July 30, Beijing would not snow

Summer snow whether is it possible?

Meteorologists detailed snow principle emphasizes the recent Beijing impossible snow

Recently, Beijing newspaper report said on 30 July at 18: 10 p.m., East third ring road, HongQiao area long appeared last approximately 5 minutes of snowfall.

News, many people are surprised that the network is now have blogged: 7 month in summer, summer intensive weather, how will appear snowfall? summer Beijing is there may be snow?

"Beijing is no snow"

About "the cause of xiaxue," the story through the mouth of the experts gave an explanation: as the summer and warm air convection sharp, if air suddenly with ice or snow of low-level cumulonimbus clouds to the ground, local temperature too low, it will appear in a small area within a short time of falling snow.

Near many residents are said to see snow, "there are 5 coin size".

But then it begins to rain, snow and rain mixed together, such as the clouds like a fog.

Reporter continuous asked the Central meteorological station, Beijing Meteorological etc units, all respondents expressed the meteorological engineers have no evidence of Beijing on the day of the fallen snow, located in the city of several meteorological observatories have not logged into the snow, snowfall of hearsay is illusion.

The Beijing Meteorological Bureau Office Director Yang Jin Hui also stressed that: "I can responsibly say that (30 July), and there is absolutely no snow in Beijing!" as reported in expert explains, there are also some meteorologists raised objections. The national science and technology, the researchers said, "and warm air flow theory of violent confrontation", but on the day of the Beijing urban temperatures above 20 ° c has been in, even if unexpected weather conditions cause local temperature reduction nor less than 0 ℃, the maximum is rain, no snow. Senior Engineer of BeijingMunicipal meteorological observatory Zhang Ying also stated in an interview, on the day of the Beijing air below zero in the 3200 meters height (i.e. 3200 m altitude above atmospheric temperature is below zero), in this case, there is no snow in Beijing.

Snowfall of two basic conditions

All precipitation must meet two basic criteria: one is the air there is enough moisture saturation, can form a precipitation clouds; the second is a cloud of dust containing granulated or Crystal, they can form a rain or snow "condensation nuclei".

Last descent is rain or snow, depending on the temperature. If the surface temperature is above 0 ° c, could even snowflakes in the high-altitude-temperature formation of clouds, before falling to the ground it melts.

Artificial snow in principle, when the natural formation of air and clouds do not have the snow conditions, cloud cover and spray some low particulate matter may cause condensation to form can overcome air buoyancy of snowflakes.

Initially, people tried many interesting methods of artificial snow on the ground, for example, the release of large amounts of smoke and fire into the air; the kite into the air, and then power up the kite, use EDM on producing Crystal; flight into cloud sow seeds of liquid water and dust ... But these effects are not very satisfactory.

Finally, they finally found the most suitable material for spraying snow — dry ice.

Dry ice is the solid carbon dioxide, its temperature is usually lower than minus 78.5 ℃. In 1946, the researchers will dry ice granulated Isaac to a temperature of about minus 20 ° c at the top of the cloud, snow soon soared from this drop down. This is because the solid carbon dioxide Crystal while meeting the "low" and "condensation nuclei", these two conditions make clouds water vapor condensation in quickly. Now people need rain or snowfall, the use of artillery mount fired into the air, ice also sometimes use aircraft or small rocket to spray dry ice.

Thus, in any event, the decision of snow, not the key factor is that rainfall in surface temperature.

The scene with artificial snow

Beijing, "snow" message appeared in the press, journalists found at a site in an article called "snow" in July might be a record company artificial snow.

Press followed by and the record companies were contacted.

According to the head of the Department for Business Alliance introduced Ms., 30 July 18 o'clock, the record company staff in a long near HongQiao about 20-storey office building's top photography MV. for drama, film crew by a snow machine for artificial snow. Snow grooming machines work for about 10 minutes. But then, the wind and rain interrupted the snow and photography activities. At that time, the film crew of snow grooming process time is very short, and 5 minutes from the "snow day".

Ms. told reporters, when their next July to see the "snow" reports and relevant experts, considers possible explanations and their company's image, then publish a relevant message.

She also said that he could not confirm, artificial snow and was witness to see snow near is relevant.

Snow grooming machine can be a certain percentage of air and water, snow, and a large number of drops of water, spraying condensation in the air, eventually forming a realistic snow.

Because snow water mixing additives, therefore it is difficult to melt the snow.

Summer or snow

According to the Beijing Meteorological records, the summer in recent decades, Beijing has seen snow weather.

Availability of experts also noted that, in BeijingLocated in the plain, less prone to summer snowfall of environmental conditions, but higher in elevation or mountains high, of most snow is not impossible. 1981: June 1, Shanxi guancen forest area lowered snow, up to 25 cm deep. In 1987, 5 June, the day of Zhangjiakou snow, temperatures dropped to minus 7 degrees centigrade. 5 June 2006, Hami, Xinjiang barkol along the tianshan area in an abrupt drop in small to medium snow. This year also just "two xiaxue", one in 11 June, located in China's largest inland lake Qinghai Lake, another snow on 20 June in Gansu province lowered Gannan Tibetan Autonomous Prefecture.

Summer snow is rare, highly ornamental, but such extreme abnormal weather has brought to life a lot of trouble.

For example, this year the Gansu province in Gannan Tibetan Autonomous Prefecture of snowfall, causing local farmers to grow large quantities of barley, livestock grazing also froze to death, the loss suffered large animal husbandry.

Not only Chinese summer snowfall occurs, abnormal climate in the world.

2004 11 July, Germany Bavarian mountain, storm into the Blizzard, local temperature has dropped to-6 ° c, 10 years in Germany in July, the minimum temperature records.

Sweden, Australia, Italy and the United Kingdom also have appeared in recent years, summer snowfall with varying degrees of disruption of normal life.

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Causes of abnormal climate

Scientists believe that lead to global climate anomalies of landmark phenomenon mainly has the following two ways:

1. greenhouse effect

Due to the global forest area in the meantime factories, automobile and household fuel produces large amounts of carbon dioxide continue to increase, some harmful gases also caused serious damage to the ozone layer, which lead to global temperature rise, the formation of the "greenhouse effect".

The gradual warming of the climate affect the circulation of induced abnormal rainfall or drought.

2, the El Niño phenomenon

El Niño refers to the eastern equatorial Pacific sea water temperature is too high fo

r the State continued for six months to one year, but recent research has shown that the effects of the El Niño phenomenon is beyond the scope of the Eastern Pacific, Indian Ocean, and even the global climate is affected by an exception.

In addition, sustainable urbanization, population concentrated in urban air temperature is higher than in the suburbs, in the small range will result in increased air flow.

A large number of factories in the city and the emission of smoke, and the atmosphere of "condensation nuclei", this is also the increase in weather, rain and snow.

Interviews/reporter Wu Yun Pu