美国·内布拉斯加州上空的乳状云

2019 December 15 Mammatus Clouds over Nebraska Image Credit & Copyright: Jorn Olsen Photography Explanation: When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As ...