Work Description

Title: Supplementary Particle Optical Property Data for "Aerosol radiative forcing from the 2010 Eyjafjallajökull volcanic eruptions" Open Access Deposited

http://creativecommons.org/publicdomain/zero/1.0/
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Methodology
  • A detailed description of the methodology used to create these ash particle optical properties can be found in the accompanying journal article (Flanner et al., 2014, doi:10.1002/2014JD021977). Briefly, these properties were generated with Mie solutions and refractive indices described in the journal article. Calculations were done for 100 particle sizes within each size bin, and sub-bin weighting was achieved with a lognormal size distribution of effective radius 2.24um and geometric standard deviation of 2.8, representing global-mean properties of the ash fields that we applied. Properties are listed for 14 shortwave bands and 16 longwave bands, with spectral boundaries corresponding to those used in the Rapid Radiative Transfer Model (RRTMG) embedded in the Community Atmosphere Model. Properties were calculated at 100 wavelengths within each spectral band. Sub-band spectral weighting was achieved with top-of-atmosphere spectral irradiance data for shortwave properties, and with a 250 K Planck function for longwave properties. An ash density of 2600 kg m^-3 was assumed for translating Mie properties into mass-normalized optical properties. Note that imaginary refractive indices do not change monotonically with scenario in all parts of the longwave spectrum and generally exhibit smaller relative differences than the shortwave scenarios of refractive index (Figure 1). This leads to mass absorption cross-sections that are not always monotonic with scenario (e.g., for some wavelength bands and particle sizes the longwave mass absorption in the low scenario exceeds that in the high scenario). Integrated over all particle sizes and wavelengths, however, these scenarios lead to their respective ordering of global-mean longwave radiative forcing by ash.
Description
  • This dataset includes spectrally-resolved optical properties for volcanic ash particles from the 2010 Eyjafjallajökull volcanic eruptions. These properties were used in the climate simulations described by Flanner et al. (2014, doi:10.1002/2014JD021977) to quantify ash radiative forcing from the eruptions.
Creator
Depositor
  • flanner@umich.edu
Contact information
Discipline
Funding agency
  • National Science Foundation (NSF)
ORSP grant number
  • F033563
Keyword
Citations to related material
  • Flanner, M. G., A. S. Gardner,S. Eckhardt, A. Stohl, and J. Perket(2014), Aerosol radiative forcing fromthe 2010 Eyjafjallajökull volcaniceruptions,J. Geophys. Res.Atmos.,119, 9481–9491,doi:10.1002/2014JD021977
Related items in Deep Blue
Resource type
Last modified
  • 10/01/2020
Published
  • 10/01/2020
Language
DOI
  • https://doi.org/10.7302/pz7e-r328
License
To Cite this Work:
Mark Flanner (2020). Supplementary Particle Optical Property Data for "Aerosol radiative forcing from the 2010 Eyjafjallajökull volcanic eruptions" [Data set]. University of Michigan - Deep Blue. https://doi.org/10.7302/pz7e-r328

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Files (Count: 8; Size: 135 KB)

Supplementary Particle Optical Property Data for:

Aerosol radiative forcing from the 2010 Eyjafjallajokull volcanic eruptions
DOI: 10.1002/2014JD021977
Article number: 2014JD021977

M. G. Flanner(1), A. S. Gardner(2), S. Eckhardt(3), A. Stohl(3), J. Perket(1)

(1) Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan, USA.

(2) Graduate School of Geography, Clark University, Worchester, Massachusetts, USA.

(3) Norwegian Institute for Air Research, Kjeller, Norway

Journal of Geophysical Research, April 2014

This supplementary material consists of: (1) a pdf file (text01.pdf) that includes a table of optical properties of non-spherical ash particles, and (2) tables of ash optical properties (ts01.txt - ts06.txt) applied in our calculations of ash radiative forcing.

1. text01.pdf is self-describing

2. The six tables of ash optical properties represent:
ts01.txt: Shortwave properties used for the low forcing scenario
ts02.txt: Shortwave properties used for the central forcing scenario
ts03.txt: Shortwave properties used for the high forcing scenario
ts04.txt: Longwave properties used for the low forcing scenario
ts05.txt: Longwave properties used for the central forcing scenario
ts06.txt: Longwave properties used for the high forcing scenario

Each table includes 5 columns:
2.1: Beginning of wavelength interval represented by optical properties in the row
2.2: End of wavelength interval represented by optical properties in the row
2.3: Mass absorption cross-section (units of m^2 kg^-1)
2.4: Single-scatter albedo (fraction)
2.5: Scattering asymmetry parameter (dimensionless)

Each table lists optical properties for each of the 4 ash particle size bins applied in our modeling. These properties were generated with Mie solutions and refractive indices described in the text. Calculations were done for 100 particle sizes within each size bin, and sub-bin weighting was achieved with a lognormal size distribution of effective radius 2.24um and geometric standard deviation of 2.8, representing global-mean properties of the ash fields that we applied. Properties are listed for 14 shortwave bands and 16 longwave bands, with spectral boundaries corresponding to those used in the Rapid Radiative Transfer Model (RRTMG) embedded in the Community Atmosphere Model. Properties were calculated at 100 wavelengths within each spectral band. Sub-band spectral weighting was achieved with top-of-atmosphere spectral irradiance data for shortwave properties, and with a 250 K Planck function for longwave properties. An ash density of 2600 kg m^-3 was assumed for translating Mie properties into mass-normalized optical properties. Note that imaginary refractive indices do not change monotonically with scenario in all parts of the longwave spectrum and generally exhibit smaller relative differences than the shortwave scenarios of refractive index (Figure 1). This leads to mass absorption cross-sections that are not always monotonic with scenario (e.g., for some wavelength bands and particle sizes the longwave mass absorption in the low scenario exceeds that in the high scenario). Integrated over all particle sizes and wavelengths, however, these scenarios lead to their respective ordering of global-mean longwave radiative forcing by ash.

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