What does the salinity of ocean waters depend on? The temperature of the waters of the world's oceans: what is it, what does it depend on and how is it related to humans. Movement of water in the oceans Sea currents

In the open ocean, the water is clearer than near the shores, since there are more impurities in the water near the shores. Depending on the type of impurities, water may have a different color. For example, the waters of the Yellow Sea have a yellow tint due to silt of this color, which enters the sea along with the waters of the rivers flowing into it.

Compared to land, water heats up more slowly and cools down more slowly. Its heat capacity is greater. In warm times, ocean water accumulates a huge amount of heat and, cooling in cold times, releases it. Therefore, the World Ocean significantly influences the temperature of land when winds blow from it to the continents.

With depth, the temperature of ocean waters drops and already deeper than 200 m it can be around zero or even lower.

The temperature of the upper layers of the waters of the World Ocean, as well as on land, depends on the latitude of the area. It is much warmer at the equator than at the poles. In temperate zones, water is warmer in summer than in winter. The average temperature of the surface waters of the World Ocean is about +17 °C.

An important property of the ocean is its salinity. In fact, sea water is bitterly salty. Various salts are dissolved in it. Salinity shows how many grams of salts are dissolved in 1 liter of water. Salinity is measured in ppm (‰). The average salinity of the waters of the World Ocean is about 35‰. This means that 35 grams of various salts are dissolved in 1 liter of ocean water.

There are many different substances dissolved in the oceans, but the most common is table salt.

The salinity of ocean waters is not the same everywhere. This is not how the rivers entering the seas influence it. They desalinate nearby waters. Melting ice also makes the water less salty. Currents transport water and affect salinity. Salinity is especially affected by precipitation. Where there is a lot of rain, the salinity is less. In places where there is high temperature and little precipitation, salinity is high, since at high temperatures water evaporates more.

Salinity and temperature affect the density of water. Cold water is heavier than warm water, and saltier water is heavier than less salty water. The different densities of water cause it to move.

The amount of substances dissolved in water affects its freezing point. The more there are, the lower the temperature the water freezes. So on average, ocean water freezes at a temperature of –2 °C.

Living organisms living in the seas and oceans are adapted to a certain salinity.

Gases are also dissolved in water. So the amount of oxygen in water decreases with increasing temperature. Therefore, in warm waters the number of living organisms is less than in relatively colder ones. With depth, the amount of oxygen also decreases.

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 reservoirs? Such dreams are especially relevant in the winter cold. Today you won’t surprise anyone with New Year’s trips into real summer. With hot sun, hot sand and a gentle sea of ​​the most amazing color. And this opportunity exists thanks to the temperature characteristics of the World Ocean.

The world's oceans are much larger in area than land. Therefore, it is not surprising that it receives much more solar heat. But even the sun's rays are not able to warm it up completely evenly and systematically. Only a shallow layer on the surface receives heat. Its thickness is only a few meters. But through 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 ocean bottom is +2-0C. Moreover, when diving to depths, the temperature of the water in the world's oceans first changes in sharp jumps, and only when falling lower does it begin to change towards a smooth decrease.

The further you move away from the equator, the lower the water surface temperature becomes. This is obvious and directly related to the total amount of warm sunlight received. And since the Earth has the shape of a ball, the rays fall on it at different angles. Thus, the equator receives 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 World Ocean.

What determines the temperature of the world's oceans?

When considering why and how water temperatures change, climate and geographic location are key factors. If the waters are surrounded by endless deserts, like the Red Sea, then they can 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 operate. At the same time, cold masses move towards warm ones. Mixing of giant water masses occurs. The wind is also capable of mixing surface layers. In this regard, of course, the example of the Pacific Ocean, which occupies almost half of the entire world ocean and a third of the entire planet Earth, is indicative. Thus, during 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 water temperature in the world's oceans is +17.5C.

Considering the average temperature of ocean water, we can state the following: the surface layer of the Pacific Ocean is the warmest +19.4C. Second place goes to Indian +17.3C. The surface water temperature of the Atlantic Ocean is +16.5C – third place. The champion for the coldest water - just 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 enormous size there are areas where it can drop to -1C in winter (Bering Strait).

Effect of salinity

High salinity is a distinctive feature of the waters of the world's oceans. According to this criterion, it many times exceeds the indicators of waters on land. Sea water contains 44 chemical elements, but the largest amount among them is salt. To understand how much salt is in the World Ocean, you need to imagine the following picture: a layer of salt evenly scattered over land will be equal to a thickness of 150 meters.

The oceans can be ranked according to salinity as follows:

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

Density directly depends on this. 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 the existing difference:

• Evaporation;
• Ice formation;
• Decrease in 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 runoff and the melting of ice. And the increase in salinity is actively promoted by evaporation and ice formation.

For example, the Red Sea has no rivers flowing into it, but there is very high evaporation due to strong solar heating and low precipitation. As a result, the salinity is 42%. And if we take the Baltic Sea into consideration, then its salinity does not exceed 1%o and it is, in fact, 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.

At what water temperature is it better to swim?

On the shore of any sea it is very difficult to resist the desire to swim. The sea, waves, sand act as tempters. But some are tempted by the opportunity to dive into a winter ice hole, while others will enjoy swimming 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 an ordinary average swim in a pond. The normal temperature is considered to be +22 - +24C. It is important to understand that when immersed in water, the human body is exposed not only to the temperature of the surrounding liquid, but also to such factors as:

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

Yet the human body is capable of adapting to numerous changes in the external environment. It can either harden or relax through the process of thermoregulation. Therefore, the statement that there is nothing better than warm water is not always correct in everything. Very warm waters contribute to the development and reproduction of a huge number of harmful microorganisms and unpleasant infections. Swimming in such conditions poses a threat not only to children, but also to adults. Therefore, it is completely reasonable that residents of different continents and regions have their own comfort zone for swimming. Here we can cite the example of residents of the Greek coast with water temperatures 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

For expectant mothers, as well as small children, warm water is most suitable for bathing. Often, sea baths are chosen for this. The recommended temperature during pregnancy should not be below +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 maintained, direct sunlight should be avoided and it is advisable to avoid possible thermal changes. And no matter how much you enjoy being in the arms of warm sea waves, you should not overuse long swims. It is believed that the optimal duration of water procedures for pregnant women should not be more than 15-20 minutes.

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

1. What determines the salinity of ocean waters?

The world ocean, the main part of the hydrosphere, is a continuous water shell of the globe. The waters of the World Ocean are heterogeneous in composition and differ in salinity, temperature, transparency and other characteristics.

The salinity of water in the ocean depends on the conditions of evaporation of water from the surface and the influx of fresh water from the land surface and with atmospheric precipitation. Water evaporation occurs more intensely in equatorial and tropical latitudes and slows down in temperate and subpolar latitudes. If we compare the salinity of the northern and southern seas, we can establish that the water in the southern seas is saltier. The salinity of water in the oceans also varies depending on the geographical location, however, in the ocean the mixing of water occurs more intensely than in more closed seas, therefore the difference in the salinity of the ocean water masses will not be too sharp, as in seas. The most saline (more than 37% o) are the ocean waters in the tropics.

2. What are the differences in ocean water temperature?

The water temperature in the World Ocean also varies depending on geographic latitude. In tropical and equatorial latitudes, the water temperature can reach +30 °C and above; in the polar regions it drops to -2 °C. At lower temperatures, ocean water freezes. Seasonal changes in ocean water temperature are more pronounced in the temperate climate zone. The average annual temperature of the World Ocean is 3 °C higher than the average land temperature. This heat is transferred to land using air masses in the atmosphere.

3. In what areas of the ocean does ice form? How do they affect the nature of the Earth and human economic activity?

The waters of the World Ocean freeze in arctic, subarctic and partly in temperate latitudes. The resulting ice cover affects the climate of the continents and makes it difficult to use cheap sea transport in the north to transport goods.

4. What is called water mass? Name the main types of water masses. What water masses are found in the surface layer of the ocean? Material from the site

Water masses, by analogy with air masses, are named according to the geographical zone in which they were formed. Each water mass (tropical, equatorial, arctic) has its own characteristic properties and differs from the rest in salinity, temperature, transparency and other characteristics. Water masses differ not only depending on the geographic latitude of their formation, but also depending on their depth. Surface waters differ from deep and bottom waters. Deep and bottom waters are practically not affected by sunlight and heat. Their properties are more constant throughout the world's oceans, in contrast to surface waters, the properties of which depend on the amount of heat and light received. There is much more warm water on Earth than cold water. Residents of temperate latitudes spend their New Year holidays with great pleasure on the coasts of those seas and oceans where the water is warm and clean. Sunbathing under the hot sun, swimming in salty and warm water, people restore strength and improve their health.

Didn't find what you were looking for? Use the search

On this page there is material on the following topics:

• "The world's oceans are the main part of the hydrosphere" answers
• short message about the world's oceans
• what water masses are released in the surface layer of the ocean
• transparency of equatorial water masses
• report on the geography of the world's oceans

Several years ago I was on vacation in Crimea. It was the height of summer, the sun was hot, but one day the water temperature for some reason dropped sharply. It turned out that it was a cold current. But the temperature of the seas and oceans is influenced by some other factors.

What causes ocean water temperature to change?

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 ocean water temperature:

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

The closer the location to the equator, the higher the temperature level will be. This situation occurs due to the fact that most of the solar heat reaches the Earth near the equator. The temperature of ocean waters at the equator can reach +29°C.

The temperature of sea water depends very much on what land area is nearby. For example, in the Red Sea the water warms up very well, since there are hot deserts around. The water circulates constantly, allowing it to spread evenly. All this happens thanks to warm and cold currents. Warm ones carry well-heated water from the equator region, and cold ones carry cool water from the extreme points of our planet.

How does water temperature change at depth?

Under bright sunlight, only the surface of the water can heat up. Heat can penetrate approximately several meters from it. Warm water reaches 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. This picture 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 drops to 0°C. But at the very bottom the temperature becomes positive and reaches +2°C. The Earth's mantle heats the Earth's crust, which is much thinner at the bottom of the ocean.

10. Temperature in the ocean.

© Vladimir Kalanov,
"Knowledge is power".

You can often hear the expressions “warm sea” or “cold, icy sea.” If we keep in mind only the temperature of the water, it turns out that the difference between the warm and cold sea is completely insignificant and concerns only the upper, relatively thin layer of water. Therefore, the mentioned expressions can only be perceived as a literary image, as a familiar speech cliche.

The world's oceans as a whole are a colossal reservoir of cold water, on top of which, and even then not everywhere, there is a thin layer of slightly warmer water. Water warmer than 10 degrees makes up only about 8 percent of the total water reserves of the world's oceans. This warm layer on average reaches a thickness of no more than 100 meters. Below it, at great depths, the water temperature ranges from one to four degrees Celsius. 75% of ocean water has this temperature. In deep-sea trenches, as well as in the surface layers of the polar regions, the water has an even lower temperature.

The temperature regime of the ocean is exceptionally stable. If on a global scale the absolute difference in air temperatures reaches 150°C, then the difference between the maximum and minimum surface temperature There is, on average, an order of magnitude less water in the ocean.

In absolute values, this difference in different areas of the World Ocean ranges from 4-5°C to 10-12°C during a year. For example, the temperature fluctuation of the surface waters of the Pacific Ocean in the area of ​​​​the Hawaiian Islands during the year is no more than 4°C, and in the area south of the Aleutian Islands - 6-8°C. Only in shallow coastal areas of the seas of temperate climate zones can these fluctuations be greater. For example, off the northern coast of the Sea of ​​Okhotsk, the difference in average surface water temperatures in the warmest and coldest months of the year reaches 10-12°C.

Concerning daily fluctuations surface water temperature, then in the open sea they are only 0.2-0.4 degrees. Only in clear sunny weather in the warmest month of summer can they reach 2 degrees. Daily temperature fluctuations affect a very thin surface layer of ocean water.

Solar radiation warms the water in the ocean, even in the equatorial zone, to a very small depth (up to 8-10 meters). The thermal energy of the Sun penetrates into deeper layers only due to the mixing of water masses. The most active role in mixing sea water belongs to the wind. The depth of wind mixing of water is usually 30-40 m. At the equator, provided there is good wind mixing, the Sun warms the water to a depth of 80-100 m.

In the most restless ocean latitudes, the depth of thermal mixing is much greater. For example, in the South Pacific, in the strip of storms between the 50th and 60th parallels, the wind mixes water to depths of 50-65 meters, and south of the Hawaiian Islands - even to a depth of 100 meters.

The intensity of thermal mixing is especially high in areas of powerful ocean currents. For example, south of Australia, thermal mixing of water occurs to a depth of 400-500 m.

In this regard, we must clarify some terms used in oceanology.

Mixing, or vertical water exchange, comes in two types: frictional And convective . Frictional mixing occurs in a moving stream of water due to differences in the speed of its individual layers. This mixing of water occurs when exposed to wind or tide (low tide) in the sea. Convective (density) mixing occurs when, for some reason, the density of the overlying layer of sea water turns out to be higher than the density of the underlying layer. At such moments in the sea there is vertical water circulation . The most intense vertical circulation occurs in winter conditions.

The density of ocean water increases with depth. The normal increase in density with depth is called direct stratification of ocean waters . It also happens reverse density stratification , but it is observed as a short-term phenomenon in the ocean.

The temperature of surface water is most stable in the equatorial zone of the ocean. Here it is within 20-30°C. The sun in this zone brings approximately the same amount of heat at any time of the year, and the wind constantly mixes the water. Therefore, a constant water temperature is maintained around the clock. In the open ocean, the highest surface water temperatures occur in the zone from 5 to 10 degrees north latitude. In bays, water temperatures can be higher than in the open ocean. For example, in the Persian Gulf in summer the water warms up to 33°C.

The surface water temperature in the tropical zone is almost constant throughout the year. It never drops below 20°C, and in the equatorial zone it approaches 30 degrees. In shallow water near the shore during the day, the water can warm up to 35-40°C. But in the open sea the temperature is maintained with amazing constancy (26-28 degrees) around the clock.

In temperate zones, the temperature of surface waters is naturally lower than in near-equatorial zones, and the difference between summer and winter temperatures is already noticeable and reaches 9-10 degrees. For example, in the Pacific Ocean in the region of 40 degrees north latitude, the average surface water temperature is about 10 degrees in February, and about 20 in August.

Sea water heats up as a result of its absorption of solar energy. It is known that water does not transmit the red rays of the solar spectrum well, and long-wave infrared rays, which carry the bulk of the thermal energy, penetrate only a few centimeters into the water. Therefore, heating of the deeper layers of the ocean occurs not due to the direct absorption of solar heat, but due to vertical movements of water masses. But even in the equatorial zone, where the sun's rays are directed almost at right angles to the surface of the ocean, and the wind actively mixes the water, it remains constantly cold deeper than 300 meters. Seasonal fluctuations hardly affect the depths of the sea. In the tropics, under a layer of warm water there is a zone 300-400 meters thick, where the temperature quickly drops with depth. The area of ​​rapid temperature drop is called thermocline. Here, every 10 meters of depth, the temperature drops by about 1 degree. In the next layer 1-1.5 km thick. the rate of temperature decline slows down sharply. At the lower boundary of this layer, the water temperature does not exceed 2-3°C. In deeper layers, the temperature drop continues, but occurs even more slowly. Layers of ocean water, starting from a depth of 1.2-1.5 km, no longer respond at all to changes in external temperatures. In the bottom layer of water, the temperature rises slightly, which is explained by the influence of the heat of the earth’s crust. The monstrous pressure existing at great depths also prevents a further drop in water temperature. Thus, the water of the polar regions, cooled at the surface, dropping to a depth of 5 km, where the pressure increases 500 times, will have a temperature 0.5 degrees higher than the original.

The subpolar region, like the equatorial zone, is a zone of stable surface water temperatures. Here the sun's rays fall at an acute angle to the surface of the ocean, as if sliding above the surface. A significant part of them does not penetrate into the water, but is reflected from it and goes into outer space. In the polar regions, the temperature of surface waters in summer can rise to 10 degrees, and in winter drop to 4-0 or even minus 2 degrees. As is known, sea water can be in a liquid state even at negative temperatures, because it is a fairly saturated solution of salts, which reduces the freezing point of pure water by about 1.5 degrees.

The Weddell Sea off the coast of Antarctica is considered the coldest region of the world's oceans. Here the ocean water has the lowest temperature. The waters of the Southern Hemisphere are generally much colder than the waters of the Northern Hemisphere. This difference is explained by the warming effect of the continents, the area of ​​which in the Southern Hemisphere of the Earth is significantly smaller. Therefore, the so-called thermal equator of the World Ocean, i.e. the line of highest surface water temperatures is shifted relative to the geographic equator to the north. The average annual surface temperature of the ocean at the thermal equator is about 28°C in open waters and about 32°C in closed seas. Such temperatures remain stable and constant for many years, centuries, millennia and probably millions of years.

Geographers and astronomers, taking as a basis the height of the Sun above the horizon, theoretically divided the Earth's surface using two tropics and two polar circles into five geometrically regular zones or climatic zones.

In the World Ocean, generally speaking, the same climatic zones are distinguished. But such a formal division is not always consistent with the interests of specific types of science and practice. For example, in oceanology, climatology, biology, as well as in agricultural practice, zones established only on the basis of geographic latitude often do not coincide with real climatic zones, with the actual zonality of the distribution of precipitation, plants, and animals. For marine biologists, navigators, and fishermen, it is not the Arctic Circle itself that is important; they are primarily interested in the border of floating ice.

Climatic zones (belts) in the World Ocean.

Scientists from different specialties do not have a common opinion, for example, on the question of what is considered the tropical zone of the ocean, where it begins and where it ends. Some experts consider the tropical zone of the ocean only that belt north and south of the equator in which coral reefs can exist. Others believe that such a zone covers the distribution area of ​​​​sea turtles, etc. Some scientists consider it necessary to distinguish special subtropical and subarctic zones.

Climatologists and weather forecasters, who in their work must take into account the influence of numerous natural factors - temperature, humidity, strength and direction of prevailing winds, amount of precipitation, proximity of the ocean, length of seasons, etc., divide the Earth into as many as 13 zones: one equatorial and two each of subequatorial, tropical, subtropical, temperate, subpolar and polar.

These examples show a completely normal situation in science, when each special discipline requires special initial, basic conditions for solving the problems it faces and obtaining specific results. The main thing that we must note in the issue of zonation of the Earth and the World Ocean is that, firstly, the latitudinal zonation of both land and ocean has no or almost no relation to the temperature regime of the ocean depths and to the physical and biological processes. Secondly, any zonal division of the Earth and the ocean is conditional and cannot be universal for all branches of science and practice.

The main source of data is ARGO buoys. The fields were obtained using optimal analysis.

Our website contains a map of surface temperatures of the World Ocean, which shows the water temperature at a specific point in the ocean at any given moment in real time. Information about the temperature of ocean water is transmitted to the weather service of many countries from several thousand ship and stationary weather stations, as well as numerous sensors - buoys that are installed at anchors or drifting in various areas of the World Ocean. This entire system was created by the combined efforts of dozens of countries around the world. The value of such a system is obvious: it is an important element of the World Weather Watch and, together with weather satellites, contributes to the production of data for global weather analyzes and forecasts. And everyone needs a reliable weather forecast: scientists, drivers of ships and aircraft, fishermen, tourists.

© Vladimir Kalanov,
"Knowledge is power"