Especially in autumn and winter when the air is not so unstable, cumulus clouds may merge and cover a large part of the sky. They become altocumulus.
英
美
- 此外,尤其是秋天和冬天时,天气没那么不稳定,积云会聚合在一起,一大片的覆盖部份的天空,出现了高积云。