A warm blob of water lurking in the Pacific Ocean in 2014 and 2015 led to
a spike in ozone levels across the western U.S., new research suggests.
The blob of warm water, which sat about 310 miles off the Oregon coast,
was linked to a high-pressure system in the atmosphere that resulted in warm,
calm air and sunny skies across nearly a quarter of the country, said study
co-author Dan Jaffe, an atmospheric scientist at the University of Washington
Bothell.
Those atmospheric conditions sped up the formation of ozone in the
atmosphere, Jaffe added. (Ozone in the lower atmosphere is harmful to human
health, while high in the atmosphere it forms a protective layer that shields
the planet from harmful UV radiation.)
The finding suggests that these ocean patterns don't just mess with sea
life; their effects may also reach far inland, he said. [The World's 10 Most Polluted Places]
Warm
patch
The "blob" ― as meteorologists affectionately called the mass
of warm water ― occurred from the winter of 2014 through the summer of 2015,
when high sea-surface temperatures prevailed in the Northeast Pacific Ocean.
The warmer waters — about 2 to 7 degrees Fahrenheit higher than average for the
region — spanned from the coast of Sitka, Alaska, to Santa Barbara, California,
and came with a high-pressure system in the atmosphere that led to low wind
speeds, fewer storms and sunnier skies.
The warm blob scrambled the food chain and brought a host of strange
ecological effects: The toastier waters fueled some of the worst-ever toxic red
tide algal blooms , and marine mammals died in droves as they struggled to find
enough food in normally cold, food-rich waters, Jaffe said.
But the blob also had stark effects inland. In June 2015, for instance,
the average monthly air temperatures were elevated between 1.8 and 10.8 F
relative to normal in the western U.S., researchers reported Wednesday, Feb.
15, in the journal Geophysical Research Letters . These regions also
experienced more cloud-free, windless days.
Jaffe and his colleagues had been tracking levels of ozone , a compound
with three atoms of oxygen that can irritate the lungs, at the Mount Bachelor
Observatory in central Oregon.
They found record-high levels of ozone above the Oregon peak. That
spurred them to examine levels throughout the Mountain West. Sure enough, they
found highly elevated levels of ozone throughout the region.
"When you looked at where the highest temperatures were and the
unusual highest ozone levels were, you see an unusually good match," Jaffe
told Live Science.
That made the team suspect the blob may have fueled the ozone levels.
Ozone forms when hydrocarbons and nitrogen oxides, which are emitted as
pollutants from cars, undergo a complicated chemical reaction with sunlight in
the atmosphere. Both sunlight and high temperatures fuel faster
ozone-formation, whereas the wind blows away the basic building-block
pollutants, making it harder to form ozone, Jaffe said.
When they investigated ozone levels throughout the West, they found areas
with the hottest, most stagnant air also had highly elevated ozone levels,
compared with historical averages. For instance, Salt Lake City and Sacramento,
California, had unusually high levels, likely a combination of having high
emissions of the base pollutants, as well as the optimal conditions for forming
ozone, Jaffe said.
The new findings suggest the blob directly led to dangerous levels of
ozone across the western U.S.
What's not known, however, is whether climate change will lead to more of
these blobby weather patterns.
"We know it's getting warmer, and the question becomes how will
ozone change in the future?" Jaffe said.
Originally published on Live Science .
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