瑞典上空的彩虹云
(原标题: Iridescent Clouds over Sweden)
2024-07-07
浏览次数: 14
为什么这些云是多种颜色的？云中有一种相对罕见的现象，叫做彩虹，它能生动地呈现出不同寻常的颜色，甚至能同时呈现出整个光谱的颜色。这些极地平流层云，也被称为珍珠云和珍珠母云，是由几乎均匀大小的小水滴形成的。当太阳处于正确的位置时，通常是隐藏在直射视线之外，这些薄云可以以一种几乎一致的方式明显地衍射阳光，不同的颜色被不同的量所偏转。因此，不同的颜色会从稍微不同的方向呈现给观察者。许多云开始时都是均匀的区域，可以显示彩虹色，但很快就变得太厚、太混合，或者距离太阳太远，无法显示出醒目的颜色。这张特色图片和附带的视频是2019年底在瑞典奥斯特松德拍摄的。
查看原文解释
Why are these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly -- or even a whole spectrum of colors simultaneously. These polar stratospheric clouds also, known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size. When the Sun is in the right position and, typically, hidden from direct view, these thin clouds can be seen significantly diffracting sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too angularly far from the Sun to exhibit striking colors. The featured image and an accompanying video were taken late in 2019 over Ostersund, Sweden.