Upper atmospheric lightning ‘Sprite’ successfully filmed

A ‘sprite’ in which strands of red light appear in the night sky. September 2 (Photo courtesy of Nayoro Municipal Astronomical Observatory)

Lightening phenomenon known as ‘sprite’ in which red flashes of light can be seen discharging towards space from thunderclouds, was successfully filmed on the night of September 2, at the Municipal Astronomical Observatory in the city of Nayoro in northern Hokkaido. According to experts, the phenomenon occurs in the upper atmosphere between 40 and 80 kilometers above the earth. It can sometimes be seen in winter in the Hokuriku region of Japan, but is rarely filmed in Hokkaido. The observatory will soon publish still images and videos of the phenomenon on its website.

Senior member staff at the observatory, Watanabe Fumitake captured images of the light that seems to have been emitted from a thundercloud over Rebun Island, about 150 km northwest of the observatory rooftop, at around 9 pm on September 2. The flashes, which all lasted less than 0.1 seconds, were captured a total of 4 times: twice with still shots and twice with movie images. “I’ve always wanted to capture images but I’ve never heard of sightings in Hokkaido so it was surprising,” he said.

Discharges from thunderclouds usually appear as light emissions or lightning strikes in the clouds, but rarely occur as ‘sprites’ in which light is emitted over the thunderclouds. The light cannot be seen from beneath the thunderclouds and can only be observed from a distance in places where the sky is clear.

Professor Takahashi Yukihiro (Department of Earth and Planetary Sciences) of the Graduate School of Science, Hokkaido University, who is familiar with sprites, said “The research of sprites may lead to solving the mechanism of cumulonimbus clouds that cause sudden downpours. Now we know they can be seen in Hokkaido, so hopefully this will be an opportunity to expand the circle of observation.”


Nayoro Municipal Astronomical Observatory