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By Peter Rejcek
UW-Madison group marks 30 years tracking Antarctic
weather
On the roof of the Space Science and Engineering Center
(SSEC) , festooned with antenna that grab data from orbiting
satellites in space, Matthew Lazzara gestures to the various
dishes, describing the unique history of each one, as
if recounting royal lineage.
Two on top of the penthouse date back to the 1970s, he
explains. One points to a NOAA satellite that provides
imagery over the Antarctic Peninsula. Others receive information
from a pair of important Earth-observing satellites launched
by NASA, Terra and Aqua .
“A lot of different satellite observations are made
available here, which allows us to do some of the work
we do,” Lazzara explains before ducking back inside
the penthouse of the 15-story building as an October rain
drizzle on the University of Wisconsin-Madison (UW-Madison)
campus turns heavy.
That work involves making now hourly satellite composites
of the Antarctic continent and the weather systems that
swirl around and over it in the Southern Hemisphere. The
imagery is the hallmark product of the Antarctic Meteorological
Research Center (AMRC) , which occupies the ninth floor
of the SSEC.
Lazzara is the principal investigator (PI) for the center
as well as one of the PIs for the Antarctic Automatic
Weather Station (AWS) Program , a network of about 60
weather stations that collect data year-round and account
for more than half of all such observatories on the continent.
The National Science Foundation’s Office of Polar
Programs funds both programs.
Lazzara became a PI on the AWS program in 2007 and took
over the AMRC from its founder, Charles Stearns , last
year. A World War II veteran, Stearns established the
AWS program in 1980 and began generating the satellite
weather composites of Antarctica in 1992, launching the
AMRC.
Now Lazzara, who received his doctorate from UW-Madison
by studying the occurrence of fog in Antarctica, wants
to improve access to the center’s vast archive of
weather data while pursuing new research on wind and cloud
movement using the satellite composites.
The AWS system
“That’s one of the things that’s maybe
unique about our group. We release the data out rapidly,
get it out to people as fast as we can get it,” he
says. “Our goal is going to get to be a lot more
self-sufficient — easy access — all of the things
you might expect a data center would provide.”
The data are used for various purposes, from weather forecasting
for flight operations around the continent to climate
change research. Lazzara notes that information collected
from the AWS program was used in a major paper published
in the journal Nature earlier this year by Eric Steig
at the University of Washington . Steig and his co-authors
suggested that Antarctica overall is warming in step with
the rest of the planet.
Each year, a team from UW-Madison, usually with some
of their collaborators from other institutions, head to
the Ice to service and repair various AWS towers and install
new ones. For example, during the 2008-09 field season,
the group visited about 27 AWS sites and installed two
new stations.
The three-meter-tall towers — with various low-energy
sensors powered by solar and batteries — collect
basic meteorological data such as temperature, pressure
and wind speed. In the future, Lazzara’s team will
install a 30-meter-tall tower on the Ross Ice Shelf —
the first “tall tower” in the network.
The AWS system turns 30 years old this year, a significant
milestone because 30 years is the standard timeframe for
establishing climatological trends, according to Lazzara.
A few of the sites have survived for almost that long,
he said.
A tower called Ferrell (named after a U.S. Navy captain,
while many others carry the names of pilots or even family
members of the science team) has been running for 30 years
as it moves with the flow of ice on the Ross Ice Shelf
, Lazzara says. Another unit at Marble Point, near McMurdo
Station, may host some original gear from 1980 as well.
The hardware is built to military specification, Lazzara
adds, which has proved to be fairly hardy in the extreme
Antarctic environment.
“It’s a great investment that NSF has put into
the weather station program. It’s solid hardware
that can last a long, long time,” he says. Each AWS
package costs about $15,000 to $20,000.
But even the tough AWS units can get hammered by winds.
Cape Denison on the Adélie coast regularly records
wind speeds of 60 to 90 kilometers per hour, and once
clocked the winds at 196 kph.
“The Adélie coast is bad news,” Lazzara
says. “It’s a place to throw away hardware.”
A map of AWS sites in Antarctica hangs nearby in one
of the AMRC offices, showing all 120-plus stations. Lazzara
says that the continent, about 1½ times the size
of the United States, is in reality sparsely monitored.
“It looks like a big forest of weather stations,
but it really isn’t,” he says. “This is
really bare minimum of weather stations you could have
compared to what we have [in the United States."
AMRC studies
In another room at AMRC, a flat-screen monitor displays
a graphic of Antarctica, pictured upside down from the
image normally seen of the continent, with the Antarctic
Peninsula pointing up.
The perspective is deliberate: Lazzara wants to observe
the wind and weather patterns between Antarctica and New
Zealand, located in the upper left-hand corner in this
view, because of the numerous flights along that route.
The screen shows satellite images taken from the last
10 days, with swirls of clouds flashing across the picture
as time leaps in one- or three-hour chunks. The image
is composed of about 10 different geostationary (equatorial-orbiting)
and polar-orbiting satellites.
“It’s like doing a jigsaw puzzle. We’ve
done it for many, many years every three hours. Now we’re
doing it every hour, which is very exciting,” Lazzara
says.
The hourly composite has allowed his team to track clouds
more accurately, which wasn’t possible with the every-three-hour
compilations. That has provided the meteorologists a way
to calculate wind speed — an estimate they previously
used only polar orbiting or geostationary satellites to
do.
The hourly composites are timely enough to be useful
to weather forecasters, he says.
“It’s cheaper doing [the composites in] real-time.
If you go back to build these later, it’s far more
expensive,” Lazzara says. He has a different grant
from the NSF for similar composites of the Arctic.
There are some gaps in the imagery, however, as satellite
coverage is not always available throughout the day. A
full, data-rich image is possible, he explains, but it
would take a day to complete and would not be as useful.
“You can’t see the day evolve, which is what
a weather forecaster wants,” he explains.
Forecasters on the ground at South Pole Station learned
that it’s all about location, location, location
when observing the winds at the bottom of the world. AMRC
installed new instruments at the farthest end of the skiway,
or airfield landing strip, from the new research building.
To ensure the new and old equipment — located on
the other side of the elevated station — were recording
similar information, the sites ran simultaneously for
a year. An analysis of the results from the instruments
and visible observations on the ground found some striking
disparities.
“You would get [observations of] blowing snow that
doesn’t match the wind speed. It’s because the
profile of the station gets in the way,” Lazzara
says. “South Pole is now big enough that it matters
where you observe because it’s so large and influences
the weather.”
Lazzara’s own influences into the field of meteorology
include his father, who worked as an environmental sciences
high school teacher for 35 years. A native of Massachusetts,
Lazzara ended up doing his graduate work at UW-Madison
on the recommendation of a couple of undergraduate advisors
who attended the university.
In 1995, he made his first trip to Antarctica —
and has been back seven times since, returning to the
field for the 2009-10 summer season.
“I have to admit that I like the Antarctic for the
following reason, and it’s maybe one that you don’t
think of: the sharing environment, the collaborations,
a little less competitiveness,” Lazzara says.
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