Temperature and salinity of sea water. What determines the temperature of the water in the ocean? The temperature of the ocean is affected by

It has long been known that ocean waters cover most of the surface of our planet. They constitute a continuous water shell, which accounts for more than 70% of the entire geographical plane. But few people thought that the properties of ocean waters are unique. They have a huge impact on climate and economic activity of people.

Property 1. Temperature

Ocean waters can store heat. (about 10 cm deep) retain a huge amount of heat. Cooling, the ocean warms the lower layers of the atmosphere, due to which average temperature terrestrial air is +15 °C. If there were no oceans on our planet, then the average temperature would hardly reach -21 ° C. It turns out that thanks to the ability of the oceans to accumulate heat, we got a comfortable and cozy planet.

The temperature properties of oceanic waters change abruptly. The heated surface layer gradually mixes with deeper waters, as a result of which a sharp temperature drop occurs at a depth of several meters, and then a gradual decrease to the very bottom. The deep waters of the oceans have approximately the same temperature, measurements below three thousand meters usually show from +2 to 0 ° C.

As for surface water, then their temperature depends on the geographic latitude. The spherical shape of the planet determines the sun's rays to the surface. Closer to the equator, the sun gives off more heat than at the poles. So, for example, the properties of the ocean waters of the Pacific Ocean directly depend on average temperature indicators. The surface layer has the highest average temperature, which is more than +19 °C. This cannot but affect the surrounding climate, and the underwater flora and fauna. This is followed by the surface waters of which, on average, are warmed up to 17.3 ° С. Then the Atlantic, where this figure is 16.6 ° C. And the lowest average temperatures are in the Arctic Ocean - about +1 °С.

Property 2. Salinity

What other properties of ocean waters are being studied by modern scientists? they are interested in the composition sea ​​water. Ocean water is a cocktail of dozens of chemical elements, and salts play an important role in it. The salinity of ocean waters is measured in ppm. Designate it with the icon "‰". Promille means a thousandth of a number. It is estimated that a liter of ocean water has an average salinity of 35‰.

In the study of the oceans, scientists have repeatedly wondered what are the properties of ocean waters. Are they the same everywhere in the ocean? It turns out that salinity, like the average temperature, is not uniform. The indicator is influenced by a number of factors:

• quantity precipitation- rain and snow significantly reduce the overall salinity of the ocean;
• stock of large and small rivers- salinity of the oceans washing the continents with big amount full-flowing rivers, below;
• ice formation - this process increases salinity;
• melting ice - this process lowers the salinity of the water;
• evaporation of water from the surface of the ocean - salts do not evaporate with the waters, and salinity rises.

It turns out that the different salinity of the oceans is explained by the temperature of surface waters and climatic conditions. The highest average salinity is near the water of the Atlantic Ocean. However, the most salty point - the Red Sea, belongs to the Indian. The Arctic Ocean is characterized by the least indicator. These properties of the oceanic waters of the Arctic Ocean are most strongly felt near the confluence of the full-flowing rivers of Siberia. Here salinity does not exceed 10‰.

Interesting fact. The total amount of salt in the world's oceans

Scientists did not agree on how many chemical elements are dissolved in the waters of the oceans. Presumably from 44 to 75 elements. But they calculated that just an astronomical amount of salt is dissolved in the oceans, about 49 quadrillion tons. If all this salt is evaporated and dried, it will cover the surface of the land with a layer of more than 150 m.

Property 3. Density

The concept of "density" has been studied for a long time. This is the ratio of the mass of matter, in our case the oceans, to the volume occupied. Knowledge of the density value is necessary, for example, to maintain the buoyancy of ships.

Both temperature and density are heterogeneous properties of ocean waters. The average value of the latter is 1.024 g/cm³. This indicator was measured at average values ​​of temperature and salt content. However, in different parts of the World Ocean, the density varies depending on the depth of measurement, the temperature of the site, and its salinity.

Consider, for example, the properties of the oceanic waters of the Indian Ocean, and specifically the change in their density. This figure will be highest in the Suez and Persian Gulf. Here it reaches 1.03 g/cm³. In the warm and salty waters of the northwestern Indian Ocean, the figure drops to 1.024 g/cm³. And in the freshened northeastern part of the ocean and in the Bay of Bengal, where there is a lot of precipitation, the indicator is the lowest - about 1.018 g / cm³.

Density fresh water lower, which is why staying on the water in rivers and other fresh water bodies is somewhat more difficult.

Properties 4 and 5. Transparency and color

If you collect sea water in a jar, it will seem transparent. However, with an increase in the thickness of the water layer, it acquires a bluish or greenish tint. The change in color is due to the absorption and scattering of light. In addition, suspensions of various compositions affect the color of ocean waters.

bluish color pure water- the result of weak absorption of the red part of the visible spectrum. At a high concentration of phytoplankton in ocean water, it becomes blue-green or green color. This is due to the fact that phytoplankton absorbs the red part of the spectrum and reflects the green part.

The transparency of ocean water indirectly depends on the amount of suspended particles in it. In the field, transparency is determined with a Secchi disk. A flat disk, the diameter of which does not exceed 40 cm, is lowered into the water. The depth at which it becomes invisible is taken as an indicator of transparency in the area.

Properties 6 and 7. Sound propagation and electrical conductivity

Sound waves can travel thousands of kilometers under water. The average propagation speed is 1500 m/s. This indicator for sea water is higher than for fresh water. The sound always deviates slightly from the straight line.

It has a higher electrical conductivity than fresh water. The difference is 4000 times. It depends on the number of ions per unit of water volume.

Water temperature. The world ocean is not the same in different places; in total, the oceans are heated in bands of about 20 ° N w and

20° pl w that coincide with areas high pressure. This is due to low cloudiness in subtropical, tropical and subequatorial latitudes. The oceans absorb heat mainly in the 30°S - 20°N belt, and release it to the atmosphere at high latitudes. This is an important climate mitigation factor in the temperate and polar latitudes during the cold season of rockori roku.

Only the top layer of water, 1 cm thick, collects solar heat. It absorbs 94% of the solar energy that hits the surface of the ocean. From the surface, solar energy is transferred to the depths. The main role in this case is played by dynamic processes due to various reasons. Taken together, dynamic processes (vertical and horizontal movements of water) determine the good transfer of heat from the surface to different depths. Thanks to this, the waters of the oceans. Profit in all its thickness and concentrate a huge amount of heat.

Average surface water temperature. The world ocean is 17.54°. C (air temperature over the ocean 14.4 °. C). The average surface water temperature in the northern and southern polar regions of the state is -0.75 and -0.79 °, respectively. C, in the equatorial strip 26.7 °. C and 27.3°. SV Northern Hemisphere water temperature is higher than in. South, which is explained by the influence of the continents.

At great depths, the temperature distribution is determined by the deep circulation of water, which sank at high latitudes, have a lower temperature than sank at low latitudes. In the bottom layer, the temperature varies from 1.4 - 1.8 °. C at low latitudes down to 0°. From and below to high.

The salinity of ocean water is one of its most important features.

Water is the best solvent. Although it is weak (contains about 4% by weight of dissolved solids), it is very rich in qualitative composition solution. All known elements are dissolved in water, however, here they are small, in a meager amount, but in total they give significant values. Suffice it to say that, in addition to a huge amount of basic salts - NaCl, MgSO, MgCgCl 2, about 8 million tons of gold, 80 million tons of nickel, 164 million tons of silver, 800 million tons of molybdenum, and 80 billion tons of iodine are dissolved in sea water. d.

In addition to solid matter, gases (oxygen, nitrogen, carbon dioxide, and hydrogen sulfide in stagnant waters) and organic matter are also dissolved in water.

The salinity of sea water determines the temperature of its freezing and the highest density, and from them - the duration of the processes of mixing water in the oceans. Therefore, it affects air temperature and climate. Earth ml.

Salinity in. The world ocean is unevenly distributed and depends mainly on the ratio of evaporation and precipitation in the polar and subpolar regions, where water is desalinated by melting ice, the salinity is less: c. In the Arctic, it is equal to an average of 31.4 ‰ in. Antarctica - 33.93%% o.

In temperate latitudes, salinity is close to normal (average) and is about 35 ‰. This is due to the intense mixing of m of water in these latitudes. The most high salinity in the open ocean - in the subtropics of the furnace latitudes of both hemispheres (where evaporation prevails over precipitation) - more than 37.25 ‰. In the equatorial zone, due to desalination by precipitation, it is somewhat lower than the average. The highest salinity. The world ocean well in the closed seas of the tropical zone - more than 42 ‰ (Red Sea). Salinity varies very little with depth.

67 Movement of water in the oceans Sea currents

Sea currents - gradual movements of water masses in the oceans and seas, due to various forces(gravitational, friction and tidal). They play a significant role in life. World oceans and navigation; encourage the exchange of water masses, changes in coasts (destruction, alluvium of new land), shallowing of port water areas, ice transfer, etc.; great influence on the climate of different parts the globe: e.g. system emi. The North Atlantic Current moderates the climate. Europe. Sea currents differ: by origin - sea currents caused by wind friction on the sea surface (wind currents), uneven distribution of water temperature and salinity (current density), level slope (runoff currents), etc.; according to the degree of stability - stable, changing, temporary, periodic (for example, seasonal currents that change direction under the influence of monsoons) according to placement - surface, subsurface, intermediate, deep, near-bottom; By physical and chemical properties- warm, cold, desalinated, saline.

The direction of sea currents is affected by rotation. The land that deflects currents into. Northern hemisphere - to the right, c. South - left

The main surface currents arise under the influence of the trade winds blowing over the oceans all year round.

Consider currents. Pacific Ocean. The current, arising under the influence of the northeast trade wind, forms an angle of 45 ° with it, deviating to the right of the wave of the prevailing wind direction. Therefore, the current goes from east to west of the equator, a little north of it. This current creates a northeast trade wind. They call her. Northern trade wind.

The southeast trade wind forms. The south trade wind current, which deviates from the direction of the trade wind to the left by 45 °. It has the same direction as the previous one, from east to west, but passes south of the equator.

Both. The trade wind (equatorial) currents, running parallel to the equator, reach the eastern coast of the continents and branch, with one jet returning along the coast to the north, and the second to the south. Southern branch. North. The trade wind and the northern branch. South. Passat flow. They walk towards each other. Having met, they merge and through the zone of equatorial calm they go from west to east, forming an equatorial countercurrent.

Right branch. North. The trade wind current goes north along the eastern coast of the mainland as a result of rotation. On Earth, it gradually deviates from the coast and, near the 40th parallel, turns east into the open ocean. Here it is picked up by the southwest winds and forced to go in the direction from west to east. Having reached the western coast of the mainland, the current forks, its right branch goes south, deviating by rotation. Lands to the right, and therefore moves away from the shore. Having reached. The northern trade wind (equatorial) current, this branch merges with it and forms a closed northern equatorial circle of currents.

The left branch of the current is directed to the north, deflected by rotation. Land to the right, pressed against the western coast of the mainland and goes along it

Northeast winds blowing from the circumpolar space also create a current. She, carrying a very cold water, goes south along the eastern shores of the mainland. Eurasia

B. Southern hemisphere left branch. South. The trade wind current heads south along the eastern shore. Australia, rotation. The land deviates to the left and is pushed away from the shore. At the 40th parallel, this branch of the current returns to the open ocean, jumps up with northwest winds and goes from west to east. On the western shores. America forks. The left branch returns along the line. Rega mainland to the north. Deviating rotation. Lands to the left, this current departs the ox shore and joins with. South trade wind current, forming the southern equatorial ring of currents. The right branch I past the southern tip. America runs east into the neighboring ocean.

Especially terrible are the waves that arise from earthquakes and volcanic eruptions, when the waters fall on the shore. Waves of this origin are called tsunamis.

As a result of action. moon to the surface. The oceans are ebbs and flows. Very high tides occur in the bay. Saint-Malo in. France - up to 15 m. At the top of Filele Bay, the tide height can reach 18 m.

In the southern part. Atlantic Ocean high tides - up to 12-14 m - can be observed off the coast. Patagonia north of the entrance to. Strait of Magellan

IN. pacific ocean the highest tides in Sea of ​​Okhotsk off the coast. Russia

IN. Indian Ocean high tides occur along the western shores. India (up to 12 m)

The ocean receives a lot of heat from the Sun - occupying a large area, it receives more heat than land. Water has high heat capacity, therefore, a huge amount of heat accumulates in the ocean. Only the upper 10-meter layer of ocean water contains more heat than the whole. But the sun's rays heat only the upper layer of water; heat is transferred down from this layer as a result of constant mixing water. But it should be noted that the water temperature decreases with depth, first abruptly, and then smoothly. At depth, the water is almost uniform in temperature, since the depth of the oceans is mainly filled with waters of the same origin, which form in the polar regions of the Earth. At a depth more than 3-4 thousand meters the temperature usually fluctuates from +2°С to 0°С.

So, the ocean absorbs heat 25-50% more than the land. The sun heats water all summer, and in winter this heat enters the atmosphere, so without the World Ocean, such severe frosts would come on Earth that all life on the planet would die. This is its huge role for the living beings of the Earth. It has been calculated that if the oceans did not keep warm so carefully, then the average temperature on our planet would be -21 ° C, which is 36 ° lower than what we have now.

A few years ago I was vacationing in the Crimea. It was the height of summer, the sun was hot, but one day the water temperature for some reason dropped sharply. Turns out it was cold. But the temperature of the seas and oceans is influenced by some other factors.

What changes the temperature of the ocean water

Everyone knows that most of our planet is occupied not by land, but by seas and oceans. It is the water surface that absorbs a large amount of solar heat. Several factors influence the temperature of ocean water:

• geographic latitude;
• climate of nearby territories;
• currents.

The closer the location is to the equator, the higher the temperature will be. This situation is due to the fact that in the region of the equator most of the solar heat falls on the Earth. The temperature of oceanic waters at the equator can reach +29°C.

The temperature of the water in the sea is very dependent on which piece of land is nearby. For example, in the Red Sea, the water warms up very well, as there are hot deserts around. Water constantly circulates, which allows it to spread evenly. All this happens due to warm and cold currents. Warm - carry away well-heated water from the equator, and cold - carry cool water from extreme points our planet.

How does the temperature of water change at depth?

Under bright sunlight, only the surface of the water can heat up. Heat can penetrate about a few meters from it. Warm water enters the depth only due to the gradual mixing of water masses.

Of course, the greater the depth, the lower the water temperature will be. At first, it falls very sharply. Such a pattern is observed for the first 700 m, and then the temperature change occurs gradually. Since the Sun is no longer able to penetrate to such a depth, the temperature begins to decrease by about 2 ° C every 1000 m. After 4000 m, the temperature index drops to 0 ° C. But at the very bottom the temperature becomes positive and reaches +2°C. The Earth's mantle heats up the Earth's crust, which is much thinner at the bottom of the ocean.

Summer, as you know, is a fertile time for relaxation and sunbathing. But you want to swim, sunbathe and relax at any time of the year. And how long do you have to wait for the heat and warm water in the reservoirs. Such dreams are especially relevant in the winter cold. Today you will not surprise anyone with New Year's trips in the real summer. With the hot sun, hot sand and gentle sea of ​​the most amazing color. And there is such an opportunity due to the temperature features of the oceans.

The world's oceans are much larger in area than land. Therefore, it is not surprising that much more solar heat falls on it. But even the sun's rays are not able to evenly and systematically warm it completely. Only a shallow layer on the surface receives heat. Its thickness is only a few meters. But as a result of regular movement and mixing, heat can be transferred to lower layers. And already at depths of 3-4 kilometers, the average water temperature remains unchanged and near the bottom of the ocean is + 2-0C. Moreover, when diving to depths, the temperature of the water in the oceans first changes leaps and bounds, and only falling lower, it begins to change in the direction of a gradual decrease.

The further away from the equator, the lower the surface temperature of the water becomes. This is obviously and directly related to the total amount of incoming warm sunlight. And since the Earth has the shape of a ball, the rays fall on it at different angles. Thus, the equator gets much more solar heat than both poles. Therefore, the water here regularly warms up to + 28C + 29C. This explains the higher temperature of tropical waters than the average of the oceans.

What determines the temperature of the world's oceans

Considering why and how the temperature of the water changes, climate and geographical position. If the waters are surrounded by endless deserts, like the Red Sea, then they are able to warm up to + 34C. They are even higher in the Persian Gulf - up to +35.6C. Moving away from the equator, warm currents begin to work. At the same time, cold masses are directed towards warm masses. There is a mixing of giant water masses. The wind is also able to mix the surface layers. In this regard, of course, the example of the Pacific Ocean, which occupies almost half of the entire World and a third of the entire planet Earth, is indicative. Thus, in the state of a storm, the wind mixes the waters in the surface layer of the Pacific Ocean in southern latitudes to a depth of 65 meters. Mixing and dissolving, the average temperature of water in the world ocean is +17.5C.

Considering the average statistical temperature of the water of the oceans, we can state the following: the surface layer of the Pacific Ocean is the warmest + 19.4C. The second place belongs to the Indian +17.3C. The temperature of the surface waters of the Atlantic Ocean is +16.5C - the third place. The champion in the coldest water - a little above + 1C - is predictably the Arctic. But, despite the fact that the average temperature of the surface waters of the Pacific Ocean is the highest, due to its huge size, there are areas in it where it is in winter period can drop to -1C (Bering Strait).

Salinity influence

High salinity is hallmark waters of the oceans. By this criterion, it many times exceeds the indicators of waters on land. Sea water contains 44 chemical element, But the largest number among them is salt. To understand how much salt is in the oceans, you need to imagine such a picture - a layer of salt, evenly scattered over land, will be equal to a thickness of 150 meters.

The salinity of the oceans can be arranged in this way:

• Atlantic is the saltiest - 35.4%;
• Indian in the middle - 34.8%.
• The average salinity of the Pacific is the lowest - 34.5%.

This directly affects the density. Thus, the average density of water in the Pacific Ocean is also lower than in others.

The maximum salinity of tropical waters is up to 35.5-35.6 ‰ higher than the average of the World Ocean.

Why and how does the salinity of water change? There are several reasons for this difference:

• Evaporation;
• Ice cover formation;
• Decreased salinity during precipitation;
• River waters flow into the world's oceans.

Near the continents, at short distances from the coast, the salinity of the waters is not as high as in the center of the ocean, since they are affected by the desalination of river flows and the melting of ice. And the increase in salinity is actively promoted by evaporation and the formation of ice.

For example, the Red Sea has no rivers flowing into it, but there is very high evaporation due to strong solar heating and low rainfall. As a result, salinity is 42%o. And if we take the Baltic Sea into consideration, then its salinity does not exceed 1% o and, in fact, it is very close to the indicators of fresh water. This is explained by the fact that it is located in a climate with very low evaporation and the highest amount of precipitation.

What water temperature is best for swimming

On the shore of any sea it is very difficult to resist the desire to swim. The sea, waves, sand act as tempters. But someone is tempted by the opportunity to dive into a winter hole, and someone will enjoy bathing only at a water temperature of at least +20C. Everything is very individual in this world. But there is also an ordinary average person who will be happy with the usual average bathing in a pond. Normal temperature is considered to be +22 - +24C. It is important to understand that when immersed in water, the human body is affected not only by the temperature of the surrounding liquid, but also by factors such as:

1. Sun rays and air temperature;
2. Pressure;
3. The power of sea waves.

But still human body able to adapt to many changes external environment. It can either harden or relax due to the process of thermoregulation. Therefore, the statement, there is nothing better than lukewarm water, is not always and not always correct. Very warm waters contribute to the development and reproduction of a huge number of harmful microorganisms and unpleasant infections. Swimming in such conditions is a threat not only for children, but also for adults. Therefore, it is completely reasonable that residents of different continents and regions of habitat have their own comfort zone for swimming. Here we can cite as an example the inhabitants of the Greek coast with a water temperature not lower than +25C or those who live on the shores of the Baltic Sea, where, by definition, it does not exceed +20C.

What temperature is optimal for pregnant women

Expectant mothers, as well as young children, are most suitable for bathing in warm water. Often, sea baths are chosen for this. The recommended temperature during pregnancy should not be lower than + 22C. It is the most natural and safe and does not pose any threat. Nevertheless, it is important for expectant mothers to remember that even if the temperature balance is observed, direct sunlight should be avoided and it is desirable to avoid possible thermal fluctuations. And no matter how much you like being in the arms of warm sea waves, you should not abuse long bathing. It is believed that the optimal duration of water procedures for pregnant women should not be more than 15-20 minutes.

By absorbing a huge amount of heat, the ocean makes life possible on the planet. This reflects its pricelessness and necessity for all life on Earth. The sun in a certain period heats the World Ocean, and in the next period, warm water gradually warms the atmosphere with this heat. Without this process, our planet will plunge into the most severe cold, and life on Earth will perish. Scientists have calculated that left without the heat stored by the world's oceans, the average earth temperature will drop to -18C or -23C, which is 36 degrees lower than usual today.