OnDeck – July 2019

WHEN SAILING IN THE MEDITERRANEAN, POOR VISIBILITY

CONDITIONS ARE NOT AN UNCOMMON OCCURRENCE AND THE

REASON FOR IT IS DUST TRANSPORT.

This dust originates mainly in Northern Africa and the Arabic

peninsula where vast desert areas exist. Although the origins

of dust cover a vast geographical area, the media report

it as “Saharan dust transport” since the Sahara Desert is

well known to the public. The phenomenon is usually more

pronounced from the Melita (WMO classification: MetArea III

• sub-area 22) and eastwards, especially in the sub-areas of
  Gabés, Sidra, Southwest Kritiko, Southeast Kritiko, Delta and
  Crusade. Low visibility is due to several interactions between
  light and the dust particles, such as scattering and diffraction.
  Recent satellite observations showed that dust transport
  events occur more frequently in spring and summer, when
  low pressure systems over North Africa (the so called Sharav
  cyclones) are more frequent. Another cause of dust uptake
  are the Saharan heat lows. Such situations are accompanied
  by southwestern, southern and southeastern winds in the
  Eastern Mediterranean. Depending on the intensity of these
  winds, dust is transported all over Eastern Mediterranean
  and may cover the Hellenic peninsula and every so often
  Central Europe too. In the figure we observe an example of
  dust transport forecast, where the plume reaches not only
  Bulgaria but also Romania.

SAHARAN

DUST TRANSPORT

METEO REPORT

EXPERT

WORDS ATHANASSIOS ARGYRIOU

PROFESSOR, HEAD OF THE LABORATORY OF

ATMOSPHERIC PHYSICS, UNIVERSITY OF PATRAS

(Atmospheric Modeling and Weather Forecast Group, Dept. of Physics,

University of Athens, http://forecast.uoa.gr/dustindx.php).