layer extends from 150 to 600 m and is occupied by the LIW. Finally, the deep layer
goes from 600 m up to the sea bottom and is occupied by the WMDW and TDW.
Nevertheless, the intermediate layer is not only occupied by water masses originated
at the EMED, but also by others formed at the WMED. Under the influence of the
strong northerly winds, in winter, the waters in the continental shelf of the Gulf of
Lions and the continental shelf of the Balearic Sea can reach temperatures below
13
C, and even close to 11
C (Vargas-Yáñez et al. 2012a), much lower than those
of the LIW and WMDW. As these waters are located over the continental shelf
(200 m depth), under the influence of continental waters, and out of the influence of
the LIW which flows at depths between 200 and 600 m, these very cold waters reach
salinity values lower than those offshore. Therefore, a water mass with a temperature
below 13
C and salinity between 37.7 and 38.3 is formed, receiving the name of
Western Intermediate Water (WIW). WIW sinks to its equilibrium depth, between
100 and 400 m, above the LIW (Juza et al. 2019; Vargas-Yáñez et al. 2012a; Pinot
and Ganachaud 1999; Pinot et al. 1995; López-Jurado et al. 1995; López-Jurado
1990; Salat and Font 1987). Finally, Napolitano et al. (2019) have recently hypothesized that the Tyrrhenian Sea could also be a site of intermediate convection where
Tyrrhenian Intermediate Water (TIW) would be formed. Nevertheless, according to
the existent literature, this water mass has not been distinguished in the Alboran Sea.
4.3 Water Masses in the Alboran Sea
The upper layer of the Alboran Sea is filled by the AW that flows from the nearby
Gulf of Cadiz through the Strait of Gibraltar. Therefore, the temperature and salinity
values of the Alboran Sea upper layer are those of the waters in the Gulf of Cadiz,
more or less modified. The degree of modification will depend on the distance to the
Strait of Gibraltar and on the dynamics of the different areas within the Alboran Sea.
The Camarinal sill, between Point Paloma in the Spanish coast and Point Altares
in Morocco, has a maximum depth of 300 m, imposing a restriction to the entrance of
AW into the Alboran Sea. Data from MEDAR/MEDATLAS database (MEDAR
Group 2002) have been collected from 1945 to 2000 to obtain the climatological
profiles of temperature and salinity in the Gulf of Cadiz (García-Martínez et al.
2018), where the upper 300 m are occupied by the North Atlantic Central Water
(NACW), characterized by the decrease of temperature and salinity with depth. In
winter, temperature and salinity values at the sea surface are close to 16.3
C and
36.4. At 300 m these values decrease to 13.1
C and 35.8 (hereinafter, potential
temperature will be written simply as θ for brevity). In summer, surface waters warm
up to 22.23
C with a slight increase of the salinity (36.49). These surface waters are
named as Surface Atlantic Water (SAW). Both SAW and NACW can be clearly
distinguished in the Western Alboran Sea (Naranjo et al. 2015) and are shown and
labelled in Fig. 4.2 as straight black lines. This figure shows the θS values for all
oceanographic stations from the FE-92 cruise in September/October 1992 (Data
obtained from MEDAR/MEDATLAS database, MEDAR Group 2002). This
90
M. Vargas-Yáñez et al.
goes from 600 m up to the sea bottom and is occupied by the WMDW and TDW.
Nevertheless, the intermediate layer is not only occupied by water masses originated
at the EMED, but also by others formed at the WMED. Under the influence of the
strong northerly winds, in winter, the waters in the continental shelf of the Gulf of
Lions and the continental shelf of the Balearic Sea can reach temperatures below
13
C, and even close to 11
C (Vargas-Yáñez et al. 2012a), much lower than those
of the LIW and WMDW. As these waters are located over the continental shelf
(200 m depth), under the influence of continental waters, and out of the influence of
the LIW which flows at depths between 200 and 600 m, these very cold waters reach
salinity values lower than those offshore. Therefore, a water mass with a temperature
below 13
C and salinity between 37.7 and 38.3 is formed, receiving the name of
Western Intermediate Water (WIW). WIW sinks to its equilibrium depth, between
100 and 400 m, above the LIW (Juza et al. 2019; Vargas-Yáñez et al. 2012a; Pinot
and Ganachaud 1999; Pinot et al. 1995; López-Jurado et al. 1995; López-Jurado
1990; Salat and Font 1987). Finally, Napolitano et al. (2019) have recently hypothesized that the Tyrrhenian Sea could also be a site of intermediate convection where
Tyrrhenian Intermediate Water (TIW) would be formed. Nevertheless, according to
the existent literature, this water mass has not been distinguished in the Alboran Sea.
4.3 Water Masses in the Alboran Sea
The upper layer of the Alboran Sea is filled by the AW that flows from the nearby
Gulf of Cadiz through the Strait of Gibraltar. Therefore, the temperature and salinity
values of the Alboran Sea upper layer are those of the waters in the Gulf of Cadiz,
more or less modified. The degree of modification will depend on the distance to the
Strait of Gibraltar and on the dynamics of the different areas within the Alboran Sea.
The Camarinal sill, between Point Paloma in the Spanish coast and Point Altares
in Morocco, has a maximum depth of 300 m, imposing a restriction to the entrance of
AW into the Alboran Sea. Data from MEDAR/MEDATLAS database (MEDAR
Group 2002) have been collected from 1945 to 2000 to obtain the climatological
profiles of temperature and salinity in the Gulf of Cadiz (García-Martínez et al.
2018), where the upper 300 m are occupied by the North Atlantic Central Water
(NACW), characterized by the decrease of temperature and salinity with depth. In
winter, temperature and salinity values at the sea surface are close to 16.3
C and
36.4. At 300 m these values decrease to 13.1
C and 35.8 (hereinafter, potential
temperature will be written simply as θ for brevity). In summer, surface waters warm
up to 22.23
C with a slight increase of the salinity (36.49). These surface waters are
named as Surface Atlantic Water (SAW). Both SAW and NACW can be clearly
distinguished in the Western Alboran Sea (Naranjo et al. 2015) and are shown and
labelled in Fig. 4.2 as straight black lines. This figure shows the θS values for all
oceanographic stations from the FE-92 cruise in September/October 1992 (Data
obtained from MEDAR/MEDATLAS database, MEDAR Group 2002). This
90
M. Vargas-Yáñez et al.