美国威斯康辛州上空的卷轴云
2023年8月20日 A Roll Cloud Over Wisconsin Credit: Megan Hanrahan (Pierre cb), Wikipedia Explanation: What kind of cloud is this? A type of arcus cloud called a roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a ...