Economic recession impact Voters Voting behavior
Name: Li Yang Student ID：S07660
Research paper supervisor:Dr.Seku Conde
Minzu University of China
2007-2008 Academic Year
Key words: snowstorm; cause; La Nina event; atmospheric circulation anomalies; global warming
1 Introduction
Disasters caused by prolonged low temperatures, icy rain and heavy snow in the southern part of China have killed 107 people and left eight others missing. It also collapsed homes, power blackouts, closed highways , stranded millions of passengers and destroyed crops in its trail. Direct economic loss was estimated at 111.1 billion yuan (SongSt,2008).
Overall, the rare snow and freezing disaster, with four characteristics:widespread; long-lasting;high-intensity;serious-damages(LiuYi,2008).International meteorological authorities and experts analyze that continuing snowstorm in the middle-eastern China was a result of several causes combined and was mainly caused by La Nina phenomenon and abnormal atmospheric circulation. Response to the rare disaster, we should clarify the causes, master the regulation of climate change, then strengthen the disaster forecast accuracy, all these make great significance in disaster prevention and rescue in the future.
2 The impact of snowstorm
The lingering blizzard has became China's worst winter weather in half a century. It has stranded over 5.8 million people just before the Lunar New Year, the biggest festival in China when almost everyone is travelling back to home to be with their families. Bitter cold and unusually heavy snowfalls in regions of southern China accustomed to a milder climate have paralyzed road and rail links and downed power lines, leaving large swaths of the country without electricity. Power crisis, food inflation... all kinds of problems came out to be settled.
The terrible weather has been more extreme in the central provinces of Anhui, Hubei, Hunan, Guizhou et. In Anhui, more than 1.21 million people were affected, with direct losses amounting to 210 million yuan ($29 million).Snow started to fall in Anqing, Lu'an, Hefei and other cities on January 12, damaging 87,000 hectares of farmland. A total of 1,033 houses were toppled by the snow (SongSt,2008)..
In Hubei, one of the hardest hit, at least 1.1 million people in 27 cities were affected, with 10 killed, including one crushed under the collapsed roof of a gas station in Wuhan, Freezing temperatures caused water pipes to burst in Wuhan, causing drinking water shortages for more than 100,000 people (SongSt,2008).
Statistics show that the snow has so far killed at least 60 people and forced the evacuation of nearly 1.76 million people. From January 25 to 31, a total of 5.8 million passengers were stranded throughout the railway network and more than 8,000 cargo trains were affected(XinHua,2008).
Fig 1. the disaster of All the affected provinces (YaoRunfeng.et.2008)
3 main causes
3.1 La Nina event
La Nina is a large pool of unusually cold water in the equatorial Pacific that develops every few years and influences global weather. It is the climatic opposite of El Nino, which is a warming of the Pacific. During La Niña years, the trade winds are unusually strong due to an enhanced pressure gradient between the eastern and western Pacific. As a result, upwelling is enhanced along the coast of South America, contributing to colder than normal surface waters over the eastern tropical Pacific and warmer than normal surface waters in the western tropical Pacific.
Fig 2. The principle of “La Nina”(CuiJie,2008)
Changes in global atmospheric circulation patterns accompany La Niña and are responsible for weather extremes in various parts of the world that are typically opposite to those associated with El Niño. These patterns result from colder than normal ocean temperatures inhibiting the formation of rain-producing clouds over the eastern equatorial Pacific region while at the same time enhancing rainfall over the western equatorial Pacific region (Indonesia, Malaysia and northern Australia.) These patterns affect the position and intensity (weakening) of jet streams and the behavior of storms outside of the tropics in both the Northern and Southern hemispheres.
Experts said that the latest La Nina conditions had developed last August throughout the tropical Pacific and strengthened at the sharpest pace in 56 years. The sea-surface temperature during the past six months was 0.5 degree Celsius lower than normal years. Analysis showed that La Nina events this time is not only the fastest since 1951, but also the strongest in the first six months(ShenQiang,2008).
The low water temperature in the equatorial eastern Pacific Ocean makes the atmospheric circulation faster; all these abnormal directly lead cold air frequent activities. La Nina is conducive to weak the Western Pacific subtropical high pressure , and make its position easterly than perennial, which help cold air southward to China, when the airflow blocked by Hunan Nanling, it creates large-scale snowfall(FangYuan,2008). The National Climate Center predicts that this La Nina event will continue at least until summer 2008 at a medium to strong level(CuiJie,2008).
3.2 Abnormal atmospheric circulation:
Since last December, South China were affected by the warm-wet airflow from the southwest, with plenty of water vapor in the air, coupled with the enhanced La Nina phenomenon , Dong Wenjie of the National Climate Center said that blizzard mainly related to an abnormal atmospheric circulation. The cold air intersect with warm-wet air currents , then form an inversed phenomenon: warm airflow in the common height while cold air in the low-altitude; as a result, it lead to high-intensity freezing rain and snowfall in large area. The recent atmospheric circulation anomalies situation mainly performed in 4 areas (ZhengJing,2008):
3.2.1 Since January this year, atmospheric circulation showed low in east while high in West in Eurasian region which belong to high latitudes ,this circulation anomaly has maintained 19 days, which is three times more than ever, and it is he longest since 1951 , cold air is conducive to invade China from the northwest along the Hexi Corridor.
3.2.2 The western North Pacific subtropical High Voltage is stronger and Northerly, this powerful position maintained over the sea in southeast of China stably and extended to west several times, so that the well-being air intersect mainly in middle and lower reaches of the Yangtze River and south .
3.2.3 The Low Voltage in south of Qinghai-Tibet Plateau is active, which is rare in the past 10 years, it promotes warm air transfer to China along the Yunnan-Guizhou Plateau continuously.
3.2.4 In the interface of well-being air, warm air in the upper part, formed stable inversion layer in the lower of troposphere, which is the direct reason of large-scale Freezing Rain.
Based on the combination of 4 factors above, the stable abnormal atmospheric circulation situation has been maintained more than 20 days since mid-January, resulting in large-scale low-temperature freezing rain and snowstorm in eastern China continuously. However, E-type atmospheric circulation and La Nina phenomena, can only partly explain the causes of snow disaster (SongSt,2008).
3.3 Globlal warming
In the context of global warming, the frequency of disastrous weather increased, a place more of more hot dry, perhaps another place more colder with more precipitation. Based on experts’ analysis, the beginning of 2008 rain and snow weather in China and some other countries and regions as extreme weather is one of the performance of in the context of global warming. Global warming is causing extreme weather events more frequently, more volatile and more unpredictable(MaRui,2008). In recent years many countries around the world have a serious attack of cold weather and blizzards. However, in the context of global warming, extreme events continue to occur, climate disasters and their derivatives disasters has become increasingly difficult to predict (CuiJie,2008).
Guangdong Meteorological department chief experts, China Meteorological Administration, the Guangzhou Institute of Tropical marine meteorological WuDui said: "This is another form of expression of global warming, now bright and balmy days has reduce, extreme cold and extreme hot weather has increased. Overall warming trend has not changed. Another meteorology expert, an academician from Chinese Academy of Engineering Li Zechun explained:＂The extreme weather events is directly caused by the atmospheric circulation anomalies, and circulation anomalies and global warming is inseparable＂.Some non-professionals give related explanation: “After global warming, when the warm atmosphere contact with the surface of the ocean, it will have an abnormal phenomenon, which is substantial increase in extreme weather events, a certain place at a certain time, will suddenly become very cold”..Today, we still can’t unable link snow Catastrophe to global warming simply,just as the Indian Ocean Tsunami 3 years ago, and the United States Katrina Hurricane 2 years ago, they can’t equate to greenhouse. But such extreme weather events, in essence, stems from human activities lead to the abnormal weather, It should be an indisputable fact that it’s nature's wreaked revenge(Hu Shuli,2008).
3.4 Other factors:
3.4.1 Since mid-January, the Siberian cold air from north warm wet air from south intersect in the middle and lower reaches of the Yangtze River, middle and lower reaches of the Yangtze River, Anhui, Hubei in the vicinity of latitude 30 degrees, where is precisely the same intersection of west wind and trade wind, North-South flow intersection, certainly cause a heavy snow(ZhengJing，2008).
3.4.2 Another reason, many lakes in the middle and lower reaches of Yangtze River, evaporation of water vapor of local water surface is also sources of snow(ZhengJing，2008).
3.4.3 Due to the blocking of Nanling, the remaining [...]
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