Climate
At
the Adriatic, climate is mediterranean, with mild rainy winters, and hot
dry summers. The air temperature changes depending on the area. Thus,
summer temperatures in July will be about 34°C in the northern part, while
in the southern part it will rise upto 38°C. In the winter, the coldest
temperatures are noticed in the northern Adriatic (up to -16°C), while
they will not have exceeded 6°C in the southern part.
Winds
The
Adriatic region is challenging forecast region, mainly because it is surrounded
by complex mountainous topography. There are number of indentified localized
winds but bora, sirocco and north-western wind blow most often.
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Bora
Bora is a dry and cold wind blowing in bursts from the north-northeast
to the east-northeast direction. Bora may be associated with stormy
weather, with wind reaching 100 knots or more. The direction in which
the wind blows is mostly influenced by the configuration of the shore.
The strength of bora is explained by the existence of warm air over
the surface of the sea, and a cold layer of air above mountain ranges
in the littoral, which cause a strong streaming due to equating of
the pressure. Cold air tends to fill the void, which occurs due to
the rising of the warm air from the sea surface.
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Sirocco
Sirocco is a warm and moist wind which blows from the east-southeast
to south-southwest direction.Sirocco brings high waves and rain. This
wind is a characteristic for the southern Adriatic, where it blows
longer and stronger than in the northern part. In the summer, it usually
blows for couple of days, and in the winter it can last for couple
of weeks. The signs of the oncoming sirocco are the calmness of the
sea, weak changeable winds, and dimness of the horizon, the increase
of the temperature and moisture, and the gradual decrease of the pressure.
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Landward
Breeze
The landward breeze is a daily, thermic wind blowing from the direction
of the northwest, and arises as the land and the sea heat at a different
rate. It occurs from the spring to the autumn, and during the day,
it often changes the direction. The landward breeze blows more in
the southern Adriatic than in the northern Adriatic.
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Stiff
Breeze
The stiff breeze is a wind opposite of the landward breeze. It blows
during the night from the direction of the north, north-east in the
northern Adriatic, and in the southern Adriatic, from the east or
south-east. It's at its peak before the dawn, and subsides over the
night.
Waves
Waves occur primarily as the consequence of wind blowing over the water
surface. Their intensity depends on the configuration and the exposure
of the coast. Hence mixing of the surface layer with water from the deep
is enabled, and the interaction between the atmosphere and the sea. We
distinguish the crest and the trough of a wave. The length of the wave
is the distance between two troughs. Most often, heights of waves in the
Adriatic are between 0.5 and 1.5 meters, and they very rarely exceed 5
meters.
Tides
In the Adriatic, the high and low tides have relatively
small amplitudes. In the southern part, the difference is rarely above
0.4 meter, while in the northern part it is somewhat bigger, up to 1 meter
in Istria and the Gulf of Trieste. In some narrow channels and bays, the
high tide can grow considerably during a strong sirocco. That phenomenon
is characteristic for big and deep bays of the southern Adriatic. The
tides are of a mixed type, which means that their rhythm is semidiurnal
during the new and the full moon, and of a daily type during the first
and the last quarter. Their amplitudes are very irregular.
Currents
Sea currents occur under the influence of
winds, the difference in pressure, temperature, and the differences in
salinity. With respect to the direction, they can be horizontal or vertical.
There are also bottom currents which happen as the consequence of water
circulating from warmer areas to colder ones, during which the surface
layer gets cold and descends towards the seabed. Currents are weakly observable
in the Adriatic. The speed of currents changes in particular areas, but
it also depends on time periods. The average speed of currents is about
0.5 knots, but they can also rise up to 4 knots.
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