 |
| Titel |
Distribution of intermediate water masses in the subtropical northeast Atlantic |
| VerfasserIn |
I. Bashmachnikov, Â. Nascimento, F. Neves, T. Menezes, N. V. Koldunov |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1812-0784
|
| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 11, no. 5 ; Nr. 11, no. 5 (2015-10-09), S.803-827 |
| Datensatznummer |
250117295
|
| Publikation (Nr.) |
 copernicus.org/os-11-803-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| This work presents the quantitative study of climatological distributions of
mid-depth source water types in the northeast (NE) Atlantic using the optimum multiparameter analysis (OMP). It generalises a number of regional results
from particular synoptic sections. The cores of the Mediterranean Water (MW),
the modified Antarctic Intermediate Water (mAAIW) and the Subarctic
Intermediate Water (SAIW) are detected and spatial variations of their
depth/density are obtained: as expected, spreading of the water types is
predominantly isopycnic and follows the major mid-depth circulation patterns.
In some areas the turbulent transport also makes a considerable
contribution. MW in the Atlantic spreads in three cores of different density:
the upper MW core (northwest of the line 28° W,
35° N–14° W, 44° N) is found in the neutral
density range of 27.65–27.70 kg m−3 at depths of 900–1000 m;
the main MW core (between the line above and the line 35° W,
28° N–10° W, 37° N) has neutral density of around
27.75 kg m−3 and is found at 1000–1100 m; the lower MW core
(southeast of the line 35° W, 28° N–10° W,
37° N) has neutral density of around 27.80 kg m−3 and is found
at 1250–1350 m. The upper MW core has a comparatively low MW content
(below 30 %) and is speculated to be transported by the mean flow from
the northern Iberian Peninsula and the Bay of Biscay to the northern Azores.
The main MW core contains the majority of the outflowing MW. It primarily
originates from the Mediterranean undercurrent around Estremadura Promontory,
where the Joint Effect of Baroclinicity and Bottom Relief (JEBAR) overrides
the topographic β effect. It is transported west to the Azores Islands
mostly along 39° N. The lower MW core originates in the Gulf of
Cádiz, from where it is transported by the dominating flows southwestwards.
The SAIW core is detected between 27.70 and 27.75 kg m−3. It is found to
spread south along both slopes of the Mid-Atlantic Ridge (MAR). SAIW east of
the MAR mixes with the upper and the main MW cores and re-circulates in a
cyclonic gyre at 15–25° W and 34–39° N, penetrating as
far south as the Azores Current. The mAAIW core is detected between 27.60 and
27.65 kg m−3. Its northernmost spreading limit is between 25 and
29° N, but its influence can be observed along the African coast and
immediately west of the Canary Islands up to 32° N. The maximum
concentration of the mAAIW core is found south of the Canary Islands, from where
mAAIW is advected westwards, along with the westward spreading of the deep
fraction of MW. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|