The
"Kiran Poyraz"
(The
Devastating Northeaster)
Consult Piri Reis
At
certain points of the Turkish coast, two climatic regimes,
the arid and dry weather of the Anatolian Plateau and the
moist and mediterranean climate of the coast come close together.
This proximity causes some local winds, which the "Bodrumlu"s
call in general "Yayla Tepmesi", "The Kick
of the Highlands". Meant is a so called catabatic wind,
which under certain conditions may blow off the plateau –
only a short time, but with considerable force. The picturesque
Akbük is in Sadun Boro's words "in the eye"
of the Kiran wind.
In his enchanting "Vira Demir" – "Heave
Ho", Second Edition, Sadun continues on page 143:
The
indications of the Kiran:
"The
Kiran will occur in the summer months and usually in July
and August. It happens at night and a Poyraz (boreas, the
northeaster) must have blown before. Before the Kiran occurs
the weather has to be exceptionally dry, no dew will precipitate,
the hygrometer will fall. There will be no fog, no haze, visibility
will be excellent. Then, when at the summits the clouds start
to roll to the south. (…) and he continues on page 183:
then mariner, it is time that you quickly heave your anchor
and seek refuge at the north of the bay, close to the ruins
of an oil press.(…) At the jetty (of Akbük) there
is no way that you could stay."
Read
here about the "Grand Wind" in the Gökova Körfezi,
an account by a professional seaman.
I
have tried to explain the "devastator" below. With
very special thanks to Burak Günsür, naval architect.
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On
a warm summer day, air will warm up at the sea shore
as well as on the plateau. Conditions are dry, sunny,
calm.
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The
effect starts already in the late afternoon. The relatively
moist air at the seaside has a higher specific heat,
with outher words it has higher heat inertia, than
the dry air in the highlands. The air 3000 feet above
cools down more than at the seaside...
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Comes
in local effects: The landscape traps the cool and
thus heavy air in the moulds of the platea. This air
would like to sink, if it only could.
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Comes
in murphy: A local turbulence happens somewhere, enabling
the heavy air to find an escape...
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The
escaping air "autosyphons" the rest of the
air. Pretty much like honey at the rim of the honeypot.
Masses of heavy air accelerate to high velocities.
Sufficiently high to devastate anchorages in the vicinity.
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(The
picture and link below I could not resist to put in
as the "epilogue".) |
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