Description: Observations from a four-year current meter mooring at 28°44′N, 13°28′W in the Lanzarote passage are used to describe the transport variability of the Eastern Boundary Current of the North Atlantic Subtropical Gyre. Three different water masses are found in the passage: North Atlantic Central Water in the upper levels (roughly Full-size image (〈1 K)), Antarctic Intermediate Water (roughly Full-size image (〈1 K)) and Mediterranean Water in the layer above the bottom at Full-size image (〈1 K). The mean southward transport of NACW is Full-size image (〈1 K)Full-size image (〈1 K) which is the transport of the easternmost branch of the Canary Current. Fluctuations of NACW transport are large, ranging from Full-size image (〈1 K) southward to Full-size image (〈1 K) northward. Every autumn a consistent northward transport is observed, which may be related with the eastern boundary upwelling dynamics. The mean transports of AAIW and MW are Full-size image (〈1 K) northward and Full-size image (〈1 K) southward, respectively. Fluctuations of transport of AAIW and MW are large, from 1.0 to Full-size image (〈1 K) and from −0.32 to Full-size image (〈1 K), respectively. Thus, the mass transports for each water mass show a high standard deviation of comparable magnitude to the mean. This highlights the importance of the temporal variability of the currents in this passage. A remarkable feature of our observations is that the mean transports of NACW and AAIW during an El Niño event are significantly different.

Description: Highlights: • Unique 30-years data of currents and temperature below 1000 m in the Madeira Basin. • Inter-decadal and long term changes were examined between 1000 m and the bottom. • Temperature increase by 0.03 ± 0.01 °C/year (1000 m) and 0.02 ± 0.02 °C/year at 1600 m. • No significant changes at 3000 m and 5000 m at long-term scale. • The currents and kinetic energy increased in the entire water column over 30-years. Abstract: Data from the deep-sea mooring Kiel 276 (33 N, 22W), 5300 m water depth in the northeast Atlantic, was used to investigate the temporal variability of temperature and currents below the main thermocline (1000 m, 1600 m, 3000 m, 5000 m) in the 30-year period (between 1980 and 2009). Daily averages were the basis to assess the temperature and currents changes, as well as kinetic energy, from annual to decadal and long-term scales. Below the main thermocline, no seasonal signal was identified for both, temperature and currents, during the 30 years. The record-length linear temperature trends at 1000 m and 1600 m are 0.03 ± 0.01 °C year−1 and 0.02 ± 0.02 °C year−1, respectively. The mean currents also intensified within the decades in the entire water column, and as a consequence, the mean kinetic energy increased. The fluctuating kinetic energy increased on a decadal scale only at 1000 m, as a possible consequence of the increase in the strength of Mediterranean Water lenses (MEDDIES) that crossed the mooring site. During the period 2001–2009, six MEDDIES crossed the Kiel 276 site, in addition to the 10 MEDDIES identified earlier during the previous 20 years, between 1980 and 2000 (Siedler et al., 2005). The integral time scales are of the same order in all depths (between 30 to 40 days), indicating that events occur on similar time scales, with mesoscale signals dominating and being present within the entire water column.