Chakraborty studied that process in large thunderstorm systems over the tropics, using data from geostationary and circumpolar satellites.

拉伯蒂研利用同步卫星和极地卫星收的数据，在热带地区的大型雷暴系统中研究了这过程。

Cassiopeia is a circumpolar constellation, which means that due to its position in the sky near Polaris, it is always visible in the skies of the Northern Hemisphere.

仙后座拱极星座，也就说，由于处于北极星附近，在北半的空中总可以看到它。

One consequence is erratic behaviour of the northern jet stream, a circumpolar current, the oscillations of which sometimes bring cold air south and warm air north.

后果之就北半的急流发生紊乱。急流种环极气流，它的振荡有时会将冷空气带到南方，或将暖空气带到北方。

Here was an unalterable circumpolar region; but the polar patterns stereotyped in history and legend—without which it had almost seemed that a polar sky could not exist—had never been seen therein.

这不可改变的环极地区；但历史和传说中刻板的极地图案——没有它，极地天空几乎似乎不可能存在——从未在其中出现过。

Two months earlier we would have enjoyed perpetual daylight in this latitude; but night already fell for three or four hours, and later it would cast six months of shadow over these circumpolar regions.

早两月，在这纬度内，可能永远白天，但现在已经有三至四小时的黑夜了，再迟些，黑夜就要长到六月。把它的阴影遮盖这些环极圈地方。