The Siberian High, also known as the Mongolian Siberian High or the Asian High, is a large semi permanent high pressure area over Siberia caused by the joint action of multiple factors.[4]Most occur between the autumnal equinox and the winter solstice, and winter is located in SiberiaMongoliaThe center of large-scale high pressure (anticyclone) is typicalContinental air mass。
Asia is the largest continent in the world, with obvious continental climate. The east of Asia is close to the Pacific Ocean, and the air flow flows from the Pacific Oceaneurasia, forming a high pressure zone in Siberia.
The Siberian High is one of the four major seasonal atmospheric activity centers in the Northern Hemisphere. Its existence has a strong impact on eastern Asia, making the winter in this region colder than that in the same latitude.
The Siberian high refers to a large semi permanent high area formed over Siberia in winter due to the joint action of multiple factors.[4]After every autumn,Northern HemisphereThe nights are getting shorter and longer, and the ground temperature and air temperature are gradually decreasing.Due to the relatively high latitude, favorable topographic conditions and the invasion of cold air from the Arctic Ocean, Siberia has become the accumulation place of cold air.Because of the high density of cold air, the pressure in this area rises, forming the Siberian cold high pressure.
Located in Mongolia, the pressure value is 1036mb~1050mb, reaching 1075mb at the strongest and 1083.8mb at the most extreme. The influence range is within the two 1015mb lines in the north and south.Leading direction: clockwise.The north is dominated by southwest wind, the northeast is dominated by northwest wind, the southeast is dominated by north wind, and the south（Indian subcontinent: tropical air mass) is dominated by northeast wind, southwest（the arabian peninsula）Northeast wind prevails.
Land: a. denatured polar air mass, b. ice ocean air mass (dry and cold, from the Arctic Ocean), c. polar Siberian air mass, d. land denatured polar Siberian air mass (Indochina Peninsula)
Oceans: a. arriving in Japan: cold sea metamorphic polar Siberian air mass; b. southern Guangdong: warm sea metamorphic polar Siberian air mass.[1]
Activity pattern
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The Siberian High often intrudes into China under the guidance of upper air currents.From autumn to winter, the scope of influence gradually expands from north to south.The powerful Siberian high front in winter may affect the South China Sea, Philippines and Ryukyu Islands;In spring, the influence became weaker, and the scope of influence narrowed from south to north;Summer rarely affects China.
The moving speed of the Siberian High is high when it first moves out of the source area, and then gradually decreases.In mountain and hilly areas, the movement is slow;It moves faster on the plain and at sea.
According to the movement path of the Siberian high pressure and the ground situation map, when the high pressure moves southward, three kinds of weather can occur successively along the coast: the first is the cold front weather in the front, then the high pressure center weather, and finally the high pressure moves eastward as a whole or splits into several small high pressures, and the coast is controlled by the weather behind the high pressure.At this time, the cold front weather at the front of the new Siberian High will come again.The periodic activity of the Siberian high is the main feature of the weather change in winter and spring.The interval between the two cold fronts is about 7-10 days, and about 3-5 days in spring.[2]
Siberian high pressure weather
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Weather in front of high pressure
In the process of moving southward, the cold air in front of the Siberian High meets the warm air in front of it and produces a cold front.If the cold air force is strong, a strong cold front can be formed.This strong cold front may appear cold wave after passing through, so it is also called cold wave cold front.
cold frontThe meteorological changes before and after the transit are:
Cloud and precipitation This refers to the cold front cloud system and precipitation commonly seen in winter in northern China. The front is multi-layered cloud, and the cloud layer evolves from high clouds to low clouds. There is continuous precipitation, and the precipitation area is narrow. After the cold front passes through, the cloud amount decreases significantly, and the precipitation stops quickly. The cold air behind the front is affected by the warm underlying surface, constantly changing and warming, and the gas layer is unstable, and convection occurs,Therefore, cumulus clouds appear behind the front, sometimes with more cloud cover. In the southern sea area, there are more clouds and precipitation near the front, sometimes with cumulus clouds and intermittent precipitation, due to the high humidity of warm air.
When the cold front approaches, the pressure drops. When the cold front passes, the pressure is the lowest. After passing, the pressure rises sharply.
In front of the wind front, there is a southerly wind with a force of 3-4. When the cold front approaches, the pressure gradient increases, and the southerly wind increases correspondingly. After the cold front passes, the wind direction turns to the north, and the wind force suddenly increases to above force 6, or even to force 8-10. The wind force at sea is larger than that on land. The northerly gale often lasts for 1-2 days, and causes large waves and swells on the sea.Due to the influence of topography, the wind direction of the Taiwan Strait is mostly northeast, and the wind is slightly stronger. In winter, when there is cold air, northerly gales above level 6 will generally appear in the northern sea area. When the cold front stays in the southern sea area for a long time, the northerly gales will last for a long time.
Sandstorms caused by strong winds in late spring and early winter can affect the sea and reduce visibility.
When the temperature and humidity front blows southerly, the temperature and humidity both rise, and the temperature drops sharply and the humidity decreases under the control of cold air mass behind the front.
The strong cold wind in winter can affect the whole country. When it goes south, the Bohai Sea and the Yellow Sea are the most affected, followed by the East China Sea and the South China Sea. Strong cold air can affect the whole South China Sea.
If the cold air moves slowly, the front edge of the high pressure is a type of cold front air.When it comes, stratiform clouds and continuous precipitation appear. The change process of pressure, wind, temperature and humidity is similar to that of Type II cold front, but the change degree is relatively mild.
When the cold air just went down from the source to the south, it moved faster, and type II cold front air appeared in the front. Later, during the southward movement, the cold air gradually became weaker and weaker, and the movement was also slower. At this time, type I cold front weather appeared in the front. When the cold front moved to the south of the Yangtze River or the coast of South China in early winter and late spring, it was often a quasi-static front due to weakened force or terrain obstruction,Causes rainy weather lasting for a long time.
High pressure central weather
After the cold front in front of the Siberian High passes, when the wind gradually weakens and the pressure continues to rise, it indicates that the middle of the high pressure is coming. In the middle of the Siberian High, because the air mass is dry and cold, the sinking airflow prevails, the lower atmosphere is stable, and there is often inversion, so it is mostly cold, sunny and cloudless weather.In addition, due to the small wind, radiation fog will appear at night and in the morning in the harbor, and gradually disappear after sunrise. Due to the accumulation of water vapor and other impurities under the inversion layer, the visibility of the lower layer will deteriorate. The wind direction near the high pressure center is uncertain, and the wind force is small. The weather in the middle of the high pressure can last for 2-3 days. Later, with the air mass denaturation and warming, the temperature will start to rise.
High pressure rear weather
When the high pressure center enters the sea, the coast is at the rear of the high pressure. The southerly flow of the high pressure rear brings the warm and humid air from the sea to the coast, which increases the temperature and humidity of the coastal area. After the warm and humid air is lifted, it often forms stratiform clouds or stratocumulus clouds, called reflux clouds.In spring, dense fog or drizzle can also occur. When the rear of the high pressure is controlled, the air pressure gradually drops, and the wind blows southward. The wind is not strong. When the Siberian high pressure moves eastward into the sea, the degeneration disappears or merges into the Pacific high pressure, a new cold high is forming in the north, waiting to move southward. Therefore, the winter weather in China is characterized by cold warming again cold again warming again.
According to the data statistics, there is a cold air activity in about 4 days on average throughout the year, and the strong cold air activity cycle is about 7 days. It can be seen from the ground map that when the cold air invades, the main body of the high pressure often stops on the mainland and rarely moves, while the front of the high pressure is periodically diffused southward, usually the previous cold air has just entered the sea, and the gale in the sea area has not yet ended,Then came another supplement, which increased the wind again. Therefore, if you encounter cold air at sea, you should pay special attention to this feature.This process is only completed when the high-pressure main body enters the sea.[3]
