polar regionAir massA semi permanent front between a tropical air mass and a tropical air mass.It does not completely circle the hemisphere in continuous bands.Frontal zoneStrong internal baroclinicity, longitudinal directiontemperatureBig difference, yesatmosphereEnergy accumulation area.At the appropriateWeather situationLower, oftencycloneOccurring or developing on it, often accompanied by rainstorma fierce windEtcweatherIt is one of the most important frontal systems and major atmospheric systems in the middle and high latitudes.
Chinese name
Polar front
Foreign name
polar front
Discipline
meteorology
Interpretation
Semi permanent front between polar and tropical air masses
Weather situation
It is often accompanied by rainstorm, strong wind, etc
Location
It lies between 45-50 degrees north latitude in East Asia
Polar front A semi permanent front between the polar air mass and the tropical air mass.It does not completely circle the hemisphere in continuous bands.The frontal zone has strong baroclinicity and large meridional temperature difference, so it is an area of atmospheric energy accumulation.Under the appropriate weather situation, cyclones often occur or develop on it, often accompanied by heavy rain, strong wind and other severe weather. It is the most important front system and one of the main weather systems in the middle and high latitudes.The height of the upward extension of the polar front is lower than that of the subtropical front, which is sometimes limited to the middle and lower troposphere.In East Asia, the average position is between 45-50 degrees north latitude, but with seasonal changes, the north-south displacement is large.Most areas of our country are within the scope of its activities.Its location is closely related to the activities of rain belts in China, and has a great impact on the weather in China.[1]
Specific causes
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The polar front is a large cold front.It is the most important climate front in the southern and northern hemispheres, a semi permanent front between the polar air mass and the tropical air mass, and the boundary between the cold polar air flow and the warm tropical air flow.
In meteorology, the polar front is the boundary between the polar circulation and the Ferrell circulation.In the Arctic, the cold and heavy air flow from the Arctic Ocean pushes forward the hot air flow from the tropics below.Warm air moves upward along the slanting front, and some warm air flows northward and is pushed to the poles.Because of the strong force of the polar wind, the polar front belongs to the cold front.[2]
Polar front theory
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Polar front theory(pola front theory) is a theory proposed by the Norwegian (Bergen) School on the occurrence and development of temperate air pools.It was a breakthrough in meteorological science between the two world wars.In 1918, J. Piyerkenis initiatedPolar frontTheory, published MobilitycycloneThe structure of ".Polar front theoryExtratropical cycloneA clear anatomy of its structure and a detailed explanation of its history.
The main points can be summarized as follows: (1) extratropical cyclones are the result of the development of waves caused by small disturbances on the polar front;(2) When the polar front fluctuates due to external forces, the pressure near the wave front begins to drop. (3) If the fluctuation is unstable, its amplitude will followtimeAs the pressure increases, the pressure near the wave whisker will further decrease, and the cyclone will be formedcirculation, with closedIsobar；(4) Temperate zoneCyclone life historyExperience birth, maturityocclusionAnd dissipation.
The polar front theory is mainly based on the actual situation in the East Atlantic Ocean and Western Europe, through careful analysisSurface weather mapThe established one also has a slightly simple defect in theory, and has certain limitations.But for half a century, it hasMid latitudeweatherSplit andpredictionIt plays an important role.
Among the main scientists of the Norwegian School, V. Piyerkenis and Solberg focus on theoretical research, while J. Piyerkenis and Bergeron focus on synoptic analysis.The frontal cyclone model established by them is an important conceptual model for the development and evolution of mid latitude synoptic scale cyclones. Solberg put forward the concepts of polar front, cyclone family, and the process of polar front fluctuations developing into cyclones, improving the entire theory;Begilon put forward the theory of cyclone confinement, which made the life history of frontal cyclones more complete.In the 1920s, the air mass, polar front theory and frontal cyclone model were called "polar front meteorology".The theory of frontal cyclones and polar fronts is one of the main reasons why the Department of Meteorology of Bergen University was named "School".At the same time, their academic works have greatly promoted the development of meteorology, among which Physikalische Hydrodynamik (Physics and Fluid Mechanics) is the most prominent.[3]
