Science Notes: (1) Mediterranean Outflow

In contrast to the MEDOC 1970 work in the Gulf of Lion, my cruise diary contained more detailed descriptions of the science programme to be conducted in the Gulf of Cadiz. These notes were probably taken during a scientific briefing by Drs Steve Thorpe and John Simpson prior to the start of work. They are reproduced here more or less verbatim, added words are indicated [thus]. The investigations centred on (1) the Mediterranean Outflow (described below), (2) the determination of Near Bottom Currents, and (3) measurements of Current Shear…

The work site

(1) Mediterranean Outflow: [Subsurface] Waves and Microstructure

Examination of Mediterranean Water in the N. Atlantic south of Cape St. Vincent where part of the main outflow has left the bottom. Examination of the horizontal scale of microstructure of temperature and salinity at 36°15’N 8°7’W in 1500m depth. Salinity maximum [is] expected at 1100m and the outflowing layer to be about 600m thick centred at 1100m.

My sketch of the current meter mooring

[Instrumentation:] Current meter [mooring] with a surface Dhan [buoy] with radar reflector and subsurface buoyancy; 6 current meters – 2 Braincons at 1400 and 1200m and 4 Bergens at 1000, 800, 600, and 400m; chain weights acoustically released and of such weight that the whole would float if dragged into deeper water.

TSDs 4 miles east [of the mooring] using the Dhan as radar reference, 350 to 1500m on the even hour in sets of 3, a reference bottle being triggered on the first dip after which the [TSD] probe kept recording at 1000m, being brought up after the third dip to empty the bottle, get back into position, or chase after any free fall probes, etc.  It is hoped to keep the 2 hourly profiling going come what may.

Photo Gallery: Current Meter Mooring…

[I recently found some photos showing the sort of current meter technology in use around that time]

Science Notes: [(1) Current Meters ]  [(2) Bottom currents]   [(3) Free-fall Probe]

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