What are the common climate phenomena in the world?
The basic feature of El Nino phenomenon is that the sea surface temperature along the Pacific coast rises abnormally, the sea water level rises, and a warm current flows southward. It turns cold water in the East Pacific into warm water, causing tsunamis and storms, causing drought in some areas and excessive rainfall in others.
Both hurricanes and typhoons refer to tropical cyclones with wind speeds exceeding 33 m/s, but they have different names because of different regions. Strong tropical cyclones appearing in the northwest Pacific Ocean and the South China Sea are called "typhoons"; Hurricanes that occur in the Atlantic Ocean, the Caribbean Sea and the eastern North Pacific Ocean are called "hurricanes". Hurricanes can release amazing energy in one day. Hurricanes and tornadoes cannot be confused. The latter time is very short, and it is instantaneous, and the longest is no more than a few hours. In addition, tornadoes are usually accompanied by hurricanes. The biggest feature of tornado is that when it appears, it often has one or several funnel-shaped cloud columns similar to "trunk", accompanied by storm, lightning or hail. When a tornado passes through the water, it can absorb water and rise to form a water column, and then connect with the cloud, commonly known as "dragon with water". When passing through land, houses are often rolled down, and even people are sucked into the air.
One reason why tropical oceans produce hurricanes is that warm seawater is its power "fuel". Therefore, some scientists began to study whether the warming earth will bring more powerful and harmful tropical storms. Most meteorologists believe that the earth seems to be getting hotter and hotter. They think that carbon dioxide and so-called greenhouse gases in the atmosphere are warming the earth. Researchers warn that people must seriously think about the problem of global climate change decades or even centuries later. It should be pointed out that a weather and climate event, such as a strong hurricane or an active hurricane season, does not mean global warming.
Sandstorm is a general term for sandstorm and sandstorm, which refers to a serious sandstorm weather phenomenon in which strong winds blow a large amount of dust substances on the ground into the air, making the air particularly turbid and the horizontal visibility is less than 1km. Among them, sandstorm refers to a sand-laden storm formed by strong winds blowing a large number of sand near the ground; Sandstorm is a storm formed by strong winds, which brings a lot of dust and other particles into the sky.
Causes of sandstorm weather
The weather situation favorable to strong winds or strong winds, favorable distribution of dust sources and favorable air instability conditions are the main reasons for the formation of sandstorms or strong sandstorms. Strong wind is the driving force of sandstorm, and the source of sandstorm is the material basis of sandstorm. Unstable thermal conditions are conducive to the increase of wind power and the development of strong convection, thus carrying more dust and winding it higher.
In addition, drought and lack of rain in the early stage, warming weather and rising temperature are the special weather and climate background for the formation of sandstorms; The convective cells before the ground cold front develop into clouds or squall lines, which is a small and medium-sized system conducive to the development and strengthening of sandstorms. The topographic condition conducive to the increase of wind speed, that is, the narrow tube effect, is one of the favorable conditions for the formation of sandstorms.
Main hazards of sandstorm (1) gale (2) sand burial (3) soil wind erosion (4) air pollution.
Cold wave is a kind of disastrous weather in winter, and people are used to calling it cold wave. The so-called cold wave is a weather process in which cold air from the north invades China on a large scale, resulting in a large-scale sharp cooling and northerly winds. Cold waves generally 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℃ and the lowest temperature is lower than 5℃ in one day, it is called a cold wave process. It can be seen that not every cold air heading south is called a cold wave.
Main causes of cold wave
In the Arctic, due to the weak sunlight, the ground and the atmosphere get less heat, and it snows all year round. In winter, the direct sunlight passes through the equator and reaches the southern hemisphere. The arctic region is colder and wider, and the temperature is generally below MINUS 40℃-50℃. Large-scale cold air masses gather to a certain extent, and under the action of suitable high-altitude circulation, they will invade southward on a large scale, forming cold wave weather.
Harm of cold wave
1, causing freezing damage to crops (the biggest damage in autumn, winter and spring)-severe cooling.
2. Blow down ships and destroy buildings and farms-gale
3. Press power lines and power poles-heavy snow and freezing rain.
La Nina refers to the phenomenon that the sea surface temperature in the eastern and central equatorial Pacific Ocean continues to be abnormally cold (just the opposite of El Niñ o phenomenon). This is a new term used in meteorology and oceanography.
La Nina phenomenon is an abnormal cooling of seawater in the central and eastern Pacific Ocean. The east wind blows the seawater heated by the sun to the western Pacific Ocean, causing the sea level in the west to rise by nearly 60 cm compared with that in the east. The sea water temperature in the west rises, the air pressure drops, the humid air accumulates to form typhoons and tropical storms, and the bottom sea water in the east flows backward, which makes the sea water in the east Pacific cool.
cause
So, how was La Nina formed? El Nino is related to the warming of sea surface temperature and the weakening of trade winds in the equatorial Middle East Pacific, while La Nina is related to the cooling of sea surface temperature and the strengthening of trade winds in the equatorial Middle East Pacific. So La Nina is actually the product of the interaction between tropical ocean and atmosphere.
The motion of the ocean surface is mainly constrained by the sea surface wind. Because of the existence of trade winds, a large amount of warm water is blown to the equatorial western Pacific Ocean and blown away in the equatorial eastern Pacific Ocean, which is mainly supplemented by cold water below the sea surface. The SST in the equatorial eastern Pacific is obviously lower than that in the western Pacific. When the trade winds strengthen, the upwelling phenomenon of deep seawater in the equatorial eastern Pacific becomes more intense, resulting in abnormally low sea surface temperature, which makes the airflow in the equatorial eastern Pacific sink, while the upward movement of the airflow in the equatorial western Pacific intensifies, which is conducive to the strengthening of the trade winds, thus further aggravating the development of cold water in the equatorial eastern Pacific and triggering the so-called La Nina phenomenon.
frost/frostlike powder
Water vapor condenses into white crystals on the ground and the surface of low temperature objects, which is frost. If there is little water vapor and no frost, it is said that black frost has freezing damage to crops, which is called frost.
First frost is a weather phenomenon in autumn and winter. Frost is mostly in the transition season of spring and autumn, with the temperature above zero degrees Celsius during the day and below zero for a short time at night. In agrometeorology, it refers to the phenomenon that the temperature on the soil surface or near the plant crown drops below zero, causing crops to suffer. When frost occurs, it is often accompanied by or without hoarfrost. Frost without hoarfrost is called "black frost" or "frost killing". On a clear and windless night, the frost formed by radiation cooling is called "radiation frost". Frost caused by cold air intrusion is called advection frost. The frost formed by these two processes is called advection radiation frost. No matter what kind of frost appears, it will bring more or less damage to crops.
Freezing rain is a weather phenomenon seen in early winter or late winter and early spring. When the strong cold air meets the southbound warm and humid airflow, the cold air is inserted under the warm air like a wedge, and the near-surface temperature drops below zero, and the humid warm air is lifted to form clouds, causing rainfall. When raindrops fall from the air, because the temperature near the ground is very low, a layer of crystal clear thin ice will form on the surface of telephone poles, trees, vegetation and roads, which is called "freezing rain" in meteorology.
[Edit this paragraph] Reason
In winter, rain falls on trees, tall buildings, rocks, telephone poles and other objects and immediately becomes ice. People used to call it "dripping into ice". This kind of rain is called "freezing rain" in meteorology (its condensate is called "Song Yu"); It is a kind of supercooled water drop (the temperature is lower than 0℃), which is different from the common water drop that people often say. In the cloud, it should be condensed into ice particles or snowflakes, but the necessary freezing nucleus can not be found when freezing, so it becomes supercooled water droplets that can be frozen when touching objects.
"Freezing rain" falls on wires, branches and the ground, and then forms a thin layer of smooth ice. The ice is getting thicker and thicker, and it freezes while flowing in the process of condensation. As a result, a series of stalactite-like icicles and ice spines (commonly known as "ice hanging") were produced. They are crystal clear, and when they meet the sun, they emit colorful light, which is really beautiful! Unfortunately, when its weight exceeds the carrying capacity of the object, tragedy happens. To form "freezing rain", it is often inseparable from specific weather conditions to make supercooled water droplets land on the ground smoothly: the temperature of the air layer about 2000 meters near the ground is slightly lower than 0℃; The temperature of the air layer from 2000 meters to 4000 meters is higher than 0℃, which is warmer; The upper layer is lower than 0℃, so the supercooled water droplets, ice crystals and snowflakes on the upper layer of the cloud fall into the warmer gas layer and become liquid water droplets. Then it falls and enters the frozen layer which is not too thick. When they fall with the wind and are ready to freeze, they have already touched the cold objects in the form of supercooling, and suddenly formed a solid "freezing rain"!
Freezing rain is composed of supercooled water droplets, which collide with objects with a temperature below 0℃ and freeze immediately. Raindrops below 0℃ can remain supercooled in air with a temperature slightly lower than 0℃, and their appearance is the same as that of ordinary raindrops. When they fall on an object with a temperature below 0℃, they will immediately freeze into a smooth and transparent ice layer, which is called snowball. Severe snowstorms will crush trees and telephone poles, stop communication and power supply, hinder road and railway traffic, and threaten the flight safety of aircraft. When freezing rain occurs, the ground is often not too cold (0℃ ~ 3℃), the sky is unstable and there is a warm layer with a temperature higher than 0℃. Precipitation is a raindrop in the warm layer. When it falls into the atmosphere near the ground, it becomes supercooled and freezing rain, which often causes some harm.
If raindrops keep hitting the surface of these frozen objects, they will gradually form icicles. After the sun came out, the icicles in the sun shone, enchanting and charming, and the freezing rain added beautiful and moving scenery to people. But the harm it causes is also very serious. If the weight of the conductor increases after icing, it will shrink when it is cold, which will lead to the fracture of the conductor and the interruption of communication and transmission; Crops are frostbitten and frozen to death after freezing rain; If the ground freezes, traffic accidents will increase sharply. Therefore, the freezing rain for several days in a row has caused great disasters.
Tornado is a strong, small-scale air vortex, which is produced by strong convective movement of air in extremely unstable weather. It is a strong cyclone produced by funnel-shaped clouds (tornadoes) extending from the bottom of thunderstorm clouds to the ground. Its wind power can reach more than 12, and the maximum can reach more than 100 meters per second, usually accompanied by thunderstorms and sometimes hail.
Tornadoes are the product of thunderstorms in the clouds. Specifically, a tornado is a form in which a small part of the huge energy of a thunderstorm is released in a small area. The formation of tornadoes can be divided into four stages:
(1) The instability of the atmosphere produces a strong updraft, which is further strengthened due to the influence of the maximum transit airflow in the rapids.
(2) Due to the interaction with the wind with shear speed and direction in the vertical direction, the updraft starts to rotate in the middle of the troposphere, forming a mesoscale cyclone.
(3) With the development and upward extension of mesoscale cyclone to the ground, it becomes thinner and stronger. At the same time, a small area to strengthen cooperation, that is, the primary tornado is formed inside the cyclone, and the same process of producing the cyclone forms the tornado core.
(4) The rotation in the tornado core is different from that in the cyclone, and its intensity is enough to make the tornado extend to the ground. When the developing vortex reaches the ground, the ground air pressure drops sharply and the ground wind speed rises sharply, forming a tornado.
When the supercooled precipitation of rime hits the surface of an object with a temperature equal to or lower than zero degrees Celsius, a glassy, transparent or dim ice sheet with rough surface is formed, which is called rime.
The formation of strange rain head
The formation mechanism of rime and rime is similar, generally appearing on cloudy days, mostly caused by cold rain, generally lasting for a long time, with no obvious diurnal variation, and can be produced day and night. Rime is a precipitation phenomenon under a specific weather background. The typical weather of rime formation is mild cold (0-3℃), with rain, strong wind and heavy fog drops, which usually occurs when cold air meets warm air, which is very powerful. During this period, the northwest airflow and southwest airflow over the Jianghuai basin were very strong, and cold air invaded the ground. At this time, the temperature of the ground layer is low (slightly lower than zero degrees Celsius), and there is a warm air layer or cloud over 1500 to 3000 meters, forming a warm air layer or cloud. More than 3000 meters, there is an upper atmosphere, the temperature is below zero degrees Celsius, and the cloud temperature is often -65433. That is, there is an inversion layer near the ground The vertical structure of the atmosphere is cold from top to bottom and warm in the middle, with ice crystal layer, warm layer and cold layer from top to bottom.
Hail is a kind of solid precipitation. It is a spherical or conical ice block, which consists of transparent layers and opaque layers alternately. Generally, the diameter is 5 ~ 50 mm, and sometimes it can reach more than 10 cm, which is also called hail or hail block. Hail often destroys crops and threatens the safety of people and animals. This is a serious natural disaster.
Hail formation
Hail falls from the clouds like rain and snow. But the clouds that hail are very strong cumulonimbus clouds, and only very strong cumulonimbus clouds can hail.
Hail danger
Hail disaster is a serious meteorological disaster caused by strong convective weather system. Although it appears in a small range and in a short time, it is fierce and strong, and is often accompanied by sudden disastrous weather processes such as strong winds, heavy precipitation and sharp cooling. China is a country with frequent hail disasters. Hail brings huge losses to agriculture, construction, communication, electricity, transportation and people's lives and property every year. According to relevant statistics, the economic losses caused by hail in China reach hundreds of millions or even billions of yuan every year.