美国德州上空的雷暴云

2024年8月6日

Storm Cloud Over Texas
Image Credit & Copyright: Laura Rowe (Used with permission)

Explanation: What makes this storm cloud so colorful? First, the cloud itself is composed of millions of tiny droplets of water and ice. Its bottom is almost completely flat — but this isn’t unusual. Bottom flatness in clouds is generally caused by air temperature dropping as you go up, and that above a specific height, water-saturated air condenses out water droplets. The shape of the cloud middle is caused by a water-droplet-laden column of air being blown upward. Most unusual, though, are the orange and yellow colors. Both colors are caused by the cloud’s water drops reflecting sunlight. The orange color in the cloud’s middle and bottom sections are reflections of a nearly red sunset. In contrast, the yellow color of the cloud’s top results from reflection of light from a not-yet-setting Sun, where some — but less — blue light is being scattered away. Appearing to float above the plains in Texas, the featured impressive image of a dynamic cumulonimbus cloud was captured in 2021 while investigating a tornado.

Tomorrow’s picture: galaxy three

美国德州上空的雷暴云
影像提供与版权: Laura Rowe (Used with permission)

说明: 这团雷暴云为何如此多彩？这朵云是由数百万个微小的水滴和冰晶所组成，而其云底几乎是平的，不过这并无任出奇之处。云的平底，是因为随着高度的增加，空气温度下降，通常在特定的高度以上时，饱和的空气就会凝出水滴成云。云团腰部的形状，则是来自富含水滴的涌升空气柱。不过，这朵云最不寻常的是橙与黄的色彩，而这二种颜色都是因为云里的水滴反射阳光所致。云团腰部和底部的橙色，是来自水滴反映落日的火红阳光。而来自落日正在照耀云顶的较高层阳光，其中的蓝光受到散射的比率较低，因此让反射阳光的云顶呈泛黄色彩。2021年当摄影者正在追踪一个龙卷风时，拍下了这幅主题影像，而其中这团活跃的积雨云看似悬浮在德州平原的上方。

明日的图片: galaxy three