nacreous cloud
Noun: A nacreous cloud is a type of cloud that appears luminous and displays iridescent, mother-of-pearl-like colors. These clouds form at very high altitudes in the stratosphere, typically in polar regions, and are best seen when the sun is slightly below the horizon, illuminating them from below.
This term is a specific scientific and meteorological term used to describe a rare and visually striking atmospheric phenomenon. * Scientists observed brilliant nacreous clouds over Antarctica. * The sky was adorned with the shimmering, colorful bands of a nacreous cloud.
- Technical Context: In meteorology, nacreous clouds are also known as polar stratospheric clouds (PSCs). They are significant because they provide surfaces for chemical reactions that contribute to ozone depletion.
- The formation of nacreous clouds is linked to extremely cold temperatures in the stratosphere.
- Polar stratospheric cloud (PSC) (n): The formal scientific term for a nacreous cloud.
- Mother-of-pearl cloud (n): An informal, descriptive synonym for a nacreous cloud, referencing its iridescent appearance.
- Mother-of-pearl cloud
- Polar stratospheric cloud (PSC)
- There is no direct antonym, as it is a specific type of cloud. Common low-altitude clouds like stratus or cumulus are conceptually different.
Nacreous clouds are distinct from the more common iridescent clouds sometimes seen in tropospheric clouds like altocumulus. Their formation in the stratosphere under very cold conditions (-85°C or below) and their role in polar ozone chemistry make them a subject of specific scientific study.
- a luminous iridescent cloud at a high altitude that may be seen when the sun is a few degrees below the horizon