Eastern Alboran Gyre, EAG respectively). In this case, the AJ flows into the Alboran
Sea in a northeast direction, due to the orientation of the longitudinal axis of
the Strait. It continues in this direction until approximately 4
30
0 W, flowing
close to the Spanish coast. Then it turns to the southeast impinging on the African
coast to the west of Cape Tres Forcas. Part of the AJ then turns to the northeast, once
again approaching to the Spanish coast, while another part re-circulates to the west
along the Moroccan coast forming an anticyclonic gyre in the western sub-basin.
The branch of the AW that turns to the northeast at Cape Tres Forcas describes a new
anticyclonic gyre within the Eastern Alboran Sea.
The inner parts of the anticyclones are areas of convergence of surface waters.
Therefore, AW sinks and the thickness of this layer increases within the gyres. The
result is that the surface waters have a marked Atlantic character (low salinity
values), and the interface between AW and Mediterranean waters, which can be
identified as the 37.5 isohaline, deepens. The AJ surrounds the gyres. Its geostrophic
adjustment produces the tilting of isopycnals and the elevation of deep waters to the
left of the current (according to the sense of the movement, see Figs. 4.4, 4.5 and
4.6). As a consequence, strong temperature and salinity differences between the
waters to the north and to the south of the jet can be observed. This thermohaline
front extends all along the AJ from the Strait of Gibraltar to at least 1
W. It was
named by Cheney and Doblar (1982) as the Alboran Sea Frontal System. When the
EAG is well developed, the easternmost part of the frontal system extends from Cape
Gata to Oran (Algeria), coinciding with the limits of the Alboran Sea. This frontal
area creates a natural frontier between the AW recently advected into the Mediterranean Sea through the Strait of Gibraltar and the AW which has re-circulated within
the WMED and, consequently, has a larger degree of modification. Although the
Alboran Sea frontal system is a continuous feature, its eastern part has received a
Fig. 4.3 Grey lines are a sketch of the two-gyres circulation mode. The Western Alboran Gyre
(WAG), Eastern Alboran Gyre (EAG), the Alboran Sea Frontal System and the Almeria-Oran Front
are labelled. The black line is a sketch of the costal-circulation mode
94
M. Vargas-Yáñez et al.
Sea in a northeast direction, due to the orientation of the longitudinal axis of
the Strait. It continues in this direction until approximately 4
30
0 W, flowing
close to the Spanish coast. Then it turns to the southeast impinging on the African
coast to the west of Cape Tres Forcas. Part of the AJ then turns to the northeast, once
again approaching to the Spanish coast, while another part re-circulates to the west
along the Moroccan coast forming an anticyclonic gyre in the western sub-basin.
The branch of the AW that turns to the northeast at Cape Tres Forcas describes a new
anticyclonic gyre within the Eastern Alboran Sea.
The inner parts of the anticyclones are areas of convergence of surface waters.
Therefore, AW sinks and the thickness of this layer increases within the gyres. The
result is that the surface waters have a marked Atlantic character (low salinity
values), and the interface between AW and Mediterranean waters, which can be
identified as the 37.5 isohaline, deepens. The AJ surrounds the gyres. Its geostrophic
adjustment produces the tilting of isopycnals and the elevation of deep waters to the
left of the current (according to the sense of the movement, see Figs. 4.4, 4.5 and
4.6). As a consequence, strong temperature and salinity differences between the
waters to the north and to the south of the jet can be observed. This thermohaline
front extends all along the AJ from the Strait of Gibraltar to at least 1
W. It was
named by Cheney and Doblar (1982) as the Alboran Sea Frontal System. When the
EAG is well developed, the easternmost part of the frontal system extends from Cape
Gata to Oran (Algeria), coinciding with the limits of the Alboran Sea. This frontal
area creates a natural frontier between the AW recently advected into the Mediterranean Sea through the Strait of Gibraltar and the AW which has re-circulated within
the WMED and, consequently, has a larger degree of modification. Although the
Alboran Sea frontal system is a continuous feature, its eastern part has received a
Fig. 4.3 Grey lines are a sketch of the two-gyres circulation mode. The Western Alboran Gyre
(WAG), Eastern Alboran Gyre (EAG), the Alboran Sea Frontal System and the Almeria-Oran Front
are labelled. The black line is a sketch of the costal-circulation mode
94
M. Vargas-Yáñez et al.