埃特纳火山的月亮和烟圈
(原标题: Moon and Smoke Rings from Mt. Etna)
2024-04-22
浏览次数: 18
是的，但你的火山能做到吗？令一些人吃惊的是，埃特纳火山偶尔会冒出烟圈。技术上被称为漩涡环，火山的墙壁稍微减缓了外部喷出的烟雾，导致内部气体移动得更快。一圈低压形成，喷出的火山气体和火山灰形成环状，这是一种熟悉的几何结构，在上升过程中出奇地稳定。烟圈是相当罕见的，需要在正确的排气口几何形状、正确的喷射速度和外部大气相对平静的情况下形成。在这张大约两周前从意大利西西里岛的甘吉拍摄的特色照片中，可以看到多个火山烟圈。场景被黎明太阳的红光遮蔽，而背景中可以看到新月。
查看原文解释
Yes, but can your volcano do this? To the surprise of some, Mt. Etna emits, on occasion, smoke rings. Technically known as vortex rings, the walls of the volcano slightly slow the outside of emitted smoke puffs, causing the inside gas to move faster. A circle of low pressure develops so that the emitted puff of volcanic gas and ash loops around in a ring, a familiar geometric structure that can be surprisingly stable as it rises. Smoke rings are quite rare and need a coincidence of the right geometry of the vent, the right speed of ejected smoke, and the relative calmness of the outside atmosphere. In the featured image taken about two weeks ago from Gangi, Sicily, Italy, multiple volcanic smoke rings are visible. The scene is shaded by the red light of a dawn Sun, while a crescent Moon is visible in the background.
© Dario Giannobile