- Here, based simplified, are the chemical reactions in
the atmosphere, which explain how the Fukushima disaster impacted the Arctic
ozone hole.
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- The cold winter in 2010-2011 produced dense stratospheric
clouds over the Arctic, which due to the presence of water promoted chemical
reactions with various gases to produce compounds that deplete ozone over
the Arctic Circle.
-
- The Arctic ozone hole, that began expanding due to the
clouds, radically widened in March and April, coinciding with the Fukushima
disaster.
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- The damaged Fukushima reactors and burning fuel rods
released many, many tons of of iodine (a highly-reactive ozone-attacking
agent) and xenon, which soon transformed into xenon fluoride (produced
when xenon comes under UV catalysis to combine with fluorine gas in the
atmosphere).
-
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- Fluorine is abundant over the US Pacific Northwest and
Canada. The jet stream carried the iodine and newly-formed XeFl compounds
in a northeasterly direction, crossing into the Arctic circle and looping
back down over Greenland, Scandinavia and European Russia. This exactly
accounts for the oblong shape and direction of the expanded ozone hole.
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- From the Mainichi newspaper...
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- Researchers Report Unprecedented Ozone Loss In Arctic
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- 10-3-11
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- TSUKUBA, Japan (Kyodo) -- The depletion of the Arctic
ozone layer reached an unprecedented level in early 2011 and was "comparable
to that in the Antarctic," an international research team said Sunday
in the online version of the British science magazine Nature.
-
- "For the first time, sufficient loss occurred to
reasonably be described as an Arctic ozone hole," said the nine-country
team, including Hideaki Nakajima of the National Institute for Environmental
Studies in Tsukuba in Ibaraki Prefecture.
-
- "Our results show that Arctic ozone holes are possible
even with temperatures much milder than those in the Antarctic," it
also said.
-
- It is harder for ozone-destroying chlorine monoxide to
form in the stratosphere of the Arctic as winter temperatures are higher
than in the Antarctic, according to the group.
-
- But the depletion of the ozone layer over the Arctic
appears to have progressed greatly this winter to spring because unusually
cold temperatures from December through the end of March enhanced ozone-destroying
forms of chlorine.
-
- "The 2010-11 Arctic winter-spring was characterized
by an anomalously strong stratospheric polar vortex and an atypically long
continuously cold period," the team said in the article contributed
to Nature.
-
- "This was a phenomenon we had not anticipated,"
Nakajima said.
-
- "If the layer of ozone that blocks ultraviolet rays
is eradicated, it will negatively affect human health," he said, adding,
"We need to monitor the situation down the track."
-
- The team, which has been observing the distribution of
atmospheric ozone in the Northern Hemisphere, found in March that the area
of low ozone density had spread from the Arctic Sea to over Scandinavia,
northern Russia and Greenland.
-
- The loss of the ozone layer was especially prominent
in high-altitude zones, with the team estimating that around 40 percent
of the ozone layer has been lost, up from a previous reading of 30 percent.
-
- The level is comparable to that of the ozone hole that
annually appears over the Antarctic in the September-October period, it
added.
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- (Mainichi Japan) October 3, 2011
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