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| Titel |
Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere oceans |
| VerfasserIn |
H. C. Bostock, S. E. Mikaloff Fletcher, M. J. M. Williams |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 10 ; Nr. 10, no. 10 (2013-10-02), S.6199-6213 |
| Datensatznummer |
250085345
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| Publikation (Nr.) |
 copernicus.org/bg-10-6199-2013.pdf |
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| Zusammenfassung |
| Using ocean carbon data from global datasets, we have developed several
multiple linear regression (MLR) algorithms to estimate alkalinity and
dissolved inorganic carbon (DIC) in the intermediate and deep waters of the
Southern Hemisphere (south of 25° S) from only hydrographic data
(temperature, salinity and dissolved oxygen). A Monte Carlo experiment was
used to identify a potential density (σθ) of 27.5 as an
optimal break point between the two regimes with different MLR algorithms.
The algorithms provide a good estimate of DIC (R2=0.98) and alkalinity
(R2=0.91), and excellent agreement for aragonite and calcite saturation
states (R2=0.99). Combining the algorithms with the CSIRO Atlas of
Regional Seas (CARS), we have mapped the calcite saturation horizon (CSH) and
aragonite saturation horizon (ASH) for the Southern Ocean at a spatial
resolution of 0.5°. These maps are more detailed and more consistent
with the oceanography than the previously gridded GLODAP data. The high-resolution
ASH map reveals a dramatic circumpolar shoaling at the polar
front. North of 40° S the CSH is deepest in the Atlantic
(~ 4000 m) and shallower in the Pacific Ocean (~ 2750 m), while
the CSH sits between 3200 and 3400 m in the Indian Ocean. The uptake of
anthropogenic carbon by the ocean will alter the relationships between DIC
and hydrographic data in the intermediate and deep waters over time. Thus
continued sampling will be required, and the MLR algorithms will need to be
adjusted in the future to account for these changes. |
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