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User:Towerman/translation/雪

维基百科，自由的百科全书
天气條目系列之一
天气
溫帶及極地季節
熱帶季節
风暴
降水
主題（英语：Index of meteorology topics）
詞彙表
氣象主题
美國科羅拉多州森林中的雪
不同形狀的雪花

雪是降水形式的一种，是从云中降落的水的结晶状固体冰（常以雪花的形式存在）。因为雪是由小的冰颗粒物构成，所以是一种颗粒材料（英语：granular material）。它的结构开放，因此显得柔软。雪花有多种的形式和大小。球状降雪是由于在降落过程中雪被融化后又重新冻结，此类降雪有冰雹、冰丸、米雪。

雪降落的过程被称为下雪或降雪。降雪一般形成于被称为溫帶氣旋的一种低气压系统周围的空气向上运动的区域中。雪可能会在那些伴随着暖锋的天气系统里向极地方向降落，降雪发生在这些系统的逗号头型降水模式（在温带气旋的西面和向极的区域附近的逗号形状的云和降水模式）中。在有相对较暖的水体存在的地方（比如从湖泊中蒸发的水汽），大湖效应降雪变得重要，一般发生在暖湖的下风向，在温带气旋的背后的寒冷的气旋气流中。湖效应降雪在局部地区可能会非常大。雷打雪可能会发生在气旋的逗号头里和湖效应降水带里。在山区，上坡气流在上升过程中在山坡的迎风（英语：Windward and leeward）面达到极限，如果这时空气够冷的话，有可能会有大雪发生。降雪量以及对应的雪水当量降水量是由多种雨量计测量得到的。

形成

火車被雪阻着
  • 大氣中的水蒸汽直接凝华或水滴直接凝固而成，就是雪。也可說是雲中的溫度過低，小水滴結成冰晶，落到地面仍然是雪花時，就是下雪了。冰融化時會吸熱，所以地面氣溫會比下雪時低。

條件

  1. 大氣中需含有較冷的冰晶核。
  2. 充分的水汽。
  3. 0℃（冰點）以下。如該冷空氣相當強烈，並帶著濕氣，1℃至10℃的氣溫同樣可以降雪。

能降雪的地方

氣候區屬中緯度至高緯度（即大約於南回歸線以南／北回歸線以北地區）的地方就會有降雪的機會，如果於低緯度地方中有些地勢高於海拔2000米的高山或高原也有同樣的機會。

海洋氣流也能間接影響該區下雪的機會率，如果在高緯度地區一帶有較多暖流支配，會減低該區下雪的機會（例如日本本州至九州一帶）。

雪花

主条目：雪花

雪花是在雲內由微小的冰晶互撞黏在一起後形成豐富多樣的形狀。沒有兩個雪花是完全相同的，但雪花仍然謹守著最初的冰晶基本的六角形對稱標準結構。透過顯微鏡可以看見雪花錯綜複雜的構造大多都是六角形的，而雪花的中心一定呈現出對稱的六角形，它之所以有這樣的形狀，是因為它要在平面上以最有效率的方式佈置，它是結晶學的研究對象之一。

天氣非常寒冷時，冰晶不易黏在一起，雪呈細粉狀的小雪珠。雪珠是雲中溫度低於攝氏零度的許多小雲滴在冰晶上互相碰撞凝結而成，仔細觀察雪珠的形狀，可以看出小雪珠是由許多細白的冰粒聚集而成的。當冷空氣逐漸向前推移，上升氣流減弱，雲中水氣直接在冰晶上凝結成較大的形態，此即我們所見到的雪花。如果溫度接近冰點，則會落下溼雪，形成較大的雪花，特別是無風的時候。大型的星形雪花直徑可達5到7公分。多數的雪花在落下地面的途中會融化成雨，只有當接近地面的空氣夠冷，才能讓雪花落到地面成雪。

纪录

世界最高的季节降雪量有2,896 cm（1,140英寸），是于1998－1999降雪季节在美国华盛顿州贝灵厄姆附近的贝克山滑雪场处测得。[1]此前的记录为2,850 cm（1,120英寸），是于1971－1972降雪季节在美国华盛顿州的瑞尼爾山测得。[2]

世界最高年平均降雪量有1,764 cm（694英寸），[3]是于1981-2010年间在日本青森县的酸汤温泉（英语：Sukayu Onsen）处测得。

北美最高的年降雪量为1,630 cm（641英寸），[4]是在美国华盛顿州的瑞尼爾山测得。

世界最深的雪深有1,182 cm（465英寸），是于1927年2月14日在日本伊吹山的高度为1,200米（3,900 ft）处的山坡上测得。[5]

北美最高的雪深为1,150 cm（451英寸），是于1911年3月在美国加州塔马拉克（英语：Tamarack, California）2,100米（7,000 ft）高度处测得。[5]

世界上人口超过百万的大城市中降雪最多的城市是日本的札幌市，年平均降雪为595 cm（234英寸）。

雪的融化

当有能量输入的时候，积雪会由固态转变为其他形态。使积雪融化的能量可能来自下列途径：辐射（太阳发出的短波辐射或者长波热辐射）、热传导（当气温高于0℃时），或者通过落入积雪的，温度超过0℃的雨滴。积雪的融化速度，不仅取决于所输入的能量的多少，也取决于当时的气温和湿度。具体说来，空气越干燥，积雪融化的速度越慢，因为此时雪更容易升华——即固体不经由液体，直接转变为气体的过程——而升华需要较多的能量，这使得周围的积雪被冷却，从而减缓了融化的速度。

通过“湿球温度”和“露点温度”，我们可以界定积雪融化过程的三个状态。“湿球温度”指的是从干湿计的湿球温度计上读出的温度，该温度始终低于大气温度——即使大气相对湿度为100%的时候也不例外。而“露点温度”指的是，空气中所含的气态水达到饱和，从而凝结成液态水所需要的温度。露点温度又总是低于湿球温度。

  • 当湿球温度低于0℃的时候，积雪升华。这个过程十分缓慢，而此时积雪也保持干燥。在相对湿度小于20%的时候，升华甚至可以在7℃的气温下进行。
  • 当湿球温度高于0℃，而露点温度低于0℃的时候，积雪熔解。这时，固态的雪既转化为气态，同时又转化为液态。
  • 当露点温度也高于0℃的时候，积雪会融解，也就是说，积雪只从固态转变为液态。这时积雪融化的速度最快。

举例来说，在相对湿度为50%的时候，当气温低于3.5℃时，积雪升华；当气温介于3.5－10℃之间时，积雪熔解；当气温高于10℃，则积雪融解。

雪对人类社会的影响

A snow blockade in southern Minnesota, US in 1881
Driving in a blinding snowstorm can be dangerous and risky.

Substantial snowfall can disrupt public infrastructure and services, slowing human activity even in regions that are accustomed to such weather. Air and ground transport may be greatly inhibited or shut down entirely. Populations living in snow-prone areas have developed various ways to travel across the snow, such as skis, snowshoes, and sleds pulled by horses, dogs, or other animals and later, snowmobiles. Basic utilities such as electricity, telephone lines, and gas supply can also fail. In addition, snow can make roads much harder to travel and vehicles attempting to use them can easily become stuck.[6] Snowfall can have a small negative effect on yearly yield from solar photovoltaic systems.[7]

The combined effects can lead to a "snow day" on which gatherings such as school or work are officially canceled. In areas that normally have very little or no snow, a snow day may occur when there is only light accumulation or even the threat of snowfall, since those areas are unprepared to handle any amount of snow. In some areas, such as some states in the United States, schools are given a yearly quota of snow days (or "calamity days"). Once the quota is exceeded, the snow days must be made up.[8][9][10] In other states, all snow days must be made up.[11] For example, schools may extend the remaining school days later into the afternoon, shorten spring break, or delay the start of summer vacation.

Accumulated snow is removed to make travel easier and safer, and to decrease the long-term impact of a heavy snowfall. This process utilizes shovels, snowplows and snow blowers and is often assisted by sprinkling salt or other chloride-based chemicals, which reduce the melting temperature of snow.[12] In some areas with abundant snowfall, such as Yamagata Prefecture, Japan, people harvest snow and store it surrounded by insulation in ice houses. This allows the snow to be used through the summer for refrigeration and air conditioning, which requires far less electricity than traditional cooling methods.[13]

Agriculture

Snowfall can be beneficial to agriculture by serving as a thermal insulator, conserving the heat of the Earth and protecting crops from subfreezing weather. Some agricultural areas depend on an accumulation of snow during winter that will melt gradually in spring, providing water for crop growth. If it melts into water and refreezes upon sensitive crops, such as oranges, the resulting ice will protect the fruit from exposure to lower temperatures.[14]

娱乐

牛津的学生们正在制造一个大雪球

有很多种冬季運動和娱乐方式都依赖于雪，比如滑雪[15]、單板滑雪[16]、雪地摩托[17]、踏雪健行、滚雪球，堆雪人、打雪仗等。Where snow is scarce but the temperature is low enough, snow cannons may be used to produce an adequate amount for such sports.[18] Children and adults can play on a sled or ride in a sleigh. Although a person's footsteps remain a visible lifeline within a snow-covered landscape, snow cover is considered a general danger to hiking since the snow obscures landmarks and makes the landscape itself appear uniform.[19]

Making a snow angel

One of the recognizable recreational uses of snow is in building snowmen. A snowman is created by making a man shaped figure out of snow – often using a large, shaped snowball for the body and a smaller snowball for the head which is often decorated with simple household items – traditionally including a carrot for a nose, and coal for eyes, nose and mouth; occasionally including old clothes such as a top hat or scarf.

Snow can be used to make snow cones, also known as snowballs, which are usually eaten in the summer months[來源請求].[20] Flat areas of snow can be used to make snow angels, a popular pastime for children.

雪还可以被用于雪雕，是在嚴寒國家盛行的戶外藝術之一。雪雕主要就是將雪當做塑形的材料，把它捏成固定的形狀，再組合起來並修整細節，跟沙雕的原理頗為相近。很多寒冷地区城市都会在冬季举办冰雪节（英语：List of ice and snow sculpture events），雪雕和冰雕都是冰雪节的重要组成部分。比如在中國東北地區是雪雕藝術最發達的地區，特別是哈尔滨市太阳岛风景区每年都會舉辦規模盛大的雪雕藝術博覽會。

Snow can be used to alter the format of outdoor games such as Capture the flag,[21] or for snowball fights. The world's biggest snowcastle, the SnowCastle of Kemi, is built in Kemi, Finland every winter.[22] Since 1928 Michigan Technological University in Houghton, Michigan has held an annual Winter Carnival in mid-February, during which a large Snow Sculpture Contest takes place between various clubs, fraternities, and organizations in the community and the university. Each year there is a central theme, and prizes are awarded based on creativity.[23] Snowball softball tournaments are held in snowy areas, usually using a bright orange softball for visibility, and burlap sacks filled with snow for the bases.[24]

雪文化

雪害

日本的 Tsuzumi，一種不常見的雪晶，因形狀像沙漏鼓而得名
  • 造成凍傷
  • 雪融後造成水災
  • 阻塞交通
  • 路面濕滑，容易滑倒
  • 积雪过厚导致建筑屋顶坍塌

地外行星的雪

已知在火星的高纬度地区有很少量的雪。[25]在土星的卫星土卫六上，有可能存在一种由碳氫化合物构成的“雪”。[26]

虽然在金星上几乎没有水，但也存在一种与雪非常类似的自然现象。麥哲倫號探測器在金星最高的山峰上拍到了高反射的物质，它和地球上的雪非常类似。这种物质的形成过程可能与雪的形成类似，但要求的温度很高。因为其高挥发性，它不能在地表凝结，因此成为气体上升到较冷的高地，然后在那里凝结并降落。这种物质的成分还不能确定，有可能是元素碲或硫化铅（方铅矿）。[27]

参看

参考文献

  1. ^ USA Today. NOAA: Mt. Baker snowfall record sticks. 1999-08-03 [2009-06-30]. 
  2. ^ Mount Rainier National Park. Frequently Asked Questions. National Park Service. 2006-04-14 [2009-06-30]. 
  3. ^ JMA. JMA. [November 12, 2012]. 
  4. ^ Annual Snowfall Totals at Paradise, 1920 to 2011 (PDF). National Park Service. 
  5. ^ 5.0 5.1 Christopher C. Burt. Record Snow Depth (for an official site) Measured in Japan. Weather Underground. 
  6. ^ Laura Cheshire. Have Snow Shovel, Will Travel. National Snow and Ice Data Center. 1997 [2009-07-08]. 
  7. ^ Rob Andrews and Joshua M. Pearce, “Prediction of Energy Effects on Photovoltaic Systems due to Snowfall Events” in: 2012 38th IEEE Photovoltaic Specialists Conference (PVSC). Presented at the 2012 38th IEEE Photovoltaic Specialists Conference (PVSC), pp. 003386 –003391. Available: DOI open access
  8. ^ Dave Larsen. School districts are using up calamity days. Dayton Daily News (Dayton, Ohio: Cox Enterprises). 2009-01-27 [2009-02-05]. Ohio school districts can use five calamity days before they must start adding extra days to the school calendar.  [失效連結]
  9. ^ Donna Willis. Districts Consider Calamity Options. WCMH-TV (Columbus, Ohio: Media General). 2009-01-30 [2009-02-05]. 
  10. ^ Joleen Ferris. Decision for city schools to stay open prompts calls from irate parents. WKTV (Utica, New York: Smith Media). 2009-01-28 [2009-02-05]. 
  11. ^ Christine Wolff, Tanya Albert. Snow may stretch out school year. The Cincinnati Enquirer (Cincinnati, Ohio: Gannett Company). 1999-03-09 [2009-02-05]. 
  12. ^ David A. Kuemmel. Managing roadway snow and ice control operations. Transportation Research Board. 1994: 10 [2009-07-08]. ISBN 978-0-309-05666-3. 
  13. ^ United Nations Environment Programme. Using Snow For Cool, Innovative Solutions. Insight. Winter 1996 [2009-07-08]. 
  14. ^ M. Baldwin. How Cold Can Water Get?. Argonne National Laboratory. 2002-09-08 [2009-04-16]. 
  15. ^ Christopher Clarey. NAGANO '98; Building a Better Snowman Through Science. New York Times. 1998-02-01 [2009-07-08]. 
  16. ^ Sam Baldwin. Skiers vs Snowboaders: The Dying Feud. SnowSphere.com. January 2006 [2009-07-08]. 
  17. ^ Snowmobiling Facts. International Snowmobile Manufacturers Associations. 2006 [2007-04-23]. 
  18. ^ Jeffrey Selingo. Machines Let Resorts Please Skiers When Nature Won't. New York Times. 2001-02-08 [2009-07-08]. 
  19. ^ Washington Trails Association. Winter Hiking and Avalanche Danger. 2007-12-05 [2009-07-10]. 
  20. ^ Michelle Geinow. Cold Comfort: On the Cultural Significance of the Snowball in Baltimore. The City Paper. 1996-09-18 [2009-07-10]. 
  21. ^ Mary Mapes Dodge. St. Nicholas. University of Michigan. 1907: 241 [2009-07-10]. ISBN 0-217-84993-8. 
  22. ^ Adam Forrest. Snow sundayherald briefing. The Sunday Herald. January 6, 2008 [2009-07-07]. 
  23. ^ Michigan Technological University. A Frigid Place Gets a Blast From Space. 2009-05-27 [2009-07-10]. 
  24. ^ Jason Gabak. Snow softball a slippery sport. The Citizen. 2008-02-23 [2009-07-10]. 
  25. ^ Anne Minard. "Diamond Dust" Snow Falls Nightly on Mars. National Geographic News. 2009-07-02. 
  26. ^ Carolina Martinez. Massive Mountain Range Imaged on Saturn's Moon Titan. NASA. 2006-12-12. 
  27. ^ Carolyn Jones Otten. 'Heavy metal' snow on Venus is lead sulfide. Washington University in St Louis. 2004 [2007-08-21]. 

媒体

外部链接


基础条目（30KB或以上）雪(46054) en:snow 基础条目（30KB或以上）User:Towerman/translation/雪(65431)

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