eclä

Eclä is a term that refers to a specific type of atmospheric optical phenomenon. It is characterized by the appearance of a bright halo or ring of light around a celestial body, most commonly the Sun or Moon. This halo is caused by the refraction of light through ice crystals suspended in the atmosphere. The shape and size of these ice crystals, as well as the angle at which light enters them, determine the appearance of the eclä.

These ice crystals are typically hexagonal in shape and form in high-altitude clouds, such as cirrus or cirrostratus clouds. When sunlight or moonlight passes through these crystals, it is bent or diffracted, creating the colored or white rings seen in the sky. The specific colors observed in an eclä are due to the dispersion of light, similar to how a prism separates white light into its constituent colors.

Eclä are often described as beautiful and sometimes awe-inspiring, but they can also serve as an indicator of approaching weather changes. The presence of cirrus clouds, which lead to eclä, can sometimes signal the arrival of a warm front. While the phenomenon itself is purely optical and harmless, its association with certain cloud formations has led to its inclusion in folklore and weather lore in various cultures. The intensity and clarity of an eclä can vary greatly depending on atmospheric conditions.