时差N小时 为什么夜晚比白天平静(下)（在线收听）

But with cooler air sitting tight at ground level, the usual temperature pattern turns upside down for a few hundred feet above the ground.

但是随着冷空气在地表停留，地表上方几百英尺处的气温模式就会发生颠倒。

Known as a temperature inversion, this upside-down pattern acts as a barrier, dividing the cool, calm air on the ground from whatever’s happening above.

这也被称为“逆温现象”，这种颠倒的气温模式就像一道屏障，将地表较冷而平静的空气从上层大气中隔离出来。

On many calm nights, the wind still blows far overhead, but a temperature inversion prevents it from coming down to earth.

在许多平静的夜晚，风还是会从上空吹过，只不过逆温现象阻止了风吹向地面。

At sunrise, everything changes. The sun warms the earth and the lower layers of the atmosphere, mixing everything up.

等到日出后，一切都变了。太阳使地球和低层大气温度升高，所有气流融合一起。

Without the temperature inversion as a boundary, the winds gust down to the ground again, picking up the most speed on smooth landscapes with little resistance to wind.

没有逆温层隔断，风又重新吹向地面，在几乎不受阻的情况下加速吹过平坦的地面。