Etesian

The Meltemi (Greek μελτέμι Meltemi ) is the prevailing wind the summer months in the Aegean. It blows from April to October as dry Northwest, North and Northeast wind from the Greek mainland in the direction of Crete in the eastern Mediterranean. The Meltemi is perceived as cool and always brings clear weather and good, clear view with it.

Name

The word Meltemi is of Turkish origin ( meltem for " breeze, gentle wind "). The Greeks called the wind earlier ἐτησίαι etêsíai " the annual winds " ( ἐτησίος, ἐτήσιος etêsios "annual"; ἔτος Étos " year"). In the Latin version of the Acts he is called euroaquilo, whereas it is also the wrong ancient Greek terms derived ἐυροκλύδων euroklydôn and ἐυρακύλων from eurakylôn.

Modern Greek is used today for the wind, the old Turkish name Meltemi, while the Turkish etezien originally derived from Ancient Greek.

Formation

In each year put an end May, beginning of June slight north winds, the so-called prodromal symptoms. A week later, then comes the summer wind, which mitigates the heat of the blazing sun.

The Meltemi is a regional wind system and is one of the synoptic winds, whose origin is based on the complex interaction of global wind systems.

Are already a large area at the beginning of the summer half- year differences in pressure between the Azores anticyclone (H ) * one hand and the low pressure area of the summer monsoon (t ) * over Southwest Asia on the other. The position of the two pressure systems can be considered as quasi-stationary and is partly responsible for the yearly flow behavior.

As cold air flows on the eastern flank of a high and on the western flank of a low to the south, forms on the northern hemisphere flow in a north-westerly direction. Werner Rauh has called this air mass transport as Etisial flow, Hermann Flohn as summer north flow.

This flow, and thus the Meltemi, is a part of the northeast trade wind, which blows the intertropical convergence zone (ITC ) when shifted in the northern summer the subtropical high pressure belt between 35 ° and 45 ° North.

As an example of a continuous pressure differential across the Mediterranean from the Azores high to low monsoon weather conditions can be used on 11 August 2011 ( Fig. 2). The Meltemi blowing with strong gusts of up to 8 Beaufort and for Central and Northern Greece extreme weather warnings were issued.

About the Anatolian plateau (Asia Minor) and the Arabian Peninsula formed with seasonal increasingly strong sunlight heat low (t ), which amplify the low pressure influence and thus the pressure difference on. Supportive, accelerating and decisive in particular the strength of the Meltemi is the thermal low (t) over central Turkey.

Another important factor in the relationship between the atmospheric circulation and the formation of the Meltemi is the existence of an anticyclonic center (H ) over Italy, Central Europe and the Balkan Peninsula. If the Azores high pressure pushes forward with a wedge in this region in summer, it does exactly this effect of high pressure, for example, over the Balkans and Hungary, with the so-called Balkan high.

The exact location of the highs is however nebenrangig; in each case, on the Aegean a Meltemi conditions arise and relatively cool continental air flows in sequence from the region of southern Russia, Ukraine and the Caspian Sea. These air masses then flow in the opposite over the Persian Gulf thermal low (t ) and continue towards ITC (see Figure 1 / synoptic view).

In addition to the meteorological parameters of the Meltemi is influenced by the particular topographical features of the terrain. High mountains on the Greek mainland, the southern Balkans and Turkey lead to a channeling effect and while crossing a drying out of the air, which Greece brought the known bright blue and cloudless sky.

More channeling effects occur between the large number of islands of various sizes in the Aegean Sea and the mainland. In addition, mountains, the Meltemi flow are (eg the mountains of Crete) slow down the perpendicular wind flow on its windward side clearly.

Occurrence

The Meltemi blowing in the northern and central part of the Aegean Sea from the north and then fanned out like a giant gust of. In the east (Dodecanese - Rhodes ) it blows from the northwest, and then run out in the eastern Mediterranean. Near the Peloponnese the Meltemi is a bit tamer, blowing from the northeast. In the large bays on the west coast of Turkey ( Gokova Gulf, Gulluk golf ) he shift to the west. The Meltemi brings an average of 4-5 Bft., But also can blow for days with eight or more wind strengths. In particular, the southern part of the island of Karpathos is one of the safest Meltemireviere for windsurfers. The Meltemi blows here for weeks in the summer without a break day and night with winds 5-7 Bft. and may even on some days up to 9 Bft. untwist. Beginners is recommended not this area!

Its maximum is reached the Meltemi in the months of July / August. The probability is 70% from June to September. Usually he uses in the morning and blowing until sunset. It may also be that he is during the day with 6-8 Bft. blows and the night is through.

For sailors, caution is advised when in the Aegean Sea straits, through which must squeeze the Meltemi, as between Tinos and Andros. It can there 1-2 winds blow stronger, with correspondingly stronger flow. Tacking is then exhausting. The same applies to the Cape. Ridge at right angles to the flow create the lee weak wind, but further out the storm. When setting anchor in the lee of the islands strong downdrafts can occur. Especially with shore excursions should be considered an anchor watch.

Sign

The opinions, whether one can predict the wind, disperse. However, there are signs of an increased Meltemi:

• Increasing air pressure in the Balkans
• Dry air, deep blue sky
• Small clouds ball to the mountain peaks of the mainland
• Fields high fleecy clouds coming in from southwest to west