Atmos. Chem. Phys. Discuss., 12, 17943-17986, 2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Eyjafjallajökull volcano plume particle-type characterization from space-based multi-angle imaging
R. A. Kahn1 and J. Limbacher1,2
1Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
2Science Systems and Applications Inc., Lanham, MD 20706, USA

Abstract. The Multi-angle Imaging SpectroRadiometer (MISR) Research Aerosol algorithm makes it possible to study individual aerosol plumes in considerable detail. From the MISR data for two optically thick, near-source plumes from the spring 2010 eruption of the Eyjafjallajökull volcano, we map aerosol optical depth (AOD) gradients and changing aerosol particle types with this algorithm; several days downwind, we identify the occurrence of volcanic ash particles and retrieve AOD, demonstrating the extent and the limits of ash detection and mapping capability with the multi-angle, multi-spectral imaging data. Retrieved volcanic plume AOD and particle microphysical properties are distinct from background values near-source, as well as for over-water cases several days downwind. The results also provide some indication that as they evolve, plume particles brighten, and average particle size decreases. Such detailed mapping offers context for suborbital plume observations having much more limited sampling. The MISR Standard aerosol product identified similar trends in plume properties as the research algorithm, though with much smaller differences compared to background, and it does not resolve plume structure. Better optical analogs of non-spherical volcanic ash, and coincident suborbital data to validate the satellite retrieval results, are the factors most important for further advancing the remote sensing of volcanic ash plumes from space.

Citation: Kahn, R. A. and Limbacher, J.: Eyjafjallajökull volcano plume particle-type characterization from space-based multi-angle imaging, Atmos. Chem. Phys. Discuss., 12, 17943-17986, doi:10.5194/acpd-12-17943-2012, 2012.
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