Journal article
Radiative Forcing and Stratospheric Warming of Pyrocumulonimbus Smoke Aerosols: First Modeling Results With Multisensor (EPIC, CALIPSO, and CATS) Views from Space
Geophysical research letters, Vol.46(16), pp.10061-10071
08/28/2019
DOI: 10.1029/2019GL082360
Abstract
Smoke particles can be injected by pyrocumulonimbus (pyroCb) in the upper troposphere and lower stratosphere, but their effects on the radiative budget of the planet remain elusive. Here, by focusing on the record‐setting Pacific Northwest pyroCb event of August 2017, we show with satellite‐based estimates of pyroCb emissions and injection heights in a chemical transport model (GEOS‐Chem) that pyroCb smoke particles can result in radiative forcing of ∼0.02 W/m2 at the top of the atmosphere averaged globally in the 2 months following the event and up to 0.9 K/day heating in the Arctic upper troposphere and lower stratosphere. The modeled aerosol distributions agree with observations from satellites (Earth Polychromatic Imaging Camera [EPIC], Cloud‐Aerosol Transport System [CATS], and Cloud‐Aerosol Lidar with Orthogonal Polarization [CALIOP]), showing the hemispheric transport of pyroCb smoke aerosols with a lifetime of 5 months. Hence, warming by pyroCb aerosols can have similar temporal duration but opposite sign to the well‐documented cooling of volcanic aerosols and be significant for climate prediction.
Plain Language Summary
Extreme fire events can produce towering smoke plumes, which can result in the injection of smoke aerosols into the lower stratosphere (∼10 km above the surface in the midlatitudes). These stratospheric aerosols are significant because they stay in the atmosphere longer than those closer to the surface. In this study, we modeled the effects emanating from one of the largest of these fire events that happened in British Columbia, Canada, and Washington, USA, on 12 August 2017. We found that the smoke particles from this fire event had a lifetime of around 5 months and resulted in a net positive radiative forcing with warming focused in the stratosphere because smoke particle contain soot, an efficient absorber of solar radiation. This net positive radiative forcing contrasts with the cooling effects of analogous volcanic eruptions that are long thought to be dominant sources of stratospheric aerosols. Accounting for these smoke aerosols from large forest fire events in studies of atmospheric composition and climate may be more significant in the future as more large fire events are expected in a warmer climate.
Key Points
GEOS‐Chem accurately modeled the initial transport of pyrocumulonimbus aerosols showing a similar 5‐month lifetime as volcanic aerosols
Positive radiative forcing of pyroCb aerosols (+) can be similar in magnitude but opposite in sign of forcings from volcanic aerosols (−)
Direct injection of smoke aerosols into the modeled stratosphere was required for modeled and satellite‐measured aerosol profiles to agree
Details
- Title: Subtitle
- Radiative Forcing and Stratospheric Warming of Pyrocumulonimbus Smoke Aerosols: First Modeling Results With Multisensor (EPIC, CALIPSO, and CATS) Views from Space
- Creators
- Kenneth Christian - Now at NASA Postdoctoral Program, NASA Goddard Space Flight CenterJun Wang - The University of IowaCui Ge - The University of IowaDavid Peterson - Naval Research LaboratoryEdward Hyer - Naval Research LaboratoryJohn Yorks - NASA Goddard Space Flight CenterMatthew McGill - NASA Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.46(16), pp.10061-10071
- DOI
- 10.1029/2019GL082360
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 11
- Grant note
- Atmospheric Modeling and Analysis program and DSCOVR Science Team program (NNX17AB05G) Office of Naval Research (ONR) Multidisciplinary University Research Initiatives (MURI) Program (N00014-16-1-2040) NASA New Investigator Program (NNH17ZDA001N) NASA (NNX17AF63G)
- Language
- English
- Date published
- 08/28/2019
- Academic Unit
- Iowa Technology Institute; Civil and Environmental Engineering; Electrical and Computer Engineering; Physics and Astronomy; Chemical and Biochemical Engineering
- Record Identifier
- 9984104809202771
Metrics
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