やこううん
夜光雲
1. noctilucent clouds
2. Noctilucent cloudNight clouds or noctilucent clouds are tenuous cloud-like phenomena that are the "ragged-edge" of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. The name means roughly night shining in Latin. They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. They can only be observed when the Sun is below the horizon.
Read “Noctilucent cloud” on English Wikipedia
Read “夜光雲” on Japanese Wikipedia
Read “Noctilucent cloud” on DBpedia
Read “Noctilucent cloud” on English Wikipedia
Read “夜光雲” on Japanese Wikipedia
Read “Noctilucent cloud” on DBpedia
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