NASA funded researchers have linked unexplained pockets of
ozone over the Western Pacific Ocean to fires thousands of
miles away. The findings are from a 2014 field campaign over
the remote island of Guam. Scientists took to the air
aboard flying laboratories filled with instruments to study
the chemistry of the atmosphere. Measurements taken along flight
paths up to 30,000 feet revealed areas with levels of ozone that
were three times higher than normal. So while
ozone is an important shield against ultraviolet radiation in
the upper atmosphere, in the lower atmosphere it is a very
strong greenhouse gas. So what we were trying to explore, is
what was causing these very high levels of ozone in the Pacific.
The answer came from two chemicals found with the ozone
linked to forest fires and the burning of vegetation. As these
fires burn, a mix of organic compounds and gases that react
to form ozone are released into the atmosphere. They’re then
transported by winds, sometimes thousands of miles from their
source. Using a computer model, we traced the
winds back in time to their origins so we could figure out
the source of these chemicals. What the model and satellite
data showed, is that these chemicals were coming from fires
in Africa and Southeast Asia. The red and orange lines in this
visualization trace the path of high concentrations of
ozone-filled air detected in the Western Pacific to their source.
The air could be traced back ten to fifteen days to fires in
Southeast Asia and tropical Africa. In one of the remotest
parts of the Northern Hemisphere, we’re seeing impacts
from fires that are happening half a world away. So what I
think is important about this study, is that it helps us
connect these fires in Africa and Southeast Asia to processes
that are happening across the globe.