Publication Abstracts

Li et al. 2020, submitted

Li, L., N.M. Mahowald, R.L. Miller, C. Pérez García-Pando, M. Klose, D.S. Hamilton, M. Gonçalves Ageitos, P. Ginoux, Y. Balkanski, R.O. Green, O. Kalashnikova, J.F. Kok, V. Obiso, D. Paynter, and D.R. Thompson, 2020: Quantifying the range of the dust direct radiative effect due to source mineralogy uncertainty. Atmos. Chem. Phys., submitted.

The large uncertainty in mineral dust direct radiative effect (DRE) hinders projections of future climate change 20 due to anthropogenic activity. Resolving modelled dust mineral-speciation allows for spatially and temporally varying refractive indices consistent with dust aerosol composition. Here, for the first time, we quantify the range in dust DRE at the top of the atmosphere (TOA) due to current uncertainties in the surface soil mineralogical content using a dust mineral- resolving climate model. We propagate observed uncertainties in soil mineral abundances from two soil mineralogy atlases along with the optical properties of each mineral into the DRE and compare the resultant range with other sources of 25 uncertainty across six climate models. The shortwave DRE responses region-specifically to the dust burden depending on the mineral speciation and underlying shortwave surface albedo; positively when the regionally averaged annual surface albedo is larger than 0.28, and negatively otherwise. Among all minerals examined, the shortwave TOA DRE and single scattering albedo at the 0.44-0.63 µm band are most sensitive to the fractional contribution of iron oxides to the total dust composition. The global net (shortwave plus longwave) TOA DRE is estimated to be within 00.17 to +0.23 W/m2. Approximately 93% of 30 this range relates to uncertainty in the soil abundance of iron oxides. Representing iron-oxide with solely hematite optical properties leads to an overestimation of shortwave DRE by +0.1 W/m2 at the TOA, as goethite is not as absorbing as hematite in the shortwave spectrum range. Our study highlights the importance of iron oxides to the shortwave DRE: they have a disproportionally large impact on climate considering their small atmospheric mineral mass fractional burden (∼2%). An improved description of iron oxides, such as those planned in the Earth Surface Mineral Dust Source Investigation (EMIT), is thus essential for more accurate estimates of the dust DRE.

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BibTeX Citation

@unpublished{li09110p,
  author={Li, L. and Mahowald, N. M. and Miller, R. L. and Pérez García-Pando, C. and Klose, M. and Hamilton, D. S. and Gonçalves Ageitos, M. and Ginoux, P. and Balkanski, Y. and Green, R. O. and Kalashnikova, O. and Kok, J. F. and Obiso, V. and Paynter, D. and Thompson, D. R.},
  title={Quantifying the range of the dust direct radiative effect due to source mineralogy uncertainty},
  year={2020},
  journal={Atmos. Chem. Phys.},
  note={Manuscript submitted for publication}
}

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RIS Citation

TY  - UNPB
ID  - li09110p
AU  - Li, L.
AU  - Mahowald, N. M.
AU  - Miller, R. L.
AU  - Pérez García-Pando, C.
AU  - Klose, M.
AU  - Hamilton, D. S.
AU  - Gonçalves Ageitos, M.
AU  - Ginoux, P.
AU  - Balkanski, Y.
AU  - Green, R. O.
AU  - Kalashnikova, O.
AU  - Kok, J. F.
AU  - Obiso, V.
AU  - Paynter, D.
AU  - Thompson, D. R.
PY  - 2020
TI  - Quantifying the range of the dust direct radiative effect due to source mineralogy uncertainty
JA  - Atmos. Chem. Phys.
ER  -

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