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Climatological variations of total alkalinity and total inorganic carbon in the Mediterranean Sea surface waters.
- Source :
- Earth System Dynamics Discussions; 2015, Vol. 6 Issue 2, p1499-1533, 35p
- Publication Year :
- 2015
-
Abstract
- A compilation of several cruises data from 1998 to 2013 was used to derive polynomial fits that estimate total alkalinity (A<subscript>T</subscript>) and total inorganic carbon (C<subscript>T</subscript>) from measurements of salinity and temperature in the Mediterranean Sea surface waters. The optimal equations were chosen based on the 10-fold cross validation results and revealed that a second and third order polynomials fit the A<subscript>T</subscript> and C<subscript>T</subscript> data respectively. The AT surface fit showed an improved root mean square error (RMSE) of ±10.6 μmol kg<superscript>-1</superscript>. Furthermore we present the first annual mean C<subscript>T</subscript> parameterization for the Mediterranean Sea surface waters with a RMSE of ±14.3 μmol kg<superscript>-1</superscript>. Excluding the marginal seas of the Adriatic and the Aegean, these equations can be used to estimate A<subscript>T</subscript> and C<subscript>T</subscript> in case of the lack of measurements. The seven years averages (2005-2012) mapped using the quarter degree climatologies of the World Ocean Atlas 2013 showed that in surface waters A<subscript>T</subscript> and C<subscript>T</subscript> have similar patterns with an increasing eastward gradient. The surface variability is influenced by the inflow of cold Atlantic waters through the Strait of Gibraltar and by the oligotrophic and thermohaline gradient that characterize the Mediterranean Sea. The summer-winter seasonality was also mapped and showed different patterns for A<subscript>T</subscript> and C<subscript>T</subscript>. During the winter, the A<subscript>T</subscript> and C<subscript>T</subscript> concentrations were higher in the western than in the eastern basin, primarily due to the deepening of the mixed layer and upwelling of dense waters. The opposite was observed in the summer where the eastern basin was marked by higher A<subscript>T</subscript> and C<subscript>T</subscript> concentrations than in winter. The strong evaporation that takes place in this season along with the ultra-oligotrophy of the eastern basin determines the increase of both A<subscript>T</subscript> and C<subscript>T</subscript> concentrations. [ABSTRACT FROM AUTHOR]
- Subjects :
- CLIMATOLOGY
ALKALINITY
SALINITY
Subjects
Details
- Language :
- English
- ISSN :
- 21904995
- Volume :
- 6
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Earth System Dynamics Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 111574203
- Full Text :
- https://doi.org/10.5194/esdd-6-1499-2015