Noctilucent clouds are ragged extensions of a more widespread and more permanent layer which forms over the summer polar area at the mesopause . 夜光云是在夏季极地中圈顶之上形成的更广泛更持久的层的参差不齐的延伸。
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Caption : : noctilucent clouds is the name " night - shinning clouds " in latin , as its name suggest , it glow in electric bluw in deep twilight 夜光云属于罕有的大气现象，首次于1885年被发现，顾名思义，是一层在夜间发光的云。
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One of these missions , a satellite called aeronomy of ice in the mesosphere , or aim , was launched in april to study so - called noctilucent clouds ( depicted above ) , the highest layer of clouds in the atmosphere 任务其一，今年4月该局发射了一颗名为“中层大气高空冰探测” （简称aim ）的卫星以研究所谓的夜光云（如上图所示）这是大气层中最高处的云层。
