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SOCIETY NOW OPERATING
IN-HOUSE "CAL-VAL" LAB
SeaKeepers is proud to inaugurate its own calibration
laboratory. A fundamental part of every
program of scientific measurement is the routine
calibration of instruments and validation of the
resulting data. In science jargon, this
is called “cal-val.” Each SeaKeeper
1000™ system requires calibration 2-3 times
per year, and the data is validated continuously.
While critical to the success of the SeaKeepers’
ocean monitoring effort, cal-val is also expensive.
A single calibration of a CTD sensor, the basic
instrument in a SeaKeeper 1000 system, costs approximately
$1,000 when performed by an outside laboratory.
One of my first priorities when I joined SeaKeepers
two years ago was to increase the accuracy and
relevancy of our data by ensuring that we met
the highest standards of calibration and validation,”
said John Englander, CEO. “The cost of a
good calibration program was becoming exorbitant
given the increased number of our installations.”
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Technicians working
with a conductivity reference at one of the
five salinity reference baths in the new calibration
lab. On the counter immediately in front of
them is a sensor module from one of our deployed
SeaKeeper 1000 monitoring systems.
The large gray units behind them are the temperature
reference baths. The sealed bottles on the
glass shelf contain standard seawater at different
salinities, accurate to the third decimal
place. |
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Our new basic calibration laboratory in Ft. Lauderdale
will not only save time,” Englander said,
“but should reduce the cost by roughly 60
percent compared to the use of outside laboratories.”
The lab was assembled thanks to the generosity
of its members and several donations of high-quality
surplus equipment by government agencies and scientific
institutions. Geoff Morrison, Technical Director,
describes the new cal lab, “as a truly first
class facility. We can do calibrations to
the third decimal point.”
Indeed, the degree of accuracy raises an interesting
issue. In any scientific measurement, precision
and accuracy are very important. SeaKeepers’
instruments were chosen and designed for a very
high level of accuracy -- enabling climatological
rather than meteorological precision. This
is an important distinction. For weather
or meteorological purposes it might suffice to
know that the sea surface temperature is accurate
to a single degree. But to be useful in
long term climate studies, scientists require
temperature accuracy to a hundredth of a degree.
To obtain this and have the readings consistent
over many months requires the thermometers be
read and be calibrated to a thousandth of a degree.
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Geoff Morrison (left) explains
the proper operation of the Triple Point of
Water apparatus to Mike Turner, field technician.
The TPW is one of the sophisticated devices
in the new SeaKeeper Calibration laboratory
that will ensure that the SeaKeeper systems
can measure seawater temperatures down to
the 3rd and 3rd decimal place.
This degree of accuracy is appropriate when
generating scientific data of use in climatalogical
studies – a significantly higher standard
than normal meteorology. |
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Fortunately Morrison's broad industry background
and physics training provided ample expertise and
experience to set up the cal lab, train staff, and
monitor calibration lab operating standards, established
by the National Institute of Standards. To
achieve an accuracy of three decimal points utilizes
an absolute principle of physics. There is
only one exact point where water can be maintained
simultaneously in the gaseous, liquid, and frozen
states and it is specified by an exact temperature
and pressure known as the “triple point of
water.” The new calibration laboratory
is equipped with the sophisticated apparatus needed
to achieve this point and results in the high quality
scientific data the SeaKeepers Society is helping
to gather and distribute with its cost effective
SeaKeeper 1000 ocean and atmospheric monitoring
system. |
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