No way to know weather the North Atlantic conveior is slowing down or not

Hello again folks,

just saw an interesting article on NewScientist.com. It appears that
there is quite a bit more uncertainty about how climate change is
affecting the so called North Atlantic Conveior than previously was
thought.

Here below the entire article.

Cheers, Einar
-----------------------------------------------------------------------

http://environment.newscientist.com/...modellers.html

"Fickle ocean current foils climate modellers

* 14:46 16 August 2007
* NewScientist.com news service
* Stephen Battersby

The North Atlantic is stirring fitfully. A new monitoring system has
shown that the ocean's currents change rapidly, surging or slowing
from one week to the next. That makes it difficult to judge whether
they really are slowing down over the long term, as one study has
suggested.

An overall slowdown might be bad news for Europe, which is warmed by a
current called the North Atlantic Drift, and it might be even worse
for the rest of the world because the North Atlantic forms a vital
piece of planetary plumbing. When the North Atlantic Drift reaches the
Arctic, it cools, sinks and flows back to the south, helping to drive
global ocean circulation.

The risk is that climate change will melt ice and increase rainfall
around the Arctic, flushing fresh, less dense water into the Arctic
Ocean. That could interfere with the crucial sinking process, slowing
the current down or even cutting it off. Some have even claimed this
could plunge Europe into a new ice age, though most climatologists now
dismiss this extreme scenario as just another climate change myth.

Most ocean models predict that a substantial slowdown is unlikely
until late this century, but in 2005 a team of oceanographers led by
Harry Bryden of Southampton University, UK, announced evidence that
the vital "overturning circulation" of the North Atlantic had already
slowed by 30%.

However, they conceded that natural variability might explain their
data, because the only measurements available were intermittent ones
made over the past half century by oceanographers on ships.
RAPID measures

Now for the first time scientists can monitor the ocean continuously,
thanks largely to RAPID, an array of instruments strung on cables
moored to the seabed. RAPID measures the ocean's pressure profile,
which scientists can use to calculate how water is flowing.

An international team, including Bryden, has now taken the first year
of data from RAPID and combined it with two other sources: space-based
measurements of wind-blown surface currents, and the flow of the gulf
stream between Florida and the Bahamas, which is revealed by its
electrical effect on submarine telephone cables.

What they see is that the overturning circulation fluctuates wildly,
between 35 million tonnes a second and just 4 million tonnes a second.
All the earlier measurements lie within that range. "It is now going
to be difficult to make robust estimates of overturning based on
earlier results," says Stuart Cunningham, also of Southampton
University and lead author of the new study. "This defines an
unambiguous baseline against which future change may be gauged."

Cunningham still suspects that overturning circulation is slowing
down, pointing to an ocean model published last year by Carl Wunsch of
the Massachusetts Institute of Technology in which it fell by 14%
between 1993 and 2004.

However, finding out for sure will take some time. At present RAPID is
funded until 2014, but it may be decades before scientists understand
the natural variability of the ocean and identify any effects of human-
driven climate change. "We hope to be able to explain all variability
eventually," Cunningham told New Scientist.

Journal reference: Science, vol 317 p 935"

Einar wrote:

Hello again folks,

just saw an interesting article on NewScientist.com.
[snip]

"New Scientist" is crap. Put on long pants.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

In article ,
says...

Einar wrote:

Hello again folks,

just saw an interesting article on NewScientist.com.
[snip]

"New Scientist" is crap. Put on long pants.

Maybe that's why all "real" scientists go to the original reports.
-----------------------------------
Science 17 August 2007:
Vol. 317. no. 5840, pp. 938 - 941
DOI: 10.1126/science.1141293

Reports
Observed Flow Compensation Associated with the MOC at 26.5°N in the
Atlantic
T. Kanzow, S. A. Cunningham, D. Rayner, J. J.-M. Hirschi, W. E. Johns,
M. O. Baringer, H. L. Bryden, L. M. Beal, C. S. Meinen, J. Marotzke

The Atlantic meridional overturning circulation (MOC), which provides
one-quarter of the global meridional heat transport, is composed of a
number of separate flow components. How changes in the strength of each
of those components may affect that of the others has been unclear
because of a lack of adequate data. We continuously observed the MOC at
26.5°N for 1 year using end-point measurements of density, bottom
pressure, and ocean currents; cable measurements across the Straits of
Florida; and wind stress. The different transport components largely
compensate for each other, thus confirming the validity of our
monitoring approach. The MOC varied over the period of observation by
±5.7 x 106 cubic meters per second, with density-inferred and
wind-driven transports contributing equally to it. We find evidence for
depth-independent compensation for the wind-driven surface flow.
-------------------------

--
Eric Swanson --- E-mail address: e_swanson(at)skybest.com :-)
--------------------------------------------------------------

Einar wrote:
Hello again folks,

just saw an interesting article on NewScientist.com. It appears that
there is quite a bit more uncertainty about how climate change is
affecting the so called North Atlantic Conveior than previously was
thought.

Who said they were certain about how climate change is affecting the
North Atlantic "Conveier"?

Eric Swanson wrote:
In article ,
says...

Einar wrote:

Hello again folks,

just saw an interesting article on NewScientist.com.
[snip]

"New Scientist" is crap. Put on long pants.

Maybe that's why all "real" scientists go to the original reports.
-----------------------------------
Science 17 August 2007:
Vol. 317. no. 5840, pp. 938 - 941
DOI: 10.1126/science.1141293

Reports
Observed Flow Compensation Associated with the MOC at 26.5°N in the
Atlantic
T. Kanzow, S. A. Cunningham, D. Rayner, J. J.-M. Hirschi, W. E. Johns,
M. O. Baringer, H. L. Bryden, L. M. Beal, C. S. Meinen, J. Marotzke

The Atlantic meridional overturning circulation (MOC), which provides
one-quarter of the global meridional heat transport, is composed of a
number of separate flow components. How changes in the strength of each
of those components may affect that of the others has been unclear
because of a lack of adequate data. We continuously observed the MOC at
26.5°N for 1 year using end-point measurements of density, bottom
pressure, and ocean currents; cable measurements across the Straits of
Florida; and wind stress. The different transport components largely
compensate for each other, thus confirming the validity of our
monitoring approach. The MOC varied over the period of observation by
±5.7 x 106 cubic meters per second, with density-inferred and
wind-driven transports contributing equally to it. We find evidence for
depth-independent compensation for the wind-driven surface flow.
-------------------------

--
Eric Swanson --- E-mail address: e_swanson(at)skybest.com :-)
--------------------------------------------------------------

Interesting. If you have got reliable data for flow rates at different
depths, then that´s good! Might mean your measurements actually make
sence.

Cheers, Einar