On the meridional ageostrophic transport in the tropical Atlantic
The meridional Ekman volume, heat, and salt transport across two trans-Atlantic sections near 14.5° N and 11° S were estimated using in situ observations, wind products, and model data. A meridional ageostrophic velocity was obtained as the difference between the directly measured total velocity...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
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| Series: | Ocean Science |
| Online Access: | https://www.ocean-sci.net/13/531/2017/os-13-531-2017.pdf |
| Summary: | The meridional Ekman volume, heat, and salt transport across two
trans-Atlantic sections near 14.5° N and 11° S were
estimated using in situ observations, wind products, and model data. A
meridional ageostrophic velocity was obtained as the difference between the
directly measured total velocity and the geostrophic velocity derived from
observations. Interpreting the section mean ageostrophy to be the result of
an Ekman balance, the meridional Ekman transport of 6. 2 ± 2. 3 Sv
northward at 14.5° N and 11. 7 ± 2. 1 Sv southward at
11° S is estimated. The integration uses the top of the pycnocline
as an approximation for the Ekman depth, which is on average about
20 m deeper than the mixed layer depth. The Ekman transport estimated
based on the velocity observations agrees well with the predictions from
in situ wind stress data of 6. 7 ± 3. 5 Sv at 14.5° N and
13. 6 ± 3. 3 Sv at 11° S. The meridional Ekman heat and
salt fluxes calculated from sea surface temperature and salinity data or from
high-resolution temperature and salinity profile data differ only marginally.
The errors in the Ekman heat and salt flux calculation were dominated by the
uncertainty of the Ekman volume transport estimates. |
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| ISSN: | 1812-0784 1812-0792 |