What's up with the solar halo

Solar halo is a very normal natural phenomenon. When a storm comes, everyone can see the solar halo. And against the backdrop of the solar halo, the sky will look clearer, more transparent and very clean. The solar halo is generally formed by refraction of ice crystals and other materials in the sky, and the formation process is relatively complicated. So, what's up with solar halos?

1. What is the solar halo?

Because high-altitude cirrus clouds usually precede storms. Note how clear the sky looks in these halo photos. After all, you can see the sun or the moon. However, the halos actually mean that there are high-altitude, thin cirrus clouds floating more than 20,000 feet in the air. These clouds contain millions of tiny ice crystals. The halos you see are caused by a combination of light refraction and light reflection from these ice crystals. The orderly, oriented arrangement of the crystals works with the eye to allow us to see halos.

2. Introduction to Solar Halo

Cirrostratus clouds are at an altitude of about 5500-8000 meters. These clouds are caused by the expansion and cooling of moist air as it makes a large, slow, oblique upward movement. Thus, they are associated with mobile cyclones and warm fronts and are located at the top of the thunderstorm layer. Sometimes, they are also associated with tropical cyclones because the winds above tropical cyclones blow from within the cyclone to the outside, blowing cirrostratus clouds away from where they were formed.

Cirrostratus clouds have a large range, reaching hundreds to thousands of kilometers, and have a fairly wide and continuous cloud curtain. It is composed entirely of ice crystals, and the cloud base has a wispy structure that allows the light of the sun and the moon to pass through, casting shadows on the ground. Halos are often visible in clouds. If the cirrostratus clouds thicken and lower, and the system develops, it usually indicates that a weather system is affecting the measuring station. Hence people have a saying that "sun halo means rain at midnight, moon halo means wind at noon". However, if there is no significant development, or even if the cloud cover decreases, there will be no significant changes in the weather in the future.

Cirrostratus clouds mark moist areas at high altitudes and large areas of rising air. These two conditions are closely related to the formation of precipitation. During cold periods, especially when they transform into altocumulus and rain clouds, they represent the arrival of cyclones and long-term stable precipitation. In summer, they signal the arrival of storms and tropical cyclones.