EGU21-13606, updated on 14 Jan 2022
https://doi.org/10.5194/egusphere-egu21-13606
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Towards understanding the size distribution, composition and optical properties of freshly emitted dust and its relationship with the parent sediment

Carlos Pérez García-Pando1,2, Cristina González-Florez1, Adolfo González-Romero1, Agnesh Panta3, Jesús Yus-Díez4, Andrés Alastuey4, Konrad Kandler3, Martina Klose5, Xavier Querol4, Cristina Reche4, Marco Pandolfi4, Sylvain Dupont6, Vicken Etyemezian7, George Nikolich7, Jeronimo Escribano1, Roger Clark8, Bethany Elhmann9, Rebecca Greenberger9, Kamal Tajeddine10, and Matic Ivančič11
Carlos Pérez García-Pando et al.
  • 1Barcelona Supercomputing Center, Barcelona, Spain
  • 2ICREA, Catalan Institution for Research and Advanced Studies, Barcelona, Spain
  • 3Technical University of Darmstadt, Darmstadt, Germany,
  • 4Spanish National Research Council, Institute of Environmental Assessment and Water Research, Barcelona, Spain
  • 5Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 6ISPA, INRA, Bordeaux Sciences Agro, Villenave d'Ornon, France
  • 7Desert Research Institute, Las Vegas, US
  • 8Planetary Science Institute, Arizona, US
  • 9California Institute of Technology, Pasadena, CA, United States
  • 10Cady Ayyad University, Marrakesh, Morocco
  • 11AEROSOL d.o.o., Ljubljana, Slovenia

The physical and chemical properties of dust, i.e. its particle size distribution (PSD), mineralogical composition, shape and mixing state determine its climate effects. However, the lack of experimental data and understanding of the emitted dust and its relationship with the parent sediment and atmospheric forcing limit the extension of climate and dust models to account for potentially important regional variations in dust properties. In this context, the FRontiers in dust minerAloGical coMposition and its Effects upoN climate (FRAGMENT) project is dedicated to understand, constrain and calculate the global mineralogical composition of dust along with its effects upon climate. In September 2019, we conducted an intensive dust field campaign as a part of FRAGMENT near M’hamid El Ghizlane in Morocco, at the edge of the Sahara Desert. During the measurement period, dust events occurred frequently (about every 1-2 days) with varying intensity.

 

In this contribution, we provide a comprehensive overview and analysis of the sediment and airborne samples collected, and of the time-resolved measurements of dust concentration, PSD, optical properties and atmospheric forcing. We use mineralogical analyses of wet-sieved (totally disturbed) and dry-sieved (minimally disturbed) sediment samples at high particle-size resolution to better understand the fragmentation of sediment aggregates during wind erosion. We analyse the temporal variability of the number and volume PSDs along with the associated size-resolved dust emission fluxes using data from three optical particle counters deployed at different heights. We discuss the size-resolved particle composition, morphology, and mixing-state of the suspended dust determined by single particle analysis with electron microscopy coupled with energy dispersive X-ray detection from samples collected on sticky carbon substrates with cascade impactors, flat-plate samplers, and free-wing impactors. Finally, scattering coefficients at 450, 525 and 635 nm and seven different angles (from 0º to 90º) obtained with a polar nephelometer and absorption coefficients at 370, 470, 520, 590, 660, 880 and 950 nm obtained with an aethalometer are used to analyse the variability of extensive and intensive optical parameters, such as scattering and absorption Ångström exponents (SAE and AAE), backscatter fraction (BF) and multi-wavelength single scattering albedo (SSA) for both PM2.5 and PM10 dust fractions in combination with PSD and meteorological measurements.

How to cite: Pérez García-Pando, C., González-Florez, C., González-Romero, A., Panta, A., Yus-Díez, J., Alastuey, A., Kandler, K., Klose, M., Querol, X., Reche, C., Pandolfi, M., Dupont, S., Etyemezian, V., Nikolich, G., Escribano, J., Clark, R., Elhmann, B., Greenberger, R., Tajeddine, K., and Ivančič, M.: Towards understanding the size distribution, composition and optical properties of freshly emitted dust and its relationship with the parent sediment, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13606, https://doi.org/10.5194/egusphere-egu21-13606, 2021.

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