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一过程。

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.

仙后座是拱极星座，也就是说，于处于北极星附近，在北半球的空中总是可以看到它。

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.

后果之一就是北半球的急流发生紊乱。急流是一种环极气流，它的振荡有时空气带到南方，或暖空气带到北方。

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.

早两个月，在这纬度内，可能永远是白天，但现在已经有三至四小时的黑夜了，再迟一些，黑夜就要长到六个月。把它的阴影遮盖这些环极圈地方。