Cold wave is a kind of natureWeather phenomenonAs the name suggests, it is coldcold airIt means that it flows like the tide. It belongs to air（cold air）A form of mobility.[14]The cold wave comes fromHigh latitudeThe cold air in the regionWeather situationLower rapidly strengthen and centerLow latitudeRegional invasion, causing severe temperature drop, strong wind, rain and snow weather in large areas along the route.This kind of cold air southward invasion reaches a certain standard, which is called cold wave.
Cold wave refers to the cold air coming from the polar regions or cold zones in the winter half year, which invades the middle and low latitudes on a large scale like the tide.When the cold wave attacks, the temperature will drop sharply, accompanied by strong wind, rain and snow.Industrial and agricultural production, people's life andhuman health And so on.
The cold wave invading China is mainly caused byarcticZoneRussiaOfSiberiaas well asMongoliaOutbreaks in other placesCold high pressure。Most of these areas are located in the Arctic. There is no sunshine in winter for a long time, and they are covered with ice and snow everywhere. The air mass staying in these areas is getting colder and drierCold air massAccumulate to a certain extent, when the air pressure increases to far higher than that in the south, it is like a flood stored on a mountain. Whenever there is an opportunity, it will flood and pour to the south with lower air pressure, which forms a cold wave.
In January 2024, according to the China Meteorological Administration, the cold wave process in China has been numbered since November 2023.This is an important measure to improve the accuracy and service level of cold wave forecast and warning。[17]
Cold wave is a strong cold air activity that the polar region or cold zone invades to the lower latitude zone[16]。It is not that all cold air attacks are called cold waves. Generally, after cold air attacks a place, if the temperature of those places can be reduced by 8% in a day (24 hours)centigradeWhen the lowest temperature on that day is below 4 ℃, this cold air is called cold wave.[14]
Guangdong Meteorological BureauThe cold wave standard is defined as: within one dayDaily average temperatureA drop of more than 8 ℃, or a sharp drop of 10 ℃ in the average temperature within two days, while the minimum temperature drops to 5 ℃ or below.[13]
Cold wave is a kind of disastrous weather in winter. People are used to calling cold wave cold current.[1]This kind of cold air southward invasion reaches a certain standard, which is called cold wave.[2]
Standard:Affected by geographical environment and climate conditions,Cold wave standardNot the same.China formulated by the Central Meteorological Observatory in 2006Cold air classThe standard of cold wave stipulated in the national standard is: after the cold air in a certain area passes through the border, the temperature drops by more than 8 ℃ within 24 hours, and the minimum temperature drops below 4 ℃;Or the temperature drops more than 10 ℃ within 48 hours, and the minimum temperature drops below 4 ℃;Or the temperature drops by more than 12 ℃ continuously within 72 hours, and the minimum temperature is below 4 ℃.[14]
Because of ChinaVast territoryThe climate in the south and the north is very different. Generally speaking, the cold wave standard adopted in the north is: the temperature drop is more than 10 ℃ in 24 hours, or more than 12 ℃ in 48 hours, and the minimum temperature is less than 4 ℃;The cold wave standard adopted in the south is: the temperature drop is more than 8 ℃ in 24 hours, or more than 10 ℃ in 48 hours, and the minimum temperature is less than 5 ℃.[9]
In 2016, due to the strong cold wave weather, the ground snow of Guangzhou Bureau
Therefore, there is another supplementary provision: the temperature in the middle and lower reaches of the Yangtze River and the areas to the north will drop by more than 10 degrees Celsius within 48 hours, and the minimum temperature in the middle and lower reaches of the Yangtze River will be below 4 degrees Celsius (changed toJianghuai regionThe lowest temperature is below 4 ℃), three on landGreater Administrative RegionThere is a gale above level 5,the bohai sea, the Yellow Sea and the East China Sea have gales of force 7 or aboveCold Wave WarningStandards.If the temperature in the above areas drops by more than 14 degrees Celsius within 48 hours, there are 3 – 4 large administrative regions on the land with strong winds of 5 – 7, and there are strong winds of 7 or more in all coastal sea areas, it is the standard of strong cold wave.
Causes
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Geographical factors
As the Antarctic continent is surrounded by vast oceans, the oceans willAntarcticaIt is far away from other continents.SaltwaterSpecific heat capacityLarge, so the ocean absorbs or releases a lot of heat every time it warms or cools by 1 degree.When cold air passes over the ocean, the slow cooling of the ocean will release a lot of heat to weaken the cold air.together withsouthern hemisphereOfWesterliesIt is complete and strong, and the cold air is trapped in the Antarctic continent by strong westerlies, which is difficult to overflow, so cold waves rarely occur in the southern hemisphere.The northern hemisphere is different,EurasiaandNorth AmericaConnectedArcticAnd low latitudes, the high mountains and plateaus on the land cut off the westerlies, resulting in the westerlies in the northern hemisphere being far less powerful than those in the southern hemisphere and the westerliesDiscontinuityThe land temperature rises and cools quickly. When winter comes in the Northern Hemisphere, the temperature of these two continents will be as low as minus dozens of degrees, which will not weaken the cold air. Therefore, the cold air in the Arctic can move southward along these two continents and invade low latitude regions.Therefore, winter in the Northern Hemisphere is much colder than that in the Southern Hemisphere, and cold waves occur frequently every year.
China is located ineurasiaSoutheast of.Going north from ChinaMongoliaAnd Siberia in Russia.Siberia has a cold climate. If you go further north, you will reach the northernmost region of the earth - the Arctic.It's colder there than in Siberia,Cold periodLonger.The first cold wave that affects China isarctic oceanOn the ice surface, and then in Siberia orMongolian PlateauIt was strengthened, and the last way was south.stayNorth America, cold wave is mainly formed in the Arctic andCanadaOfYukonandhudson bay 。
Located in the high latitude Arctic, Siberia, Mongolian PlateauYukon Plateau, Hudson Bay area, year-roundOblique projection, ground acceptancesunlightHas very little heat.Especially in winter,Direct sunlightMoving southward, the angle of solar radiation in the northern hemisphere becomes smaller and smaller. Therefore, the solar heat absorbed by the ground becomes less and less, and the temperature of the ground surface becomes very low.In the Arctic Ocean region in winter, the temperature is often below - 20 ℃, and can reach - 60 ℃~- 70 ℃ at the lowest temperature.JanuaryAverage temperatureUsually below - 40 ℃.
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, the direct sunlight crosses the equator and reaches the southern hemisphere. The cold degree in the Arctic region is even stronger and the range is expanded. The average 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。[10]
Cold Wave Sweeps Most of China[2]
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, thus forming a powerful, deep and broadCold high pressure。[10]
In 2016, due to the strong cold wave weather, the ground snow of Guangzhou Bureau
When the force of this cold high-pressure system is strong enough, it will rush to China like the tide that broke the dike, bringing severe cooling to China. There will be cooling, strong wind, rain, snow or freezing weather in succession, which will affect a wide range of areas. This is called cold wave.[10]
Cold high-pressure air mass pushes forward to form a cold front
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.[10]
People affected by cold air
Most of the cold air in the northern hemisphere is formed in the Arctic Ocean, then strengthened in Siberia, Canada and other regions, and then further south.
There is also a strong cold high on the Antarctic continent in the southern hemisphere, and the cold air accumulated on the Antarctic continent is more powerful and stable than that in the northern hemisphere.However, due to the existence of a complete and strong westerly belt in the southern hemisphere, cold air is blocked by the westerly belt on the Antarctic continent, and it is difficult to invade the middle and low latitudes. As Antarctica is surrounded by vast oceans, the ocean will weaken the influence of cold air.Therefore, cold waves rarely occur in the southern hemisphere, and the activity range of cold air andActivity frequencyAre smaller than those in the northern hemisphere.
2008 Snow Disaster - Guangzhou Railway Station
Region of origin
(1) To the west of Xindi Island
Cold airBarents Sea, frontSoviet UnionEurope enters China.It occurs most frequently and reaches the intensity of cold wave most.
(2) On the ocean east of Xindi Island
Most cold air flows throughKara Sea, Taimel Peninsula and the former Soviet Union entered China.Although it occurs less frequently, the temperature is low and can reach the intensity of cold wave.
Cold air passes through southern Europe of the former Soviet Union ormediterranean sea、Black Sea、Caspian SeaEnter China.It occurs many times, but the temperature is not very low, and generally cannot reach the intensity of cold wave, but it can reach the intensity of cold wave if it joins with cold air from other sources.
The cold wave invading China has three main paths:
(1) West Road: FromSiberiaThe west enters Xinjiang, China, viaHexi CorridorPushing southeast;
(2) Middle road: after entering China from central Siberia and MongoliaHetao regionAnd central and southern China;
(3) East Road: enter China from eastern Siberia or eastern MongoliaNortheast China, viaNorth Chinago down south;
(4) East Jiaxi Road: cold air from the east roadHetaoThe downstream goes south, and the cold air from the west road goes down from the southeast of Qinghai. The two cold air streams are often on the east side of the Loess Plateau,Yellow River、Yangtze RiverThe confluence will cause a wide range of rain and snow weather, and then the two cold air will merge to the south, resulting in strong wind and obvious cooling.
Composition
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Polar vortex
Northern Hemispherewinterpolar regiontroposphereCircumpolar cyclonic type on the upper and middle 500hPavortex, called polar vortex.It is a symbol of large-scale extremely cold air. The ground is shallow cold high pressure, and 700hPa turns into low pressure circulation.
Polar high pressure
(1) There is a completeAnticycloneCirculation, can analyze no less than one closedcontour；
(2) There is a considerable range of separate warm centers andGeopotentialHeight field coordination;
(3) The main part of warm high pressure is north of 70 ° N;
(4) The high pressure is maintained for more than three days.
Cold wave surface high pressure
During the whole process of cold wavecold frontThe rear ground high pressure, most of which belong to thermal asymmetric system, is strong in front of the high pressureCold advection；At the rearWarm advection, Central AreaTemperature advectionTends to zero, and a few high pressures are always cold.Representablecold airThe center moving path can be used as the moving path of cold air.
Cold front of cold wave
At the front edge of the cold wave surface high pressure, there is a strong cold front as the front of the cold wave, which inclines to the cold air side with the height, and there is a strongFrontal zoneThe front zone structure is 300 hPa and belowIsobaric surfaceThere are obviousCold troughAnd frontal zone.
Formation process
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short-term
Short and medium term of cold waveSynoptic processIt is divided into three categories:
(1) Small groove development type;
(2) Low trough eastward moving type;
(3) Horizontal groove (turn to vertical) type.
Small groove development type
The essence is to develop small unstable grooves and ridgesAtlanticThe Great Fall to East Siberiaflow patternEvolved intoEast AsiaThe process of inverted Ω flow pattern led the cold air west of Xindi Island to the south, and took the northwest path to invade China through Siberia and Mongolia.
Low trough eastward moving type
During the eastward movement of the European trough, fresh cold air from the north was incorporated, which made the trough develop and led to a cold wave process.The cold wave of eastward moving trough should pay attention to the combination of two streams of cold air.[11-12]
Horizontal groove (turn to vertical) type
When the East Asia inverted Ω flow pattern was established, the polar vortex extended an east-west trough westward, before and after which were northerly winds (340 ° – 20 °) andWesterly wind(300 ° – 250 °).
metaphase
The medium term process is a large circulation background before the onset of cold wave.
a. Initial stage: the two northern oceanic ridges develop towards the poles, and the polar vortex divides into two parts, moving to the east and west respectivelyTwo hemispheres, (or polar vortex deviates fromEastern Hemisphere）In the eastern hemisphere, two oceanic ridges hold a large polar vortex, forming a large inverted Ω flow pattern
b. Incubation stage: large inverted Ω flow patternAsiaRegional contractionEast AsiaThe regional inverted Ω flow pattern, the Asian polar vortex strengthened and pressed southward, the front area at the bottom of the polar vortex strengthened, and there are oftenlong waveThe development or horizontal trough slowly moves south, forming a situation of strong cold air brewing.
c. Outbreak stage:Mid latitudeThe rapid development of the long wave, or the horizontal trough turning to the vertical, or the horizontal trough pressing southward, led the cold air to invade China.lastEast Asia troughDeepen the reconstruction, and the process ends.
The establishment of East Asia inverted Ω flow pattern is mainlythe Ural MountainsandSea of OkhotskTwo regions haveHigh pressure ridgeDeveloping towards the polar region and forming in the Arctic OceanAnticycloneIt is formed by getting through.Forecasters often regard the high pressure ridge of Ural Mountain as the key system for forecasting cold wave and strong cold air.To sum up, the key system for the medium term cold wave forecast should be the warm ridge over the two oceans.
main features
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Cold wave is common in ChinaDisastrous weather, which occurs more frequently and has a wide range of activities.[14]It is not that all cold air attacks are called cold waves. Generally, after the cold air attacks a certain place, if the temperature of those places can be reduced by more than 10 degrees Celsius within a day (24 hours), and the minimum temperature of that day is below 5 degrees Celsius, the cold air is called a cold wave.[15]
Cold wave outbreaks have different characteristics in different geographical environments.In the northwest desert and loess plateau, strong wind and little snow are very easy to causeSandstorm weather。In Inner Mongolia grassland, there are strong windsSnow blowingAnd cold weather.In North ChinaHuang Huai RegionThe cold wave often blows with wind and snow.In the northeast, it is more violent wind and snow, and the snowfall is the highest in the country.It is often accompanied by cold wind and bitter rain in Jiangnan.[10]It can occur from September to May of the next year, mainly from March to April, and most parts of China are affected.
Basic categories
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China Academy of Meteorological SciencesAccording to the Cold Wave Yearbook, the cold air process can be divided into four levels: national cold wave, regional cold wave, strong cold air and general cold air.
National cold wave: the total temperature drop in the process of daily average temperature is>10 ℃, negativeParallaxOfabsolute valueThere are at least 32 stations in the north (accounting for one third of the stations in the north) and at least 13 stations in the south (accounting for about one fourth of the stations in the south) with the number of stations ＞ 5 ℃;Or if the total number of stations reaching the above impact intensity in the north and south exceeds 40, the total temperature drop in the process is greater than 7 ℃, and the total number of stations with the absolute value of negative anomaly greater than 3 ℃ exceeds 90 (accounting for 60% of the total number of stations in the north and south), it will be regarded as a "national cold wave".
Regional cold wave: where the total temperature drop in the process of daily average temperature is greater than 10 ℃, and the number of stations in the north and south with the absolute value of negative anomaly greater than 5 ℃ exceeds 20, while the total temperature drop in the process is greater than 7 ℃, the absolute value of negative anomaly greater than 3 ℃, and the number of stations in the north and south with more than 40, it is regarded as a "regional cold wave".
A cold wave is coming
Strong cold air: when the number of stations that also affect the intensity reaches more than half of the regional cold wave standard, it will be regarded as "strong cold air".
General cold air: when the number of stations with the same impact on the intensity reaches more than half of the strong cold air standard, or the total temperature drop in the process of daily average temperature is greater than 7 ℃, and the total number of stations with the absolute value of negative anomaly greater than 3 ℃ exceeds 20;Or the process that does not meet the above standards but causes certain disasters shall be regarded as "general cold air".[3]
2. The value of the cold center on the altitude map;High altitude frontal zone intensity;Cold zone range and cold advection intensity;
3. Cold front intensity (temperature horizontal gradient size) on the ground map;The strength of the center of pressure change behind the cold front;frontal surfaceOther nearbyMeteorological elementsAnd weather phenomenon can also indirectly explain the intensity of cold wave.
Main hazards
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Cold wave is a kind of large-scaleSynoptic process, which will cause severe cooling, strong wind and snow weather in a large range along the way.Strong wind caused by cold wavefrost、snowstorm、RimeSuch disasters have a great impact on agriculture, transportation, electricity, navigation and people's health.Cold wave and strong cold air usually bring strong wind and cooling weather, which is the main disastrous weather in winter half year of China.Cold waves and strong winds pose a great threat to coastal areas.
Extensive snowfall caused by cold wave
The rain, snow and freezing weather brought by the cold wave do great harm to transportation.FrigidMovement speedIt is tens of thousands of meters per hour, about the same speed as the train.The cold wave that affects China 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, goes south through western Siberia, enters Xinjiang, China, and then invades North China and Central Plains along the Hexi Corridor untilsouth ChinaEven in the southwest.The second is the Middle Road.Strong cold air from SiberiaLake BaikalAnd Mongolia, passing through ChinaInner Mongolia Autonomous Region, entering North China to Southeastcoastal areas。The third is East Road.Cold air flows southward from northeast Siberia, sometimes through northeast China, sometimes throughSea of Japan、Korean Peninsula, intrusionEastern ChinaCoastal area.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.
Cold wave and strong wind
Cold wave gale is gale weather caused by cold wave weather.Cold wave and strong wind cover a wide area, ChinaNorthern regionInner Mongolia, Gansu, Ningxia, northern Shaanxi, northern Shanxi, Hebei, northern Henan, HeilongjiangJilinandLiaoningAnd other places are cold wave and gale prone areas, from the south of Huaihe River to ChinaSouth China SeaCold waves and strong winds can also appear in the central sea area.The cold wave gale is mainly northerly gale, and the wind force is usually 5-6. When the cold air is strong or the ground low pressure develops strongly, the wind force can reach 7-8, and the instantaneous wind force will be larger.
Cold Wave and Strong Wind in Chinageographical distributionIt is widely distributed throughout the country. The distribution of annual gale frequency (days) has regional characteristics. The annual average days of gale in most regions are about 20-70 days,Northwest China, North ChinaNortheast ChinaandQinghai Tibet PlateauBetween 10 and 75 days, southwest China, southern China andYangtze river basin3 to 25 days.There are threeGale daysHigh frequency area: the first is the Qinghai Tibet Plateau, with annual gale days of 75~100 days and above, which is the largest high incidence area of gale weather in China, often causingSnow covered plateauappearGale disaster, affecting animal husbandry production.The second is the north of Inner Mongolia and the northwest of Xinjiang, which is the only way for cold wave invasion. In particular, the north of Inner Mongolia has flat terrain, cold waves and strong winds are unimpeded, and the number of strong wind days is up to 50~80 days, leading to sandstorms andwind erosionDesertification is very serious, which has a great impact on agriculture and animal husbandry.The third high frequency area of gale is in the northeastSongliao Plain, the number of gale days is about 25-50 daysNortheast cycloneAreas with strengthened development, and its west hasGreater Khingan RangeandInner Mongolia Plateau, in the eastXiaoxing'an MountainsandChangbai Mountain, topographicalNarrow tube effectIncreased wind power.The frequent cold waves and strong winds in spring often causeSpring drought, affecting the production of spring sowing.There are obvious seasonal differences in the distribution of seasonal days of cold wave gales in China.In most regions, the number of strong wind days in spring is more than that in winter and autumn, and the number of strong wind days in summer is the least.
The disasters caused by cold wave and gale mainly depend on the wind force and the duration of gale.In terms of the whole countryMaximum wind speedIn addition to high mountains and powerful terrain, only the north of Inner Mongolia has experienced cold wave gales of more than 40m/s.According to the statistics of gale process for many years, the gale in the coastal area of China is longer than that in the inland area, the gale in the north is longer than that in the south, and the north gale lasts longer than that in the south.The impact of cold wave and strong wind on agricultural productionFishery production, shipping and military activities will have a great impact, and serious disasters may resultnational economyAnd bring huge losses.
Cold wave and frost damage
An obvious feature of cold wave weather is severe cooling, which can lead to cropsFrost damage, river port freezing, traffic disruption disasters,Regular meetingsBring economic losses to industry and agriculture.Cold wave and frost damage, especially in winterOverwintering cropThe frost damage.Cold wave weather processIt is a weather process in which a large scale of strong cold air in high latitudes moves southward, causing severe cooling and strong wind to appear in the passing places.
When the temperature drops below 0 ℃ (freezing point) or continues below 0 ℃ for a long time, it will cause the plants of overwintering crops to freeze and lose all physiological activities, causing plants to wither or die. Severe low temperature can also cause livestock to get sick or freeze to death, causing serious farming and animal husbandrymeteorological disaster Namely, cold wave and freezing damage.Cold wave freezing damage is mainly caused by low temperature below 0 ℃ (freezing point)plant tissue Suffer from freezing.Many research results show that freezing of cell tissue caused by low temperature is the cause of plant death.
Frost damage poses a great threat to agriculture, such as China'sWinter wheatandcitrusProduction often suffers great losses due to freezing damage.Cold wave and frost damage not only depend onCold wave pathAnd intensity, and it is also related to crop types andgeographical positionThere is close relationship.In China, the winter wheat area in the north is the most affected by the frost damage, and the area with the most frost damage is the northern agriculturean agricultural regionandMiddle and lower reaches of the Yangtze River。
The winter wheat area north of the Yangtze River has less snow,Autumn drought, cold air activities are frequent, and cold air is easy to accumulate in mountains and rivers, often causing freezing damage;In the Yangtze River basin and its southern region, due to many hills and mountains, the cold air is blocked by mountains to the south, and stays and accumulatesDongting LakeBasin, Zhejiang and FujianHilly areaFrost damage occurs with long duration, low temperature, and often accompanied by snowFreezing rainIn the weather, some rivers and lakes are frozen, making wheat, rapeBroad bean, peas and citrusEconomic forestSuffer from severe frost damage.In the desert andAlpine mountain areaBecause there are few overwintering crops, the cold wave has little impact on agricultural production.
Cold wave and snow disaster
During the cold wave, the most prominent weather is snow (rain), strong wind and severe cooling.Proper snow cover in winter will increasesoil moisture It is beneficial to freeze pest eggs and reduce air pollution, but the cold wave brings too much snow, even for several days or moresnowstormWill cause disasters.In the pastoral area, it is caused by cold waves and snowstorms“snowstorm disaster”，forage grasscoverSnow depthBuried, livestock can not eat fresh grass and dry grass can not be supplied, resulting in starvation or disease, resulting in a large number of deaths, which is very harmful to animal husbandry.
2008 Snow Disaster
The length of the possible occurrence period of snow disasters is determined by the beginning and ending periods of snow cover.The earlier the first day of snow, the later the whole day, the longer the period of snow disaster, and vice versa.Snow disasters in most pastoral areas in China may start from October to November and end in March to April, with a possible occurrence period of about 6 months.However, the initial stages of snow disasters may vary greatly,Plain areaIt is generally postponed from northeast to southwest, and the mountain and plateau pastoral areas followAltitudeIncrease and advance.The ending period is just the opposite to the beginning period. It is gradually advanced from northeast to southwest, and the mountain and plateau pastoral areas are postponed with the increase of altitude4500 above sea levelAbove mAlpine pastoral areaThe snow disaster may occur from the middle of August to the middle of July of the next year, almost all year round.
The length of snow cover period only reflects the possible occurrence period of snow disaster, and whether snow disaster is formed depends onSnow Depth , density, forage height and livestock condition.According to the survey and analysis of pastoral areas, the actual occurrence of snow disasters in China's pastoral areas is mainly from October to May of the next year, mainly in November and March April, accounting for 50% and 40% of the total annual frequency respectively.Due to theSnow volumeLarge, the snow on the surface can be melted day by day and frozen at night, forming an ice shell, making it difficult for livestock to break through the ice and snow to eat, causing "hunger disaster".Livestock from March to AprilFatnessWorst of all, some pastoral areas are in the lambing conservation period, during which cold air activities are most frequent. Once snow disasters occur, livestock losses will be large.In addition, the degree of snow disaster damage and the economic losses caused by snow disaster also vary greatly due to the physiological characteristics and disaster resistance of various livestock.
2008 Snow Disaster
Snow disaster has a great impact on agriculture and animal husbandry in northern China, commonly known as "white disaster" in meteorology.The main defensive measures are as follows:
Establish forage bank
This is the main strategic measure to resist the snow disaster.Prepare enough forage before winter. In areas with good conditions, it can be expandedGrassland areaAnd establishment laborFeed base, PlantingFeed cropAnd fine forage to provide sufficient forage for the forage bank to solve the feed problem during the snow disaster period.
Strengthen shed construction
After the snow disaster, livestock shall be kept in captivity to avoid direct damage from wind and snow.If on the way of grazing and changing fields, it is necessary to use windproof and sunny dry terrain to buildWindbreak wallSnow proof wall, try to avoid cold and freeze as much as possible to reduce the harm of snowstorm.
When the intensity of the snow disaster is not strong, machinery or horses can be used to break the snow. That is, on the snow covered grassland, the horses will be herded first, then the cattle, and finally the sheep
Strengthen early warning
Relevant departments should closely monitor those that may cause snowstormsWeather situation, forecast the intensity and impact range of the snowstorm in advance, and issue relevant early warning signals to remind all sectors to take precautions in advance.
In addition, the snow disaster is not only harmful to animal husbandry in pastoral areas, but also harmful toUrban transportationIt can also have a serious impact, so when heavy snow falls, the expressway and urban areas should timely remove the snow on the road.In order to accelerate the melting of snow, it can be spread on the roadDeicing agent。In case of severe cold wave and snowstorm, travel or parking shall be avoided. When necessary, the transportation department shall close the highway, railway and shipping traffic to prevent traffic accidents.Respond to greenhouse, greenhouse andBarnAnd other agricultural facilities.Prevent being crushed by heavy snow or blown down by strong wind.
Cold Wave and Glaze
Generally, in early winter or late winter and early spring, supercooling in clouds caused by cold wave and cooling weatherLiquid precipitationWhen touching ground objects, they will directly freeze into ice, forming glaze.In winter and spring, we can often see wires and branches wrapped or hung with a layer of crystal snow, which is called rime.Some people equate glaze with freezing rain. In fact, the physical mechanism and results of the formation of glaze and freezing rain are indeed the same, but there are still some differences.Frozen rain is a kind ofWeather phenomenonThe glaze is the result of freezing rain and is a disaster or landscape.
In most cases, glaze is a disastrous weather phenomenon.The thickness of severe glaze can reach several centimeters, which can crush trees, wires andElectric pole, causing power supply and communication interruption, impeding highway and railway traffic and threatening aircraftflight safety。
In China, the most rime occurs in Guizhou, followed by Hunan, Hubei, Henan and Jiangnan.Shandong, HebeiLiaodong Peninsula, Shaanxi and Gansu, including southeast Gansu, Shaanxiguanzhong region More;However, rime rarely appears in Sichuan, Yunnan, Ningxia, Shanxi and the coastal areas of South China.
Glaze occurs in GuizhouWeather daysMost, but the duration of each glaze is not long. The number of days in Hubei, Hunan, Henan, Jiangxi and Anhui provinces is slightly less, but the duration of each glaze weather is longer. Changde, Hunan and HubeiZhong XiangThe longest rime weather lasts 466 hours and 443 hours, about 20 days;The duration of rime is also the shortest in areas where rime rarely occurs, usually less than 10 hours.
Around the middle of November every year, rime begins to appear in the north, and in the south, until December.However, rime may appear in Hubei in the middle of November. The rime starts earlier and ends later than the middle of March;The glaze in Liaodong Peninsula ended in early April,East ChinaCoastal and South China coastal areas ended earlier from the end of January to the beginning of February.Glaze occurs in January and February in most regions of China, and less in March;However, Urumqi, Liaoning, Hebei, Shandong and other places in Xinjiang have the most in November and March, and fewer in January and February.
Most of the rime in northern China disappeared after it appeared, but it also expanded toSouthern regionSometimes it finally disappears in Guizhou.The source of rime in South China is mainly Guizhou. The occurrence of rime accounts for about 84% of the total number, and only 16% of the total number occurs in Hunan.Glaze disappeared in about 94% of stations in Guizhou and about 6% in Hunan.
The possibility and degree of disasters caused by rime greatly exceedRimeIn high latitude areas, rime is a frequent disastrous weather phenomenon.The main method to eliminate the rime disaster is to take artificial ice falling measures when the rime occurs, mobilize the residents along the transmission line to constantly scrape the rime off the lines, and take support measures for trees and power grids;Installing deicing equipment on the aircraft or simply flying around the freezing rain area can partially reduce the damage caused by glaze.
Cold wave forecast
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Cold wave forecastIt should include: strong cold air accumulation forecast of cold wave;Outbreak forecast of cold wave;Cold wave path and intensity prediction;cold waveweather forecast
A cold wave is coming
1. The focus of the small groove development prediction: the temperature and pressure field structure of the small groove itself;Whether the upstream ridge develops;The position of the south branch fluctuation;Upstream and downstream effects:East Asia troughWhether the eastward movement is weakened.
2. Prediction focus of the trough moving eastward: whether there is a small trough moving near the northwest side of the trough, whether there is fresh cold air added into the troughPosterior ridgeTo the Caspian SeaBlack Seaandthe Ural MountainsWhether it can develop.
3．Transverse grooveThe focus of vertical prediction: the temperature and pressure field structure of the horizontal trough itself (not conducive to the development of the ridge),Wind fieldThe collapse or discontinuous retreat of high resistance,Long wave adjustment。
In January 2016, affected by the strong cold air, there will be strong cooling and strong wind weather from north to south in central and eastern China from the night of the 21st to the 25th. The temperature in most areas will drop by 6~10 ℃, and the local temperature will drop by 12~14 ℃ (Figure 1);The minimum temperature in the middle and lower reaches of the Yangtze River will drop to about - 10 ℃, and the 0 ℃ line will press southward to the central part of South China (Figure 2).The minimum temperature in some areas of central and southern Anhui, northwest Zhejiang, northwest Fujian, and northern Guangdong may approach or break through the historyextremum。The lowest temperature in the north of the Yangtze River occurs in the early morning of the 23rd or 24th, and the lowest temperature in the south of the Yangtze River occurs in the early morning of the 24th or 25th.[4]
In January 2024, according to the China Meteorological Administration, the cold wave process in China has been numbered since November 2023.This is an important measure to improve the accuracy and service level of cold wave forecast and warning。
Alert ID
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1. Frost damage to crops (the biggest damage in autumn and spring, when seedlings are unearthed in spring, they will freeze to death in case of significant cooling, and when crops are not mature in autumn, they will experience cooling, which will reduce crop production) - intense cooling
Cold wave and strong cold air usually bring strong wind and cooling weather, which is the main disastrous weather in winter half year of China.
The rain, snow and freezing weather brought by the cold waveTransportationThe harm is not small.Can causeRailway stationThe turnout is frozen and the rail is buried by snow,communication signals Failure, train operation is blocked.After the rain and snow,Icy Road Slipping, traffic accidents increased significantly.
Standard: within 48 hoursMinimum temperatureIt will drop by more than 8 ℃, the lowest temperatureLess than or equal to4 ℃, and the average land wind force can reach above level 5;Or it has dropped by more than 8 ℃, the minimum temperature is less than or equal to 4 ℃, and the average wind force is above level 5, which may continue.Defense Guide:
Cold wave blue warning
1. The government and relevant departments shall make preparations for cold wave prevention according to their responsibilities;
Standard:24 hoursThe minimum temperature inside will drop by more than 10 ℃, the minimum temperature is less than or equal to 4 ℃, and the average wind force on land can reach above force 6;Or it has dropped by more than 10 ℃, the minimum temperature is less than or equal to 4 ℃, and the average wind force is above level 6, which may continue.
Cold wave yellow warning
1. The government and relevant departments shall do a good job in preventing cold waves according to their responsibilities;
2. Pay attention to adding clothes to keep warm and take good care of the old, weak and sick;
3. Rightlivestock、poultryTake cold prevention measures for tropical and subtropical fruits and related aquatic products and crops;
Standard: within 24 hours, the minimum temperature will drop by more than 12 ℃, the minimum temperature is less than or equal to 0 ℃, and the average land wind force can reach above level 6;Or it has dropped by more than 12 ℃, the minimum temperature is less than or equal to 0 ℃, and the average wind force is above level 6, which may continue.
1. The government and relevant departments shall do a good job in emergency work against cold wave according to their responsibilities;
2. Pay attention to cold prevention and warmth preservation;
3. Agriculture, aquaculture, animal husbandry, etc. should actively take frost prevention, freezing and other cold prevention measures to minimize losses;
Standard: within 24 hours, the minimum temperature will drop by more than 16 ℃, the minimum temperature is less than or equal to 0 ℃, and the average land wind force can reach above level 6;Or it has dropped by more than 16 ℃, the minimum temperature is less than or equal to 0 ℃, and the average wind force is above level 6, which may continue.
Cold wave red warning
1. The government and relevant departments should do a good job in emergency and rescue work against cold waves according to their responsibilities;
2. Pay attention to cold prevention and warmth preservation;
3. Agriculture, aquaculture, animal husbandry, etc. should actively take frost prevention, freezing and other cold prevention measures to minimize losses;
4. Do a good job of wind protection.
preventive measure
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In winter and spring, cold wave and strong wind often cause great impact and disaster on crops and people's production and life.Gale disasterThe following points should be achieved:
Attach great importance to
Timely carry out all defense work.All localities and relevant departments should attach great importance to immediate action, take effective response measures, and organize defense work in a timely and responsible manner.At the same time, usenews media, e-commerceSMSAnd quickly release the weather change process and its related information and defense measures to the public so that the masses and relevant units can carry out defense work in a timely manner.
take steps
Ensure the safety of agricultural production.Counties (cities, districts) and citiesagricultural bureauWe should organize agricultural technicians to go to the front line, actively guide and help the masses to take various defensive and remedial measures, and minimize disaster losses.withFacility agricultureIn order to focus on defense, we should carefully strengthen and compact the shedPellicle, thermal insulation and antifreeze, etc.Strengthen the reinforcement of pens and the immunization of livestock and poultry, keep young animals warm, improve the cold resistance and disease resistance of livestock and poultry, and ensure the safety of livestock and poultry.[5]
Take immediate action
Do a good job in other aspects.All localities and relevant departments should act quickly, clarify responsibilities, implement tasksConstruction site、outdoor advertising, power facilities, urban and rural dilapidated houses and other key parts, carefully investigate, prevent possible problems in advance, take strong measures to ensuremasseslifeProperty security。
traffic safety
The strong wind has a great impact on the operation of sea, land and air traffic. Personnel engaged in offshore operations should stop operations, return to the port for shelter, reinforce vessels anddrilling platformAnd other measures;Strengthen the dynamic supervision of ships, conduct on-site patrol andOn site inspectionWork;Pay close attention to the weather change, strictly implement the provisions of wind resistance level, and strictly prohibit risky navigation beyond the wind resistance level.Strengthen duty, keep regular lookout and drive carefully;Strengthen the ship shore linkage, the main management personnel of the enterprise actively, actively and comprehensively grasp the ship status, and timely eliminate potentialUnsafe factors。In case of strong wind, the airport andexpressway, under special circumstances,Passenger trainAlso shut down to prevent strong windtraffic accident。
Breed breeding
Plant freeze injuryIt is caused when strong cold air bursts southward and causes severe coolingOverwintering cropAnd fruit trees are frozen, causingplantDeath or partial death, therefore defensefreeze injuryOn the one hand, efforts should be made to improve the ability of overwintering crops and economic fruit trees to resist low temperatures; on the other hand, measures should be taken to block the invasion of cold wind and reduce the intensity of cooling.The effective measures to prevent frost damage mainly include: cultivationCold tolerant variety, improve frost resistance
Breeding of overwintering crops or subtropical economic fruit treesCold toleranceIt is a strategic measure to avoid or reduce frost damage to improve the frost resistance of plants with strong varieties.
Pre winter management
Strengthen pre winter management and enhance frost resistance
The quality of cultivation management directly affects the frost resistance of overwintering crops and fruit trees. Therefore, good cultivation management before winter is a defenseCold wave and frost damageImportant measures.
In the northern edge area of subtropical citrus cultivation in China, it is beneficial to make full use of mountains or water bodiesMicroclimateResources and environmentCultivating citrus can effectively avoid or alleviate the cold wave and freeze injury.
A cold wave is coming
matters needing attention
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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 when going out.
4. Old and weak patients, especiallycardiovascularPatientsasthmaPatients and other people who are sensitive to temperature changes should try not to go out.
5. Pay attention to rest, and don't get too tired.
Prevent frost damageStrategic measuresIn addition, a variety of cold proof and antifreeze measures can be taken before and during the winter low temperature.The government and relevant departments shall do a good job in emergency and rescue work against cold wave according to their responsibilities;Pay attention to keeping warm from cold;AgricultureAquaculture、Animal HusbandryWe should actively take frost prevention, freezing and other cold prevention measures to minimize losses and do a good job in wind prevention.
Use covers to protect the aboveground or underground parts of plants that are afraid of freezing, and reduce the groundLong wave radiationTo prevent the cold wind from invading, thus playing the role of cold prevention.There are two kinds of mulch: horizontal and vertical, including those directly covering crops or fruit treesBuild a shedCovered and bandaged.WindbreakIt also has good effect on preventing frost damage, and different types of wind barriers with different inclinations can be designed according to the actual situation.
Spraying agent
It is mainly used for antifreeze of fruit trees.sprayChemicalsThe first is to usegrowth hormoneControl the growth law of fruit trees and enhance the frost resistance.Chemical method is an emergency measure to prevent freezing damage, and short-term cold wave cooling forecast must be mastered.
In addition, after the cold wave, some simple remedial measures can be taken for different crops.For example, prying mud for root protection, pressing grass for seedling protection, etc.For spring potatoesSpring soybean, can take a small car in timeArched shedProtect against cold.After all kinds of crops are frozen, it is necessary to timelyPursueModerate quick effectnitrogenous fertilizerAnd potash fertilizer, applied per mu (1/15hm ²)ureaandpotassium chloride3~5kg each, so as to promote the plant to resume growth as soon as possible.
the way to distinguish
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Every winter, strong cold air moves southward many times, causing a large range of cooling in China.Many Chinese media are used to calling it "cold current", which is incorrect.This phenomenon should be called "cold wave".So what is "cold wave" and what is "cold current".How to distinguish them.The following is a specific explanation:
Cold wave is a kind of common disastrous weather in China, which occurs frequently,Scope of activitiesvast.Cold wave, as its name implies, means that cold air flows like tide.However, it does not mean that all cold air attacks are called cold waves. Generally, after the cold air attacks a certain place, if the temperature of those places can be reduced by more than 10 ℃ within a day (24 hours)Minimum temperatureWhen the temperature is below 5 ℃ again, this cold air is called cold wave.However, due to localgeographical environmentandclimatic conditions The cold wave standard is also different.
Cause of cold wave: The cold wave invading China is mainly caused byarcticZoneRussiaSiberia andthe people's republic ofmongolia Cold high pressure moving southward broke out in other places.Most of these areas are distributed in the Arctic. There is no sunshine in winter for a long time, and they are covered with ice and snow everywhere. The air mass staying in these areas is like lying in a large natural ice cellar, getting colder and drierCold air massWhen the air pressure increases to a certain degree, which is far higher than that in the south, it is like a flood stored on a mountainhave a chance to, and flood and pour to the south with low pressure, which forms a cold wave.
The result of cold wave: where the wind direction changes rapidly, the wind speed increases, the air pressure rises suddenly, the temperature drops sharply, and it may rain, snow, frost and freeze at the same time.The cold wave moves southward in northwest China, Inner Mongolia andNorthern regionIt is often windy and sandy.stayHuaihe RiverThe area to the north is generally characterized by little rain and occasional snowfall.After crossing the Huaihe River, precipitation opportunities increase.In winter in China, cold waves usually occur every 3 to 8 days, but the relatively strong cold waves are about 4 times a year on average.Roughly from the end of October to late January of the next year, cold waves also occur in late February in some years.When the cold wave flows southward,Warm airAs a result, the areas we pass through will be affected by warm air and the temperature will rise significantly.If the area we passed was already inWarm air massUnder control, under the continuous transmission of warm air in front of the cold wave, the temperature will also rise violently.Therefore, it is often necessary to warm for a day or two before the cold wave.
The path of the cold wave invading China: The cold wave invading China is not always the same. It depends on which part of the cold air in the Arctic and Siberia has the highest pressure and which part of China has the lowest pressure.In addition, it is also affected by China's high mountains.
Then what kind of phenomenon is the cold current.To understand what is a cold current, we should first understand what isocean current。The water on the surface of the ocean flows regularly and slowly along a certain direction with a huge scale and relatively stable speed. It is called ocean current, also called ocean current.According to its nature, ocean currents can be divided into warm currents and cold currents.Where the current flows,Sea water temperatureIt is called warm current when the water temperature is higher than that of the passing sea areaLow latitudeflow toHigh latitudeAll of the currents are warm currents;Where the current flows, the sea water temperature is lower than the sea water temperature in the passing sea area, it is called cold current. Generally, the current flowing from high latitude to low latitude belongs to cold current.The east-west current is generally warm, and only the southern hemisphere currentWesterly drift, due toAntarctic continentAnd offshorefloating iceThe sea water temperature is low and belongs to the nature of cold current.
Impact of current:ocean currentThe main impact of the cold current is that it has a great impact on the coastal climate of the mainlandCoastal zoneThe temperature and precipitation of.The sea area and coastal zone where the warm current flows generally have higher temperature, moist air and abundant rainfall than other sea areas at the same latitude, which is beneficial toagricultural production。
The main causes of ocean current are: the sea surface is blown by long-term and stable wind direction;In addition, the density of sea water, the height of sea surfaceDeflection force of earth rotationIt is related to the land contour and the distribution of islands.Although the distribution and flow direction of ocean currents are complex, there are still laws to follow.
2. A high latitude circulation is formed north of 40 ° or 60 ° north latitude.Its circulation direction is counterclockwise, cold current in the west and warm current in the east.
4. The east-west current, except the westerly drift in the southern hemisphere, is warm.
From the above analysis, it can be seen that cold wave is a form of air (cold air) flow, and cold current is a category of ocean current (sea water) flow.Therefore, cold wave and cold current are two completely different concepts, and they cannot be confused.
Cold Wave Benefits
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Cold waves also have beneficial effects.geographerThe analysis of the research shows that the cold wave contributes to the heat exchange on the earth's surface.As the latitude increases, the earth receivessolar radiationThe energy gradually weakens, so the earth forms tropical, temperate 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.[6]
Miyako Wind Power Station, Japan
Meteorologists believe that cold wave is the guarantee of favorable weather conditions.For example, China is affected by the monsoon, and the winter climate is dryDry season。But when the cold wave invades south, it often brings a wide range of rain and snow weather, which alleviates thedrought severityTo benefit crops.The sentence "Snow augurs a good year"Agricultural proverbsWhy can it spread among the people through the ages.that is becauseSnow waterInnitridesHigh content, more than 5 times of ordinary water, can makenitrogenSubstantial improvement.Snow water can also accelerate the soilOrganic matterDecomposition, thus increasingOrganic fertilizer。Heavy snow covers winter crops, just like cotton quilts, which can resist cold and keep warm.There is a saying that "the cold winter is not cold, and the coming year is not rich", which also has its scientific truth.cropsPest controlExperts believe that the low temperature brought by the cold wave is the most effective natural "pesticide", which can kill a large number of people who are hiding in the soil for winterpestAnd germs, or inhibit their growth to reduce the disease and insect pests in the coming year.According to localagricultural technician stationinvestigationdata displayIn the year with heavy snow, pesticide can be saved by more than 60%.[6]
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.[6]
Related news
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At the beginning of April 1983, the thickness of the cold wave snow in the western mountainous area of southern Xinjiang reached 1m, onlyWensu CountyAbout 30% of young animals were lost.[6]
Winter and spring of 1956~1957, 1965~1966, 1976~1977,TibetThere were three times of extensive, intensive, deep snow, long duration and serious disasterssnowstorm。[6]
From October 24 to 29, 1977, it rained and snowed in most parts of northern China, and in northern China and eastern ChinaHeavy rain(snow), of whichInner MongoliaUniversal descentBlizzard, the largest in the north of XimengSnow volumeUp to 58mm,Uzbek LeagueNorthChifengNorth of the city, north of Zhemeng andXing'an LeagueThe snowfall in the pastoral area of Hulun League is 25-47mm. The snow thickness in the above areas is 16-33cm, and locally 60-100cm, which is rare in recent 40 yearsRoad closure, traffic interruption, causing serious snow disaster.[6]
Large scale low temperature, rain and snow, freezing, etc. in China since January 10, 2008natural disaster（Snow Disaster in China in 2008）。Shanghai, Zhejiang, Jiangsu, Anhui, Jiangxi, Henan, Hubei, Hunan, Guangdong, Guangxi, Chongqing, Sichuan, Guizhou, Yunnan, Shaanxi, Gansu, QinghaiNingxia, Xinjiang andXinjiang Production and Construction Corps20 provinces (autonomous regions and cities) are affected by low temperature, rain, snow and freezing disasters to varying degrees.As of February 24, 129 people had died, 4 people were missing, and 1.66 million people had been relocated urgently;The affected area of crops is 178 million mu, the disaster area is 87.64 million mu, and the yield is 25.36 million mu;485000 houses collapsed and 1686000 damaged;DisasterDirect economic loss151.65 billion yuanRMB。The damaged forest area is about 279 million mu, 30000 treesNational key protected wildlifeFrozen to death in snow disaster orfrostbite；The affected population has exceeded 100 million.Seven provinces, including Hunan, Hubei, Guizhou, Guangxi, Jiangxi, Anhui and Sichuan, were the hardest hit.[6]
China News NetworkJanuary 19,SiberiaThere is an overwhelming cold wave waiting to start. Affected by it, 8 provinces and cities in the south will welcome a wide range of rain and snowFreezing weather。With the arrival of cold air, most parts of the country will start the "ice model".[7]
At 18:00 on March 7, 2016,Chinese Central Meteorological StationRelease cold waveYellow warningIt is expected that from the night of the 7th to the 11th, most of central and eastern China will experience strong wind, cooling, rain and snow from north to south, and the temperature in most areas will drop 6-10 ℃[8]。
