The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring
Temperature–salinity profiles from the region studied in the North Atlantic Tracer Release Experiment (NATRE) show large isopycnal excursions at depths just below the thermocline. It is proposed here that these thermohaline filaments result from the mesoscale stirring of large-scale temperature and...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Meteorological Society
2010
|
| Online Access: | http://hdl.handle.net/1721.1/54832 https://orcid.org/0000-0002-3736-1956 |
| _version_ | 1826194395014103040 |
|---|---|
| author | Smith, K. Shafer Ferrari, Raffaele |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Smith, K. Shafer Ferrari, Raffaele |
| author_sort | Smith, K. Shafer |
| collection | MIT |
| description | Temperature–salinity profiles from the region studied in the North Atlantic Tracer Release Experiment (NATRE) show large isopycnal excursions at depths just below the thermocline. It is proposed here that these thermohaline filaments result from the mesoscale stirring of large-scale temperature and salinity gradients by geostrophic turbulence, resulting in a direct cascade of thermohaline variance to small scales. This hypothesis is investigated as follows: Measurements from NATRE are used to generate mean temperature, salinity, and shear profiles. The mean stratification and shear are used as the background state in a high-resolution horizontally homogeneous quasigeostrophic model. The mean state is baroclinically unstable, and the model produces a vigorous eddy field. Temperature and salinity are stirred laterally in each density layer by the geostrophic velocity and vertical advection is by the ageostrophic velocity. The simulated temperature–salinity diagram exhibits fluctuations at depths just below the thermocline of similar magnitude to those found in the NATRE data. It is shown that vertical diffusion is sufficient to absorb the laterally driven cascade of tracer variance through an amplification of filamentary slopes by small-scale shear. These results suggest that there is a strong coupling between vertical mixing and horizontal stirring in the ocean at scales below the deformation radius. |
| first_indexed | 2024-09-23T09:55:27Z |
| format | Article |
| id | mit-1721.1/54832 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:55:27Z |
| publishDate | 2010 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/548322022-09-30T17:43:08Z The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring Smith, K. Shafer Ferrari, Raffaele Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Ferrari, Raffaele Ferrari, Raffaele Temperature–salinity profiles from the region studied in the North Atlantic Tracer Release Experiment (NATRE) show large isopycnal excursions at depths just below the thermocline. It is proposed here that these thermohaline filaments result from the mesoscale stirring of large-scale temperature and salinity gradients by geostrophic turbulence, resulting in a direct cascade of thermohaline variance to small scales. This hypothesis is investigated as follows: Measurements from NATRE are used to generate mean temperature, salinity, and shear profiles. The mean stratification and shear are used as the background state in a high-resolution horizontally homogeneous quasigeostrophic model. The mean state is baroclinically unstable, and the model produces a vigorous eddy field. Temperature and salinity are stirred laterally in each density layer by the geostrophic velocity and vertical advection is by the ageostrophic velocity. The simulated temperature–salinity diagram exhibits fluctuations at depths just below the thermocline of similar magnitude to those found in the NATRE data. It is shown that vertical diffusion is sufficient to absorb the laterally driven cascade of tracer variance through an amplification of filamentary slopes by small-scale shear. These results suggest that there is a strong coupling between vertical mixing and horizontal stirring in the ocean at scales below the deformation radius. 2010-05-21T14:50:07Z 2010-05-21T14:50:07Z 2009-10 2009-03 Article http://purl.org/eprint/type/JournalArticle 0022-3670 1520-0485 http://hdl.handle.net/1721.1/54832 Smith, K. Shafer, and Raffaele Ferrari. “The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring.” Journal of Physical Oceanography 39.10 (2009): 2477-2501. © 2009 American Meteorological Society https://orcid.org/0000-0002-3736-1956 en_US http://dx.doi.org/10.1175/2009jpo4103.1 Journal of Physical Oceanography Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society |
| spellingShingle | Smith, K. Shafer Ferrari, Raffaele The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title | The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title_full | The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title_fullStr | The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title_full_unstemmed | The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title_short | The Production and Dissipation of Compensated Thermohaline Variance by Mesoscale Stirring |
| title_sort | production and dissipation of compensated thermohaline variance by mesoscale stirring |
| url | http://hdl.handle.net/1721.1/54832 https://orcid.org/0000-0002-3736-1956 |
| work_keys_str_mv | AT smithkshafer theproductionanddissipationofcompensatedthermohalinevariancebymesoscalestirring AT ferrariraffaele theproductionanddissipationofcompensatedthermohalinevariancebymesoscalestirring AT smithkshafer productionanddissipationofcompensatedthermohalinevariancebymesoscalestirring AT ferrariraffaele productionanddissipationofcompensatedthermohalinevariancebymesoscalestirring |