奇怪的波浪形狀的云滾過(guò)皮斯加山

奇怪的波浪形狀的云滾過(guò)皮斯加山

(Photo: Grant W. Goodge/Wikimedia Commons)

At first glance, you might assume this image is the result of some elaborate Photoshop trick, but trust us, it's 100 percent real!

乍一看，你可能會(huì)認(rèn)為這張照片是ps出來(lái)的，但是相信我們，這是百分百真實(shí)的!

These bizarre, tubular clouds spotted looming over Mount Pisgah in Asheville, North Carolina, were created by a Kelvin-Helmholtz instability, a natural phenomenon that occurs when there's a difference in velocity between two interacting fluids. The clouds are named after Lord Kelvin and Hermann von Helmholtz, who studied the physics behind this beautiful phenomenon. An example almost everyone has seen is when wind blows over water.

這些奇怪的管狀云隱約出現(xiàn)在北卡羅來(lái)納州阿什維爾的皮斯加山上，它們是由凱爾文-亥姆霍茲不穩(wěn)定性造成的，這是一種自然現(xiàn)象，當(dāng)兩種相互作用的流體的速度不同時(shí)，就會(huì)發(fā)生這種不穩(wěn)定性。這些云是以開(kāi)爾文勛爵和赫爾曼•馮•赫姆霍爾茲的名字命名的，他們研究了這一美麗現(xiàn)象背后的物理學(xué)。一個(gè)幾乎每個(gè)人都見(jiàn)過(guò)的例子是風(fēng)吹過(guò)水面。

It works like this: First, air is pushed up the steep slopes of the mountain to form clouds in a process known as "orographic lift." Next, swift winds collide with those newly formed clouds, and the resulting Kelvin-Helmholtz instability causes them to curl like giant ocean waves. As EarthSky explains, The clouds are a good indication of instability, meaning if you see these when you fly, it might be a bumpy flight.

它的工作原理是這樣的：首先，空氣被推到陡峭的山坡上形成云，這個(gè)過(guò)程被稱為“地形抬升”。接下來(lái)，疾風(fēng)與這些新形成的云發(fā)生碰撞，由此產(chǎn)生的凱爾文-亥姆霍茲不穩(wěn)定性使它們像巨大的海浪一樣卷起。正如EarthSky解釋的那樣，這些云是不穩(wěn)定的一個(gè)很好的跡象，這意味著如果你在飛行時(shí)看到這些云，可能是一次顛簸的飛行。

More proof that fact is often stranger than fiction.

事實(shí)往往比小說(shuō)更能證明這一點(diǎn)。