黄色一级a毛片-日韩欧美在线免费观看-亚洲天堂影音先锋-性欧美大战久久久久久久83-ww欧美-一区福利-97高清国语自产拍-人人看人人爽-天堂网一区-久久水蜜桃-久久久久久黄-男人j进入女人j内部免费网站-波多野结衣精品在线-99热这里精品-99精品网-日韩在线网

The science behind snowflakes

雪花背后的學(xué)問

譯銳翻譯   2020-12-25   16:13 p.m.

A snowflake is a small weather feature that can pack a big punch.

作為一種氣候特點(diǎn)，雪花是微不足道的。但是，雪花背后的科學(xué)卻會(huì)讓你大吃一驚。

Many are made up of just one single ice crystal while some, more elaborate snowflakes are comprised of as many as 200 ice crystals fused together.

有許多雪花只由一片冰晶組成。但是，也有一些雪花，一些更加精致的雪花可以由多達(dá)200片冰晶融合而成。

All flakes maintain the same six-sided basic shape, though no two snowflakes will have exactly the same arrangement of molecules.

所有的雪花都擁有相同的六邊形。但是，沒有兩片雪花的分子排列是完完全全一模一樣的。

This makes each one unique.

這樣說來，每片雪花都是獨(dú)一無二的。

No two snowflakes are the same

沒有哪兩片雪花是相同的

Like fingerprints, no two snowflakes are exactly alike. In fact they are so diverse, there is actually an?international classification system for snowflakes. This system is broken down into mostly eight principal snow crystal types: stellar dendrites, sectored plates, rimed crystals, hollow columns, needles, spatial dendrites, capped columns and irregular forms.

和指紋一樣，沒有哪兩片雪花是完完全全一模一樣的。事實(shí)上，雪花非常多種多樣。對于雪花，國際上實(shí)際還有一套分類體系。該體系將雪花分為8大類：恒星樹枝狀、扇形板狀、邊緣晶體、空心圓柱、針狀、空間樹枝狀、帶帽圓柱和不規(guī)則形狀。

To understand how they get their unique shape, we must start at the beginning. A snowflake first forms when an extremely cold water droplet freezes onto a pollen or dust particle in the sky.

要想了解為什么雪花會(huì)有不同的形狀，我們就要從雪花形成之初開始說起。當(dāng)遇到極寒天氣時(shí)，水滴會(huì)冰凍成花粉狀或塵土狀，這時(shí)雪花初次形成。

"This creates an ice crystal," according to the National Oceanic and Atmospheric Administration (NOAA). "As the ice crystal falls to the ground, water vapor freezes onto the primary crystal, building new crystals -- the six arms of the snowflake."

根據(jù)國家海洋和氣象局（NOAA）介紹，“這就形成了冰晶。當(dāng)冰晶落到地面時(shí)，水蒸氣會(huì)冷凍成初生晶，并形成新的冰晶-一片六角形的雪花。”

Each individual snowflake encounters slightly different atmospheric conditions on its path from sky to ground. Therefore, they all end up unique, while still maintaining the basic six-sided structure.

每片雪花在從天空飄落到地面的過程中都會(huì)遇到稍許不同的氣候條件。因此，所有的雪花形成后，盡管都具有基本的六邊形，但是都是與眾不同的。

"Ultimately, it is the temperature at which a crystal forms — and to a lesser extent the humidity of the air — that determines the basic shape of the ice crystal. Thus, we see long needle-like crystals at 23 degrees F and very flat plate-like crystals at 5 degrees F. "

“最終起作用的是冰晶形成時(shí)的溫度-其次是空氣的濕度。空氣的濕度決定了冰晶的基本形狀。因此，在23華氏度時(shí)，我們會(huì)看到長長的像針一樣的冰晶。在5華氏度時(shí)，則會(huì)看到非常扁平的、像盤子一樣的冰晶。”

Although the core six-sided shape is always maintained, each of the six arms may branch off in new directions, or change shape as it incurs slight changes in the surrounding temperature or humidity, but because each of those arms is experiencing the exact same atmospheric conditions, all the arms will look identical.

盡管最基本的六邊形往往能夠保留下來，但是每個(gè)邊都會(huì)朝著新的方向分叉，或當(dāng)周圍的溫度或濕度有細(xì)微變化時(shí)，形狀發(fā)生改變。但是，由于每個(gè)邊所經(jīng)歷的氣候條件都完全相同，因此所有的邊看上去都是一模一樣的。

Cold air is paramount冷空氣至關(guān)重要

As the famous quote says "To appreciate the beauty of a snowflake it is necessary to stand out in the cold."

就像一句著名的引文所說：“唯有矗立在寒冷中方能欣賞到雪花的美。”

The temperatures at the surface are only part of the story though. You really have to look at the entire column of air to know what type of precipitation you will get.

地表溫度僅僅是一部分。要想知道會(huì)產(chǎn)生哪種降水，則需要查看整個(gè)空氣量。

Most precipitation that forms in wintertime clouds starts out as snow because the top layer of the storm is usually cold enough to create snowflakes. Precipitation continues to fall as snow when the temperature remains at or below 32 degrees F from the cloud base to the ground.

絕大多數(shù)在冬季的云里形成的降水會(huì)首先以雪花形式出現(xiàn)，這是因?yàn)楸╋L(fēng)雪的最高處通常足夠寒冷并可以形成雪花。當(dāng)溫度保持在或低于32華氏度時(shí)，降水會(huì)繼續(xù)以雪花形式從云端降落到地面。

"As a general rule, though, snow will not form if the ground temperature is at least 41 degrees F (5 degrees C)," according to?the National Snow and Ice Data Center (NSIDC) website.

根據(jù)國家冰雪數(shù)據(jù)中心網(wǎng)站的介紹，“一般而言，如果地面溫度至少在41華氏度（或5攝氏度）時(shí)，則不會(huì)形成雪。”

"While it can be too warm to snow, it cannot be too cold to snow. Snow can occur even at incredibly low temperatures as long as there is some source of moisture and some way to lift or cool the air. It is true, however, that most heavy snowfalls occur when there is relatively warm air near the ground—typically -9 degrees C (15 degrees F) or warmer—since warmer air can hold more water vapor."

“盡管太溫暖就無法下雪，但是不會(huì)出現(xiàn)因?yàn)樘涠鵁o法下雪的情況。即使是在非常低的溫度下，雪花也可能會(huì)出現(xiàn)，只要空氣中存在某些濕度源和某些可以將空氣抬升或冷卻的途徑。事實(shí)上，當(dāng)?shù)孛娓浇目諝庀鄬嘏?通常為零下9攝氏度（15華氏度）或更暖時(shí)，往往會(huì)出現(xiàn)大雪天氣--因?yàn)楦訙嘏奶鞖庖部梢员Ａ糇「嗟乃魵狻！?/p>

The NSIDC explains that while most snowflakes are less than 0.5 inches across, some can reach sizes nearing 2 inches across. In order to get such large snowflakes, however, you need very specific weather conditions including near-freezing temperatures, light winds and unstable atmospheric conditions.

NSIDC解釋說，盡管絕大多數(shù)雪花的直徑都少于0.5英寸，但是有些雪花的直徑也可以達(dá)到將近2英寸。要想天空中下起如此大的雪花，就需要達(dá)到非常特定的天氣條件，包括接近零度的氣溫、微風(fēng)和不穩(wěn)定的氣候條件。

Frozen precipitation and travel do not mix well凍雪和交通格格不入

What's interesting about snowflakes is that independently they are quite delicate, but in large enough quantities they can shut down a city.

關(guān)于雪花有趣的一點(diǎn)是，它們一片片單獨(dú)看起來非常纖巧，但是如果是很多雪花放在一起，它們就會(huì)導(dǎo)致一座城市與外界隔絕。

Snow isn't the only form of frozen precipitation, but it is the most complex. In addition to snow, you can also have sleet, freezing rain, hail and graupel.

雪花并非是唯一一種冰凍降水，但是它卻是最復(fù)雜的。除了雪花，還會(huì)有雨夾雪、凍雨、冰雹和霰。

Graupel occurs when supercooled water droplets collect on the outer surface of snowflakes. It happens when temperatures at the surface are above freezing and the air aloft is very cold.

當(dāng)超級冷的水滴在雪花外表面聚集時(shí)，就會(huì)形成霰。當(dāng)?shù)乇頊囟雀哂诹愣龋巧戏娇諝鈪s十分寒冷時(shí)，就會(huì)出現(xiàn)霰。

Sleet is actually just rain (liquid precipitation) that freezes on its way down to the ground as it hits cooler pockets of air near the surface.

雨夾雪實(shí)際上就是雨（液體狀降水）。降水在從空中下降到地面的過程中遇到了地面附近更冷的空氣團(tuán)時(shí)，降水發(fā)生了冰凍。

Hail is actually falling raindrops that get caught up in a thunderstorm's strong updraft winds. They then get carried aloft into the coldest part of the cloud tops and freeze.

冰雹實(shí)際上是下降的雨滴被雷暴天氣強(qiáng)烈的上升氣流所困住并因此被向上帶到最冷的云層中并結(jié)凍。

If you are driving you can actually hear graupel and sleet as they hit your windshield of your car because of their composition. It tends to make a "tap, tap, tap" sounds as it hits the glass and bounces slightly.

如果你正在開車，你會(huì)聽到霰和雨夾雪打在擋風(fēng)玻璃上的聲音。因?yàn)樗鼈兊臉?gòu)成，它們在掉落在玻璃上時(shí)會(huì)發(fā)出“啪啪聲”并會(huì)輕輕彈起。

Hail also makes noise, but more importantly, it can cause significant damage to a vehicle because they are usually much larger in size.

冰雹也會(huì)發(fā)出噪音，但是更為重要的一點(diǎn)是，冰雹會(huì)對車輛造成極大的損害，這是因?yàn)楸⒌捏w積通常要比前面二者大得多。

Freezing rain is when the entire column of air is warm and the surface is at or below the freezing mark, resulting in rain actually freezing on contact. This is one of the more dangerous kinds of precipitation because if you are out walking or driving, it appears as though it is just raining. However, what you can't see is that those rain drops are turning into ice as soon as they make contact with the road, sidewalk or even your vehicle.

凍雨是當(dāng)整個(gè)空氣都很溫暖并且地表溫度處于或低于零度時(shí)，雨水會(huì)在接觸地面時(shí)冰凍。這是最為危險(xiǎn)的一種降水現(xiàn)象，因?yàn)槿绻悴叫型獬龌蜷_車時(shí)，凍雨看上去好像僅僅是在下雨。但是，你無法看見的是，這些雨滴一接觸地面、人行道或甚至你的車輛時(shí)，就會(huì)變成冰。

來源：CNN，編輯&翻譯：譯銳翻譯Susan