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| Titel |
Use of the CALIOP vertical feature mask for evaluating global aerosol models |
| VerfasserIn |
E. P. Nowottnick, P. R. Colarco, E. J. Welton, A. da Silva |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 9 ; Nr. 8, no. 9 (2015-09-09), S.3647-3669 |
| Datensatznummer |
250116571
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| Publikation (Nr.) |
 copernicus.org/amt-8-3647-2015.pdf |
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| Zusammenfassung |
| We use observations from the space-based Cloud-Aerosol Lidar with Orthogonal
Polarization (CALIOP) to evaluate global aerosol distributions simulated in
the NASA Modern Era Retrospective Analysis for Research and Applications
aerosol reanalysis (MERRAero). We focus particularly on an evaluation of
aerosol types, using the CALIOP vertical feature mask (VFM) algorithm, and
look especially at Saharan dust distributions during July 2009. MERRAero
consists of an aerosol simulation produced in the Goddard Earth Observing
System version 5 (GEOS-5) Earth system model and incorporates assimilation
of MODIS-derived aerosol optical thickness (AOT) to constrain column aerosol
loadings. For comparison to the CALIOP VFM we construct two synthetic VFMs
using the MERRAero aerosol distributions: a CALIOP-like VFM in which we
simulate the total attenuated backscatter and particle depolarization ratio
from the MERRAero output and pass those into the CALIOP VFM typing algorithm
(MERRAero-CALIOP), and an extinction-based VFM in which we use the
MERRAero-simulated species-resolved extinction to map the MERRAero species to the
CALIOP VFM types (MERRAero-Extinction). By comparing the MERRAero-CALIOP VFM
to CALIOP VFM, we can diagnose the aerosol transport and speciation in
MERRAero. By comparing the MERRAero-CALIOP and MERRAero-Extinction-simulated
VFM, we perform a simple observing system experiment (OSE), which is useful
for identifying limitations of the CALIOP VFM algorithm itself. We find that,
despite having our column AOT constrained by MODIS, comparison to the CALIOP
VFM reveals a greater occurrence of dusty aerosol layers in our
MERRAero-CALIOP VFM due to errors in MERRAero aerosol speciation.
Additionally, we find that the CALIOP VFM algorithm is challenged when
classifying aerosol features when multiple aerosol types are present, as our
application of the CALIOP VFM algorithm to MERRAero aerosol distributions
classified marine-dominated aerosol layers with low aerosol loadings as
polluted dust when the contribution of dust to the total extinction was low. |
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