15 August 2020 | New Scientist | 29Green lantern
Photo European Space AgencyPIERCING through the winter sky,
this green light looks like part of
a dazzling natural phenomenon.
In fact, the strikingly clear single
beam is from a laser fired at the
European Space Agency’s research
station in Antarctica to probe
atmospheric conditions, including
the impact of pollutants.
The pulsed laser is part of the
Concordia station’s Light Detection
and Ranging (LIDAR) instruments,
and it is emitted for 60 seconds
every 5 minutes during winter
there. LIDAR works like radar,
but uses reflected light rather than
radio waves to sense. Researchers
at what is the world’s most remote
research station use it to probe
our atmosphere’s boundary layer,
which extends from the ground
to around 1 kilometre up.
The instrument directs the
laser within this section and uses
scattered light to measure the likes
of temperature, cloud formation
and aerosol particles.
While greenhouse gases warm
the planet, chlorofluorocarbons –
long-lived chemicals that came
from sources such as spray cans –
degrade the ozone layer, which
helps protect the surface from
UV radiation. Both effects, mostly
human created, influence the
atmospheric boundary layer and
contribute to climate change at
the surface. The conditions in
Antarctica make the boundary
layer easier to study.
ESA released this picture as its
human space flight and robotic
explorations image of the week. ❚Gege LiES
A/I
PE
V/P
NR
A–
S.T
HO
OL
EN