noun
upper atmosphere; upper air
Technical term used in meteorology and atmospheric science to refer to the region of the atmosphere above the lower troposphere.
高層大気の観測には気球が使われる。
Balloons are used to observe the upper atmosphere.
Similar meaning, but 高層大気 is more common in meteorological contexts, while 上層大気 can be used more broadly for upper layers of the atmosphere.
Compound of 高層 (high layer) and 大気 (atmosphere).