According to the staff of the Meteorological Bureau, the green flash is a phenomenon of sunlight refraction, which often occurs at sunset. When the red, orange, and yellow light falls on the horizon,Green light with a longer wavelength is seen, forming a green flash, which is a rare atmospheric optical phenomenon.
Green flashes often occur when the sun sinks in the west and disappears from the ground. Sometimes a green light is emitted from the top edge of the sun. The duration is usually less than 1 second, and only a few can last for several seconds from 238 to 87, so it is called ” Green flash”.
Now it is only known that the green flash can only be seen in the low, flat and vast places, such as the seaside or the prairie, when the weather is very clear and there are no clouds on the horizon.