Related Experiment Video
Updated: Aug 8, 2025
10:28
Investigating the Relationship between Sea Surface Chlorophyll and Major Features of the South China Sea with Satellite Information
Published on: June 13, 2020
5.9K
Stratospheric chlorine processing after the 2020 Australian wildfires derived from satellite data
Peidong Wang1, Susan Solomon1, Kane Stone1
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139.
Summary
Australian wildfires unexpectedly altered stratospheric chemistry, activating chlorine on organic aerosols even at warmer temperatures. This research reveals new insights into ozone depletion pathways.
Area of Science:
- Atmospheric Chemistry
- Stratospheric Science
- Wildfire Impacts
Background:
- 2019-2020 Australian wildfires released unprecedented organic matter into the stratosphere.
- Heterogeneous chlorine activation typically occurs on polar stratospheric clouds (PSCs) in polar regions at low temperatures (<195 K).
- Previous understanding limited the assessment of these reactions to polar winter conditions.
Purpose of the Study:
- To evaluate heterogeneous reactions on organic aerosols impacting stratospheric chlorine and ozone.
- To quantitatively assess atmospheric evidence for these reactions using satellite data.
- To investigate wildfire-driven changes in stratospheric chemistry.
Main Methods:
- Utilized satellite data analysis for polar (65-90°S) and midlatitude (40-55°S) regions.
- Developed an approach to quantitatively assess atmospheric evidence for heterogeneous reactions.
- Compared chemical changes in 2020 to previous years.
Main Results:
- Heterogeneous reactions occurred on organic aerosols at 220 K in austral autumn 2020, at midlatitudes and polar regions.
- Observed unexpected changes in hydrochloric acid (HCl) and chlorine nitrate (ClONO2).
- Confirmed strong dependence of chlorine activation on water vapor pressure, increasing near the tropopause.
Conclusions:
- Wildfire-derived organic aerosols facilitate heterogeneous chlorine activation at warmer temperatures than previously thought.
- These reactions significantly influence stratospheric ozone depletion chemistry under both background and wildfire conditions.
- Findings enhance understanding of stratospheric chemical processes and ozone recovery.
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