The impact of the Pacific Decadal Oscillation on springtime dust activity in Syria
The increasing trend of aerosol optical depth in the Middle East and a recent severe dust storm in Syria have raised questions as to whether dust storms will increase and promoted investigations on the dust activities driven by the natural climate variability underlying the ongoing human perturb...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/13431/2016/acp-16-13431-2016.pdf |
| Summary: | The increasing trend of aerosol optical depth in the
Middle East and a recent severe dust storm in Syria have raised questions as
to whether dust storms will increase and promoted investigations on the dust
activities driven by the natural climate variability underlying the ongoing
human perturbations such as the Syrian civil war. This study examined the
influences of the Pacific Decadal Oscillation (PDO) on dust activities in
Syria using an innovative dust optical depth (DOD) dataset derived from
Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue aerosol
products. A significantly negative correlation is found between the Syrian
DOD and the PDO in spring from 2003 to 2015. High DOD in spring is associated
with lower geopotential height over the Middle East, Europe, and North
Africa, accompanied by near-surface anomalous westerly winds over the
Mediterranean basin and southerly winds over the eastern Arabian Peninsula.
These large-scale patterns promote the formation of the cyclones over the
Middle East to trigger dust storms and also facilitate the transport of dust
from North Africa, Iraq, and Saudi Arabia to Syria, where the transported
dust dominates the seasonal mean DOD in spring. A negative PDO not only
creates circulation anomalies favorable to high DOD in Syria but also
suppresses precipitation in dust source regions over the eastern and southern
Arabian Peninsula and northeastern Africa.<br><br>On the daily scale, in addition to the favorable large-scale condition
associated with a negative PDO, enhanced atmospheric instability in Syria
(associated with increased precipitation in Turkey and northern Syria) is
also critical for the development of strong springtime dust storms in Syria. |
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| ISSN: | 1680-7316 1680-7324 |