February
19, 2007
WHITE-KNUCKLE
ATMOSPHERIC SCIENCE TAKES PLACE
Science
doesn’t always happen at a lab bench. For University of Toronto Mississauga
physicist Kent Moore, it happens while strapped
into a four-point harness, flying head-on into hurricane-force winds
off the
southern tip of Greenland.
Moore, chair of the
Department of Chemical and Physical Sciences,
is heading to Greenland
from Feb. 18 to Mar.
11 as part of the Greenland Flow Distortion experiment (GFDex), an
International Polar Year research project involving Canadian, British,
Norwegian and Icelandic scientists. Moore, a professor of atmospheric
physics,
is leading the Canadian contingent.
GFDex will provide
the first evidence of the role that Greenland
plays in distorting atmospheric flow around its
massive land and ice mass, affecting European and Asian weather
systems.
Moreover, the findings may reveal how sea and atmospheric interactions
in the
Arctic and North Atlantic
areas influence
climate.
At the heart of
GFDex are wind patterns known as “tip jets”.
Greenland, an icy obstacle more than three times the size of Texas,
forces air to go around its bulk and
creates regions of high wind speeds. Tip jets travel east from the tip
of
Greenland towards Iceland,
at speeds of 30 to 40 meters per second. Just as wind blows heat away
from the
body, making windy winter days feel even colder, tip jets blow heat
away from
the surface of the ocean. This now-cooler, denser water sinks;
affecting
currents of circulating warm and cool water within the ocean.
About two years ago,
Moore
discovered a different kind of tip jet, one that blows west towards Labrador. Now known as reverse
tip jets, these also force
circulation of water over the Labrador Sea to the west of Greenland.
“We’ve seen these things in satellite imagery, but
no one’s ever actually
observed them,” says Moore.
“We’ll be making the first in situ observations of
these jets. It’s kind of
exciting.”
The data will help
scientists understand how the flow of air
around Greenland
affects weather downwind. “If
things are happening near Greenland today, probably two days from now
that [air
mass] will move down over Europe,” says Moore.
“Two or three days after it’s affected Europe, it
affects Asia and then
ultimately comes around and affects North
America.
So Greenland
ultimately affects the whole
Northern Hemisphere…our knowledge will potentially help
improve forecasts.”
Moore is also hoping the
findings will clarify the climate
processes affecting Greenland’s
glaciers,
which have shrunk significantly in the past few years.
“There’s evidence that
the ice cap is retreating quite dramatically. In 2003, a cyclone came
up on the
east side of Greenland and there was a huge melting event,”
says Moore.
“It’s one of my
hopes that we’ll be able to understand a bit more about the
processes that
determine the mass balance of the Greenland
ice cap.”
Making these
observations requires both advanced technology
and a cast-iron stomach. Moore and his colleagues, along with graduate
students
and post-doctoral fellows, will be making 17 flights into the tip jets
in a
British research aircraft called FAAM (Facility for Airborne
Atmospheric
Measurements). Pods and sensors stud the outside of the aircraft. Most
of the
seats have been removed, creating space for racks of instruments
measuring the
presence of ice in the clouds, temperature, pressure and humidity.
On-board
radar gathers information on precipitation, and helps
Moore—who, as a mission
scientist, will sit in the cockpit—to direct the pilots where
to fly. At the
same time, “sondes”—paper towel
tube-sized devices on small parachutes—are
dropped from the back of the plane. Equipped with a barometer,
thermometer,
global positioning system and humidity sensor, each sonde radios its
measurements back to the plane and provides a profile of conditions
below the
aircraft.
In order to get the
best data, the researchers need to fly
just 100 feet above the heaving seas, in winds of more than 140
kilometers per
hour. “In these conditions and at these levels, the
turbulence will be quite
severe,” says Moore.
“Once, on a similar flight in the Arctic,
the
lens of my glasses popped out!”
The GFDex experiment
is funded by the U.K.’s
Natural
Environment Research Council, the Canadian Fund for Climate and
Atmospheric
Sciences, the European Fleet for Airborne Research and EUCOS, the
Composite
Observing System program of 21 European meteorological services.
##
Contact:
Nicolle
Wahl
University of
Toronto
905-569-4656
wahlnico@utm.utoronto.ca
This text derived from:
http://www.news.utoronto.ca/
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