Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km

Abdulmonam M. Aldhaif, Connor Stahl, Rachel A. Braun, Mohammad A. Moghaddam, Taylor Shingler, Ewan Crosbie, Patricia Sawamura, Hossein Dadashazar, Luke Ziemba, Jose L. Jimenez, Pedro Campuzano-Jost, Armin Sorooshian

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

This study reports a characterization of the real part of dry particle refractive index (n) at 532 nm based on airborne measurements over the United States, Canada, the Pacific Ocean, and the Gulf of Mexico from the 2012 Deep Convective Clouds and Chemistry (DC3) and 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaigns. Effective n values are reported, with the limitations and uncertainties discussed. Eight air mass types were identified based on criteria related to gas-phase tracer concentrations, location, and altitude. Average values of n for these air types ranged from 1.50 to 1.53. Values of n for the organic aerosol (OA) fraction (nOA) were calculated using a linear mixing rule for each air mass type, with 1.52 shown to be a good approximation for all OA. Case studies detailing vertical structure revealed that n and nOA increased with altitude, simultaneous with enhancements in the mass fraction of OA. Values of nOA were positively (negatively) correlated with the O:C (H:C) ratio in the absence of biomass burning influence; in contrast, the cumulative data set revealed a slight decrease in nOA as a function of the O:C ratio. The performance of parametric (multiple linear regression) and nonparametric (Gaussian process regression) methods in predicting n based on aerosol composition data is discussed. It is shown that even small perturbations in n values significantly impact aerosol optical depth retrievals, radiative forcing, and optical sizing instruments, emphasizing the importance of further improving the understanding of this important aerosol property.

Original languageEnglish (US)
Pages (from-to)8283-8300
Number of pages18
JournalJournal of Geophysical Research: Atmospheres
Volume123
Issue number15
DOIs
StatePublished - Aug 16 2018

Fingerprint

refractive index
aerosols
Aerosols
Refractive index
refractivity
aerosol
air mass
air masses
aerosol composition
air
aerosol property
convective cloud
regression analysis
radiative forcing
biomass burning
optical equipment
Air
Atmospheric composition
optical depth
atmospheric composition

Keywords

  • aerosol
  • aerosol optical depth
  • DC3
  • radiative forcing
  • refractive index
  • SEACRS

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km. / Aldhaif, Abdulmonam M.; Stahl, Connor; Braun, Rachel A.; Moghaddam, Mohammad A.; Shingler, Taylor; Crosbie, Ewan; Sawamura, Patricia; Dadashazar, Hossein; Ziemba, Luke; Jimenez, Jose L.; Campuzano-Jost, Pedro; Sorooshian, Armin.

In: Journal of Geophysical Research: Atmospheres, Vol. 123, No. 15, 16.08.2018, p. 8283-8300.

Research output: Contribution to journalArticle

Aldhaif, AM, Stahl, C, Braun, RA, Moghaddam, MA, Shingler, T, Crosbie, E, Sawamura, P, Dadashazar, H, Ziemba, L, Jimenez, JL, Campuzano-Jost, P & Sorooshian, A 2018, 'Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km', Journal of Geophysical Research: Atmospheres, vol. 123, no. 15, pp. 8283-8300. https://doi.org/10.1029/2018JD028504
Aldhaif, Abdulmonam M. ; Stahl, Connor ; Braun, Rachel A. ; Moghaddam, Mohammad A. ; Shingler, Taylor ; Crosbie, Ewan ; Sawamura, Patricia ; Dadashazar, Hossein ; Ziemba, Luke ; Jimenez, Jose L. ; Campuzano-Jost, Pedro ; Sorooshian, Armin. / Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km. In: Journal of Geophysical Research: Atmospheres. 2018 ; Vol. 123, No. 15. pp. 8283-8300.
@article{eb0e7d9cf3cd4f8c8964dcb4d84af089,
title = "Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km",
abstract = "This study reports a characterization of the real part of dry particle refractive index (n) at 532 nm based on airborne measurements over the United States, Canada, the Pacific Ocean, and the Gulf of Mexico from the 2012 Deep Convective Clouds and Chemistry (DC3) and 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaigns. Effective n values are reported, with the limitations and uncertainties discussed. Eight air mass types were identified based on criteria related to gas-phase tracer concentrations, location, and altitude. Average values of n for these air types ranged from 1.50 to 1.53. Values of n for the organic aerosol (OA) fraction (nOA) were calculated using a linear mixing rule for each air mass type, with 1.52 shown to be a good approximation for all OA. Case studies detailing vertical structure revealed that n and nOA increased with altitude, simultaneous with enhancements in the mass fraction of OA. Values of nOA were positively (negatively) correlated with the O:C (H:C) ratio in the absence of biomass burning influence; in contrast, the cumulative data set revealed a slight decrease in nOA as a function of the O:C ratio. The performance of parametric (multiple linear regression) and nonparametric (Gaussian process regression) methods in predicting n based on aerosol composition data is discussed. It is shown that even small perturbations in n values significantly impact aerosol optical depth retrievals, radiative forcing, and optical sizing instruments, emphasizing the importance of further improving the understanding of this important aerosol property.",
keywords = "aerosol, aerosol optical depth, DC3, radiative forcing, refractive index, SEACRS",
author = "Aldhaif, {Abdulmonam M.} and Connor Stahl and Braun, {Rachel A.} and Moghaddam, {Mohammad A.} and Taylor Shingler and Ewan Crosbie and Patricia Sawamura and Hossein Dadashazar and Luke Ziemba and Jimenez, {Jose L.} and Pedro Campuzano-Jost and Armin Sorooshian",
year = "2018",
month = "8",
day = "16",
doi = "10.1029/2018JD028504",
language = "English (US)",
volume = "123",
pages = "8283--8300",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
publisher = "Wiley-Blackwell",
number = "15",

}

TY - JOUR

T1 - Characterization of the Real Part of Dry Aerosol Refractive Index Over North America From the Surface to 12 km

AU - Aldhaif, Abdulmonam M.

AU - Stahl, Connor

AU - Braun, Rachel A.

AU - Moghaddam, Mohammad A.

AU - Shingler, Taylor

AU - Crosbie, Ewan

AU - Sawamura, Patricia

AU - Dadashazar, Hossein

AU - Ziemba, Luke

AU - Jimenez, Jose L.

AU - Campuzano-Jost, Pedro

AU - Sorooshian, Armin

PY - 2018/8/16

Y1 - 2018/8/16

N2 - This study reports a characterization of the real part of dry particle refractive index (n) at 532 nm based on airborne measurements over the United States, Canada, the Pacific Ocean, and the Gulf of Mexico from the 2012 Deep Convective Clouds and Chemistry (DC3) and 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaigns. Effective n values are reported, with the limitations and uncertainties discussed. Eight air mass types were identified based on criteria related to gas-phase tracer concentrations, location, and altitude. Average values of n for these air types ranged from 1.50 to 1.53. Values of n for the organic aerosol (OA) fraction (nOA) were calculated using a linear mixing rule for each air mass type, with 1.52 shown to be a good approximation for all OA. Case studies detailing vertical structure revealed that n and nOA increased with altitude, simultaneous with enhancements in the mass fraction of OA. Values of nOA were positively (negatively) correlated with the O:C (H:C) ratio in the absence of biomass burning influence; in contrast, the cumulative data set revealed a slight decrease in nOA as a function of the O:C ratio. The performance of parametric (multiple linear regression) and nonparametric (Gaussian process regression) methods in predicting n based on aerosol composition data is discussed. It is shown that even small perturbations in n values significantly impact aerosol optical depth retrievals, radiative forcing, and optical sizing instruments, emphasizing the importance of further improving the understanding of this important aerosol property.

AB - This study reports a characterization of the real part of dry particle refractive index (n) at 532 nm based on airborne measurements over the United States, Canada, the Pacific Ocean, and the Gulf of Mexico from the 2012 Deep Convective Clouds and Chemistry (DC3) and 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaigns. Effective n values are reported, with the limitations and uncertainties discussed. Eight air mass types were identified based on criteria related to gas-phase tracer concentrations, location, and altitude. Average values of n for these air types ranged from 1.50 to 1.53. Values of n for the organic aerosol (OA) fraction (nOA) were calculated using a linear mixing rule for each air mass type, with 1.52 shown to be a good approximation for all OA. Case studies detailing vertical structure revealed that n and nOA increased with altitude, simultaneous with enhancements in the mass fraction of OA. Values of nOA were positively (negatively) correlated with the O:C (H:C) ratio in the absence of biomass burning influence; in contrast, the cumulative data set revealed a slight decrease in nOA as a function of the O:C ratio. The performance of parametric (multiple linear regression) and nonparametric (Gaussian process regression) methods in predicting n based on aerosol composition data is discussed. It is shown that even small perturbations in n values significantly impact aerosol optical depth retrievals, radiative forcing, and optical sizing instruments, emphasizing the importance of further improving the understanding of this important aerosol property.

KW - aerosol

KW - aerosol optical depth

KW - DC3

KW - radiative forcing

KW - refractive index

KW - SEACRS

UR - http://www.scopus.com/inward/record.url?scp=85052201254&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85052201254&partnerID=8YFLogxK

U2 - 10.1029/2018JD028504

DO - 10.1029/2018JD028504

M3 - Article

AN - SCOPUS:85052201254

VL - 123

SP - 8283

EP - 8300

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9380

IS - 15

ER -