20 Oct 2021
20 Oct 2021
Status: this preprint is currently under review for the journal AMT.

Identification of Smoke and Sulfuric Acid Aerosol in SAGE III/ISS Extinction Spectra Following the 2019 Raikoke Eruption

Travis Knepp1, Larry Thomason1, Mahesh Kovilakam2,1, Jason Tackett1, Jayanta Kar2,1, Robert Damadeo1, and David Flittner1 Travis Knepp et al.
  • 1NASA Langley Research Center, Hampton, Virginia 23681, USA
  • 2Science Systems and Applications, Inc. Hampton, Virginia 23666, USA

Abstract. The 2019 eruption of Raikoke was the largest volcanic eruption since 2011 and it was coincident with 2 major wildfires in the northern hemisphere. The impact of these events was manifest in the SAGE III/ISS extinction coefficient measurements. As the volcanic aerosol layers moved southward, a secondary peak emerged at an altitude higher than that which is expected for sulfuric acid aerosol. It was hypothesized that this secondary plume may contain a non-negligible amount of smoke contribution. We developed a technique to classify the composition of enhanced aerosol layers as either smoke or sulfuric acid aerosol. This method takes advantage of the different spectral properties of smoke and sulfuric acid aerosol, which is manifest in distinctly different spectral slopes in the SAGE III/ISS data. Herein we demonstrate the utility of this method using 4 case-study events (2018 Ambae eruption, 2019 Ulawun eruption, 2017 Canadian pyroCb, and 2020 Australian pyroCb) and provide corroborative data from the CALIOP instrument before applying it to the Raikoke plumes. We determined that, in the time period following the Raikoke eruption, smoke and sulfuric acid aerosol were present throughout the atmosphere and the 2 aerosol types were preferentially partitioned to higher (smoke) and lower (sulfuric acid) altitudes. Herein, we present an evaluation of the performance of this classification scheme within the context of the aforementioned case-study events followed by a brief discussion of this method's applicability to other events as well as its limitations.

Travis Knepp et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-333', Anonymous Referee #1, 24 Nov 2021
  • RC2: 'Comment on amt-2021-333', Michael Fromm, 24 Nov 2021
  • RC3: 'Comment on amt-2021-333', Anonymous Referee #3, 08 Dec 2021
  • RC4: 'Comment on amt-2021-333', Anonymous Referee #4, 14 Dec 2021

Travis Knepp et al.

Travis Knepp et al.


Total article views: 633 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
455 161 17 633 7 8
  • HTML: 455
  • PDF: 161
  • XML: 17
  • Total: 633
  • BibTeX: 7
  • EndNote: 8
Views and downloads (calculated since 20 Oct 2021)
Cumulative views and downloads (calculated since 20 Oct 2021)

Viewed (geographical distribution)

Total article views: 620 (including HTML, PDF, and XML) Thereof 620 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 18 May 2022
Short summary
Raikoke erupted in June 2019, coincident with 2 major wildfires. The Raikoke plume ascended in a manner not expected from solely volcanic aerosol, so it was suspected that the plume may contain smoke. We used aerosol profiles from the SAGE III/ISS instrument to develop an aerosol classification method that was tested on 4 case-study events (2 volcanic, 2 fire) and supported with CALIOP aerosol products. The method worked well in identifying smoke and volcanic aerosol in the stratosphere.