The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations
Abstract As the climate system warms, megafires have become more frequent with devastating effects. A byproduct of these events is the creation of smoke plumes that can rise into the stratosphere and spread across the globe where they reside for many months. To gain a deeper understanding of the plu...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Geophysical Union (AGU)
2023-04-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2022MS003432 |
| _version_ | 1827797234084741120 |
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| author | S. R. Guimond J. Reisner M. Dubey |
| author_facet | S. R. Guimond J. Reisner M. Dubey |
| author_sort | S. R. Guimond |
| collection | DOAJ |
| description | Abstract As the climate system warms, megafires have become more frequent with devastating effects. A byproduct of these events is the creation of smoke plumes that can rise into the stratosphere and spread across the globe where they reside for many months. To gain a deeper understanding of the plume dynamics, global climate simulations of a megafire were performed at a wide range of grid spacings from 2.0° down to 7 km, including a 7 km nonhydrostatic experiment. The analysis focuses on how the resolved dynamics affects the specification of the plume characteristics such as injection height and black carbon (BC) mass. Prior studies initialize the smoke plume at one or a few grid points and this is shown here to produce severely dissipative dynamics. In order to validate such simulations with observations, enhancements of the plume characteristics to offset the dissipation is necessary. Using a numerically converged simulation, sensitivity tests show that to approximate the observed stratospheric lifetime, a reduction in BC fraction by 50% is necessary for external mixtures. The vorticity dynamics of the plume is also analyzed with a Lagrangian budget to understand the mechanisms responsible for the evolution of a collocated anticyclonic vortex. The results can be distilled down into a simple conceptual model. As the plume rises, the air diverges at the top of the updraft where the largest concentrations of smoke are found. This divergence induces a dilution of the background cyclonic absolute vorticity producing an anticyclonic vortex. Vortex decay occurs from opposite arguments. |
| first_indexed | 2024-03-11T19:19:17Z |
| format | Article |
| id | doaj.art-963fa59d5ceb44908e4678e86257b432 |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-03-11T19:19:17Z |
| publishDate | 2023-04-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-963fa59d5ceb44908e4678e86257b4322023-10-07T19:57:25ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662023-04-01154n/an/a10.1029/2022MS003432The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical InterpretationsS. R. Guimond0J. Reisner1M. Dubey2Joint Center for Earth Systems Technology and Department of Physics University of Maryland Baltimore County Baltimore MD USALos Alamos National Laboratory Los Alamos NM USALos Alamos National Laboratory Los Alamos NM USAAbstract As the climate system warms, megafires have become more frequent with devastating effects. A byproduct of these events is the creation of smoke plumes that can rise into the stratosphere and spread across the globe where they reside for many months. To gain a deeper understanding of the plume dynamics, global climate simulations of a megafire were performed at a wide range of grid spacings from 2.0° down to 7 km, including a 7 km nonhydrostatic experiment. The analysis focuses on how the resolved dynamics affects the specification of the plume characteristics such as injection height and black carbon (BC) mass. Prior studies initialize the smoke plume at one or a few grid points and this is shown here to produce severely dissipative dynamics. In order to validate such simulations with observations, enhancements of the plume characteristics to offset the dissipation is necessary. Using a numerically converged simulation, sensitivity tests show that to approximate the observed stratospheric lifetime, a reduction in BC fraction by 50% is necessary for external mixtures. The vorticity dynamics of the plume is also analyzed with a Lagrangian budget to understand the mechanisms responsible for the evolution of a collocated anticyclonic vortex. The results can be distilled down into a simple conceptual model. As the plume rises, the air diverges at the top of the updraft where the largest concentrations of smoke are found. This divergence induces a dilution of the background cyclonic absolute vorticity producing an anticyclonic vortex. Vortex decay occurs from opposite arguments.https://doi.org/10.1029/2022MS003432wildfiressmoke plumesclimate modelingspectral analysisvorticity dynamics |
| spellingShingle | S. R. Guimond J. Reisner M. Dubey The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations Journal of Advances in Modeling Earth Systems wildfires smoke plumes climate modeling spectral analysis vorticity dynamics |
| title | The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations |
| title_full | The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations |
| title_fullStr | The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations |
| title_full_unstemmed | The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations |
| title_short | The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations |
| title_sort | dynamics of megafire smoke plumes in climate models why a converged solution matters for physical interpretations |
| topic | wildfires smoke plumes climate modeling spectral analysis vorticity dynamics |
| url | https://doi.org/10.1029/2022MS003432 |
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