Extreme dust storm over the eastern Mediterranean in September 2015: satellite, lidar, and surface observations in the Cyprus region
A record-breaking dust storm originating from desert regions in northern Syria and Iraq occurred over the eastern Mediterranean in September 2015. In this contribution of a series of two articles (part 1, observations; part 2, atmospheric modeling), we provide a comprehensive overview of the aero...
Main Authors: | , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-11-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://www.atmos-chem-phys.net/16/13711/2016/acp-16-13711-2016.pdf |
Summary: | A record-breaking dust storm originating from desert regions in northern
Syria and Iraq occurred over the eastern Mediterranean in September 2015. In
this contribution of a series of two articles (part 1, observations; part 2,
atmospheric modeling), we provide a comprehensive overview of the aerosol
conditions during this extreme dust outbreak in the Cyprus region. These observations are based on satellite observations (MODIS, moderate resolution imaging spectroradiometer) of aerosol optical thickness (AOT) and Ångström exponent, surface particle mass (PM<sub>10</sub>) concentrations measured at four sites in Cyprus, visibility observations at three airports in southern Cyprus and corresponding conversion products (particle extinction coefficient, dust mass concentrations), EARLINET (European Aerosol Research Lidar Network) lidar observations of dust vertical layering over Limassol, particle optical
properties (backscatter, extinction, lidar ratio, linear depolarization
ratio), and derived profiles of dust mass concentrations. Maximum 550 nm AOT
exceeded values of 5.0, according to MODIS, and the mass loads
were correspondingly > 10 g m<sup>−2</sup> over Larnaca and Limassol during the passage of an extremely dense dust front on 8 September 2015. Hourly mean PM<sub>10</sub> values were close to 8000 µg m<sup>−3</sup> and the observed meteorological optical range (visibility) was reduced to 300–750 m at Larnaca and Limassol. The visibility observations suggest peak values of the near-surface total suspended particle (TSP) extinction coefficients of 6000 Mm<sup>−1</sup> and thus TSP mass concentrations of 10 000 µg m<sup>−3</sup>. The
Raman polarization lidar observations mainly indicated a double layer structure
of the dust plumes (reaching to about 4 km height), pointing to at least two
different dust source regions. Dust particle extinction coefficients (532 nm)
already exceeded 1000 Mm<sup>−1</sup> and the mass concentrations reached
2000 µg m<sup>−3</sup> in the elevated dust layers on
7 September, more than 12 h before the peak dust front on 8 September
reached the Limassol lidar station around local noon. Typical Middle Eastern
dust lidar ratios around 40 sr were observed in the dense dust plumes. The
particle depolarization ratio decreased from around 0.3 in the lofted dense
dust layers to 0.2 at the end of the dust period (11 September),
indicating an increasing impact of anthropogenic haze. |
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ISSN: | 1680-7316 1680-7324 |