The sensitivity of the results to the data processing methodology seems to be
caused by the data scarcity. Llasses et al. (2015), Jordà and Gomis (2013), Beuvier
et al. (2010) showed that the oceanographic data available during the twentieth
century and the existing monitoring programs were not adequate for the detection of
temperature and salinity long-term trends at the different layers of the WMED.
Vargas-Yáñez et al. (2010a, b, 2017) pointed out that the detection of trends in the
upper layer of the WMED was not possible because of the data scarcity and the high
temporal variability at short time scales, but considered that the existence of
warming trends in the deep waters could not be explained only on the basis of the
salinity increase of the AW and/or LIW. Garcia-Martinez et al. (2018) showed by
means of a simple box model that the salinity increase of the AW and LIW, which
contribute to the WMDW formation, could partially explain its warming, but the
temperature increase of the upper layer was also necessary to explain the observed
trends. The use of SST data from radiometers operated from satellites has shown
Fig. 4.8 Time series for SST and potential temperature and salinity at the upper, intermediate and
deep layers of the Alboran Sea. (a) Blue line is the Sea Surface Temperature obtained from satellite
data averaged for the Alboran Sea. Red line is the annual time series of potential temperature for the
upper layer of the Alboran Sea (0–150 m). The shaded grey area in all panels represents the
uncertainty associated to the different data analysis methods. (b) Red line is the annual salinity time
series for the upper layer of the Alboran Sea. (c) and (d) are respectively the same as (a) and (b) for
the intermediate layer (150–600 m) and (e) and (f) are for the deep layer (600 m to the sea bottom)
4 The Oceanographic and Climatic Context
103
caused by the data scarcity. Llasses et al. (2015), Jordà and Gomis (2013), Beuvier
et al. (2010) showed that the oceanographic data available during the twentieth
century and the existing monitoring programs were not adequate for the detection of
temperature and salinity long-term trends at the different layers of the WMED.
Vargas-Yáñez et al. (2010a, b, 2017) pointed out that the detection of trends in the
upper layer of the WMED was not possible because of the data scarcity and the high
temporal variability at short time scales, but considered that the existence of
warming trends in the deep waters could not be explained only on the basis of the
salinity increase of the AW and/or LIW. Garcia-Martinez et al. (2018) showed by
means of a simple box model that the salinity increase of the AW and LIW, which
contribute to the WMDW formation, could partially explain its warming, but the
temperature increase of the upper layer was also necessary to explain the observed
trends. The use of SST data from radiometers operated from satellites has shown
Fig. 4.8 Time series for SST and potential temperature and salinity at the upper, intermediate and
deep layers of the Alboran Sea. (a) Blue line is the Sea Surface Temperature obtained from satellite
data averaged for the Alboran Sea. Red line is the annual time series of potential temperature for the
upper layer of the Alboran Sea (0–150 m). The shaded grey area in all panels represents the
uncertainty associated to the different data analysis methods. (b) Red line is the annual salinity time
series for the upper layer of the Alboran Sea. (c) and (d) are respectively the same as (a) and (b) for
the intermediate layer (150–600 m) and (e) and (f) are for the deep layer (600 m to the sea bottom)
4 The Oceanographic and Climatic Context
103