Fire rainbows

FIRE RAINBOWS

MADE BYHUSSAN ARA

INTRODUCTION A lot of natural phenomenon occur every day, in front of us, without us being known. While some of them occur once or twice a year and they are even less noticeable. There is another category which occurs rarely on a specific place and on a specific time and they can only be observed in certain conditions and those conditions are of course rare that is why we call such phenomenon as rare phenomenon. Occurrence of fire rainbows is one such phenomenon which occurs rarely in certain conditions.

TERMINOLOGY•“Fire Rainbows” are neither fire, nor rainbows

• But are so called because of their brilliant pastel colors and flame like appearance.

• Technically they are known as circumhorizontal arc

•An ice halo formed by hexagonal, plate-shaped ice crystals in high level cirrus clouds.

•Precisely scientists call it as CHA

FORMATION•A CHA is caused by the refraction though ice crystals in cirrus clouds of light from the sun.

•Refraction happens when the speed of light is reduced inside a particular medium.

•This particular refraction happens when light goes from air without cloud to air containing cloud.

• In this case it is vital that the cloud is cirrus in shape.

•A cirrus cloud is one of those thin, wispy ones, often with tufts sticking out like disheveled hair!• They can be huge – covering so much of the sky that you cannot see where one ends and another begins• When they are a massive sheet they are called cirrostratus.

•At specific angle when the sunlight strikes one of the six faces of hexagonal ice crystal it divides into various wavelengths•The light goes in through one of the side faces of the crystal. Then it is refracted and it leaves through the bottom horizontal face.• It is vital that the crystal is aligned just so as otherwise the light will not separate in to the rainbow like colors we expect. •If the alignment is correct then the whole cirrus cloud will “explode” in to a flaming, fire rainbow!

CONDITIONSThe conditions required to form a “fire rainbow” are very precise:

•The sun has to be at an elevation of 58° or greater.

•There must be high altitude cirrus clouds with plate-shaped ice crystals, and sunlight has to enter the ice crystals at a specific angle.

•The ice crystals in the cirrus cloud have to be horizontal to refract the sun. If they are then the arc is formed.

WHO CAN SEE IT?•The position of the observer is also important. •Circumhorizontal arcs cannot be seen in locations north of 55°N or south of 55°S.•Likewise there are certain times of the year when they are visible.

WHEN THEY OCCUR?•Brightly colored circumhorizontal arc occur mostly during the summer •Between particular latitudes.•When the sun is very high in the sky, and that a cirrus cloud or haze be present and contain plate-shaped ice crystals.

CONCLUSION Fire rainbows are actually an optical phenomenon which occurs rarely due to its requirements of its occurrence. It is naturally occurring and everything which is created by nature is worth watching and worth praising!

THANK YOU!