362
('AHI. H . GIBSON ET AL.
was 370 cm at 23 m according to the temperature-depth profile obtained
from an XBT taken at the time of the measurement.
Figure 5 shows a typical cold film temperature spectrum measured using
the same bridge arrangement as in the Cromwell current experiment, except
with a low impedance cable only 150 m long rather than the 600-m armor
cable. A Princeton Applied Research HR 124 lock-in amplifier was used as a
phase sensitive detector in thc ac bridge. The spectrum in Fig. 5 shows a
10'
100
10'
10'
FREQUENCY (HzI
Fic; 5. Temperature spectrum from FLlP 2\27/72. Cold film (20 min) ( x ). Depth I20 m.
0 -= 7.2 cm/scc.
well-delined viscous convective subrange -1' from an inertial subrange
+ f ' . s ' 3 . A y: value of 1.6 x 10--' 'jC2/sec is indicated as well as c4 of
0.1 cm2/sec3. These values may be somewhat high since the low frequency
portion of the spectrum niight be affected by surface wave motion at the low
mean velocity of 7.2 cm/sec. The value of E , for the ducted current meter was
only 0.04 cm2/sec versus c4 = 0.1. Reducing the j'. 5'-3 spectral level t o a
value corresponding to E,, = 0.04 only reduces y: to a value of 1.3 x
10- ' ,'CZ/sec, however.
Table 111 summarizes and defines various parameters determined in the
FLIP experiments of 2/27/1972 and 2/28/1972. As indicated, diffusivity parameters I!, and D, were both about 100cm2/sec for 23 m on 2/28 and
('AHI. H . GIBSON ET AL.
was 370 cm at 23 m according to the temperature-depth profile obtained
from an XBT taken at the time of the measurement.
Figure 5 shows a typical cold film temperature spectrum measured using
the same bridge arrangement as in the Cromwell current experiment, except
with a low impedance cable only 150 m long rather than the 600-m armor
cable. A Princeton Applied Research HR 124 lock-in amplifier was used as a
phase sensitive detector in thc ac bridge. The spectrum in Fig. 5 shows a
10'
100
10'
10'
FREQUENCY (HzI
Fic; 5. Temperature spectrum from FLlP 2\27/72. Cold film (20 min) ( x ). Depth I20 m.
0 -= 7.2 cm/scc.
well-delined viscous convective subrange -1' from an inertial subrange
+ f ' . s ' 3 . A y: value of 1.6 x 10--' 'jC2/sec is indicated as well as c4 of
0.1 cm2/sec3. These values may be somewhat high since the low frequency
portion of the spectrum niight be affected by surface wave motion at the low
mean velocity of 7.2 cm/sec. The value of E , for the ducted current meter was
only 0.04 cm2/sec versus c4 = 0.1. Reducing the j'. 5'-3 spectral level t o a
value corresponding to E,, = 0.04 only reduces y: to a value of 1.3 x
10- ' ,'CZ/sec, however.
Table 111 summarizes and defines various parameters determined in the
FLIP experiments of 2/27/1972 and 2/28/1972. As indicated, diffusivity parameters I!, and D, were both about 100cm2/sec for 23 m on 2/28 and