Subtropical surface layer salinity budget and the role of mesoscale turbulence
17 pages, 8 figures The subtropical North Atlantic exhibits the saltiest surface waters of the open ocean. Eventually that water subducted from the surface and exported toward the Equator, as a subsurface salinity maximum (S-max) forming the lower limb of the subtropical cell. Climatologically, the...
| Published in: | Journal of Geophysical Research: Oceans |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
American Geophysical Union
2014
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10261/103423 https://doi.org/10.1002/2013JC009715 |
| Summary: | 17 pages, 8 figures The subtropical North Atlantic exhibits the saltiest surface waters of the open ocean. Eventually that water subducted from the surface and exported toward the Equator, as a subsurface salinity maximum (S-max) forming the lower limb of the subtropical cell. Climatologically, the winter subtropical surface water, coinciding with the deepest mixed layer of 100 m, is saltier and colder than the S-max. Towed CTD measurements in March/April 2013 (a component of the field program SPURS) within the North Atlantic subtropical surface salinity maximum reveal several relatively fresh, warm anomalies, which deviate strongly from climatological conditions. These features introduce a large amount of freshwater into the subtropical region, exceeding the amount introduced by local rain events. Observed scales and evolution of the features strongly suggest a connection to mesoscale dynamics. This is supported by high-resolution regional model output, which produces an abundance of features that are similar in scale and structure to those observed. It is hypothesized that turbulent transport in the surface ocean is a crucial process for setting mixed layer characteristics, which spread into S-max stratum. High variability in the EKE implies a high potential for interannual variability in the resulting S-max water properties by ocean dynamics in addition to the variability caused by air sea fluxes. This has likely consequences to the meridional transport of heat and freshwater of the subtropical cell in the North Atlantic and to the larger-scale ocean and climate system. Key Points Distinct fresh features are observed within the subtropical North Atlantic Mesoscale turbulence is significant in governing the surface salinity © 2014. American Geophysical Union. All Rights Reserved Support for this research was provided by NASA NNX09AU68G. [.] The SPURS-MIDAS cruise was part of the MIDAS-6 project funded by the Spanish National R1D Plan under grant AYA2010-22062-C05-01. Jordi Font was supported under the ... |
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