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Effects of forest fire smoke and volcanism on the stratospheric aerosol

Sandvik, Oscar LU orcid (2021)
Abstract
This thesis explores the stratospheric aerosol through both in-situ measurements and remote sensing. The background stratospheric aerosol is complex and is perturbed by injections of forest fire smoke particles and by particles formed from volcanic SO2. Climate models need accurate description of the stratospheric aerosol in order to have sound radiation budgets. Using the remote sensing technique of satellite borne lidar, it was seen that volcanic eruptions increased the stratospheric optical depth on average by 40 % in the period between 2006 and 2015. Forest fires also increased the stratospheric optical depth but their effect was found to disappear faster than the effect from volcanic eruptions. By investigating in-situ samples, the... (More)
This thesis explores the stratospheric aerosol through both in-situ measurements and remote sensing. The background stratospheric aerosol is complex and is perturbed by injections of forest fire smoke particles and by particles formed from volcanic SO2. Climate models need accurate description of the stratospheric aerosol in order to have sound radiation budgets. Using the remote sensing technique of satellite borne lidar, it was seen that volcanic eruptions increased the stratospheric optical depth on average by 40 % in the period between 2006 and 2015. Forest fires also increased the stratospheric optical depth but their effect was found to disappear faster than the effect from volcanic eruptions. By investigating in-situ samples, the background aerosol was found to contain a carbonaceous fraction that seems to be produced in the stratosphere. In order to better portray fresh volcanic emissions of SO2, a new method of compiling SO2 datasets with high vertical resolution was developed. This method combined many lidar observations of the aerosol formed from SO2 to provide vertical distributions of the SO2 gas. The lidar used in this thesis is CALIOP which is aboard the CALIPSO satellite. The satellite was launched in 2006 and CALIOP is still operational. This lidar measures the radiation scattering from the aerosol at a high vertical resolution. Measurement of elemental concentrations and other in-situ measurements were done using the IAGOS-CARIBIC aircraft platform. Both CALIOP and IAGOS-CARIBIC have long successful histories of measurements which allowed long-term effects to be studied. A comparison between the in-situ measurements from IAGOS-CARIBIC and the remote sensing measurements by CALIOP was also made. If the measurements are taken sufficiently above the tropopause, then the calculated scattering based on in-situ IAGOS-CARIBIC measurements of sulphur, water and carbon are similar to the scattering measured by CALIOP. In the vicinity of the tropopause, additional aerosol components and water uptake are needed to explain the scattering from stratospheric aerosol. (Less)
Abstract (Swedish)
Denna avhandling utforskar den stratosfäriska aerosolen genom både in-situ mätningar och fjärranalys. Bakgrundsaerosolen är komplex och påverkas av injektioner av skogsbrandrökspartiklar och av partiklar skapade från vulkaniskt SO2. Klimatmodeller behöver träffsäkra beskrivningar av den stratosfäriska aerosolen för att ha rimliga strålningsbudgetar. Genom att använda fjärranalystekniken satellitburen lidar kunde det ses att vulkaniska utbrott höjde det stratosfäriska optiska djupet i genomsnitt med 40 % i perioden mellan 2006 och 2015. Skogsbränder höjde också det stratosfäriska optiska djupet men deras effekt försvann snabbare än effekten från vulkaniska utbrott. Genom att studera in-situ prover sågs att bakgrundsaerosolen innehåller en... (More)
Denna avhandling utforskar den stratosfäriska aerosolen genom både in-situ mätningar och fjärranalys. Bakgrundsaerosolen är komplex och påverkas av injektioner av skogsbrandrökspartiklar och av partiklar skapade från vulkaniskt SO2. Klimatmodeller behöver träffsäkra beskrivningar av den stratosfäriska aerosolen för att ha rimliga strålningsbudgetar. Genom att använda fjärranalystekniken satellitburen lidar kunde det ses att vulkaniska utbrott höjde det stratosfäriska optiska djupet i genomsnitt med 40 % i perioden mellan 2006 och 2015. Skogsbränder höjde också det stratosfäriska optiska djupet men deras effekt försvann snabbare än effekten från vulkaniska utbrott. Genom att studera in-situ prover sågs att bakgrundsaerosolen innehåller en kolfraktion som verkar produceras i stratosfären. För att bättre förstå färska vulkaniska utsläpp av SO2 utvecklades en ny metod för att sätta ihop SO2-dataset med hög vertikal upplösning. Denna metod kombinerade många lidar observationer av aerosolen som bildats ur SO2 för att producera vertikala distributioner av SO2 gasen. Lidarn som har använts i denna avhandling heter CALIOP som är på CALIPSO satelliten. Satelliten sköts upp 2006 och CALIOP är fortfarande igång. Denna lidar mäter strålningsspridningen från aerosolen med hög vertikal upplösning. Mätningar av grundämneskoncentrationer och andra in-situ mätningar gjordes med flygplansplattformen IAGOS-CARIBIC. Både CALIOP och IAGOS-CARIBIC framgångsrikt gjort mätningar under lång tid vilket har gjort långtidsstudier möjliga. En jämförelse mellan in-situ mätningar från IAGOS-CARIBIC och fjärranalysmätningar från CALIOP har också gjorts. Om mätningarna är tillräckligt högt över tropopausen är den spridning som beräknats från IAGOS-CARIBICs mätningar av svavel, vatten och kol liknande den spridning som mätts med CALIOP. I närheten av tropopausen behövs andra aerosolkomponenter och vattenupptag för att förklara ljusspridningen från stratosfärsaerosolen. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr. Timmreck, Claudia, Max-Planck-Institute of Meteorology, Germany.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Fjärranalys, Stratosfärsaerosol, Skogsbrandsrök, Vulkanism, CALIOP, FLEXPART, CALIPSO, AIRS, IAGOS-CARIBIC, Remote Sensing, Stratospheric aerosol, Forest fire smoke, Volcanism, CALIOP, FLEXPART, CALIPSO, AIRS, IAGOS-CARIBIC, Fysicumarkivet A:2021:Sandvik
pages
64 pages
publisher
Department of Physics, Lund University
defense location
Lecture hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund. Zoom: https://lu-se.zoom.us/j/67945239653?pwd=eUV2NTdKbFVoSHM2VG96Rm9keFZ2Zz09
defense date
2021-03-19 09:15:00
ISBN
978-91-7895-765-1
978-91-7895-766-8
project
Effects of forest fire smoke and volcanism on the stratospheric aerosol
language
English
LU publication?
yes
id
f8d9c6d2-7e28-4fbe-86b8-6e8f8e015653
date added to LUP
2021-02-25 14:14:31
date last changed
2021-07-08 14:01:02
@phdthesis{f8d9c6d2-7e28-4fbe-86b8-6e8f8e015653,
  abstract     = {{This thesis explores the stratospheric aerosol through both in-situ measurements and remote sensing. The background stratospheric aerosol is complex and is perturbed by injections of forest fire smoke particles and by particles formed from volcanic SO2. Climate models need accurate description of the stratospheric aerosol in order to have sound radiation budgets. Using the remote sensing technique of satellite borne lidar, it was seen that volcanic eruptions increased the stratospheric optical depth on average by 40 % in the period between 2006 and 2015. Forest fires also increased the stratospheric optical depth but their effect was found to disappear faster than the effect from volcanic eruptions. By investigating in-situ samples, the background aerosol was found to contain a carbonaceous fraction that seems to be produced in the stratosphere. In order to better portray fresh volcanic emissions of SO2, a new method of compiling SO2 datasets with high vertical resolution was developed. This method combined many lidar observations of the aerosol formed from SO2 to provide vertical distributions of the SO2 gas. The lidar used in this thesis is CALIOP which is aboard the CALIPSO satellite. The satellite was launched in 2006 and CALIOP is still operational. This lidar measures the radiation scattering from the aerosol at a high vertical resolution. Measurement of elemental concentrations and other in-situ measurements were done using the IAGOS-CARIBIC aircraft platform. Both CALIOP and IAGOS-CARIBIC have long successful histories of measurements which allowed long-term effects to be studied. A comparison between the in-situ measurements from IAGOS-CARIBIC and the remote sensing measurements by CALIOP was also made. If the measurements are taken sufficiently above the tropopause, then the calculated scattering based on in-situ IAGOS-CARIBIC measurements of sulphur, water and carbon are similar to the scattering measured by CALIOP. In the vicinity of the tropopause, additional aerosol components and water uptake are needed to explain the scattering from stratospheric aerosol.}},
  author       = {{Sandvik, Oscar}},
  isbn         = {{978-91-7895-765-1}},
  keywords     = {{Fjärranalys; Stratosfärsaerosol; Skogsbrandsrök; Vulkanism; CALIOP; FLEXPART; CALIPSO; AIRS; IAGOS-CARIBIC; Remote Sensing; Stratospheric aerosol; Forest fire smoke; Volcanism; CALIOP; FLEXPART; CALIPSO; AIRS; IAGOS-CARIBIC; Fysicumarkivet A:2021:Sandvik}},
  language     = {{eng}},
  month        = {{03}},
  publisher    = {{Department of Physics, Lund University}},
  school       = {{Lund University}},
  title        = {{Effects of forest fire smoke and volcanism on the stratospheric aerosol}},
  url          = {{https://lup.lub.lu.se/search/files/94502943/Oscar_Sandvik_web.pdf}},
  year         = {{2021}},
}