Brindley, H, Knippertz, P, Ryder, C et al. (1 more author) (2012) A critical evaluation of the ability of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) thermal infrared red-green-blue rendering to identify dust events: Theoretical analysis. Journal of Geophysical Research D: Atmospheres, 117 (7). D07201. ISSN 0148-0227
Abstract
Using a combination of idealized radiative transfer simulations and a case study from the first field campaign of the Saharan Mineral Dust Experiment (SAMUM) in southern Morocco, this paper provides a systematic assessment of the limitations of the widely used Spinning Enhanced Visible and Infrared Imager (SEVIRI) red-green-blue (RGB) thermal infrared dust product. Both analyses indicate that the ability of the product to identify dust, via its characteristic pink coloring, is strongly dependent on the column water vapor, the lower tropospheric lapse rate, and dust altitude. In particular, when column water vapor exceeds ∼20-25 mm, dust presence, even for visible optical depths of the order 0.8, is effectively masked. Variability in dust optical properties also has a marked impact on the imagery, primarily as a result of variability in dust composition. There is a moderate sensitivity to the satellite viewing geometry, particularly in moist conditions. The underlying surface can act to confound the signal seen through variations in spectral emissivity, which are predominantly manifested in the 8.7 m SEVIRI channel. In addition, if a temperature inversion is present, typical of early morning conditions over the Sahara and Sahel, an increased dust loading can actually reduce the pink coloring of the RGB image compared to pristine conditions. Attempts to match specific SEVIRI observations to simulations using SAMUM measurements are challenging because of high uncertainties in surface skin temperature and emissivity. Recommendations concerning the use and interpretation of the SEVIRI RGB imagery are provided on the basis of these findings.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2012, American Geophysical Union. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | Critical evaluation; Dust composition; Dust event; Dust loading; Field campaign; Lapse rate; Mineral dust; Moist conditions; Optical depth; Radiative transfer simulations; Red green blues; RGB images; Spectral emissivity; Spinning Enhanced Visible and Infrared Imager; Surface skin temperature; Systematic assessment; Temperature inversions; Thermal infrared; Underlying surface |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Oct 2013 09:44 |
Last Modified: | 29 Mar 2018 16:35 |
Published Version: | http://dx.doi.org/10.1029/2011JD017326 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1029/2011JD017326 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:76596 |