Nacreous clouds are rare, high-altitude clouds known for their iridescent, pearl-like colors. According to provided information, they are especially visible after sunset and before sunrise because of the colored light they reflect.
Understanding Nacreous Clouds
Here's a breakdown of what makes these clouds unique:
- Rarity: Nacreous clouds are not commonly observed.
- High Altitude: These clouds form in the stratosphere, at extremely high altitudes (approximately 15-25 km or 9-16 miles).
- Iridescence: The most distinctive feature is their vibrant colors, reminiscent of oil on water. This iridescence is due to diffraction of sunlight by ice crystals of uniform size within the cloud.
Key Characteristics Summarized
| Feature | Description |
|---|---|
| Appearance | Iridescent, pearl-like colors |
| Altitude | Very high, located in the stratosphere (15-25 km) |
| Visibility | Best viewed after sunset and before sunrise |
| Rarity | Rare occurrences |
| Cause of Color | Diffraction of sunlight by uniform ice crystals |
Additional points about nacreous clouds
- Polar Stratospheric Clouds (PSCs): Nacreous clouds are a type of Polar Stratospheric Cloud.
- Formation Conditions: These clouds require extremely cold temperatures (around -80°C or -112°F) to form.
- Environmental Concerns: While beautiful, PSCs (including nacreous clouds) are linked to ozone depletion because they provide surfaces for chemical reactions that destroy ozone.
