atmospheric effect

One of the strangest atmospheric phenomena must be the parhelion. It is an atmospheric phenomenon caused by the sun, although it can also be considered a phenomenon of astronomical origin. It usually appears under certain unique environmental conditions and for a short time.

In this article we are going to tell you what the parhelion is, how it is formed and what effects it has.

What is parhelion

Parhelion phenomenon

It is a type of atmospheric phenomenon that is caused by the sun. They are two small glows that form on both sides of the sun when there is a certain type of cloud. The types of clouds that are needed for parhelion to occur are those of the cirrus type. These clouds have a filament-like appearance and some of them look like cotton flakes. For this type of atmospheric phenomena to occur, these types of clouds must exist since they contain ice crystals that act as small prisms. These small ice crystals are responsible for refracted the sun's rays. This means that they will deflect part of the sun's rays to another place forming the parhelion.

These environmental conditions occur very infrequently in only some areas of the planet. You could say that this phenomenon is like seeing a sun behind the cloud but less bright than the real sun. Not always when this phenomenon occurs the two parhelios are seen. Often times there are only cirrus clouds on one side of the sun and only a parhelion forms. They are only more luminous points of an iridescent halo that surrounds the sun. It is very rare that the halo can be seen in its entirety.

As expected, it is an atmospheric phenomenon that does not always look the same. Sometimes the parhelion appears as a round-shaped light spot. With these types of shapes the sun appears less bright. On the other hand, at other times we can find a more elongated aspect vertically or it decomposes in the colors of the rainbow. Only on some occasions can you see some fragments smaller than the rainbow. I have to confuse these fragments with the rainbow since the parhelion always appears next to the sun, while the rainbow appears on the side of the sky opposite the sun.

When does the parhelion appear

solar halo

Until the moment when nothing is known about this atmospheric phenomenon, nothing of it is taken into account. However, once we know of the existence of the parhelion, it is when we begin to be attentive to this phenomenon. It can be seen more often than it stays. It is usually seen at dusk or in the morning when the sun is below the horizon.

Parhelion usually appears exactly at an inclination of 22 degrees from the sun, due to the angle with which the light rays are refracted. You can get to find this. The sky where the following is done: the first thing is to place the arm fully extended forward and open the hand. When the sun is covered with the hand we can see that the parhelion should be approximately where the tip of the little finger indicates. It can be said that we are measuring the sky with the palm of our hand. If there are cirrus clouds in that part, it is possible that the parhelion will form. It can be found both to the right and to the left of the sun or both.

The word parhelio comes from the Greek para-Helios. This can be interpreted as being similar to the sun. Although it is much less frequent, on some occasions a lunar parhelion can also be found. The effect is the same and the way to capture it the same. The problem with this is that it can only be seen when there is a full moon and cirrus clouds must exist in position to be able to refract the little light from the moon.



Although it is not very long, this phenomenon seems documented since ancient times. An example of this is that it is named in the first book of La República. Here we can find various characters who are engaging in a philosophical conversation. In this conversation you can see how one of the characters asked about an atmospheric phenomenon observed in the city of Rome. This phenomenon is called Parhelio and refers to a phenomenon with which "two suns" can be seen with the naked eye.

Today we know that this is not true since They are just ice crystals that are responsible for refracting the sunlight.

Many people do not know why there is more of this phenomenon in winter. It is not strange that in the middle of winter we can register temperatures of -20 degrees in many parts of the world such as the northern United States. In these areas there is a freezing environment with extreme environmental conditions that are perfect to promote the generation of this kind of phenomena. The formation of the parhelion requires the formation of ice crystals in cirrus clouds.

However, these halos have nothing to do with rainbows, as we mentioned before. They always manifest next to the sun, while the rainbow appears on the opposite side.

Implications and effects

What this optical phenomenon implies in the sky. It is what we ask ourselves a lot. The fact that a parhelion appears in the sky anticipates certain meteorological changes that can occur as the weather is approaching. And it is that if we see a parhelion it is possible that looming in storms that will deliver short-term rainfall. Many of the farmers in the areas of the world where this type of phenomenon can be seen more frequently are those who consider the parhelion as a sign of the arrival of bad weather. Cirrus clouds in many places are formed only in the days before the appearance of storms.

Other times, when the halo has a more oval shape, it can be predicted that the weather will worsen in a period of 12-24 hours.

I hope that with this information you can learn more about parhelion in its characteristics.

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