Baltic Sea when warm. Baltic Sea

The Baltic Sea is real amazing place. Perhaps everyone who has already been lucky enough to visit its shores will agree with this statement. There is everything that a modern person needs. Romantics will discover amazing sunsets and sunrises, businessmen understand how profitable its ports can be in terms of cargo transportation, and travelers tired of the eternal running around will surely be surprised by the spaciousness and special peace.

Among other things, bays Baltic Sea have become a habitat for a huge number of marine animals and birds, which automatically means that its role in the planet's ecosystem is generally difficult to overestimate.

This article will tell in more detail about all the nuances of this part of the oceans. The reader will receive valuable information not only about where the Baltic Sea is located, but also about its characteristic features. Reasonable reasons why you should choose this direction as a vacation spot next year will also be indicated.

general information

The Baltic Sea has a very peculiar shape and is located in the very north of Europe. This inland marginal surface of the World Ocean is surrounded on almost all sides by land and protrudes quite far into the northwestern part of Eurasia.

Only in the southwestern part through the Danish straits (Eressun (Sund), Great Belt and Small Belt) does it have access to the North Sea through the Kattegat and Skagerrak straits.

The maritime boundary lines with the Sound Strait pass through the Stevne lighthouse and Cape Falstersbuudde, with the Great Belt Strait - Cape Gulletav, Klint and Kappel (Lolland Island), and with the Small Belt Strait - Cape Falschert, Cape Weisnes and Nakke (about . Eryo).

The Baltic Sea, the rest on which is considered one of the most pleasant in the Russian Federation, belongs to the Atlantic Ocean basin.

Not everyone knows that in terms of salt content it is the most freshwater of all. This is due, first of all, to the fact that forty rivers flow into it. fresh water. The coast of the Baltic Sea differs in shape and structure. - It has a shallow depth, and its bottom is quite uneven.

All this indicates that this part of the world ocean is located within the boundaries of the continental shelf.

Geographic features

In Ancient Russia, the sea was called Varangian (from the Varangians) or Svebskoe (Sveiskoe) - this is how the Swedes were called during the Middle Ages. In the annalistic sources of Ancient Greece and Rome, the Baltic island is found, and in Western European writings of the 11th century. the Baltic Sea is mentioned. But the basis of this name can be both Lithuanian baltas and Latvian balts, meaning the white color of the sandy shores.

In the XVIII century. the sea was already nicknamed the Baltic, but now it is commonly known as the Baltic Sea. However, the semantic meaning of this name has not yet been determined.

The water area occupies almost 420.0 thousand square meters. km, which almost corresponds to the size of the Black Sea (422.0 thousand sq. km). The volume of water in the sea is about 22.0 thousand cubic km.

The total length of the coast is 7 thousand km. The shores of the Baltic Sea are available in such states as Sweden, Finland, Russia, Poland, Germany and Denmark. The Russian Federation owns almost 500 km of the coastline located in the northwestern part of Europe.

The list of large islands includes: Gotland, Bornholm, Rügen, Oland, Wolin, Saaremaa and Alandia. The main river systems flowing into the water area are the Neva, Neman, Narva, Pregolya, Vistula and Oder.

The Baltic Sea, a photo of which can be found in almost every publication dedicated to the water surface of our planet, is known for its features.

Its ecosystem is considered very vulnerable, due to some natural factors.

This is a shallow inland sea, separated from the Atlantic by the Scandinavian Peninsula and connected to the ocean by narrow and shallow straits that prevent free water exchange between the two basins. It takes about 20-40 years for the complete renewal of water.

The coastline is heavily indented and forms many bays. The largest bays of the Baltic are Riga, Botanichesky, Finnish and Curonian. The latter is a freshwater bay-lagoon separated from the sea by the Curonian Spit.

The eastern part of the Gulf of Finland was named the Neva Bay. By the way, in the north-east of the bay, on the Russian-Finnish border, there is a similar Vyborgsky. The Saimaa Canal opens here, which is the most important transport route. The north coast is protected by high rocky shores and narrow winding bays. The central transit ports of the Baltic are Hamburg (Germany) and St. Petersburg (Russia), which have access to the sea and serve as the sea gates of Europe and Russia.

Bottom relief

Not everyone knows that the Baltic Sea, where rest has already become quite familiar for many, has a very complex and uneven bottom topography. In the southern part it is flat, in the north it is uneven and rocky.

The coast of the Baltic Sea is covered with bottom sediments, among which sand prevails. But most of the bottom consists of bottom sediments of green, black and brown clayey silt of glacial origin.

The sea goes deep into the land and is located within the continental shelf. The average depth of the pool is about 51 meters. Near the islands and on the shallows, there is a zone of shallow water up to 12 meters deep. At the bottom there are several basins with a depth of up to 200 meters. The largest is the Landsort Depression (470 m.)

Climatic conditions of the Baltic

Due to geographical features, the climate of the Baltic is not severe and close to the conditions temperate latitudes. Many complain that, they say, the Baltic Sea is cold, however, this is nothing more than a delusion.

In general, there is also some similarity with the climate of the continental type. Big impact on local weather have the Siberian and Azov anticyclones and the Icelandic low. The seasonal features of the climate of the Baltic Sea depend on this.

Windy and cloudy weather is typical for autumn and winter. The coldest months are January and February. In the central part of the Baltic, it drops to an average of 3°C below zero, in the north and east - to 8°C below zero. The temperature in the Baltic Sea at this time of the year approaches -3-5 C. Occasionally, under the influence of the Arctic masses, the air can cool down to 35 degrees below zero.

In the spring and summer, the winds weaken. Spring is cool. Northerly winds, which bring colder air, have a great influence on the climate. With the onset of heat, moderate western and northwestern winds predominantly blow. Therefore, summer is mostly cool and humid. The average temperature in July in the Botanical Bay rises to 14-15°C, in other areas of the sea - 16-18°C. Hot weather happens rarely and only during the period of inflows of Mediterranean air masses.

The water in the Baltic Sea (temperature and salinity) depends on the part. In winter, it is warmer in the open sea than off the coast. AT summer time the most low temperature- near the western shores in the central and southern strip of the sea. Such fluctuations near the western coast are associated with the movement of warm upper layers of water by westerly winds and their replacement by colder deep waters.

local flora

It should be noted that the Baltic and North Seas as a whole can boast of a variety of flora.

The main part of the underwater flora consists of representatives of the Atlantic species, which live mainly in the southern and southwestern parts of the Baltic Sea.

The flora includes various types of algae, among which are peridine, cyanide, planktonic diatoms, benthic brown algae (kelp, fucus, ectocarpus and pilayella), red algae (rhodomela, polysiphonia and phyllophora), as well as blue-green algae.

Fauna of the Baltic Sea

It's no secret that both winter and summer water temperatures in the Baltic Sea hardly contribute to the appearance of a huge number of marine life.

The local fauna is represented by three groups of animals and fish, different in their origin.

The first includes representatives of a brackish-water arctic species that belonged to the descendants of the ancient Arctic Ocean. One of the inhabitants of this group is the Baltic seal.

The second one consists of commercial fish(herring, cod, sprat and flounder). They also include valuable species such as salmon and eel.

The third group includes freshwater species, distributed mainly in the desalinated waters of the Botanical and Finnish Gulfs, but also found in salt water bodies (freshwater rotifers).

Fisheries freshwater fish are zander, pike, bream, roach and perch. It should be noted that the water temperature in the Baltic Sea allows fishing almost throughout the entire calendar year. This has a beneficial effect on the budget of countries and regions located on its territory.

Baltic Sea. Economic importance

Due to the natural conditions, the Baltic waters are of great economic importance. Their biological resources are of great value and are widely used by man.

The sea is home to many species of flora and fauna that serve for fishing activities. For example, the temperature of the water in the Baltic Sea favors the active reproduction of Baltic herring, which occupies a special place in the fishery.

Also here is the catch of sprat, salmon, smelt, lamprey, cod and eel. The bays of the Baltic Sea are famous for the extraction of various algae.

To date, a new direction has appeared for the development of mariculture, which is a promising industry for fish production. Marine farms are being created for the artificial breeding of various commercial species fish, etc. Fortunately, the temperature of the Baltic Sea in Kaliningrad and other coastal cities, as mentioned above, allows sailors to go to sea at almost any time of the year.

Local shores are rich in coastal-marine placers of minerals. In the Kaliningrad region, for example, developments are currently underway for underwater mining of amber contained in alluvial deposits. The Baltic Sea (Russia) is also being studied for the development of oil deposits found in the thickness of the seabed. Iron-manganese formations were also found.

The Baltic Sea, the temperature of which even in summer rarely rises above +17 C, plays an important role in the transport and economic relations between the countries of Europe, carrying out shipping.

Thanks to the developed sea and river communications, large cargo and passenger transportations are actively taking place.

The water temperature of the Baltic Sea and the main recreational resources of the region

The favorable conditions of this area have long been used by man for recreational purposes.

The mild climate, sandy beaches and pine forests attract a large number of tourists. Cruise routes operate on the sea all year round, and in the warm season people come for rest and treatment.

During the Soviet period, the USSR owned about 25% of the coast of the Baltic Sea. As a result of its collapse, the length of the coast has decreased to 7%, and now only 500 km belong to Russia. After such a sharp reduction in territories, the role of recreational resources has increased significantly. Every year, a huge number of vacationers go to the Baltic Sea. - Kaliningrad, St. Petersburg, Nida, Svetlogorsk and other cities of the Russian Federation never lack tourists.

In the western part of Sosnovy Bor there is an almost untouched coastal strip of sandy beaches. Sea water here is much cleaner than in the resorts of Jurmala. In the future, these places can be used as resorts and sanatoriums, which will become no less popular than, for example, Ust-Narva.

Unfortunately, rest on the Baltic Sea is fraught with some difficulties. The thing is that the possibilities of sea beach pastime are significantly influenced by various environmental problems characteristic of coastal zones.

For this reason, many beaches in the summer season become unsuitable for swimming and close. Although for a huge number of vacationers, a vacation on the Baltic Sea is not only a chance to swim or sunbathe. Many go here for the purest air and breathtaking scenery.

Svetlovodsk and Zelenogradsk - the best Russian resorts

The main resort towns on this coast of Russia are Svetlogorsk and Zelenogradsk.

Despite the fact that the Baltic Sea, the photo of which can be found in almost all prospectuses dedicated to the recreational resources of our country, is northern and the water does not warm up much, many people prefer to spend time on the beach.

The weather in summer is sunny and the water can reach temperatures up to 20 degrees Celsius, which is quite favorable for taking such invigorating and relaxing sunbathing. If passive pastime is the purpose of your vacation, you should not choose for these purposes big cities For example, Kaliningrad. The Baltic Sea, whose water temperature ranges from +17 to +18 C in summer, is unlikely to please you. Experienced travelers are advised to give preference to more modest settlements

Some of them are worth discussing in more detail.

Svetlogorsk is the most famous resort. Beach with fine sand, clean and well maintained. For the convenience of vacationers, the necessary beach equipment is provided - umbrellas and sunbeds. There are many cafes and souvenir shops on the city promenade. The only drawback is a large number of people, both on the main street and on the beach. An important role in choosing a place to stay is played by the price level for hotel and excursion services, transport services, cafes, etc.

The cost of a taxi in the city is about 100 rubles, delivery to or from the airport - up to 850 rubles, a trip to Kaliningrad - within 600 rubles. The cheapest option is buses and trains. Travel by public transport to Zelenogradsk will cost 50.00-100.00 rubles. The average cost of apartments in hotels in Svetlogorsk is about 2000.00-2500.00 rubles per day. Rates for accommodation in rooms range from 1500.00-5000.00 rubles per day. There are many cafes in the resort where you can have a cheap meal (400.00-800.00 rubles for two).

Prices for sightseeing trips depend on the route and program (500.00-1500.00 rubles per person). Small souvenirs for relatives and friends will cost between 100.00-150.00 rubles, and branded amber products can cost more than 1000.00 rubles.

Another equally popular resort is Zelenogradsk, the advantage of which is a more relaxed atmosphere, the absence of a large tourist flow and a convenient location from the regional center. There are good transport links. The city attracts visitors with its architecture and winding streets. Along the coast there is a new spacious promenade where you can walk and spend time with family or friends.

Unlike Svetlogorsk, prices in hotels and hotels are quite reasonable, while the service is high level. You can find housing in the private sector near the sea. In many hotels, when ordering rooms, an advance payment of up to 25% of the accommodation cost is provided, which must be transferred by bank transfer. On the promenade next to the sea, there are many cafes and restaurants where you can have a tasty and inexpensive meal. The beach in the city is sandy, long and well-groomed.

The seashore is comfortable, with a gentle entrance and shallow depth.

Five reasons to go to the Baltic Sea

With the advent of summer, many seek to spend their holidays in the south or in exotic countries where there is a lot of sun, warm sea and hot sand. But there are those who prefer the beauty of northern nature and the amber shores of the Baltic, pine forests and sand dunes. Of course, the Baltic coast cannot be compared with the popular resorts of Turkey and Spain, but even here rest has its advantages.

1.Convenient location

The proximity of the Baltic Sea resorts will allow you to avoid long flights and high vacation costs. Especially if you are traveling with small children. For example, a plane flight in the direction of Moscow-Riga takes only about two hours, and the ticket price will be from 9700.00 rubles. From Riga by car in 30-40 minutes you can easily reach Jurmala. It is worth noting that it is not necessary to choose the Baltic resorts located outside of Russia and go to Latvia, Lithuania, Estonia or Germany, Sweden, Finland and Denmark. You can have a great rest in the Kaliningrad region of Russia at the resorts of Svetlogorsk or Zelenogradsk. For such a trip, visa documents are not required, which is an additional plus.

2. Affordable prices to rest

Unlike southern resorts spending time on the Baltic Sea involves housing at very affordable prices.

For example, apartments in hotels in Palanga (Lithuania) cost from 1200.00 rubles per day. For this cost, a comfortable room with all amenities and close to the sea will be provided.

Accommodation in hotels in Jurmala (Latvia) will cost from about 1800.00 rubles per night. At the Estonian resort in Pärnu - from 1450.00 rubles per night.

And in the Latvian capital Riga, you can find hotels from 220.00 rubles per day.

3. Lack of acclimatization

Usually on popular resorts in the summer season it is hot, and the air warms up above 35 degrees Celsius. Just for lovers of comfort and coolness, the Baltic Sea is suitable. Kaliningrad, where the air temperature stays at +22+24 for almost the entire summer, is always glad to see guests.

As you know, exhausting heat exhausts a person and in most cases it takes time to acclimatize. The Baltic climate is warm and temperate. These places are great for a relaxing family holiday with young children.

4. Favorable conditions for recovery

The waters of the Baltic are known for their beneficial properties and are saturated with mineral salts, while the shores are rich in mineral springs and peat mud deposits, which are used to improve the body. Also unique natural conditions: clean air with the scent of pine trees, the freshness of the sea breeze and gentle sand on the seashore. You can relax and improve your health in sanatoriums, mud baths and mineral springs. Especially popular are the sanatorium complexes of Kołobrzeg in Poland.

5. Natural beauty of the Baltic coast

The resorts of the southern countries are notable for their tropical splendor, fun and incendiary discos and parties. But northern nature The amber region also has its own unique charm.

Everything is different here: a pleasant climate, picturesque landscapes, coniferous forests and sand dunes. And walking along the coast after a storm, you can find sunny pieces of amber - an unusual and mysterious stone.

The cities of the Baltic coast have preserved the atmosphere of antiquity and cozy quiet streets. There are many natural and historical attractions.

The Baltic Sea is one of those that washes the borders of our homeland. It has long been associated with the North, inflexibility and inflexibility. No wonder in the old days it was called Varangian. It occupies an area of ​​386 thousand square kilometers, deeply digging into the land and connecting with the Atlantic Ocean through the North Sea only through narrow straits - Øresund, Greater and Lesser Belts, Kattegat.

But despite all the seeming severity, the Baltic Sea remains favorite place recreation for many Russians, residents of the Baltic countries, Finland, Sweden. The main secret is simple - you just need to know what water temperature prevails in one or another time of the year.

The main resorts of this coast are Narva, Jurmala, Sestroretsk, Zelenogradsk, Sopot. Many tourists come here every year to improve their health and relax on the sea coast. The water temperature in the Baltic Sea, of course, is not as high as in the Black, Mediterranean or, even more so, in the Red Sea. However, even here there is the concept of a resort bathing season. It doesn't last long. It usually falls during the summer months, when the water temperature of the Baltic Sea can reach a record high of 24 degrees Celsius. Then it's the bathers' turn. Usually this is the period from June to the end of July. At all resorts, this time varies slightly, moreover, in some of them, the swimming period in the sea is no more than 4-5 days a year. The fact is that the Baltic Sea is shallow near the coast, and therefore cools quickly. But tourists can always enjoy the cool fresh air, sandy beaches and forests that surround the coast.

Among other things, the Baltic Sea is famous for its thalassotherapy, that is, the use of algae, water and sea mud for cosmetic and health purposes. This resort area is especially developed, since it is here that the water temperature in the Baltic Sea reaches its highest point - this place warms up well. The second such resort, as if intended for tourists, is a closed bay of the same name.

But in general, if you are going to visit the Baltic Sea, the water temperature in summer is from 10 to 17 degrees. So keep this in mind if you are planning your spa holiday program. But besides swimming, there is always something to do there. Excursions to the Curonian Spit, Jurmala, mud treatment in Pärnu are especially good in this regard. It is also worth noting that, due to the peculiarities of the climate in the Baltic Sea, there is such a natural phenomenon as the meeting of fresh and salt water. In the vicinity of the town of Skagen, in Denmark, the North and Baltic Seas merge, forming a stunningly beautiful phenomenon of displacement of fresh and salt water by each other. The water temperature in the Baltic Sea in summer at this point does not exceed 9, but even the most sophisticated tourists should look at the struggle of the elements from the outside. Therefore, do not be afraid of the severity of the Baltic Sea, sometimes it is gentle and warm.

Deeply cut into the land, the Baltic Sea has a very complex outline of the coast and forms large bays: Bothnian, Finnish and Riga. This sea has land borders almost everywhere, and only from the Danish Straits (Great and Small Belt, Sound, Farman Belt) is it separated by conditional lines passing between certain points on their coasts. Due to the peculiar regime, the Danish Straits do not belong to the Baltic Sea. They associate him with North Sea and across it to the Atlantic Ocean. The depths above the rapids separating the Baltic Sea from the straits are small: above the Darser threshold - 18 m, above the Drogden threshold - 7 m. The cross-sectional area in these places is 0.225 and 0.08 km 2, respectively. The Baltic Sea is weakly connected with the North Sea and has limited water exchange with it, and even more so with the Atlantic Ocean.

It belongs to the type of inland seas. Its area is 419 thousand km 2, volume - 21.5 thousand km 3, average depth - 51 m, maximum depth - 470 m.

Bottom relief

The bottom relief of the Baltic Sea is uneven. The sea lies entirely within the shelf. The bottom of its basin is indented by underwater depressions, separated by hills and socles of islands. In the western part of the sea there are shallow Arkon (53 m) and Bornholm (105 m) depressions, separated by about. Bornholm. In the central regions of the sea, rather vast areas are occupied by the Gotland (up to 250 m) and Gdansk (up to 116 m) basins. North of about. Gotland lies the Landsort Depression, where the greatest depth of the Baltic Sea is recorded. This depression forms a narrow trench with depths of more than 400 m, which stretches from the northeast to the southwest, and then to the south. Between this trough and the Norrköping depression located to the south, an underwater hill stretches with depths of about 112 m. Further south, the depths again increase slightly. On the border of the central regions with the Gulf of Finland, the depth is about 100 m, with the Bothnian - about 50 m, and with the Riga - 25-30 m. The bottom relief of these bays is very complex.

Bottom relief and currents of the Baltic Sea

Climate

The climate of the Baltic Sea is of maritime temperate latitudes with features of continentality. The peculiar configuration of the sea and a significant length from north to south and from west to east create differences in climatic conditions in different areas of the sea.

The Icelandic low, as well as the Siberian and Azores anticyclones, most significantly affect the weather. The nature of their interaction determines the seasonal features of the weather. In autumn and especially winter time Icelandic Low and Siberian High interact intensively, which enhances cyclonic activity over the sea. In this regard, in autumn and winter, deep cyclones often pass, which bring with them cloudy weather with strong southwestern and western winds.

In the coldest months - January and February - average temperature air temperature in the central part of the sea is -3° in the north and -5-8° in the east. With rare and short-term intrusions of cold Arctic air associated with the strengthening of the Polar High, the air temperature over the sea drops to -30° and even to -35°.

In the spring-summer season, the Siberian High collapses, and the Baltic Sea is affected by the Icelandic Low, the Azores and, to some extent, the Polar High. The sea itself is located in a zone of low pressure, along which cyclones from the Atlantic Ocean are less deep than in winter. In this regard, in spring the winds are very unstable in direction and low in speed. Northerly winds usually cause cold spring on the Baltic Sea.

In summer, predominantly western, northwestern and southwestern weak to moderate winds blow. Associated with them is the cool and humid climate characteristic of the sea. summer weather. The average monthly temperature of the warmest month - July - is 14-15° in the Gulf of Bothnia and 16-18° in other areas of the sea. Hot weather is rare. It is caused by short-term inflows of warm Mediterranean air.

Hydrology

About 250 rivers flow into the Baltic Sea. The largest number waters are brought per year by the Neva - an average of 83.5 km 3, the Vistula - 30 km 3, the Neman - 21 km 3, the Daugava - about 20 km 3. The runoff is unevenly distributed across the regions. So, in the Gulf of Bothnia it is 181 km 3 /year, in Finland - 110, in Riga - 37, in the central part of the Baltic - 112 km 3 /year.

Geographical position, shallow water, complex bottom topography, limited water exchange with the North Sea, significant river runoff, and climate features have a decisive influence on hydrological conditions.

The Baltic Sea is characterized by some features of the eastern subtype of the subarctic structure. However, in the shallow Baltic Sea, it is represented mainly by surface and partially intermediate waters, significantly transformed under the influence of local conditions (limited water exchange, river runoff, etc.). The water masses that make up the structure of the waters of the Baltic Sea are not identical in their characteristics in different areas and change with the seasons. This is one of the distinguishing features of the Baltic Sea.

Water temperature and salinity

In most areas of the Baltic Sea, surface and deep water masses are distinguished, between which lies a transitional layer.

Surface water (0-20 m, in some places 0-90 m) with a temperature of 0 to 20°C, a salinity of approximately 7-8‰ is formed in the sea itself as a result of its interaction with the atmosphere (precipitation, evaporation) and with the waters of the continental runoff. This water has winter and summer modifications. In the warm season, a cold intermediate layer is developed in it, the formation of which is associated with a significant summer heating of the sea surface.

The temperature of deep water (50-60 m - bottom, 100 m - bottom) - from 1 to 15 °, salinity - 10-18.5‰. Her education is associated with entering the sea deep waters through the Danish Straits and with mixing processes.

The transitional layer (20-60 m, 90-100 m) has a temperature of 2-6°C, salinity of 8-10‰, and is formed mainly by mixing surface and deep waters.

In some areas of the sea, the structure of the waters has its own characteristics. For example, in the Arkon region, there is no cold intermediate layer in summer, which is explained by the relatively shallow depth of this part of the sea and the influence of horizontal advection. The Bornholm region is characterized by a warm layer (7-11°) observed in winter and summer. It is formed warm waters coming here from the slightly warmer Arkona basin.

In winter, the water temperature is somewhat lower near the coast than in the open parts of the sea, while it is slightly higher near the western coast than near the eastern one. Thus, the average monthly water temperature in February near Ventspils is 0.7°, at the same latitude in the open sea - about 2°, and near the western coast - 1°.

Water temperature and salinity at the surface of the Baltic Sea in summer

In summer, the temperature of surface waters is not the same in different parts of the sea.

The decrease in temperature near the western coasts, in the central and southern regions is explained by the predominance of westerly winds, driving the surface layers of water from the western shores. Colder underlying waters rise to the surface. In addition, a cold current from the Gulf of Bothnia passes along the Swedish coast to the south.

Clearly pronounced seasonal changes in water temperature cover only the upper 50-60 m; deeper, the temperature changes very little. In the cold season, it remains approximately the same from the surface to the horizons of 50-60 m, and deeper it drops somewhat to the bottom.

Water temperature (°С) on a longitudinal section in the Baltic Sea

In the warm season, the increase in water temperature as a result of mixing extends to horizons of 20–30 m. From there, it abruptly decreases to horizons of 50–60 m and then again rises somewhat towards the bottom. The cold intermediate layer persists in summer, when the surface layer warms up and the thermocline is more pronounced than in spring.

Limited water exchange with the North Sea and significant river runoff result in low salinity. On the sea surface, it decreases from west to east, which is associated with the predominant flow of river waters into the eastern part of the Baltic. In the northern and central regions of the basin, salinity somewhat decreases from east to west, since in cyclonic circulation, saline waters are transported from south to northeast along the eastern coast of the sea further than along the western one. A decrease in surface salinity can also be traced from south to north, as well as in bays.

AT autumn-winter season the salinity of the upper layers increases somewhat due to a reduction in river runoff and salinization during ice formation. In spring and summer, salinity on the surface decreases by 0.2-0.5‰ compared to the cold half-year. This is explained by the desalination effect of continental runoff and the spring melting of ice. Almost throughout the sea, a significant increase in salinity from the surface to the bottom is noticeable.

For example, in the Bornholm Basin, salinity at the surface is 7‰ and about 20‰ at the bottom. The change in salinity with depth is basically the same throughout the sea, with the exception of the Gulf of Bothnia. In the southwestern and partly central regions of the sea, it gradually and slightly increases from the surface to horizons of 30-50 m, below, between 60-80 m, there is a sharp layer of a jump (halocline), deeper than which the salinity again slightly increases towards the bottom. In the central and northeastern parts, salinity increases very slowly from the surface to 70–80 m horizons; deeper, at 80–100 m horizons, there is a halo wedge, and then salinity slightly increases to the bottom. In the Gulf of Bothnia, salinity increases from the surface to the bottom by only 1-2‰.

In autumn-winter time, the flow of North Sea waters into the Baltic Sea increases, and in summer-autumn it somewhat decreases, which leads to an increase or decrease in the salinity of deep waters, respectively.

In addition to seasonal fluctuations in salinity, the Baltic Sea, unlike many seas of the World Ocean, is characterized by its significant interannual changes.

Observations of salinity in the Baltic Sea from the beginning of this century until recent years show that it tends to increase, against which short-term fluctuations appear. Changes in salinity in the basins of the sea are determined by the inflow of water through the Danish Straits, which in turn depends on hydrometeorological processes. These include, in particular, the variability of large-scale atmospheric circulation. The long-term weakening of cyclonic activity and the long-term development of anticyclonic conditions over Europe lead to a decrease in precipitation and, as a consequence, to a decrease in river runoff. Changes in salinity in the Baltic Sea are also associated with fluctuations in the values ​​of continental runoff. With a large river runoff, the level of the Baltic Sea slightly rises and the sewage flow from it intensifies, which in the shallow zone of the Danish Straits (the smallest depth here is 18 m) limits the access of salt water from the Kattegat to the Baltic. With a decrease in river flow, saline waters more freely penetrate into the sea. In this regard, fluctuations in the inflow of saline waters into the Baltic are in good agreement with changes in the water content of the rivers of the Baltic basin. AT last years an increase in salinity is noted not only in the bottom layers of the basins, but also in the upper horizons. At present, the salinity of the upper layer (20-40 m) has increased by 0.5‰ compared to the average long-term value.

Salinity (‰) on a longitudinal section in the Baltic Sea

Salinity variability in the Baltic Sea is one of the most important factors regulating many physical, chemical and biological processes. Due to the low salinity of the surface waters of the sea, their density is also low and decreases from south to north, varying slightly from season to season. Density increases with depth. In the areas of distribution of saline Kattegat waters, especially in basins at the horizons of 50-70 m, a constant layer of a density jump (pycnocline) is created. Above it, in the surface horizons (20-30 m), a seasonal layer of large vertical density gradients is formed, due to a sharp change in water temperature at these horizons.

Water circulation and currents

In the Gulf of Bothnia and in the shallow area adjacent to it, a density jump is observed only in the upper (20-30 m) layer, where it is formed in spring due to freshening by river runoff, and in summer due to heating of the surface layer of the sea. A permanent lower layer of the density jump is not formed in these parts of the sea, since deep saline waters do not penetrate here and year-round stratification of waters does not exist here.

Water circulation in the Baltic Sea

The vertical distribution of oceanological characteristics in the Baltic Sea shows that in the southern and central regions the sea is divided by a density jump layer into upper (0-70 m) and lower (from 70 m to the bottom) layers. In late summer - early autumn, when weak winds prevail over the sea, wind mixing extends to horizons of 10-15 m in the northern part of the sea and to horizons of 5-10 m in the central and southern parts and serves as the main factor in the formation of the upper homogeneous layer. During autumn and winter, with an increase in wind speeds over the sea, mixing penetrates to horizons of 20–30 m in the central and southern regions, and up to 10–15 m in the east, since relatively weak winds blow here. As autumn cooling intensifies (October - November), the intensity of convective mixing increases. During these months, in the central and southern regions of the sea, in the Arkon, Gotland and Bornholm depressions, it covers a layer from the surface up to about 50-60 m. ) and is limited by the density jump layer. In the northern part of the sea, in the Gulf of Bothnia and in the west of the Gulf of Finland, where autumn cooling is more significant than in other areas, convection penetrates to horizons of 60-70 m.

The renewal of deep waters, the sea occurs mainly due to the inflow of the Kattegat waters. With their active inflow, the deep and bottom layers of the Baltic Sea are well ventilated, and with small amounts of salt water flowing into the sea at great depths, stagnation occurs in the depressions up to the formation of hydrogen sulfide.

The strongest wind waves are observed in autumn and winter in open, deep areas of the sea with prolonged and strong southwestern winds. Stormy 7-8-point winds develop waves up to 5-6 m high and 50-70 m long. In the Gulf of Finland, strong winds of these directions form waves 3-4 m high. In the Gulf of Bothnia, storm waves reach a height of 4-5 m. big waves come in November. In winter, with more strong winds the formation of high and long waves is prevented by ice.

As in other seas of the northern hemisphere, the surface circulation of the Baltic Sea has a general cyclonic character. Surface currents are formed in the northern part of the sea as a result of the confluence of waters emerging from the Gulf of Bothnia and the Gulf of Finland. The general flow is directed along the Scandinavian coast to the southwest. Going around on both sides about. Bornholm, he is heading through the Danish Straits to the North Sea. At the southern coast, the current is directed to the east. Near the Gulf of Gdansk, it turns north and moves along the eastern coast to about. Khnum. Here it branches into three streams. One of them goes through the Irben Strait to the Gulf of Riga, where, together with the waters of the Daugava, it creates a circular current directed counterclockwise. Another stream enters the Gulf of Finland and along its southern coast extends almost to the mouth of the Neva, then turns to the northwest and, moving along the northern coast, leaves the bay together with river waters. The third flow goes to the north and through the straits of the Aland skerries penetrates into the Gulf of Bothnia. Here, along the Finnish coast, the current rises to the north, goes around the northern coast of the bay and descends to the south along the coast of Sweden. In the central part of the bay, there is a closed circular counterclockwise current.

The speed of the permanent currents of the Baltic Sea is very low and is approximately 3-4 cm/s. Sometimes it increases to 10-15 cm/s. The current pattern is very unstable and is often disturbed by the wind.

The prevailing wind currents in the sea are especially intense in autumn and winter, and during strong storms their speed can reach 100-150 cm/s.

Deep circulation in the Baltic Sea is determined by the flow of water through the Danish straits. The inlet current in them usually passes to horizons of 10-15 m. Then this water, being denser, descends into the underlying layers and is slowly transported by the deep current, first to the east and then to the north. With strong westerly winds, water from the Kattegat flows into the Baltic Sea almost along the entire cross section of the straits. Eastern winds, on the contrary, intensify the outlet current, which extends to the horizons of 20 m, and the inlet current remains only near the bottom.

Due to the high degree of isolation from the World Ocean, the tides in the Baltic Sea are almost invisible. Fluctuations in the level of the tidal character in individual points do not exceed 10-20 cm. The average sea level experiences secular, long-term, inter-annual and intra-annual fluctuations. They can be associated with a change in the volume of water in the sea as a whole and then have the same value for any point in the sea. The secular level fluctuations (except for changes in the volume of water in the sea) reflect the vertical movements of the shores. These movements are most noticeable in the north of the Gulf of Bothnia, where the rate of land rise reaches 0.90-0.95 cm/year, while in the south the rise is replaced by the sinking of the coast at a rate of 0.05-0.15 cm/year.

In the seasonal course of the Baltic Sea level, two minima and two maxima are clearly expressed. The lowest level is observed in spring. With the arrival of spring flood waters, it gradually rises, reaching a maximum in August or September. After that, the level goes down. The secondary autumn low is coming. With the development of intense cyclonic activity, westerly winds drive water through the straits into the sea, the level rises again and reaches a secondary, but less pronounced maximum in winter. The height difference between the summer maximum and the spring minimum is 22-28 cm. It is greater in the bays and less in the open sea.

Surge fluctuations in the level occur quite quickly and reach significant values. AT open areas sea, they are approximately 0.5 m, and at the tops of bays and bays there are 1-1.5 and even 2 m. The combined effect of wind and a sharp change atmospheric pressure(during the passage of cyclones) cause seiche fluctuations in the level surface with a period of 24-26 hours. Level changes associated with seiches do not exceed 20-30 cm in the open part of the sea and reach 1.5 m in the Neva Bay. Complex seiche level fluctuations are one of the characteristic features regime of the Baltic Sea.

The catastrophic St. Petersburg floods are connected with sea level fluctuations. They occur when the level rise is due to the simultaneous action of several factors. Cyclones that cross the Baltic Sea from the southwest to the northeast cause winds that drive water from the western regions of the sea and overtake it into northeastern part Gulf of Finland, where the sea level rises. Passing cyclones also cause seiche fluctuations in the level, at which the level rises in the Aland region. From here, a free seiche wave, driven by western winds, enters the Gulf of Finland and, together with the surge of water, causes a significant increase (up to 1-2 m and even 3-4 m) in the level at its top. This prevents the flow of the Neva water into the Gulf of Finland. The water level in the Neva is rapidly rising, which leads to floods, including catastrophic ones.

ice coverage

The Baltic Sea is covered with ice in some areas. The earliest (around the beginning of November) ice forms in the northeastern part of the Gulf of Bothnia, in small bays and off the coast. Then the shallow areas of the Gulf of Finland begin to freeze. The maximum development of the ice cover reaches in early March. By this time, motionless ice occupies the northern part of the Gulf of Bothnia, the region of the Aland skerries and the eastern part of the Gulf of Finland. Floating ice occurs in the open areas of the northeastern part of the sea.

The distribution of fixed and floating ice in the Baltic Sea depends on the severity of the winter. Moreover, in mild winters, ice, having appeared, may completely disappear, and then appear again. In severe winters, the thickness of immobile ice reaches 1 m, and floating ice - 40-60 cm.

Melting begins in late March - early April. Liberation of the sea ice is coming from southwest to northeast.

Only in severe winters in the north of the Gulf of Bothnia, ice can be found in June. However, the sea is cleared of ice every year.

Economic importance

Freshwater fish species live in the significantly freshened waters of the bays of the Baltic Sea: crucian carp, bream, chub, pike, etc. There are also fish that spend only part of their lives in fresh waters, the rest of the time they live in the salty waters of the sea. These are now rare Baltic whitefish, typical inhabitants of the cold and clean lakes of Karelia and Siberia.

Especially valuable fish- Baltic salmon (salmon), which forms an isolated herd here. The main habitats of salmon are the rivers of the Gulf of Bothnia, the Gulf of Finland and the Gulf of Riga. She spends the first two or three years of her life mainly in the southern part of the Baltic Sea, and then goes to spawn in the rivers.

Purely marine fish species are common in the central regions of the Baltic, where salinity is relatively high, although some of them also enter fairly fresh bays. For example, herring lives in the Gulf of Finland and Riga. More saltwater fish - Baltic cod - do not enter the fresh and warm bays. Eel is a unique species.

In fishing, the main place is occupied by herring, sprat, cod, river flounder, smelt, perch and various types of freshwater fish.

1) Baltic Sea.
2) The Baltic Sea belongs to the basin of the Atlantic Ocean.
3). Its area is 415 thousand sq. km. For comparison, the Black Sea is 422 thousand sq. km., Azov, only 39 thousand sq. km. .sq.km. Beloe - 90 thousand sq. km. Karskoe - 883 thousand sq. km., Laptev Sea - 650 thousand sq. km., East Siberian - 901 thousand sq. km., Chukchi - 582 thousand sq. km. .km., Beringovo-2314 thousand sq. km., Okhotsk-1590 thousand sq. km. and Japanese - 978 thousand square kilometers. These are the seas washing Russia.
4)Temperature water in the Gulf of Finland in summer is 15-17 °C, in the Gulf of Bothnia 9-13 °C, in the center of the sea 14-17 °C. With increasing depth, the temperature slowly decreases. In winter, the average water temperature is + 6 * C.
5)If you look at the outlines of the sea, you can see its dissection. Its separate parts - Katgegat and the straits of the Small and Big Belt, form a natural transition between the Baltic and the North Sea, and in the north and east the bays adjoin the sea: Bothnian, Finnish and Riga.
6) The islands of the Baltic Sea - Muhu, Pel, Aland, Ven, Zeeland, Merket, Gotland, about, Haiumaa and others.
7) The Baltic Sea is an inland sea. Its volume is 21.5 thousand km³ , the average depth is 51 m, the greatest depth is 470 m. The deeper, the lower the temperature.
8) The salinity of the Baltic Sea is low, it has different layers in terms of salinity.
The salinity of surface waters is 7-8 ppm, at the bottom it is much saltier.
9) About a hundred rivers, large and small, flow into the Baltic Sea, of which
Neman, Vistula, Pregolya, Pene, Oder, Leba, Lielupe, Daugava, Pärnu, Narva, Ne-va, Turne-Elv and others.
10) Biological resources. - herring and cod, which make up about 90% of all production. In addition, flounder and salmon are caught. There are large stocks of crustaceans, as well as molluscs.
11) A large amount of chemical toxic waste has been dumped into the Baltic Sea. There are many ships sunk during the war, downed aircraft with undecontaminated ammunition., On the one hand, the waste waters of enterprises and factories are drained. And on the other hand, a huge amount of cargo is transported by sea and through it around the world.
12) The Baltic Sea is covered with ice in some places. . The largest ice cover is reached in early March, fixed ice occupies the northern part of the Gulf of Bothnia, the eastern part of the Gulf of Finland. And floating ice is in the center. In severe winters, the ice thickness reaches 1 m, and floating ice - 40-60 cm. Melting begins at the end of March, the sea is annually cleared of ice.
13) In question 10, the answer can be added that a lot of fish are still caught, such as salmon, herring, sprats.
14) Environmental problems are covered in question 11. It can be added that because of the runoff into the sea, a huge amount of algae began to grow in it, violating the ecosystem of the sea. Measures are needed to neutralize chemical waste from the sea.

The Baltic Sea is cool, however maximum temperatures water in some years reaches 24 °. The weather charts show a small amount comfortable weather related to the central summer months, however, even at this time, windy, cloudy and rainy days are frequent. At the resorts and tourist bases of the Gulf of Finland (near Leningrad) bathing season lasts an average of 1.5 months. The sea is shallow, so when the winds and air temperature drops, it quickly cools down. But sandy beaches and coastal forests are beautiful.

On the Estonian coast, swimming most often begins in June. But there are still few days when the water temperature stays above 17°C (4-5). In the Gulf of Pärnu, western and southwestern winds prevail, which contribute to the surge of warm surface waters from the shallow Gulf of Riga. The undulating nature of the bottom of the Pärnu Bay prevents warm surface water from escaping, even with winds from land. In the bay itself, the water warms up well. All this noticeably improves the conditions near the famous resort of Pärnu.

In the Gulf of Riga, especially in shallow parts near the coast, in June you can swim for 15-20 days.

July - best month for swimming almost everywhere in the European part of the USSR: the water in rivers and lakes warmed up and the difference in its temperature from north to south is the smallest in a year.

In the Baltic, the weather is unstable, capricious, and there are storms. So in Tallinn and Liepaja, swimming is only possible for 15 days, and in the southern parts of this coast - up to 28.

In August, at the beginning of the month, the water is warm, and by the end, a decrease in both air and water temperatures is already felt. From Leningrad to Tallinn in August they bathe for 18-23 days, the same number in the Gulf of Riga. Near Kaliningrad, thalassotherapy is possible for almost the entire month of August (27-31 days). In this area, especially favorable conditions for swimming near the resort of Svetlogorsk, where the sea is shallow.

In early September, with a continuing decrease in the arrival of solar heat and a drop in air and water temperatures, especially significant in the north, compared to southern parts territory, in the Baltic the swimming season ends even in its southernmost parts (the zone and resorts near Kaliningrad). Sometimes, however, when the weather is calm and warm, they continue to swim here even in the first September days. Here, on average, the swimming season lasts about two months.

A unique place with highly favorable conditions for water activities, in particular for sailing and swimming, is the Curonian Spit in Lithuania. Magnificent are its high dunes, beaches made of fine sand well warmed by the sun, forests descending to the very water. Particularly stringent environmental protection measures and visitor restrictions are being implemented here due to the danger of increased sand blowing and the occurrence of sand drifts, which can greatly affect settlements, forests and numerous wild animals here.

The special value of such places as Juodkrante, Nida, Rybache, located on a narrow, 1.5-2 km, Curonian Spit, lies in the fact that, depending on the temperature of the water, air and wind speed, you can swim, go in for water sports and sunbathe as in the relatively deep-water Baltic Sea and on its shores, and in the shallower and wind-protected Curonian Lagoon, located between the spit and the mainland. This also allows you to use different wind speeds when sailing.

In summer, the water in the bay has more high temperature than on the high seas. In this regard, in the cool and windy 1962, the swimming season in the Nida region on the shore high seas lasted 30 days, and on the shore of the bay - 42 days. In the hot year of 1964 - 71 and 88 days, respectively. On average, the difference usually does not exceed half a month.

On the entire Baltic coast, due to the lack of heat, except for abnormally hot summers, as well as due to the shallow water of most beaches, during sunbathing and air bathing and swimming, it is necessary to use natural protection from frequent winds (trees, shrubs, sand dunes), as well as to build artificial protective devices (baths, solariums, changing rooms, closed bridges for getting off and out of the water, barriers with high reflectivity of sunlight, etc.). All this helps to create more comfortable conditions for thalassotherapy in the Baltic region.