This is because the winds normally vary widely between the near-surface and the upper atmosphere, home to the eastward-flowing jet stream.
这是因为风通常从近地高度和高空大气层之间变化很大，进入高层后会并入向东流动的气流中。
2
The sinking air is also carried along the surface to the equator, where it rises again, strengthening the already-powerful western winds in the upper atmosphere in the tropics.
下沉到海水表面的空气也会顺流而下到赤道附近，在那里它又变强，加强热带地区高空大气的西风。
3
And upper-atmosphere winds in the hurricane region are affected by conditions in distant oceans, especially in the north Atlantic and the tropical Pacific.