water vapor. We conducted multiple ensemble simulations with different injection configurations to test
the evolution of <span class="inline-formula">SO<sub>2</sub></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="6060a0eb6022af681aa55d19b3180df9"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-471-2023-ie00001.svg" width="29pt" height="17pt" src="acp-23-471-2023-ie00001.png"/></svg:svg></span></span>, ash masses, stratospheric aerosol optical depth, surface area density (SAD), and the stratospheric
temperature response against available observations. We found that the volcanic cloud evolution is sensitive to the altitude where volcanic debris
is initially injected and the initial concentrations of the eruption products that affect radiative heating and lofting of the volcanic cloud. The
numerical experiments with the injection of 12 <span class="inline-formula">Mt SO<sub>2</sub></span>, 75 <span class="inline-formula">Mt</span> of volcanic ash, and 150 <span class="inline-formula">Mt</span> of water vapor at
20 <span class="inline-formula">km</span> show the best agreement with the observation aerosol optical depth and stratospheric temperature response. Volcanic water injected
by eruptive jet and/or intruding through the tropopause accelerates <span class="inline-formula">SO<sub>2</sub></span> oxidation. But the mass of volcanic water retained in the
stratosphere is controlled by the stratospheric temperature at the injection level. For example, if volcanic materials are released in the cold point above
the tropical tropopause, most of the injected water freezes and sediments as ice crystals. The water vapor directly injected into the volcanic cloud
increases the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="06a1e144313624090049b6627390d3e8"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-471-2023-ie00002.svg" width="29pt" height="17pt" src="acp-23-471-2023-ie00002.png"/></svg:svg></span></span> mass and stratospheric aerosol optical depth by about 5 %. The coarse ash comprises 98 % of the ash injected
mass. It sediments within a few days, but aged submicron ash could stay in the stratosphere for a few months providing SAD for heterogeneous
chemistry. The presence of ash accelerates the <span class="inline-formula">SO<sub>2</sub></span> oxidation by 10 %–20 % due to heterogeneous chemistry, radiative heating,
lofting, and faster dispersion of volcanic debris. Ash aging affects its lifetime and optical properties, almost doubling the ash radiative
heating. The 2.5-year simulations show that the stratospheric temperature anomalies forced by radiative heating of volcanic debris in our
experiments with the 20 <span class="inline-formula">km</span> injection height agree well with observations and reanalysis data. This indicates that the model captures the
long-term evolution and climate effect of the Pinatubo volcanic cloud. The volcanic cloud's initial lofting, facilitated by ash particles' radiative
heating, controls the oxidation rate of <span class="inline-formula">SO<sub>2</sub></span>. Ash accelerates the formation of the sulfate layer in the first 2 months after the
eruption. We also found that the interactive calculations of <span class="inline-formula">OH</span> and heterogeneous chemistry increase the volcanic cloud sensitivity to water
vapor and ash injections. All those factors must be accounted for in modeling the impact of large-scale volcanic injections on climate and
stratospheric chemistry.</p> |
| first_indexed | 2024-04-10T23:26:08Z |
| format | Article |
| id | doaj.art-36ebac6b755d45978a6f7872398e6fed |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-10T23:26:08Z |
| publishDate | 2023-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-36ebac6b755d45978a6f7872398e6fed2023-01-12T12:02:13ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-01-012347150010.5194/acp-23-471-2023The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloudM. Abdelkader0G. Stenchikov1A. Pozzer2H. Tost3J. Lelieveld4Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi ArabiaDivision of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi ArabiaAir Chemistry Department, Max Planck Institute for Chemistry, Mainz, 55128, GermanyInstitute for Atmospheric Physics, Johannes Gutenberg University of Mainz, Mainz, 55128, GermanyAir Chemistry Department, Max Planck Institute for Chemistry, Mainz, 55128, Germany<p>We employ the ECHAM5/MESSy2 atmospheric chemistry general circulation model (EMAC) that incorporates calculations of gas-phase and heterogeneous chemistry coupled with the ozone cycle and aerosol formation, transport, and microphysics to calculate the 1991 Pinatubo volcanic cloud. We considered simultaneous injections of <span class="inline-formula">SO<sub>2</sub></span>, volcanic ash, and water vapor. We conducted multiple ensemble simulations with different injection configurations to test the evolution of <span class="inline-formula">SO<sub>2</sub></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="6060a0eb6022af681aa55d19b3180df9"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-471-2023-ie00001.svg" width="29pt" height="17pt" src="acp-23-471-2023-ie00001.png"/></svg:svg></span></span>, ash masses, stratospheric aerosol optical depth, surface area density (SAD), and the stratospheric temperature response against available observations. We found that the volcanic cloud evolution is sensitive to the altitude where volcanic debris is initially injected and the initial concentrations of the eruption products that affect radiative heating and lofting of the volcanic cloud. The numerical experiments with the injection of 12 <span class="inline-formula">Mt SO<sub>2</sub></span>, 75 <span class="inline-formula">Mt</span> of volcanic ash, and 150 <span class="inline-formula">Mt</span> of water vapor at 20 <span class="inline-formula">km</span> show the best agreement with the observation aerosol optical depth and stratospheric temperature response. Volcanic water injected by eruptive jet and/or intruding through the tropopause accelerates <span class="inline-formula">SO<sub>2</sub></span> oxidation. But the mass of volcanic water retained in the stratosphere is controlled by the stratospheric temperature at the injection level. For example, if volcanic materials are released in the cold point above the tropical tropopause, most of the injected water freezes and sediments as ice crystals. The water vapor directly injected into the volcanic cloud increases the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="06a1e144313624090049b6627390d3e8"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-471-2023-ie00002.svg" width="29pt" height="17pt" src="acp-23-471-2023-ie00002.png"/></svg:svg></span></span> mass and stratospheric aerosol optical depth by about 5 %. The coarse ash comprises 98 % of the ash injected mass. It sediments within a few days, but aged submicron ash could stay in the stratosphere for a few months providing SAD for heterogeneous chemistry. The presence of ash accelerates the <span class="inline-formula">SO<sub>2</sub></span> oxidation by 10 %–20 % due to heterogeneous chemistry, radiative heating, lofting, and faster dispersion of volcanic debris. Ash aging affects its lifetime and optical properties, almost doubling the ash radiative heating. The 2.5-year simulations show that the stratospheric temperature anomalies forced by radiative heating of volcanic debris in our experiments with the 20 <span class="inline-formula">km</span> injection height agree well with observations and reanalysis data. This indicates that the model captures the long-term evolution and climate effect of the Pinatubo volcanic cloud. The volcanic cloud's initial lofting, facilitated by ash particles' radiative heating, controls the oxidation rate of <span class="inline-formula">SO<sub>2</sub></span>. Ash accelerates the formation of the sulfate layer in the first 2 months after the eruption. We also found that the interactive calculations of <span class="inline-formula">OH</span> and heterogeneous chemistry increase the volcanic cloud sensitivity to water vapor and ash injections. All those factors must be accounted for in modeling the impact of large-scale volcanic injections on climate and stratospheric chemistry.</p>https://acp.copernicus.org/articles/23/471/2023/acp-23-471-2023.pdf |
| spellingShingle | M. Abdelkader G. Stenchikov A. Pozzer H. Tost J. Lelieveld The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud Atmospheric Chemistry and Physics |
| title | The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud |
| title_full | The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud |
| title_fullStr | The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud |
| title_full_unstemmed | The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud |
| title_short | The effect of ash, water vapor, and heterogeneous chemistry on the evolution of a Pinatubo-size volcanic cloud |
| title_sort | effect of ash water vapor and heterogeneous chemistry on the evolution of a pinatubo size volcanic cloud |
| url | https://acp.copernicus.org/articles/23/471/2023/acp-23-471-2023.pdf |
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