The day dawned sunless and with a low cloud base.

黎明时天气阴沉，云层压得很低。

The formation of the channel is initiated when electrons surge from the cloud base toward the ground.

当电子从云层底部涌向地面时，通道就开始形成了。

FYI, one aircraft has landed and reported cloud base 80m, visibility 1km. What is your intention?

通知你，一架飞机降落并报告，云高80米，能见度1公里，你的意图是什么？

Cloud droplet spectra could be formed in a comparatively low level above cloud base and developed later in higher levels.

在积云云底之上较底的高度上可以较早地形成较为稳定的云滴谱谱型，而在较高的高度上则要晚一些。

Cloud base height as an important cloud macro physical parameter, plays an important role in energy exchanges between the cloud-layer and the surface.

云底高度作为重要的云宏观物理特征参数，在云层与地表之间的能量交换中起着重要作用。