The cloud cover has been broken as rapidly rising air broke through a cold air cap.

快速上升的空气冲破了冷空气层覆盖层，云层覆盖面就破碎了。

youdao

It shows a man at a typewriter and above his head, taking up more than half of the canvas and appearing in a purple cloud, is frontiersman Daniel Boone, wearing his coonskin cap and carrying his long rifle.

VOA: standard.2010.08.09