An anticyclone is a horizontal air vortex whose central pressure is higher than the surrounding pressurePneumatic systemHigh pressure in.In the anticyclone of the Northern Hemisphere, the horizontal airflow at the lower level isClockwiseoutwardDivergenceThe anticyclone in the southern hemisphere diverges counterclockwise.The horizontal scale of an anticyclone is larger than that of a cyclone, such as Mongolia in winterSiberian highIt occupies 1/4 of the area of Eurasia.Each anticycloneCentral air pressureThe value is generally 1020~1060hPa, and the highest pressure recorded is 1101.6hPa.The wind speed is small in the anticycloneMaximum wind speedIt is only 20-30m/s, and the wind in the central area is weak.Under the control of the anticyclone, the weather is mostly sunny.
backcycloneOfCentral air pressuremosthigh, graduallyOutsideDeliverreduce。In the Northern Hemisphere, the air in the anticyclone region flows clockwise.Its diameter ranges from several hundred kilometers in small to five or six thousand kilometers in large, such as the Mongolia Siberia High in winter and the Pacific Ocean in summerSubtropical zoneHigh pressure.As the air in the anticyclone diffuses around, the downdraft is formed.Therefore, when an anticyclone controls the local area, the weather is generally good.More wintersClear and cold weather, sunny and hot in summerHigh temperature weatherIn spring and autumn, the weather is sunny, sunny and crisp.
Chinese name
Anticyclone
Foreign name
anticyclone
Alias
High barometric pressure
Features
The central air pressure is higher than the surrounding air pressure
Type
Horizontal air vortex
Northern Hemisphere
The horizontal airflow at the lower level is clockwise
Anticyclone is also called high pressure.Cyclone and anticyclone are two aspects of a system.[4]An anticyclone is a horizontal air vortex that occupies three dimensions of space and has a higher central pressure than its surroundings, also known as high pressure.The names of cyclone and anticyclone come from the atmospheric flow field, while the names of high pressure and low pressure come from the pressure field.The size of cyclones and anticyclones is measured by the range of the outermost closed isobars on the ground map.The horizontal scale of a cyclone is generally 1000 km, with the largest reaching 2000 – 3000 km and the smaller only 200 – 300 km.The horizontal scale of an anticyclone is generally much larger than that of a cyclone. The strength of a cyclone that can reach thousands of kilometers in a strong development and the intensity of an anticyclone are expressed by the value of the central pressure. The lower the central pressure of a cyclone, the greater the intensity;The higher the central pressure of the anticyclone, the greater the intensity.
Generally, the central pressure of surface cyclones ranges from 1010 to 970 hPa, which can be lower than 935 hPa for strong cyclones, and 920 hPa for ocean cyclones.The central pressure of surface anticyclone is generally 1020-1030hPa, and it can reach 1079.1hPa if it is strong.In the Northern Hemisphere, the air rotates counterclockwise around the center in a cyclone, and clockwise around the center in an anticyclone.In the southern hemisphere, the air flow is opposite.Cyclones can be divided into extratropical cyclones and tropical cyclones according to the occurrence area, and anticyclones can be divided into polar anticyclones, extratropical anticyclones andsubtropical anticyclone 。Cyclone and anticyclone are two important weather systems that cause weather changes.Extratropical cyclones and anticyclones occur in the middle and high latitudes, accompanied by the upper frontal zone.Their occurrence, development and movement are closely related to the high-altitude weather system.[1]
In the low-pressure atmosphere, especially near the ground, because the anticyclone airflow rotates outward from the center.Therefore, there must be downdraft at the center of the anticyclone to supplement the air flowing outward.Otherwise, anticyclones cannot exist and develop.Therefore, the existence and development of an anticyclone must have a complete circulation system that closely combines vertical and horizontal movements.The downdraft at the center of the anticyclone is not conducive to the formation of clouds and rain.Therefore, the weather under the control of an anticyclone is generally sunny and cloudless.In summer, the weather is hot and dry.If the anticyclone is stable and inactive for a long time, drought often occurs.
An anticyclone is a large-scale air vortex occupying three-dimensional space.In the Northern Hemisphere, the airflow in the anticyclone area rotates clockwise from the center outward, and counterclockwise in the Southern Hemisphere.The air flow near the surface of the anticyclone radiates from the center to the surroundings in the horizontal direction, and the air in the vertical direction supplements from top to bottom.The air temperature rises during the sinking process, and the water vapor is not easy to condense.The calm weather and obvious inversion layer phenomenon under the control of anticyclone are also not conducive to the diffusion of pollutants in the atmosphere.[4-5]
Strength classification
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Intensity of anticyclone
The strength of anti cyclones varies.Its strength can be measured by its maximum wind speed: a large maximum wind speed means strong, and a small maximum wind speed means weak.In a strong anticyclone, the maximum wind speed on the ground is 20-30 m/s.
The central pressure of anticyclones is often used to indicate their strength.The central pressure of the surface anticyclone is generally 1020-1030 mbar, and the highest cold wave pressure in winter was over 1078.9 mbar.
Classification of anticyclones
There are many classification methods for anticyclones. According to the geographical location where they are generated, anticyclones can be divided into extratropical anticyclonessubtropical anticyclone andPolar anticyclone。
According to different structures, anticyclones can be divided into cold anticyclones (orCold high pressure）Warm anticyclone (orWarm high pressure）。
There is no insurmountable gap between cyclones.Different types of cyclones and anticyclones;They will transform each other under certain conditions.For example, a frontal cyclone can be transformed into a frontless cyclone (cold vortex) under certain conditions, and a frontless cyclone (hot low pressure) can be transformed into a frontal cyclone under certain conditions;Cold anticyclones can also be transformed into warm anticyclones.Both cyclones and anticyclones should be regarded as conditional, changeable and mutually transformative.
type
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Anticyclones are divided intocold anticyclone （Cold high pressure）Warm anticyclone（Warm high pressure）。Cold high pressure (such as XiboLeah high pressure）Generally, the intensity is reduced to very weak at the height of 3~4km, warm high pressure (such asSubtropical high)It is a deep system that can extend toTropopause。Anticyclone press
The generated geographical locations are divided intoextratropical anticyclone 、subtropical anticyclone andPolar anticyclone。According to the structure of anticyclone, it can be divided into cold anticyclone (cold high pressure) and warm anticyclone (warm high pressure).
Extratropical cold anticyclones and cold waves
Anticyclone
In the winter half year, the surface of the continent is cooled by intense radiation, and the air gathers on the continent to form a cold high pressure.Mongolia Siberian High over Eurasia in WinterIs the most powerful and influential in the worldCold high pressure, itsThe area of influence can reach Italy in central Europe to the west and Nansha Islands in China to the southeast, resulting in strong wind and cooling weather in the area.At the leading edge of cold air andWarm airRainfall and/or snow weather will be formed at the intersection, and sunny weather will be maintained when the main body of cold high pressure reaches the area.
extratropical anticyclone
The extratropical anticyclone refers to the anticyclone active in the middle and high latitudes.Generally, it can be divided into two types: one is relatively stable cold anticyclone;The other is an anticyclone that moves with a frontal cyclone, called a mobile anticyclone.
Cold anticyclones and cold waves
Cold anticyclones occur in extremely cold middle and high latitudes, such as Greenland, Canada, the Arctic, Siberia and Mongolia in the Northern Hemisphere, and are most common in winter.Its powerful force and wide range of influence often cause temperature drop, strong wind and precipitation in active areas, which is the most prominent weather process in winter in middle and high latitudes.
The cold anticyclone appears in the near surface layer and is composed of cold air, which is very powerful. The central pressure reaches 1030-1040hPa, and when it is strong, it reaches 1080hPa.According to the principle of statics, it weakens with height and becomes a cold low area at high altitude. Therefore, the cold high pressure is a shallow weather system with an average thickness of less than 3-4 km. The track above 700 hPa is not clear, and the track above 500 hPa is completely non-existent.The horizontal range of cold anticyclones is very large, with a diameter of thousands of meters, which can almost be compared with the area of continents and oceans.Asia is a vast continent, with low temperature in the northern part of the country in the winter half year, and the Qinghai Tibet Plateau and the east-west high mountains in the southern part of the country block cold air from moving southward, making it the region with the most frequent and powerful cold anticyclone activities in the northern hemisphere.Cold anticyclones are often stationary and inactive during their development and enhancement, but when the high-altitude situation changes, they will move under the guidance of high-altitude airflow.When it moves to the south, it will cause a cold air attack. If the cold air is very strong, like a cold tide rolling in, it will cause severe cooling, frost, strong wind and other disastrous weather in the area through which it flows. This large-scale strong cold air activity is called cold wave.
According to the regulations of the National Meteorological Administration of China, when the temperature drops by more than 10 ℃ within 24 hours due to the invasion of cold air, and the lowest temperature drops below 5 ℃, it is the standard for issuing cold wave warning.However, from the perspective of harmfulness, this standard is slightly higher, especially when the minimum temperature in the south often does not drop below 5 ℃, which will cause great harm to crops.At the same time, this regulation does not specify the scope of 10 ℃ temperature drop.Therefore, the National Meteorological Administration has made supplementary provisions to the above standards: the temperature in the middle and lower reaches of the Yangtze River and its northern areas drops by more than 10 ℃ within 48 hours, the minimum temperature in the middle and lower reaches of the Yangtze River is less than or equal to 4 ℃ (the minimum temperature in the Yangtze Huaihe River region is changed to be less than or equal to 4 ℃ in spring and autumn), and there is a force 5 gale in three major administrative regions on land,the bohai seaThe Yellow Sea and the East China Sea have gales of force 7 or above, which serve as the cold wave warning standard.If the temperature drops to more than 14 ℃ within 48 hours in the above areas, and the rest are the same as above, it is a strong cold wave alarm standard.According to the above standard statistics, there were 138 cold waves from 1951 to 1976 in China, with an average of about 5 times a year.
Cold wave mainly occurs from November to April. There are more cold waves in late autumn, early winter, late winter and early spring, but less cold waves in late winter. This is mainly because the definition of cold wave only considers the cooling range.Spring and autumn are just during the period of large-scale average circulation adjustment. The cold and warm air changes frequently, so there are many cold air activities. The cold air in winter is in an absolute dominant position in most regions of China. The weather situation is stable, and the cold air activities are relatively reduced.The cold air retreats to high latitude in summer, and China is seldom affected by it.The frequency of cold waves varies from year to year. Taking China as an example, there were 10 cold waves in 1965-1966 and 1968-1969, only one cold wave in 1974-1975, and only two cold waves in 1970-1971 and 1972-1973.In the late 1960s, there were an average of seven times a year, while in the early 1970s, there were only three times a year, which was quite different.[1]
stayNorthern and Southern HemispheresThe latitude range from 25 ° to 35 ° isSubtropical highzone。Due to the difference of land sea distribution and topography, the subtropical high fault is divided into several closed centers, that is, the subtropical high.Northern HemisphereSubtropical high beltstaySummer half yearSplit into: EastPacific high, Western Pacific High, North African High andNorth Atlantic High。Winter half yearyes:North Pacific High pressure, North Atlantic high pressure and North Africa high pressure.Subtropical high is strong in summer and weak in winter, and large in summer and small in winter.
Anticyclone on the left
Subtropical highIt is a stable, less dynamic, extremely deep warm high-pressure, with a wide range ofDowndraftUnder its control, the weather is sunny.Eastern ChinaIn the North PacificSubtropical highTo the west, it gradually expands westward and northward in summer, and transports water vapor with southeast wind direction to eastern China. It is one of the important water vapor sources of precipitation in eastern ChinaJianghuai River BasinThe heavy rain is closely related to it.In midsummer, such asSubtropical ridgeStretch toJianghuai regionThe downdraft on the ridge makes it difficult for water vapor to condense into clouds, instead, it is extremely hot and rainlessSummer droughtWeather.In winter, the North PacificSubtropical zoneHigh pressure directionHawaiiThe direction is narrowed and weakened, which has little impact on China's weather and climate.Similar phenomena to those in eastern China can also occur in the eastern part of the United States and the eastern coast of other continents in subtropical latitudes.
The mainland is controlled by the subtropical high all the year round,Climatic anomalyDry, forming world-famous deserts, such as Africasahara desert。
distribution
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The path of an anticyclone is not as clear as that of a cyclone.As the air sinks at 25 °~30 ° south and north latitudes, it diffuses near the ground to form an anticyclone, so it exists all year round on the oceansubtropical anticyclone 。On the mainland, subtropical anticyclones tend to develop well in winter months;In summer, due to the high temperature, various monsoon forms, and the anticyclone belt is broken.
Relevant knowledge
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cold wave
Anticyclone
cold waveIt's a kind of winterDisastrous weatherThe masses are used to calling the cold wavecold current。The so-called cold wave means that the cold air from the north has invaded China on a large scale to the south, causing a sharp cooling and northward movementgaleOfSynoptic process。Cold waves usually occur in late autumn, winter and early spring.According to the regulations of China's meteorological department, if the temperature drop caused by cold air intrusion reaches more than 10 ℃ in one day, and the minimum temperature is below 5 ℃, the cold air outbreak process is called a cold wave process.It can be seen that not every time cold air moves southward is called a cold wave.
In the Arctic, due to the weak sunlight, the ground and atmosphere get less heat, and it is ice and snow all the year round.In winter,sunlightThe cold degree in the Arctic region is stronger and the range is expanded. The temperature is generally below - 40 ℃ - 50 ℃.Wide rangeCold air massGather to a certain extent at a suitable heightatmospheric circulationUnder the action, it will invade southward on a large scale, formingCold Wave Weather。
China is located in the southeast of Eurasia.Going north from ChinaMongoliaAnd Siberia in Russia.Siberia is a place with a very cold climate. If you go further north, you will reach the northernmost region of the earth - the Arctic.Where compared toSiberiaThe area is colder and the cold period is longer.Affecting our countrycold waveIt was formed from those places.
Anticyclone
be locatedHigh latitudeOfArcticAnd SiberiaMongolian PlateauAround the region, it is affected all the year roundsunlightThe ground receives little heat from the sunlight due to oblique radiation.Especially in winter, when the sun light moves southward, the angle of sunlight in the northern hemisphere becomes smaller and smaller. Therefore, the sun heat absorbed by the ground becomes less and less, and the temperature of the ground surface becomes very low.In winterarctic oceanIn the region, the temperature is often below - 20 ℃, and can reach - 60 ℃ - - 70 ℃ at the lowest temperature.The average temperature in January is usually below - 40 ℃.Because the Arctic andSiberiaThe temperature in the area is very low, and the density of the atmosphere will increase greatly. The air will shrink and sink continuously, making the pressure increase. In this way, a powerful, deep and broadCold high pressureAir mass。When the cold and high pressure force increases to a certain extent, it will rush towards our country like the tide breaking the dike. This iscold wave。
every timeOutbreak of cold waveLater, the cold air in Siberia will be reduced, and the pressure will also be reduced.However, after a period of time, the cold air again gathers and accumulates, giving birth to a new cold wave.
Cold wave invasion path
According to statistics, about 95% of cold air passes throughSiberiaIn the middle part (70 °~90 ° E, 43 °~65 ° N), it accumulates and strengthens there.This area is called the key area of cold wave.There are four main ways to invade China from key areas:
（1） The northwest road (middle road) cold air flows from the key area through Mongolia to the south near Hetao in China and directly to the middle and lower reaches of the Yangtze River and Jiangnan region.The cold air following this path is generated in the area north of the Yangtze Rivercold waveThe weather is dominated by northerly gales and cooling. After arriving in the south of the Yangtze River, it may develop with rain and snow due to active fluctuations in the southern branch front.
（2） The cold air from the east road passes through Mongolia from the key area to the north of North China. While the main force of the cold air continues to move eastward, the low level cold air turns to the southwest, invades North China through the Bohai Sea, and then reaches the Lianghu Basin from the lower reaches of the Yellow River to the south.The cold air coming down this path often causes northeast gales in the Bohai Sea, the Yellow Sea, the lower reaches of the Yellow River and the lower reaches of the Yangtze River, and north and east Chinabackflow, the temperature is low, and there is continuous rainy and snowy weather.
（3） The cold air from the West Road passes through Xinjiang, QinghaiTibet PlateauThe southeast side goes down to the south, which has a great impact on the northwest, southwest and Jiangnan regions of China, but the cooling amplitude is not large. However, when the fluctuations of the southern branch front area and the northern branch front area are in the same phase and superimposed, they can also cause significant cooling.
（4） The cold air from the east road to the west road flows southward from the downstream of Hetao, and the cold air from the west road flows southeastward from Qinghai. The two cold air streams are often on the east side of the Loess Plateau,Yellow RiverThe confluence of the Yangtze River, the Yangtze River, and the confluence caused a wide range of rain and snow weather. Then the two cold air merged southward, resulting in strong wind and obvious cooling.[2]
Impact of cold wave
cold waveAnd strong cold airgaleCooling weather is the main weather in winter half year in ChinaDisastrous weather。Cold wave and strong wind pose a great threat to coastal areas, such as the cold wave and strong wind attack from April 21 to 25, 1969the bohai sea, Yellow Sea, Hebei, Shandong, Henan and other provinces, land wind force 7-8, sea wind force 8-10.Positive value at this timeAstronomical tide , the cold wave broke outBohai Bay、Laizhou BayRare in decadesStorm surge。In the north coast of Shandong, the sea water rose by more than 3 meters and destroyed more than 50 kilometers of seawalls,Seawater backflow30-40 km.
The rain, snow and freezing weather brought by the cold wave do great harm to transportation.For example, a cold wave in late November 1987 caused many station turnouts under the jurisdiction of Harbin, Shenyang, Beijing, Urumqi and other railway bureaus to freeze, the tracks were buried in snow, communication signals failed, and train operation was blocked.After the rain and snow, the roads became icy and slippery, and traffic accidents increased significantly.cold waveThe attack is very harmful to human health,galeCool weather is easy to induceCatch a cold、TracheitisCoronary heart diseasepulmonary heart disease, Strokeasthma、myocardial infarction、angina pectoris、migraineAnd other diseases, sometimesAggravation of illness。
The strong wind and cooling weather brought by the cold wave have a great impact on ship transportation. In order to protect the safety of ships, crew members and passengers, some preventive measures should be taken;Heavy wind and snow will reduce the visibility, and make the ship difficult to operate, causing serious deflection and deviation, which will pose a threat to the safety of the transmitting ship.For this reason, the ship should timely select a safe place to berth "wind breaking" according to their respective wind resistance capacity, and display the signal, sound the number and take various safety measures as required;The ice and snow, deck, gangway and gangway shall be cleaned in time, and anti sliding pads shall be paved to avoid industrial accidents;The rafter pen pipe system shall be wrapped with warm materials and the residual water shall be discharged.Prevent the tube wall from cracking due to icing inside the tube.In northern rivers, ships should be prepared for docking and winter to prevent freezing in the channel.[3]
What is rarely mentioned is that cold waves also have beneficial effects.The research and analysis of geographers show that cold waves contribute to the heat exchange on the earth's surface.As the latitude increases, the earth receives less solar radiation energy, so the earth forms a tropical zoneTemperate and cold zones。The cold wave carries a large amount of cold air pouring into the tropics, making the ground heat exchange on a large scale, which is very helpful for the ecological balance of nature and the prosperity of species.
Anticyclone
Meteorologists believe that cold wave is the guarantee of favorable weather conditions.Affected by the monsoon, China has a dry winter climate, which is a dry season.However, when the cold wave invades south, it often brings a wide range of rain and snow weather, easing the drought in winter and benefiting crops.“Snow augurs a good year”This sentenceAgricultural proverbsWhy can it spread among the people through the ages?This is because the nitrogen content in snow water is high, more than 5 times that of ordinary water, which can makenitrogenSubstantial improvement.Snow water can also accelerate the decomposition of soil organic matter, thus increasing theOrganic fertilizer。Heavy snow covers winter crops, just like cotton quilts, which can resist cold and keep warm.There is a saying“It is not cold in cold winter, but not abundant in the coming year”, which also has its scientific reason.Experts in crop pest control believe that,cold waveThe low temperature it brings is the most effective natural "insecticide" at present, which can kill a large number of pests and germs hiding in the soil for winter, or inhibit their breeding, and reduce the pests and diseases in the coming year.According to the survey data of agricultural technology stations around the country, pesticides can be saved by more than 60% in years with heavy snow and winter.
Cold wave can also bringWind resources。Scientists believe that wind is a valuable pollution-free power resource.Remarkable JapanMiyako IslandThe power generation efficiency of wind power station in cold wave period is 1.5 times of that in normal times.
Scope of influence
Its east-west length can reach hundreds to thousands of kilometers, but its thickness is generally only two or three kilometers.cold waveIts moving speed is tens of thousands of meters per hour, which is similar to the speed of trains.The cold wave that affects our country has three routes: one is the West Road.This is the earliest and most frequent route that affects China.Strong cold air starts from the Arctic and passes throughSiberiaGo south in the west, enter Xinjiang, then followHexi Corridor, invading North Chinacentral plains, until South China and even Southwest China.The second is the Middle Road.Strong cold air from SiberiaLake Baikalandthe people's republic ofmongolia Belt, passing through the Inner Mongolia Autonomous Region of China, entering North China untilSoutheast CoastRegion.The third is East Road.Cold air flows southward from northeast Siberia, sometimes through northeast China, sometimes throughSea of Japan, Korean Peninsula, invading the eastern coastal area of China.The main force of the cold wave going south from this route is to the east, and the force is generally not very strong, and the frequency is not too many.
characteristiccold waveOutbreaks have different characteristics in different geographical environments.In the northwest desert and loess plateaugaleLess snow, easy to causeSandstorm weather。In Inner Mongolia grassland, it is windy, snowy and cold weather.In North ChinaHuang Huai RegionThe cold wave often blows with wind and snow.In the northeast, it shows stronger wind and snow,SnowfallIt ranks first in the country.It is often accompanied by cold wind and bitter rain in Jiangnan.
Anticyclone
The prevention of cold wave should be strengthenedweather forecast, release accurate cold wave information or alarm in advance
1. When the temperature drops suddenly, pay attention to clothes, especially hands and face.
2. Close the doors and windows and fasten the outdoor structures.
3. Be careful of slipping and falling when going out
4. Elderly and infirm patients, especially cardiovascular patients, asthma patients and other people who are sensitive to temperature changes should try not to go out
6. BewareGas poisoningIn particular, families that use coal stoves for heating should be more careful.
cyclone
cyclone
In the northern (southern) hemisphere, the horizontal flow in the atmosphere rotates counterclockwise (clockwise)vortex。In the northern hemisphere, it leans to the right, and vice versa.At the same height,cycloneThe air pressure in the center is lower than that around, also called low pressure.
Cyclones are approximately circular or elliptical in size.The horizontal scale of small cyclones is several hundred kilometers, and the large ones can reach three or four thousand kilometers.In cyclones, the weather often changes violently, which is the most concerned and studied by peopleweather system 。Usually, according to the main area of cyclone formation and activity orThermalStructure.It can be divided intoExtratropical cyclone、Tropical cycloneandpolar cyclone Sexual vortex, etc;According to thermal structure, it can be divided intocold cyclone andThermal low pressureEtc.There is vortex movement in the atmosphere similar to that in riversClockwiseAnd counter clockwise rotation:cycloneAnd anticyclone are large-scale horizontal vortex movements in the atmosphere.
Cyclone, in the Northern Hemisphere, the air moves counterclockwise,Central air pressureThe lowest is gradually increasing outward, and the air continuously flows into the center to form updraft, also known asLow atmospheric pressure。Its diameter ranges from tens of kilometers to thousands of kilometers.When cyclones affect, rainy weather andgaleEtc.There are all kinds of large and small eddies in the atmosphereRotate counterclockwise, YesClockwise rotationAmong them, large horizontal eddies are called cyclones and anticyclones respectively, namely low pressure and high pressure.
term
cyclone: Cyclone is also calledLow atmospheric pressureCyclone.Occupying three dimensions and at the same height（Isobaric surface）Upper, with closed isobaric (high) line,Central air pressure(height) lower than the surrounding large vortex.In the Northern Hemisphere, airRotate counterclockwise；In the southern hemisphere, the direction of rotation is opposite to that of anticyclone: also known as anticycloneHigh barometric pressure。Cyclone and anticyclone are two aspects of a system.
Cold vortex: Coldvortex Short name of.The strength of the vortex whose center is cooler than the surrounding vortex increases with the increase of height.
Northeast cold vortex: Large cold vortex at high altitude active in or near Northeast China.It is a deep system that can last 3-4 days or more.
Southwest vortex: also referred to as southwest vortex.stayTibet PlateauAnd the special terrain in southwest ChinacirculationUnder the joint action, it is a shallow vortex generated in the low altitude of southwest China.
