“Yayla Tepmesi”, the katabatic winds of Mt. Kiran at Akbük
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.
On a warm summer day, air will warm up at the sea shore as well as on the plateau. Conditions are dry, sunny, calm.
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…
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.
Comes in murphy: A local turbulence happens somewhere, enabling the heavy air to find an escape…
he 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.
(The picture and link below I could not resist to put in as the “epilogue”.)