Halo Around The Sun 日暈

2007年3月21日，中午1點半至2點半，馬來西亞北部的檳島上空出現日晕環奇景。
日晕是日光通过云层中的冰晶时，经折射而形成的光现象，围绕太阳环形，呈彩色。日晕的出现，往往预示天气要有一定的变化。
日晕是卷云、卷层云形成的环绕在太阳周围的彩色（或白色）光环或光弧，色带排列内红外紫。日晕有时也被称为“日枷”，有全晕圈和缺口晕。
据专家介绍，日晕是日光通过卷层云时，受到冰晶的折射或反射而形成。当光线射入卷层云中的冰晶后，经过两次折射，分散成不同方向的各色光。实际上，有卷层云时，天空飘浮着无数冰晶，在太阳周围的同一圆圈上的冰晶，都能将同颜色的光折射到我们的眼睛里而形成内红外紫的晕环。天空中有由冰晶组成的卷层云时，往往在太阳周围出现一个或两个以上以太阳为中心内红外紫的彩色光环，有时还会出现很多彩色或白色的光点和光弧，这些光环、光点和光弧统称为晕。

This amazing Phenomenon was seen most of the Penang Island's area at about 1.30pm to 2.30pm, 21/03/2007.
A halo (Greek: ἅλως; also known as a nimbus or Gloriole) is a ring of light that surrounds an object.
Halos, also known as icebows, are optical phenomena that appear near or around the Sun or Moon, and sometimes near other strong light sources such as street lights. There are many types of optical halos, but they are mostly caused by ice crystals in cold cirrus clouds located high (5–10 km, or 3–6 miles) in the upper troposphere. The particular shape and orientation of the crystals is responsible for the type of halo observed. Light is reflected and refracted by the ice crystals and may split up into colors because of dispersion, similarly to the rainbow.
en.wikipedia.org/wiki/Halo_(optical_phenomenon)