noun
polar mesospheric clouds
Technical term in atmospheric science; refers to clouds in the polar mesosphere, also known as noctilucent clouds when visible at twilight.
極中間圏雲は、夏の高緯度地方で観測されることが多い。
Polar mesospheric clouds are often observed in high-latitude regions during summer.
夜光雲 (noctilucent clouds) is a more common term for the same phenomenon when visible at twilight; 極中間圏雲 is the formal scientific name.
Compound of 極 (polar), 中間圏 (mesosphere), and 雲 (cloud). A direct calque from English 'polar mesospheric clouds'.