The upper clouds can circle the planet in four days or even less, and no one knows why.

高空云能在四天或更少时间里环绕卫星一周，没人知道为什么。

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Precipitation from warm front rainbands often involves "seeding" by ice particles falling from the upper clouds layers.

暖锋雨带的降水经常随着来自上层云层“散布”的冰粒。

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The TC4 project will generate new data on the icy cirrus clouds that are formed in the upper atmosphere by heat-driven, or convective, storm systems that coalesce over warm waters in the tropics.

TC4工程将研究出关于含冰卷云的各种资料，这种云层是在大气上层中通过受热量驱使或对流的暴风雨变化过程中形成的，而此暴风雨也是与热带暖水海洋上空的状况密切相关。

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TC4 project will generate new data on the icy cirrus clouds that are formed in the upper atmosphere by heat-driven, or convective, storm systems that coalesce over warm waters in the tropics.

ECONOMIST: Climatology

The cloud characteristics included differences in the ease with which moist air in the tropics travels into the upper atmosphere, the speed with which raindrops fatten and the level of humidity required for clouds to form.

ECONOMIST: Climatology: Grey-sky thinking | The