Satellite retrievals of dust aerosol over the Red Sea and the Persian Gulf (2005–2015)
The inter-annual variability of the dust aerosol presence over the Red Sea and the Persian Gulf is analysed over the period 2005–2015. Particular attention is paid to the variation in loading across the Red Sea, which has previously been shown to have a strong, seasonally dependent latitudinal gradi...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/17/3987/2017/acp-17-3987-2017.pdf |
| Summary: | The inter-annual variability of the dust aerosol presence over the
Red Sea and the Persian Gulf is analysed over the period 2005–2015.
Particular attention is paid to the variation in loading across the Red Sea,
which has previously been shown to have a strong, seasonally dependent
latitudinal gradient. Over the 11 years considered, the July mean 630 nm
aerosol optical depth (AOD) derived from the Spinning Enhanced Visible and
InfraRed Imager (SEVIRI) varies between 0.48 and 1.45 in the southern half of
the Red Sea. In the north, the equivalent variation is between 0.22 and 0.66.
The temporal and spatial pattern of variability captured by SEVIRI is also
seen in AOD retrievals from the MODerate Imaging Spectroradiometer (MODIS),
but there is a systematic offset between the two records. Comparisons of both
sets of retrievals with ship- and land-based AERONET measurements show a high
degree of correlation with biases of < 0.08. However, these comparisons
typically only sample relatively low aerosol loadings. When both records are
stratified by AOD retrievals from the Multi-angle Imaging SpectroRadiometer
(MISR), opposing behaviour is revealed at high MISR AODs ( > 1), with
offsets of +0.19 for MODIS and −0.06 for SEVIRI. Similar behaviour is also
seen over the Persian Gulf. Analysis of the scattering angles at which
retrievals from the SEVIRI and MODIS measurements are typically performed in
these regions suggests that assumptions concerning particle sphericity may be
responsible for the differences seen. |
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| ISSN: | 1680-7316 1680-7324 |