BEIJING, July 2 (Xinhuanet) -- The first detailed
images from space of mysterious clouds brightening and moving slowly outward
from Earth's polar regions have been recorded by a new NASA satellite.
The clouds' official names are "night-shining" or
"noctilucent and scientists know very little about how they form and their
behavior.
"It is clear that these clouds are changing, a sign
that a part of our atmosphere is changing and we do not understand how, why or
what it means," said atmospheric scientist James Russell III of Hampton
University in Hampton, Virginia. "These observations suggest a connection with
global change in the lower atmosphere and could represent an early warning that
our Earth environment is being changed."
The Aeronomy of Ice in the Mesosphere satellite first
imaged the noctilucent clouds May 25. People on the ground began seeing them
June 6 over Northern Europe.
The clouds form 50 miles above the Earth¡¯s surface,
in an upper layer of the atmosphere called the mesosphere. The puffs of water
vapor and crystals appear during summer months above the Northern Hemisphere's
pole as well the Southern Hemisphere's pole in summer.
AIM will record two complete cloud seasons over both
regions, effectively documenting an entire life cycle of the shiny clouds for
the first time. Researchers hope to figure out why noctilucent clouds form and
how they might be related to global climate change.
(Agencies)