tropical sea – an unparalleled source of entertainment and beauty. Running as a narrow strip between Africa and Arabia for 1500 miles, the Red Sea joins at its southern tip the Indian Ocean through the Strait of Bab-El-Mandab, while at its northern head it branches into the twin gulfs of Suez and Aqaba. Unlike the arid lands of desert and semi-desert on either side, the Red Sea is framed with thousands of untouched coral reefs, oases of teeming under-water life basking into its shallow waters.The Red Sea is characterized by its high salinity – a consequence both of the hot climate and the absence of any river adding fresh water to the sea. The surface sea temperature ranges, according to the time of the year, from approximately 20 to 26 degrees Celsius in the northern part, and from 25 to 31 deg. C in the central and southern parts. Clear skies, strong sunlight and the absence of inflowing sediments contribute to excellent underwater visibility, leading to the Red Sea waters being among the clearest waters in the world.The normal tides are small and occur on a semi-diurnal (twice a day) basis, with the whole sea oscillating around a nodal point approximately at the latitude of Port Sudan. The Peak tides, at the northern and southern ends, are of about half a meter, while in the center there is no virtual daily tide. There are, however, throughout the Red Sea, seasonal variations in water level over a longer period, the mean water level in Summer being nearly a meter lower than it in Winter.
The Seasonal tides, and the pattern of prevailing winds and currents, are all influenced by the change between summer and winter monsoons in the Indian Ocean. During the summer northerly winds prevail through the whole Red Sea, the main surface current generated by these winds is to the south, and water is driven out of the Red Sea, thus lowering its level. During winter the prevailing winds are still northerly in the northern half, but in the southern part are from the south, and these winds generate a northerly current, thus bringing water back into the Red Sea again.