The Adriatic was named after Adria, a town that used to be a port at the Italian coast. Adriatic Sea, especially its eastern coast is adorned with hundreds of islands, islets, cliffs, bays and coves and is unique in Europe. It is attractive for cruising with yacht, speedboat or sailing boat but also for modern aquanauts who find pleasure under the sea.
The Adriatic comprises the area between the Balkan and Apennine peninsula. The eastern coast from Prevlaka to the cape Savudrija belongs to Croatia with all its islands, islets and cliffs along the coast as well as Palagruza islands. Our sea is the shallowest in Istria, where the depth does not exceed 50 metres and from Pula, the seafloor is slightly lowering and creating a long, narrow valley stretching from the island Zirje towards Italy called Jabuka depression. From Jabuka depression the bottom rises to Palagruza reef where the biggest depth is 130 metres. Towards the south, the bottom drops steeply towards South Adriatic valley where the highest measured depth is around 1300 metres
In the Adriatic, the high and low tides have relatively small amplitudes. In the southern part, the difference is about few dozen centimetres at most, while in the northern part it is somewhat larger. The tides are of a mixed type, which means that their rhythm is semidiurnal during the new and full moon and of a daily type during the first and the last quarter. The tides are significantly affected by the atmospheric pressure, so at the change of 1 hPa, the sea level will change 1 centimetre. Since the changes are small, while diving, we do not need to take them into account.
Sea currents are weakly noticeable in the Adriatic. In some narrow canals and passages (e.g. Pasman channel or the passage at Grebeni near Dubrovnik) the currents are strong and should be paid attention to. 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 reach the speed of 4 knots.
The salinity of the Adriatic Sea is 38.30 per mill averagely, i.e. there is 38.30 g of salt dissolved in 1 kg of water. In the northern part, the salinity is somewhat lower than in the middle and southern part because of the influence of the Po River.
The Adriatic Sea has a very marked annual change of the surface temperature. The average annual temperature is 11°C. During the winter, the sea is the coldest and the surface temperature is about 7°C, very seldom, it can drop below that too.
In the spring, the sea becomes warmer, and the surface temperature rises to 18°C. In the summer, the warming is high and the sea temperature reaches up to 27°C in the southern Adriatic and Istria. In the Adriatic, thermo clines, i.e. parts of the water column of the same temperature, are very well distinguished.
Waves at the Adriatic
The strength of winds depends on the configuration and exposure of the coast. Most often, the wave heights at the Adriatic are around 0,5 and 1.5 meter. The waves consequently occurred at sirocco are notably higher than those caused by bora.