How does the ocean climate differ from the sea climate? Maritime climate: definition, features, areas
Areas with a marine climate on Earth according to the Köppen classification
Maritime climate (oceanic climate) - climate of regions close to the sea, characterized by small daily and annual air temperature amplitudes, high humidity, cool summer and mild winter (in temperate latitudes ah), large clouds caused by intense cyclonic activity and strong winds. In a maritime climate, the onset of high and low temperatures is delayed (compared to areas with a continental climate) by 1-2 months, and spring can be colder than autumn. It is formed under conditions of the prevailing influence on the atmosphere of oceanic spaces.
Similar climate at least, in temperature range, also exists in tropical highlands even at a considerable distance from any coast. Typically, according to the Köppen climate classification, it is classified as CFB or Cwb (oceanic climate). The slight temperature fluctuation is not a result of proximity to coastline, slight temperature fluctuations between seasons also characterize tropical lowlands; But the highlands are high enough above sea level that one month of the year has an average temperature below 18 C and cannot be classified as a true tropical climate. Unlike actual oceanic climates, these places with humid high-altitude tropical climates can experience noticeable winter droughts, as in Mexico City. As with oceanic climates, winters are relatively warm and summers are relatively cool, so agricultural potential in oceanic climates and humid tropical climates is high mountain climate, almost identical. The oceanic climate is most dominant in Europe, where it extends much further than on other continents.
1. Precipitation
Precipitation occurs constantly in areas with an oceanic climate, with the exception of some tropical mountainous areas, which should be classified as tropical savanna or semi-desert climates (through the dry season in winter), but have low temperatures through the altitude position (according to the Koppen classification Cwb). According to some provisions of the Koppen classification system, part of the north- west coast The Pacific and south-central Chile are sometimes considered a type of Mediterranean climate (according to the Köppen classification Csb) through summer droughts.
2. Temperature
There are very large temperature variations in areas with oceanic climates; in low latitudes the climate is almost subtropical from a temperature point of view, but average temperature has a difference - cool, but not cold, winter and warm, but not hot, summer. Average temperature at the most warm month should not exceed 22 C, and at the most cold month should be higher than -3 C (Although American scientists interpret 0 C as a cold month). Weather conditions in the subpolar oceanic climate zone (according to the Köppen classification Cfc), has long but relatively mild winters (the coldest month is warmer than -3 C or 0 C) and short and cool summers (average temperature not lower than 10 C), and for four months climate examples include the coastal regions of Iceland in the Northern Hemisphere and the extreme south of Chile V Southern Hemisphere.
3. Additional information
UK has maritime climate, by dominance southwest winds from the Atlantic Ocean. The average annual temperature variation in the UK is only about 24 C. Although the west coast of Alaska has a maritime climate, the lack of an equally powerful warm Pacific Current in the upper mid-latitudes means that the region has generally colder winters, and has more rainfall in the form of snow. Another example is the coastal areas of south-eastern Western Australia.
4. Countries and regions with a temperate maritime climate
- Northern and Western France
- Western and northwestern parts of Germany
- Western Switzerland (low-lying areas)
- Northern Spain (so-called "Green Spain")
- Far North of Portugal
- Southwestern Norway
- Part of Denmark
- Northern Türkiye
- Tasmania, (Australia)
- Southern Victoria and New South Wales, (Australia)
- Western areas on the south coast of Western Australia
- Central Argentina
- Southern Chile
- Western Oregon, Washington and mid-coast Alaska (USA)
- Northwestern region of California (USA)
- Western British Columbia (Canada)
- Highlands in some tropical countries (e.g. highlands of the Indian subcontinent, Latin America, southern and central Africa, according to the Köppen classification Cwb)
- Part of Southern and South Eastern South Africa
- Some mountainous areas throughout southern Europe
- Parts of the Himalayas
Regions with an average winter temperature of between -3 C and 0 C have a maritime climate in all other respects.
Climate- This is a long-term weather regime characteristic of a particular area. It manifests itself in the regular change of all types of weather observed in this area.
Climate influences living and inanimate nature. Are closely dependent on climate water bodies, soil, vegetation, animals. Certain sectors of the economy, primarily agriculture, are also very dependent on climate.
Climate is formed as a result of the interaction of many factors: quantity solar radiation, arriving at the earth's surface; atmospheric circulation; the nature of the underlying surface. At the same time, climate-forming factors themselves depend on the geographical conditions of a given area, primarily on geographical latitude.
The geographic latitude of the area determines the angle of incidence of the sun's rays, obtaining a certain amount of heat. However, receiving heat from the Sun also depends on proximity to the ocean. In places far from the oceans, there is little precipitation, and the precipitation regime is uneven (in warm period more than in cold weather), cloudiness is low, winter is cold, summer is warm, the annual temperature range is large. This climate is called continental, as it is typical for places located in the interior of continents. A maritime climate is formed over the water surface, which is characterized by: a smooth variation in air temperature, with small daily and annual temperature amplitudes, large clouds, and a uniform and fairly large amount of precipitation.
The climate is also greatly influenced by sea currents. Warm currents warm the atmosphere in the areas where they flow. For example, the warm North Atlantic Current creates favorable conditions for the growth of forests in the southern part of the Scandinavian Peninsula, with most of the island of Greenland lying at approximately the same latitudes as the Scandinavian Peninsula, but outside the zone of influence warm current, all year round covered with a thick layer of ice.
A major role in climate formation belongs to relief. You already know that with every kilometer the terrain rises, the air temperature drops by 5-6 °C. Therefore, on the high mountain slopes of the Pamirs the average annual temperature- 1 °C, although it is located just north of the tropics.
The location of mountain ranges greatly influences the climate. For example, Caucasus Mountains retain wet sea winds, and on their windward slopes facing the Black Sea, significantly more precipitation falls than on the leeward ones. At the same time, the mountains serve as an obstacle to cold northern winds.
There is a dependence of climate on prevailing winds. On the territory of the East European Plain, for almost the entire year, they are dominated by westerly winds coming from Atlantic Ocean Therefore, winters in this area are relatively mild.
Districts Far East are under the influence of monsoons. In winter, winds from the interior of the mainland constantly blow here. They are cold and very dry, so there is little precipitation. In summer, on the contrary, winds bring a lot of moisture from the Pacific Ocean. In autumn, when the wind from the ocean subsides, the weather is usually sunny and calm. This is the best time of year in the area.
Climatic characteristics are statistical inferences from long-term weather observation series (in temperate latitudes 25-50-year series are used; in the tropics their duration may be shorter), primarily on the following basic meteorological elements: atmospheric pressure, wind speed and direction, temperature and air humidity, cloudiness and precipitation. They also take into account the duration of solar radiation, visibility range, temperature of the upper layers of soil and water bodies, evaporation of water from earth's surface into the atmosphere, the height and condition of the snow cover, various atmospheric phenomena and ground hydrometeors (dew, ice, fog, thunderstorms, snowstorms, etc.). In the 20th century climatic indicators included characteristics of elements heat balance the earth's surface, such as total solar radiation, radiation balance, heat exchange values between the earth's surface and the atmosphere, heat loss for evaporation. Complex indicators are also used, i.e. functions of several elements: various coefficients, factors, indices (for example, continentality, aridity, moisture), etc.
Climate zones
Long-term averages meteorological elements(annual, seasonal, monthly, daily, etc.), their amounts, frequency, etc. are called climate standards: corresponding values for individual days, months, years, etc. are considered as a deviation from these norms.
Maps with climate indicators are called climatic(temperature distribution map, pressure distribution map, etc.).
Depending on the temperature conditions prevailing air masses and the winds emit climatic zones.
The main climatic zones are:
- equatorial;
- two tropical;
- two moderate;
- Arctic and Antarctic.
Between the main zones there are transitional climatic zones: subequatorial, subtropical, subarctic, subantarctic. IN transitional belts air masses change with the seasons. They come here from neighboring zones, so the climate is sub equatorial belt in summer it is similar to the climate of the equatorial zone, and in winter - to the tropical climate; The climate of the subtropical zones in summer is similar to the climate of the tropical zones, and in winter - to the climate of the temperate zones. This is due to the seasonal movement of atmospheric pressure belts over the globe following the Sun: in summer - to the north, in winter - to the south.
Climatic zones are divided into climatic regions. For example, in the tropical zone of Africa, areas of tropical dry and tropical humid climate, and in Eurasia the subtropical zone is divided into areas of Mediterranean, continental and monsoon climate. In mountainous areas it is formed altitudinal zone due to the fact that the air temperature decreases with altitude.
Diversity of Earth's climates
The climate classification provides an orderly system for characterizing climate types, their zoning and mapping. Let us give examples of climate types that prevail over vast territories (Table 1).
Arctic and Antarctic climate zones
Antarctic and Arctic climate dominates in Greenland and Antarctica, where average monthly temperatures are below O °C. During the dark winter season, these regions receive absolutely no solar radiation, although there are twilight and auroras. Even in summer Sun rays fall onto the earth's surface at a slight angle, which reduces the efficiency of heating. Most of incoming solar radiation is reflected by the ice. In both summer and winter, the higher elevations of the Antarctic Ice Sheet experience low temperatures. The climate of the interior of Antarctica is much colder than the climate of the Arctic, because southern mainland is distinguished by its large size and altitude, and the Arctic Ocean moderates the climate, despite wide use pack ice. During short periods of warming in summer, drifting ice sometimes melts. Precipitation on ice sheets falls in the form of snow or small particles of freezing fog. Inland areas receive only 50-125 mm of precipitation annually, but the coast can receive more than 500 mm. Sometimes cyclones bring clouds and snow to these areas. Snowfalls are often accompanied by strong winds that carry significant masses of snow, blowing it off the slope. Strong katabatic winds with snowstorms blow from the cold glacial sheet, carrying snow to the coast.
Table 1. Climates of the Earth
Climate type |
Climate zone |
Average temperature, °C |
Mode and amount of atmospheric precipitation, mm |
Atmospheric circulation |
Territory |
|
Equatorial |
Equatorial |
During a year. 2000 |
Warm and humid equatorial air masses form in areas of low atmospheric pressure |
Equatorial regions of Africa, South America and Oceania |
||
Tropical monsoon |
Subequatorial |
Mainly during the summer monsoon, 2000 |
South and Southeast Asia, Western and Central Africa, Northern Australia |
|||
tropical dry |
Tropical |
During the year, 200 |
North Africa, Central Australia |
|||
Mediterranean |
Subtropical |
Mainly in winter, 500 |
In summer there are anticyclones at high atmospheric pressure; in winter - cyclonic activity |
Mediterranean, South coast Crimea, South Africa, South Western Australia, Western California |
||
Subtropical dry |
Subtropical |
During a year. 120 |
Dry continental air masses |
Interiors of continents |
||
Temperate marine |
Moderate |
During a year. 1000 |
Western winds |
Western parts of Eurasia and North America |
||
Temperate continental |
Moderate |
During a year. 400 |
Western winds |
Interiors of continents |
||
Moderate monsoon |
Moderate |
Mainly during the summer monsoon, 560 |
Eastern edge of Eurasia |
|||
Subarctic |
Subarctic |
During the year, 200 |
Cyclones predominate |
Northern edges of Eurasia and North America |
||
Arctic (Antarctic) |
Arctic (Antarctic) |
During the year, 100 |
Anticyclones predominate |
The Arctic Ocean and mainland Australia |
Subarctic continental climate is formed in the north of the continents (see. climate map atlas). In winter, arctic air prevails here, which forms in the regions high pressure. Arctic air spreads to the eastern regions of Canada from the Arctic.
Continental subarctic climate in Asia is characterized by the largest globe annual amplitude of air temperature (60-65 °C). The continental climate here reaches its maximum value.
The average temperature in January varies across the territory from -28 to -50 °C, and in the lowlands and basins due to stagnation of air, its temperature is even lower. In Oymyakon (Yakutia), a record negative air temperature for the Northern Hemisphere was recorded (-71 °C). The air is very dry.
Summer in subarctic belt although short, it is quite warm. The average monthly temperature in July ranges from 12 to 18 °C (daytime maximum is 20-25 °C). During the summer, more than half of the annual precipitation falls, amounting to 200-300 mm on the flat territory, and up to 500 mm per year on the windward slopes of the hills.
Climate subarctic belt North America is less continental compared to the corresponding climate in Asia. Less here Cold winter and colder summers.
Temperate climate zone
Temperate climate of the western coasts of the continents has pronounced features of a marine climate and is characterized by the predominance of marine air masses throughout the year. It is observed on Atlantic coast Europe and the Pacific coast of North America. The Cordillera is a natural boundary separating the coast with a maritime climate from inland areas. The European coast, except Scandinavia, is open to free access of temperate sea air.
Permanent transfer sea air is accompanied by heavy cloudiness and causes long springs, in contrast to the interior of the continental regions of Eurasia.
Winter in temperate zone It's warm on the western coasts. The warming influence of the oceans is enhanced by warm sea currents, washing the western shores of the continents. The average temperature in January is positive and varies across the territory from north to south from 0 to 6 °C. When arctic air invades, it can drop (on the Scandinavian coast to -25 °C, and on the French coast - to -17 °C). As tropical air spreads northward, the temperature rises sharply (for example, it often reaches 10 °C). In winter, on the western coast of Scandinavia, large positive temperature deviations from the average latitude (by 20 °C) are observed. The temperature anomaly on the Pacific coast of North America is smaller and amounts to no more than 12 °C.
Summer is rarely hot. The average temperature in July is 15-16 °C.
Even during the day, the air temperature rarely exceeds 30 °C. Due to frequent cyclones, all seasons are characterized by cloudy and rainy weather. Especially a lot cloudy days happens on the west coast of North America, where before mountain systems Cordillera cyclones are forced to slow down. In connection with this, great uniformity characterizes the weather regime in southern Alaska, where there are no seasons in our understanding. Eternal autumn reigns there, and only plants remind of the onset of winter or summer. Annual precipitation ranges from 600 to 1000 mm, and on the slopes of mountain ranges - from 2000 to 6000 mm.
In conditions of sufficient moisture on the coasts, developed broadleaf forests, and in conditions of excess - conifers. Lack of summer heat reduces upper limit forests in the mountains up to 500-700 m above sea level.
Temperate climate of the eastern coasts of the continents has monsoonal features and is accompanied seasonal change winds: in winter, north-western currents predominate, in summer - south-eastern ones. It is well expressed on the eastern coast of Eurasia.
In winter, cold continental temperate air spreads along the continental coast with the northwest wind, which causes low average temperatures winter months(from -20 to -25 °C). Predominantly clear, dry, windy weather. IN southern regions There is little precipitation along the coast. The north of the Amur region, Sakhalin and Kamchatka often fall under the influence of cyclones moving over the Pacific Ocean. Therefore, in winter there is a heavy snow cover, especially in Kamchatka, where it maximum height reaches 2 m.
In summer, temperate sea air spreads along the Eurasian coast with a southeast wind. Summers are warm, with an average July temperature of 14 to 18 °C. Frequent precipitation is caused by cyclonic activity. Their annual quantity is 600-1000 mm, with most of them falling in summer. Fogs are common at this time of year.
Unlike Eurasia, East Coast North America is characterized by maritime climate, which is expressed in the predominance of winter precipitation and marine type annual progress air temperatures: the minimum occurs in February, and the maximum in August, when the ocean is warmest.
The Canadian anticyclone, unlike the Asian one, is unstable. It forms far from the coast and is often interrupted by cyclones. Winter here is mild, snowy, wet and windy. IN snowy winters the height of the snowdrifts reaches 2.5 m. With a southerly wind, there is often black ice. Therefore, some streets in some cities in eastern Canada have iron railings for pedestrians. Summer is cool and rainy. Annual precipitation is 1000 mm.
Temperate continental climate most clearly expressed on the Eurasian continent, especially in the regions of Siberia, Transbaikalia, northern Mongolia, as well as in the Great Plains in North America.
Feature of moderate continental climate is the large annual amplitude of air temperature, which can reach 50-60 °C. During the winter months, with a negative radiation balance, the earth's surface cools. The cooling effect of the land surface on the surface layers of air is especially great in Asia, where in winter a powerful Asian anticyclone forms and partly cloudy, windless weather prevails. The temperate continental air formed in the area of the anticyclone has a low temperature (-0°...-40 °C). In valleys and basins, due to radiation cooling, the air temperature can drop to -60 °C.
In midwinter, the continental air in the lower layers becomes even colder than the Arctic air. This one is very cold air The Asian anticyclone extends to Western Siberia, Kazakhstan, and southeastern regions of Europe.
The winter Canadian anticyclone is less stable than the Asian anticyclone due to the smaller size of the North American continent. Winters here are less severe, and their severity does not increase towards the center of the continent, as in Asia, but, on the contrary, decreases somewhat due to the frequent passage of cyclones. Continental temperate air in North America has a higher temperature than continental temperate air in Asia.
On the formation of the continental temperate climate significant influence provide geographical features continental territories. In North America mountain ranges The Cordillera is a natural boundary separating the coast with a maritime climate from the inland areas with a continental climate. In Eurasia, a temperate continental climate is formed over a vast expanse of land, from approximately 20 to 120° E. d. Unlike North America, Europe is open to the free penetration of sea air from the Atlantic deep into its interior. This is facilitated not only by the westerly transport of air masses, which dominates in temperate latitudes, but also by the flat nature of the relief, highly rugged coastlines and deep penetration of the Baltic and North Seas into the land. Therefore, a temperate climate of a lesser degree of continentality is formed over Europe compared to Asia.
In winter, sea Atlantic air moving over cold surface sushi of temperate latitudes of Europe, retains its physical properties, and its influence extends throughout Europe. In winter, as the Atlantic influence weakens, the air temperature decreases from west to east. In Berlin it is 0 °C in January, in Warsaw -3 °C, in Moscow -11 °C. In this case, the isotherms over Europe have a meridional orientation.
The fact that Eurasia and North America face the Arctic basin as a broad front contributes to the deep penetration of cold air masses onto the continents throughout the year. Intense meridional transport of air masses is especially characteristic of North America, where arctic and tropical air often replace each other.
Tropical air entering the plains of North America from southern cyclones, also slowly transforms due to the high speed of its movement, high moisture content and continuous low clouds.
In winter, the consequence of intense meridional circulation of air masses is the so-called “jumps” of temperatures, their large inter-day amplitude, especially in areas where cyclones are frequent: in northern Europe and Western Siberia, Great Plains of North America.
During the cold period, they fall in the form of snow, a snow cover is formed, which protects the soil from deep freezing and creates a supply of moisture in the spring. The depth of the snow cover depends on the duration of its occurrence and the amount of precipitation. In Europe, stable snow cover on flat areas forms east of Warsaw, its maximum height reaches 90 cm in the northeastern regions of Europe and Western Siberia. In the center of the Russian Plain, the height of snow cover is 30-35 cm, and in Transbaikalia - less than 20 cm. On the plains of Mongolia, in the center of the anticyclonic region, snow cover forms only in some years. Lack of snow along with low winter temperature air determines the presence permafrost, which is not observed anywhere else on the globe at these latitudes.
In North America, snow cover is negligible on the Great Plains. To the east of the plains, tropical air increasingly begins to take part in frontal processes; it aggravates frontal processes, which causes heavy snowfalls. In the Montreal area, snow cover lasts up to four months, and its height reaches 90 cm.
Summer in continental areas Eurasia is warm. The average July temperature is 18-22 °C. In the arid regions of south-eastern Europe and Central Asia The average air temperature in July reaches 24-28 °C.
In North America, continental air in summer is somewhat colder than in Asia and Europe. This is due to the smaller latitudinal extent of the continent, the large ruggedness of its northern part with bays and fjords, the abundance of large lakes, and the more intense development of cyclonic activity compared to the interior regions of Eurasia.
In the temperate zone, the annual precipitation on the flat continental areas varies from 300 to 800 mm; on the windward slopes of the Alps more than 2000 mm falls. Most of the precipitation falls in summer, which is primarily due to an increase in the moisture content of the air. In Eurasia, there is a decrease in precipitation across the territory from west to east. In addition, the amount of precipitation decreases from north to south due to a decrease in the frequency of cyclones and an increase in dry air in this direction. In North America, a decrease in precipitation across the territory is observed, on the contrary, towards the west. Why do you think?
Most of the land in the continental temperate climate zone is occupied by mountain systems. These are the Alps, Carpathians, Altai, Sayans, Cordillera, Rocky Mountains, etc. In mountainous areas, climatic conditions differ significantly from the climate of the plains. In summer, the air temperature in the mountains drops quickly with altitude. In winter, when cold air masses invade, the air temperature on the plains is often lower than in the mountains.
The influence of mountains on precipitation is great. Precipitation increases on windward slopes and at some distance in front of them, and decreases on leeward slopes. For example, differences in annual precipitation between western and eastern slopes Ural mountains in some places they reach 300 mm. In mountains, precipitation increases with altitude to a certain critical level. In the Alps the level the largest number precipitation occurs at altitudes of about 2000 m, in the Caucasus - 2500 m.
Subtropical climate zone
Continental subtropical climate determined by the seasonal change of temperate and tropical air. The average temperature of the coldest month in Central Asia is below zero in some places, in the northeast of China -5...-10°C. The average temperature of the warmest month ranges from 25-30 °C, with daily maximums exceeding 40-45 °C.
The most strongly continental climate in the air temperature regime is manifested in the southern regions of Mongolia and northern China, where the center of the Asian anticyclone is located in the winter season. Here the annual air temperature range is 35-40 °C.
Sharply continental climate V subtropical zone for the high mountain regions of the Pamirs and Tibet, the altitude of which is 3.5-4 km. The climate of the Pamirs and Tibet is characterized by cold winter, cool summers and little rainfall.
In North America, the continental arid subtropical climate is formed in closed plateaus and in intermountain basins located between the Coast and Rocky Ranges. Summers are hot and dry, especially in the south, where the average July temperature is above 30 °C. The absolute maximum temperature can reach 50 °C and above. A temperature of +56.7 °C was recorded in Death Valley!
Humid subtropical climate characteristic of the eastern coasts of continents north and south of the tropics. The main areas of distribution are the southeastern United States, some southeastern parts of Europe, northern India and Myanmar, eastern China and southern Japan, northeastern Argentina, Uruguay and southern Brazil, the coast of Natal in South Africa and the eastern coast of Australia. Summer in humid subtropics long and hot, with temperatures similar to those in the tropics. The average temperature of the warmest month exceeds +27 °C, and the maximum is +38 °C. Winters are mild, with average monthly temperatures above 0 °C, but occasional frosts have an impact detrimental influence on vegetable and citrus plantations. In the humid subtropics, average annual precipitation amounts range from 750 to 2000 mm, and the distribution of precipitation across seasons is quite uniform. In winter, rain and rare snowfalls are brought mainly by cyclones. In summer, precipitation falls mainly in the form of thunderstorms associated with powerful inflows of warm and humid oceanic air, characteristic of the monsoon circulation of East Asia. Hurricanes (or typhoons) occur in late summer and fall, especially in the Northern Hemisphere.
Subtropical climate with dry summers, typical for the western coasts of continents north and south of the tropics. In Southern Europe and North Africa, such climatic conditions are typical for the coasts of the Mediterranean Sea, which is the reason for calling this climate also Mediterranean. Similar climate in southern California, central regions Chile, southernmost Africa and parts of southern Australia. All these areas have hot summers and mild winters. As in the humid subtropics, there are occasional frosts in winter. In inland areas in summer temperatures are significantly higher than on the coasts, and often the same as in tropical deserts. Overall predominates clear weather. In summer, there are often fogs on the coasts near which ocean currents pass. For example, in San Francisco, summers are cool and foggy, and the warmest month is September. The maximum precipitation is associated with the passage of cyclones in winter, when the prevailing air currents mix towards the equator. The influence of anticyclones and downdrafts of air over the oceans cause the dry summer season. Average annual precipitation under conditions subtropical climate ranges from 380 to 900 mm and reaches maximum values on the coasts and mountain slopes. In summer, there is usually not enough rainfall for normal tree growth, and therefore a specific type of evergreen develops there. shrub vegetation, known as maquis, chaparral, mali, macchia and fynbos.
Equatorial climate zone
Equatorial climate type distributed in equatorial latitudes in the Amazon basins South America and Congo in Africa, on the Malacca Peninsula and on the islands of Southeast Asia. Usually average annual temperature about +26 °C. Due to the high midday position of the Sun above the horizon and the same length of day throughout the year, seasonal temperature fluctuations are small. Moist air, cloud cover and dense vegetation prevent night cooling and keep maximum daytime temperatures below 37°C, lower than at higher latitudes. The average annual precipitation in the humid tropics ranges from 1500 to 3000 mm and is usually evenly distributed over the seasons. Precipitation is mainly associated with the Intertropical Convergence Zone, which is located slightly north of the equator. Seasonal shifts of this zone to the north and south in some areas lead to the formation of two maximum precipitation during the year, separated by drier periods. Every day, thousands of thunderstorms roll over the humid tropics. In between, the sun shines in full force.
Seafood is one of the most valuable types of food due to its high content of easily digestible protein and microelements important for health. However, this same protein also has a downside: it is one of the most powerful and common food allergens. To the question whether a person can be intolerant to any of the seafood, the answer is clear: yes, maybe, and this type of allergy is very common. How to recognize it and how to deal with such a disease?
Causes of seafood allergies
First of all, a hyperreaction to seafood is associated with the highest concentration of protein in them. Protein compounds often provoke an allergic reaction in the body, and their increased concentration in food aggravates the situation. When receiving a large dose of specific proteins at once, the body may react inappropriately: increased production of histamine begins.
Risk group for this species intolerance are people who:
- are allergic to any other products/substances;
- diagnosed with bronchial asthma;
- There are allergy sufferers in the family.
Seafood as a class of allergens includes not only fish, shellfish and crustaceans living in the sea or ocean, but also seaweed edible (nori, seaweed). This should definitely be kept in mind by people who have a confirmed allergy to seafood. They should be careful when eating sushi and salads: they must first make sure that the dish does not contain sea plants.
Symptoms of allergy to seafood
Seafood intolerance usually manifests itself very quickly and severely. Most often, it refers to immediate allergic reactions, in which symptoms develop within a few seconds to several hours after contact with the substance.
There are three groups of symptoms:
- Gastrointestinal reaction. One of the main, but not obvious, symptoms of an allergy to seafood products is indigestion and abdominal pain. Sudden severe nausea and vomiting, stomach cramps, diarrhea, and flatulence may occur. This is not always recognized by a person as a manifestation of an allergy, but it can be part of the clinical picture and is often the very first sign of intolerance.
- Skin manifestations. Manifestations on the skin and mucous membranes include rash, swelling and itching. The rash may look like hives (spotty, all over the body) or blisters on a specific area of the skin. The rash is almost always accompanied by severe itching. Sometimes the eyes become red and swollen, and there is watery and itchy eyes. One of the most dangerous skin manifestations of a disease such as an allergy to shrimp and other seafood is tissue swelling. If it is swelling of the larynx, it can cause breathing problems, even stopping it.
- Respiratory symptoms. First of all, they are associated with the development of edema of the soft tissues of the larynx. Nasal congestion is also possible, accompanied by a runny nose with clear liquid discharge, itching in the nose and sneezing. An obsessive cough may begin, shortness of breath, wheezing, difficulty breathing may appear - these are quite serious symptoms that may indicate the onset of a severe systemic reaction.
The most dangerous types of allergic reactions are angioedema and anaphylactic shock. Both can lead to a serious condition, including death.
Therefore, if a person has:
- difficulty breathing;
- severe swelling of the face or limbs;
- sudden pallor, disturbances of consciousness;
- severe drop in blood pressure.
You should immediately call emergency help to stop the attack.
Due to the fact that seafood protein is a very strong allergen, a reaction can occur not only when eating it, but even to the smell of fish: watery eyes, itchy eyes, and a sore throat.
Diagnosis of seafood allergy
As a rule, with a quick and pronounced reaction, the reason for it becomes obvious. If a person ate mussels and developed the symptoms described above, it is logical to assume that they caused the hyperreaction. However, to confirm the diagnosis in any case, you must consult an allergist.
There are three main ways to diagnose an allergy to a specific substance:
- skin allergy tests;
- provocative tests;
- blood analysis.
The main one is skin testing, since this method is both safe and informative. There is an application and scarification method for carrying them out. In both cases, suspected allergens are applied to the skin of the forearm: with the application method, on the entire skin, and with the scarification method, the surface of the skin is lightly scratched so that the allergen gets into the subcutaneous space. The severity of the skin reaction in the test area is used to determine whether the patient is allergic.
Provocative tests carry a higher risk because they involve direct contact of the affected area with the allergen under the supervision of a specialist: for example, if a hyperreaction occurs in the eyes, the doctor instills a solution containing the antigen into the patient’s eye and monitors subsequent manifestations.
A venous blood test shows the concentration of immunoglobulins that accompany allergies. also in laboratory conditions They observe the reaction that the test blood enters into with the suspected allergen, on the basis of which a conclusion is made about possible intolerance.
Treatment and prevention
We talk about treatment when the manifestations of the allergy are obvious and its cause is precisely established. Allergy treatment includes two main areas:
- Symptom relief. First of all, it is necessary to relieve acute manifestations of the body’s hyperreaction. The choice of drugs depends on the clinical picture. These are usually antihistamines that are taken orally. If there are skin manifestations, you can supplement the medications with external agents: gels, ointments. In more severe cases, drugs and/or ointments with corticosteroids are prescribed.
- Allergen elimination. If hypersensitivity to any seafood occurs, all types of seafood are immediately excluded from the diet. That is, if you are allergic to squid, then you should not eat any other seafood, including sea plants. If the manifestations of hypersensitivity were strong, it is advisable to avoid even inhaling seafood odors and not to cook them in the presence of an allergic person.
It should also be borne in mind that an allergic reaction does not appear on the first contact with the provocateur, but on the second. Accordingly, if you once tried oysters and there was no negative reaction, this does not mean that you are not allergic to these seafood. There is always a possibility that if you use them again, the allergy will still manifest itself. It should also be borne in mind that an allergy to seafood usually includes all types at once, that is, if you react to a salad with octopus, most likely you will also be allergic to shrimp, as well as all other seafood.
It is impossible not to mention such a method of treating allergies as ASIT - allergen-specific immunotherapy. In this case, we can talk specifically about treating allergies, and not about relieving symptoms. The essence of the method is to regularly introduce low doses of the allergen into the patient’s body with a gradual increase, as if accustoming the immune system to a new substance. This method often allows you to achieve remission of allergies.
However, only a qualified specialist can make a decision about the possibility of therapy, based on many factors.
An allergic reaction to seafood is one of the most common and unpleasant types of food allergies. However, if proper therapy is prescribed and subsequent avoidance of contact with allergens, it is quite possible to never encounter its unpleasant manifestations again.
To indicate surface or underwater hazards, ensure navigation along fairways and determine the vessel’s position in coastal areas, means are displayed navigation equipment(SNO).
Depending on the location of installation, aids to navigation can be coastal or floating.
Coastal ones include beacons, lights, signs, radar stations, as well as acoustic fog alarms.
Lighthouses are special structures from 10 to 50 meters high, equipped with powerful light-optical equipment.
The lights of the lighthouses are lit from sunset to sunrise, the visibility range is at least 10 miles.
Navigation marks– lighthouse-type structures, but of a lighter design. The visibility range of the lights is up to 10 miles.
The gate signs are constructed in the form of lattice towers, on which a wooden gate shield is mounted. The alignments formed by the alignment marks are installed to guide the vessel along the fairway, as well as to determine compass corrections. Floating aids to navigation are installed at anchors near the danger or at the danger itself: signs, buoys and milestones.
Floating warning signs warn boatmasters about the presence of danger, prohibit movement in their direction and indicate a safe route.
The system provides five types of signs
1. Lateral signs. These signs (buoys and stakes) are placed to mark the sides of fairways.
The world's oceans are divided into two regions: region A and region B, which differ in the principle of using red and green colors to mark the sides of the fairway with lateral signs.
Countries that have adopted a red color for navigation aids on the left side of the fairway belong to Region A; countries that have adopted the green color of the navigation aid on the left side of the fairway are in region B. In this case, the direction of the fairway in both regions is considered from the sea. The remaining types of signs are common to regions A and B.
Region A. On the left side (Fig. 17.20) signs are displayed, completely painted in red, the top figures look like a red cylinder, the luminous buoy has a red fire. The nature of the fire is Pr 3s (flashing, period 3s).
On the right side (of the figure) signs are placed, completely painted in green, the top figures look like a green cylinder, the luminous buoy has a green fire. Character of fire – Pr 3s.
In some cases, the direction of the fairway is specifically specified. Numbers or letters can be applied to the bodies of the buoys, and the numbering or designation of the buoys with letters is carried out from the sea.
Where fairways separate To indicate the main (preferred) fairway, modified lateral signs are used.
Main fairway on the right – the color of the signs is red with a wide green horizontal stripe, the top figure is in the shape of a red cylinder, the luminous buoy is red. The nature of the fire is Pr (2+1) 9s (complex group flashing, period 9 seconds).
Main fairway on the left– the color of the signs is green with a wide red horizontal stripe, the top figure is in the shape of a green cone, the luminous buoy is green. Character of fire – Pr (2+1) 9s.
Region B. The lateral marks displayed on the left and right sides of the fairway are illuminated with green and red lights respectively.
Region A
Left side sign
Right side sign
Region B
Left side sign
Right side sign
Sign indicating that the main fairway is on the left
Sign indicating that the main fairway is on the right
They are used to protect isolated navigational hazards, as well as sunken ships. These signs indicate the direction (on the compass) from which the ship must avoid the danger. They can be placed in one, several or all sectors from danger. For fencing, buoys and poles of black and yellow color are used in various combinations (Fig. 17.28).
The top figures are two black cones placed one above the other. The light of the luminous buoys is white.
Northern buoys and milestones are placed in the northern sector to the N of danger. The signs are black at the top and yellow at the bottom. The top figures are cones with their vertices up. The nature of the fire is F (frequent).
Eastern buoys and milestones are deployed in the eastern sector to E from danger. The signs are black with a wide yellow horizontal stripe. The top figures are cones with their bases together. The nature of the fire is H (3) 10 s (three frequent flashes in a group, period 10 s).
Southern buoys and poles are placed in the southern sector to the S of danger. The signs are yellow at the top and black at the bottom. The top figures are cones with their vertices together. The nature of the fire is H (6) DlPr 15 s (six frequent flashes in a group with a long flash, period 15 s).
Western buoys and milestones are deployed in the western sector to the W of danger.
The signs are yellow with a wide black horizontal stripe. The top figures are cones with their vertices together. The nature of the fire is H (9) 15 s (nine frequent flashes in a group, period 15 s).
Signs protecting individual minor hazards.
They are positioned above the danger and can be bypassed from any side. The signs are painted black with one or more red wide horizontal stripes (Fig. 17.29). The top pieces are two black balls placed one above the other. The luminous buoy has White color. Character of fire – Pr (2) 5s.
3. Signs indicating the starting points and axis of the fairway(channel) and the middle of the passage (axial). Signs (buoys and milestones) are painted with red and white vertical stripes (Fig. 17.30). The top figure looks like a red ball. The luminous buoy has a white flame. The nature of the fire is DlPr 6s (long-flash, period 6 seconds).
They are used to mark or fence special areas or objects, for example, cable laying sites, etc.
The signs are painted yellow. Top figures - oblique cross yellow color. The luminous buoy has a yellow fire, the nature of the fire is Pr 5c.
Signs protecting certain dangers
Hello Dear friends! It's time again for some new and interesting information. 🙂 I think that an article on the topic of what types of climate there are will help you decide on a vacation in all seasons.
In winter, rain and rare snowfalls are mainly caused by cyclones. Hurricanes (or typhoons) occur in late summer and autumn, especially in the Northern Hemisphere.
This type of climate is typical of the west coast of continents in the south and north of the tropics. In North Africa and Southern Europe, such climatic conditions are characteristic of the Mediterranean coast, which also allows this climate to be called Mediterranean.
This type of climate is also found in central Chile, southern California, the extreme south of Africa and in several areas in southern Australia.
In these areas, summers are hot and winters are mild. In winter, just as in the humid subtropics, there are occasional frosts.
In the summer, temperatures in inland areas are significantly higher than on the coast, and are often the same as in tropical deserts. Also in summer, fog often occurs on the coast near which ocean currents pass.
The passage of cyclones in winter, when westerly air currents shift toward the equator, is associated with maximum precipitation. The dryness of the summer season is determined by the influence of anticyclones and declining air flows over the oceans.
In a subtropical climate, the average annual precipitation ranges from 380 mm to 900 mm, and reaches maximum values on the mountain slopes and on the coast.
In summer, there is usually not enough rainfall for normal tree growth, so a specific type of evergreen shrubby vegetation develops there, known as mali, maquis, macchia, chaparral and fynbos.
Semiarid climate of temperate latitudes.
A synonym for this type of climate is steppe climate. It is mainly characteristic of inland areas that are distant from the oceans - sources of moisture - and mainly located in the rainy shadow of high mountains.
The main areas with a semiarid climate are the Great Plains and intermountain basins of North America and the steppes of central Eurasia. Its inland location in temperate latitudes results in cold winters and hot summers.
The average temperature is below 0°C in at least one winter month, and the average temperature of the warmest summer month exceeds 21°C. Depending on the latitude, the temperature regime and the duration of the frost-free period change significantly.
The term “semiarid” is used to characterize this climate, because this climate is less dry than the arid climate proper. The annual amount of precipitation is partly more than 500 mm, but not less than 250 mm.
Since for the development of steppe vegetation in conditions more high temperatures more precipitation is needed; the latitudinal-geographical and altitudinal position of the area determine climatic changes.
Throughout the year, the general patterns of precipitation distribution for semiarid climate does not exist. For example, in those areas adjacent to areas of humid continental climate, precipitation occurs mainly in the summer, and in areas bordering the subtropics with dry summers, maximum precipitation occurs in winter.
Most of the winter precipitation comes from mid-latitude cyclones. They often fall in the form of snow and can also be accompanied by strong winds. Summer thunderstorms often include hail.
Semiarid climate of low latitudes.
This type of climate is characteristic of the edges of tropical deserts (for example, the deserts of central Australia and the Sahara), where downward air currents in subtropical zones high pressure prevents precipitation.
This climate differs from the semiarid climate of temperate latitudes warm winter and very hot summers. Average monthly temperatures are above 0°C, although sometimes there are frosts in winter, especially in those areas that are furthest from the equator and located at high altitudes.
Here, the amount of precipitation that is necessary for the existence of closed natural herbaceous vegetation is higher than in temperate latitudes. On the outer (southern and northern) outskirts of deserts, maximum precipitation falls in winter, while in the equatorial line rain falls mainly in summer.
Precipitation mainly falls in the form of thunderstorms, and in winter the rains are brought by cyclones.
Arid climate of temperate latitudes.
This type of climate is mainly characteristic of the Central Asian deserts, and in the west - only for small areas in intermountain basins.
The temperatures here are the same as in the semiarid climate regions, but there is not enough precipitation for the existence of a closed natural vegetation cover and usually the average annual precipitation does not exceed 250 mm.
The amount of precipitation, which determines aridity, as in semiarid conditions, depends on the temperature regime.
Arid climate of low latitudes.
This is a dry and hot tropical desert climate that stretches along the Southern and Northern Tropics, and is influenced by subtropical anticyclones for a significant part of the year.
Only in the mountains or on the coast, which is washed by cold ocean currents, can one find salvation from the debilitating summer heat. Summer temperatures on the plains noticeably exceed 32°C, and winter temperatures, as a rule, are above 10°C.
The average annual precipitation in most of this climatic region does not exceed 125 mm. It even happens that for several years in a row for many weather stations No precipitation is recorded at all.
The average annual precipitation can reach 380 mm, but this is only sufficient for the development of sparse desert vegetation.
Along western shores Africa and South America, where precipitation and cloud formation are hampered by cold ocean currents, are the driest areas.
Fogs are a common occurrence on this coast. They are formed by the condensation of moisture in the air over the colder surface of the ocean.
Variable humid tropical climate.
Areas of this type of climate are tropical sublatitudinal zones several degrees south and north of the equator. This climate is also called tropical monsoon climate because it prevails in those parts of South Asia that are under the influence of monsoons.
Other areas of this type of climate are the tropics Northern Australia, Africa, South and Central America. Average temperatures in winter are around 21°C, and in summer they are usually around 27°C. As a rule, the most hot month preceded summer season rains.
The average annual precipitation ranges from 750 mm to 2000 mm. The intertropical convergence zone has a decisive influence on the climate during the summer rainy season. There are often thunderstorms here, and sometimes, for a long period, there is continuous cloudiness with lingering rains.
Since this season is dominated by subtropical anticyclones, winter is dry. Rain in some areas does not fall for two or three winter months. The wet season in South Asia coincides with the summer monsoon, which Indian Ocean brings humidity, and in winter the Asian continental dry air mass spreads here.
This climate is also called a humid climate. tropical forests. It is distributed in equatorial latitudes in the Amazon basin in South America and the Congo in Africa, on the islands of Southeast Asia and on the Malacca Peninsula.
The average temperature of any month in the humid tropics is at least 17°C, and the average monthly temperature is about 26°C. As in the variably humid tropics, due to the same length of day throughout the year and the high midday solstice above the horizon, seasonal temperature fluctuations are small.
Dense vegetation cover, cloudy and wet air interfere with nighttime cooling and maintain maximum daytime temperatures below 37°C. In the humid tropics, the average annual precipitation ranges from 1500 mm to 2500 mm.
Precipitation is predominantly associated with the intertropical convergence zone, which is located slightly north of the equator. In some areas, seasonal shifts of this zone to the south and north lead to the formation of two maximum precipitation throughout the year, which are separated by drier periods. Thousands of thunderstorms pass over the humid tropics every day.
Highland climate.
Significant in high mountain areas is due to the latitudinal geographic position, different exposures of slopes in relation to moist air currents and the Sun, and orographic barriers.
Sometimes, even at the equator, snow falls in the mountains. Bottom line eternal snow descends towards the poles, reaching sea level in the polar regions. The windward slopes of mountain ranges receive more precipitation.
A decrease in temperature can be observed on mountain slopes that are open to cold air intrusions.
In general, this type of climate is characterized by higher cloud cover, lower temperatures, more complex wind patterns and greater precipitation than lowland climates at similar latitudes. Precipitation patterns and seasonal changes here it is usually the same as on the adjacent plains.
This was a description of climate types, which, I hope, greatly helped you understand this issue. See you again on the blog pages!