| Title | Mixed layer analysis of a mesoscale eddy in the Antarctic Polar Front zone |
| Author | Cisewski, B.; Strass, V.H.; Losch, M.; Prandke, H. |
| Author Affil | Cisewski, B., Alfred Wegener Institut für Polar und Meeresforschung, Bremerhaven, Federal Republic of Germany. Other: ISW-Wassermesstechnik, Federal Republic of Germany |
| Source | Journal of Geophysical Research, 113(C5), Citation C05017. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227 |
| Publication Date | 2008 |
| Notes | In English. 38 refs. Ant. Acc. No: 87406. GeoRef Acc. No: 297020 |
| Index Terms | boundary layer; conduction; diffusion; ocean currents; orientation; temperature; Antarctica; acoustic Doppler current profiler data; Antarctic Polar Front; bathymetry; conductivity; currents; eddies; eddy coefficients; mixing; ocean circulation; thermohaline circulation; vertical diffusivity |
| Abstract | Microstructure, acoustic Doppler current profiler, and conductivity- temperature-depth (CTD) profiles were taken in a mesoscale eddy in the Antarctic Polar Front Zone at about 2°15'E, 49°15'S during the R/V Polarstern cruise ANT XXI/3 within the scope of the European Iron Fertilization Experiment in January-March 2004. The mixed layer depth (MLD), calculated from the composite of CTD- and microstructure sonde (MSS)-derived data, was 97.6 ± 20.6 m. No significant correlation between the wind work (E10) and the MLD (r = 0.02 to 0.22) was found. However, the analysis revealed a negative correlation between the surface buoyancy flux (B) and the MLD 1/2 d later. Two approaches were used to estimate the actively mixing layer depth (AMLD). First, the actively mixing layer was determined subjectively by analyzing the MSS-derived density, energy dissipation, and Thorpe scale profiles, and second, the mixed layer model embedded in a general circulation model was used. The overall mean of the determined depths of the actively mixing layer (AMLDMSS = 66.4 ± 28.8 m) agreed with the model- predicted boundary layer depths (BLD) (BLDKPP = 69.1 ± 29.5 m), but the individual values sometimes were differing considerably. We deduced estimates of the vertical diffusivity (Kz) from the MSS-derived energy dissipation rates and Thorpe scales. Both methods showed that Kz decreased with depth from order of magnitude 10-1 m2 s-1 in the actively mixed layer to order of 10-4 m2 s-1 in the pycnocline. |
| URL | http://hdl.handle.net/10.1029/2007JC004372 |
| Publication Type | journal article |
| Record ID | 64001981 |