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| Titel |
Comparison of the fall rate and structure of recent T-7 XBT manufactured by Sippican and TSK |
| VerfasserIn |
S. Kizu, C. Sukigara, K. Hanawa |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 7, no. 2 ; Nr. 7, no. 2 (2011-04-07), S.231-244 |
| Datensatznummer |
250004537
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| Publikation (Nr.) |
 copernicus.org/os-7-231-2011.pdf |
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| Zusammenfassung |
| The fall rate of recent T-7 expendable bathythermograph (XBT;
760 m) is evaluated based on a series of concurrent measurement
with a calibrated Conductivity Temperature Depth profiler (CTD)
in the sea east of Japan. An emphasis is placed on comparing the
fall rates of T-7 produced by the two present manufacturers,
the Lockheed Martin Sippican Inc., and the Tsurumi Seiki
Co. Ltd., which have been believed to be identical but had
never been compared directly. It is found that the two
manufacturers' T-7 fall at rates different by about
3.5%. The Sippican T-7 falls slower than given by the
fall-rate equation (FRE) of Hanawa et al. (1995) by about
2.1%, and the TSK T-7 falls faster by about 1.4%.
The fall-rate coefficients estimated based on the
sea test by applying the equation of traditional
quadratic form, d(t)=at−bt2 where d is depth in meters and
t is the time elapsed, in seconds, are a=6.553 (m s−1)
and b=0.00221 (m s−2) for the LMS T-7, and a=6.803 (m s−1)
and b=0.00242 (m s−2) for the TSK T-7. By detail examination
of the probes, we found that the two companies' T-7 have different
total weight and many structural differences. Because the difference
in the fall rate is about twice larger than the difference in weight
(about 2%), it is inferred that the structural differences give
sizable impact to the difference in their fall rates. Our results
clearly show that the recent T-7 of the two companies needs to
be discriminated. |
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