Where is the Strait of Gibraltar?

The Atlantic and Mediterranean throats.

The Strait of Gibraltar is an important gateway connecting the Mediterranean Sea and the Atlantic Ocean. Located between the southernmost tip of Spain's Iberian Peninsula and the northwest corner of Africa, the northern shore is Spain's Gibraltar (now occupied by Britain) and the southern shore is Morocco. The total length is about 90 kilometers. The mountains on both sides of the strait are magnificent and beautiful. There are ports such as Gibraltar, Alger Silas and Ceuta along the coast.

The strait of Gibraltar is only 58 kilometers long, wide in the west and narrow in the east. At its narrowest point, it is only 65,438+03 km between Marocchi, Spain and Cape Cires, Morocco, and the eastern end of the Strait is between Gibraltar and Mount Arjo. The middle section is between Machillo and Cyrus, with a width of 22 kilometers; It enters the canyon at its widest point in the west, between Cape Trafalgar and Spett, with a width of 43 kilometers. Deep in the east and shallow in the west, the shallowest water depth is 30 1m, the deepest water depth is 1 18 1m, and the average water depth is about 375m m.

The "source of life" in the Mediterranean

The Strait of Gibraltar not only connects the Mediterranean Sea and the Atlantic Ocean, but also is the "source of life" of the Mediterranean Sea.

Due to the special geographical location of the Mediterranean, the seawater here has high salt content and high density. The average annual temperature in the Mediterranean is relatively high, which is controlled by subtropical high in summer and autumn, with strong sunshine, dry heat and little rain; In winter and spring, the warm west wind from the Atlantic Ocean blows on the sea, and the temperature is above zero degrees Celsius. In addition, around the Mediterranean Sea, except the Egyptian Nile, there are no large rivers and fresh water flowing into the Sea of China. Therefore, the salt content of the Mediterranean Sea is stable and high, with the annual average salinity of the surface water being 38 ‰ and that of the eastern sea being 39.58 ‰, which is 3-4 ‰ higher than the global annual average salinity. Moreover, in the Mediterranean Sea 122 meters deep, there is a thick, cold and salty ocean current flowing out of the Mediterranean Sea to the west. Won't the Mediterranean dry up at this rate? Don't worry, let's take a look at our Mediterranean neighbor, the Atlantic Ocean.

Because the annual average temperature of the Atlantic Ocean is lower than that of the Mediterranean Sea, and the evaporation of seawater is small, the annual average salinity of the Atlantic Ocean is also lower than that of the Mediterranean Sea, only 35 thousandths. Even the salinity of the adjacent Atlantic Ocean at the same latitude as the Mediterranean Sea is slightly higher, only 36 thousandths, thus forming an unbalanced annual average salinity between the Mediterranean Sea and the Atlantic Ocean connected by the Strait of Gibraltar. The density of seawater depends on its temperature and salinity, and more importantly, on its salinity. The higher the salinity, the higher the density, so the density of Mediterranean sea water is greater than that of Atlantic sea water.

The sea surface pressure in the Mediterranean and the Atlantic Ocean is the same, which is one atmosphere. Because the pressure of seawater is directly proportional to the density of seawater, the water pressure in the Mediterranean is higher than that in the Atlantic at the same depth, and the deeper the depth, the greater the pressure difference between them. As the pressure varies, the sea water moves. The greater the pressure difference, the more intense the movement. The water flow in the Strait is divided into two layers. The upper water (more than 200 meters) flows from the Atlantic to the Mediterranean, and the lower water (less than 200 meters) flows from the Mediterranean to the Atlantic. In this way, the seawater at the bottom of the Mediterranean Sea enters the bottom of the Atlantic Ocean through the Strait of Gibraltar, thus lifting the seawater in the Atlantic Ocean. On the surface of the Atlantic Ocean, at the rising sea level, seawater flows to the Mediterranean Sea through the Strait of Gibraltar due to pressure. Due to the shallow water at the western end of the strait and the cross sill on the seabed, the amount of seawater flowing into the Atlantic Ocean from the Mediterranean Sea is reduced, making the amount of water flowing through the strait from the Atlantic Ocean greater than that flowing into the Atlantic Ocean from the Mediterranean Sea.

In addition, besides stress, climate is also an aspect. The wind direction in the Strait of Gibraltar is mostly easterly or westerly, and the cold air mass entering the western Mediterranean from the north passes here with low-altitude and high-speed easterly winds, which is called Levant wind by the locals. The Levant wind drives the Atlantic ocean surface current (including low salinity seawater) eastward through the Strait of Gibraltar into the Mediterranean Sea, and the flow of this current is also greater than the westward current (including salty and heavy seawater) at the depth of Mediterranean Sea 122 meters. This ensures the stability of Mediterranean sea water. Therefore, the existence of the Strait of Gibraltar has contributed greatly to preventing the Mediterranean from becoming a shrinking salt country.

Moreover, this phenomenon makes the surface water of the Gibraltar Strait flow from west to east forever, so when ships sail from the Atlantic to the Mediterranean and pass through the Gibraltar Strait, they always drift with the tide. Similarly, the submarine successfully entered the Atlantic Ocean from the bottom of the Mediterranean Sea. This phenomenon was exploited by Atlantic navigators in the early days. The exploration fleets of Mediterranean countries often pass through here and reach the Atlantic Ocean, thus completing their exploration.

Sail in the strait of Gibraltar

Due to the density difference between the east and the west, the current speed from the Atlantic Ocean to the Mediterranean Sea via the Strait of Gibraltar is 4 kilometers per hour. The current in the Strait of Gibraltar is very fast, so it is not surprising that the speed of the ship will drop by 4-5 knots if it hits the top current. In April-May season, due to the water surface temperature difference between the Mediterranean Sea and the Atlantic Ocean and the intersection of warm and humid air currents above, a large area of fog will be generated, which will cover the whole Gibraltar Strait. It can be said that two people standing by the bridge can't see their fingers or the night. Such foggy days are undoubtedly terrible for sailing ships.

Important strategic position

The Strait of Gibraltar connects the throats of the Mediterranean Sea and the Atlantic Ocean, and together with the Mediterranean Sea, it forms the natural dividing line between Europe and Africa. The northern shore of the Strait is British Gibraltar and Spain, and the southern shore is Morocco. For the Atlantic and Mediterranean, the Strait of Gibraltar is really as important as their throats.

The Strait of Gibraltar connects the Mediterranean Sea and the Atlantic Ocean, and it is an important channel for the Mediterranean region to reach southern Europe, North Africa and West Asia via the Atlantic Ocean. 1869 After the opening of the Suez Canal, especially after the development of the Persian Gulf oil field, its strategic position has become more important, and it has become the "lifeline" of energy transportation in Western Europe and an important maritime transportation channel between the Atlantic Ocean and the Mediterranean Sea, the Indian Ocean and the Pacific Ocean. Now, thousands of ships pass through the strait every day, reaching100000 every year. It is one of the busiest passages of international shipping and has an important economic and strategic position.

The origin of the name

A Gibraltar comes from Arabic, and the Strait of Gibraltar is named after the port of Gibraltar built by Tariq in the northeast. At the beginning of the 8th century, when Moore joined the Meyer dynasty, Moussa? 6? 1 Ibn？ 6? 1 Nusser led the Arab army to invade North Africa, reaching the west coast of Morocco, occupying the important port of Tangier and appointing its Tariq? 6? 1 Ibn？ 6? 1 Zead is the governor of Tangier. In 7 1 1 A.D., Zeyad was ordered by Nusselt to lead 7,000 soldiers across the channel, landed forcibly in July 19, and stood on a boulder in the present-day Gibraltar port to command the operation, defeating 65,438+10,000 Spanish defenders, thus setting a good example of winning more with fewer. Then Zead ordered a castle to be built at the landing site. To commemorate the victory of this cross-sea campaign, the castle was named "Zhibur? 6? 1 Tariq "means" Tariq Mountain "in Arabic. This strait is called "straight Boolean? 6? 1 Tariq Strait ",translated as" Gibraltar "in English.

climate

The strait of Gibraltar and its adjacent areas belong to the Mediterranean climate, which is controlled by subtropical high in summer, with dry heat and little rain and strong evaporation. Winter is controlled by the westerly belt, with many cyclones, mild and rainy, and many storms in spring and autumn. In spring, due to the water surface temperature difference between the Mediterranean Sea and the Atlantic Ocean and the intersection of warm and humid air currents above, foggy weather will appear, which will cover the whole strait, with low visibility and great threat to ship navigation.