Optical Phenomena in Meteorology

Meteorological Optical Phenomena

The field of meteorology is full of fascinating sights, often unseen by those who do not venture out into nature regularly. One such category of phenomena involves the manipulation of light in the atmosphere, creating striking visual displays known as optical phenomena. These occurrences are primarily associated with clouds, rain, and sunlight, which interact with sightlines, weather conditions, and atmospheric conditions to create stunning displays. In this article, we will explore four types of these optical phenomena: zirkumzenital bows, lichte saulen, sun and haloes.

Zirkumzenitalbögen

Zirkumzenitale Bögen (ZKB) are vertical bands of color that appear above the horizon when the sky is clear and there's a low layer of moisture below the horizon. This phenomenon occurs because the rays of sunlight that make it through the atmosphere after interacting with large water droplets get refracted and reflected back upwards to form a band of colored light around the bright sun. There can be multiple zerkumzenital bows - usually two - one on either side of the sun. They can have different colors, ranging from red on the left side to greenish blue on the right side. They're most visible within an hour before noon and after dusk.

Lichte Saulen

Lichte Saulen are another type of optical phenomenon where columns of light appear in the air due to the reflection, refraction or total internal reflection of light in water droplets or ice crystals suspended in air. When sunlight penetrates moist air low down in the sky, it gets reflected off particles like dust and water droplets, forming spectacular pillars of light. These pillars can reach great heights and may seem to extend beyond the horizon. Rainbows are also a kind of lichtsäule, although they are more commonly seen under specific conditions.

Sun and Halos

A halo is a ring of light surrounding the sun or moon, caused by the reflection, refraction, diffraction, or dispersion of light in ice crystal cloud particles. It appears as a white circle around the object, with thin circular arcs on either side. Some more complex forms include supralateral arches, sublateral arches, and parhelia (sun dogs), all of which require specific atmospheric conditions and are related to halos. Halos become brightly coloured in the presence of ice-crystal clouds, with the colours being separated by narrow bands of darkness.

In conclusion, understanding these meteorological optical phenomena requires knowledge of basic physics concepts such as the behavior of light in various media, along with weather and atmospheric conditions. Studying these phenomena helps us appreciate our environment and contributes to the advancement of science.