[ASC-media] Flowerpots go overboard for climate change

Niall Byrne niall at scienceinpublic.com
Wed Aug 4 09:39:36 EST 2004

Flowerpots go overboard for climate change

And win Tasmania's Chris Watson Young Scientist of the Year and a UK visit,
courtesy of the British Council.

TWO plastic flowerpots trailing behind a fishing boat in Bass Strait are
playing a crucial role in measuring climate change.

"Sealed inside the flowerpots are sophisticated devices that are part of an
international effort to ensure accurate measurements of global sea level
change," said Chris Watson, a scientist from the University of Tasmania and
CSIRO Marine Research team.

The flowerpot buoys - affectionately known as B1 and B2 - have been deployed
under the flight path of two satellites, TOPEX/Poseidon and Jason-1.  The
satellites continuously measure ocean height as they orbit high above the

Dr John Church, from CSIRO Marine Research and a lead author on the report
on sea-level rise for the Intergovernmental Panel on Climate Change said the
satellites have revolutionised the way we observe the oceans and monitor sea
level change.  

"Keeping the satellites in check is a top priority for climate change
research," Dr Church said.  "By comparing the sea level measured from the
buoys with the sea level measured from satellites, our team can check the
accuracy and stability of the satellite system." 

Data from the instruments inside the flowerpots is used to calculate the
location and height of each buoy every second. "Our system is accurate to
about the diameter of a 10 cent piece - some 20 kilometres out to sea," Mr
Watson comments. 

The $20 flowerpots make an unlikely match for the sophisticated $40,000
Global Positioning System (GPS) receivers sealed inside.  "The flowerpots
were a perfect fit for our satellite antennae," says Mr Watson.  "They're
tough enough to withstand Bass Strait and don't get sea-sick like their

By comparing the Bass Strait results with those from Northern Hemisphere
sites in the Mediterranean Sea and near California, the scientists have
uncovered small discrepancies in the orbit of the satellites. 

Chris Watson's news story about his work has won him the 2004 Young
Scientist of the Year award. 
As part of his prize Chris will work as a journalist with The Australian and
one of News Limited's London newspapers.

The award was open to fully qualified scientists or engineers at the start
of their career. They had to write an original science news story, no more
than 550 words in length, in a style suitable for publication in The
Australian. The first part of his winning release appears above - the rest
can be seen online at www.scienceinpublic.com along with images and links. 

Chris is the newly-appointed lecturer in spatial information science at the
University of Tasmania. 

Proving that the competition is right on track, Chris confesses that,
"writing the news story was much harder than writing the scientific report".

The scientific research behind his story was recently published in two
papers in Marine Geodesy.  The research has also been presented at U.S.
National Aeronautics and Space Administration (NASA) and the French Space
Agency, Centre National d'Etudes Spatiales (CNES) Science Working Team

For interview contact Chris Watson on 03 6226 2497, cwatson at utas.edu.au

The rest of the text of Chris' winning entry follows.

"These comparisons are crucial in keeping the system in check," Mr Watson
said.  "It's a great result as the Bass Strait site is the only one of its
kind in the Southern Hemisphere."

In light of these findings, scientists have been able to change the way they
calculate the orbits.

"We have found that each satellite is now reaching or exceeding pre-launch
mission targets.  This translates to a single measurement precision of the
ocean's surface height of around 35 mm - measured from around 1340
kilometres above the Earth." Chris said.  

The flowerpot buoys are part of an instrument ensemble deployed in Bass
Strait for six months to check the performance of the new Jason-1 satellite
as it takes over from TOPEX/Poseidon.

"Jason-1 was launched in late 2001 and is definitely the new kid on the
block," Mr Watson said. Travelling at a ground speed of around 7 kilometres
a second, it takes the satellites just 10 days to cover the globe in a
criss-cross pattern.

The joint United States and French operated TOPEX/Poseidon spacecraft has
been returning information to Earth since August 1992 - an impressive record
for a mission with an initial life of 3-5 years.

Without these vital ground-based measurements, estimates of regional and
global mean sea level change would remain uncertain, greatly reducing the
capacity to monitor and manage climate change.

Safely returned from sea, B1 and B2 await their next deployment.  "Hopefully
in calmer waters." adds Chris.


Niall Byrne

Science Communication Consultant
Science in Public
PO Box 199 Drysdale 3222 Australia
(185 Scotchmans Road Portarlington 3223)
Ph +61 3 5253 1391, fax +61 3 9923 6008, mobile 0417 131 977
niall at scienceinpublic.com, www.scienceinpublic.com

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