APPARENT SURFACE CURRENTS OVER THE
MONTEREY SUBMARINE CANYON
MEASURED BY THE METHOD OF TOWED
ELECTRODES.

Karl Arthur Mahumed

mux

V

onterey, California

L

T

ET

APPARENT SURFACE CURRENTS OVER THE
MONTEREY SUBMARINE CANYON
MEASURED BY THE METHOD OF
TOWED ELECTRODES

by

Karl Arthur Mahumed

September 1975

Thesis Advisor:

R. G. Paquette

Approved for public release; distribution unlimited.

Unci nssi f i od

£l-CUt»lTV CLASSIFICATION OF THIS PUGEfH^nn r>»(« fnl.f.J

of internal waves. The observed surface currents measured
with the GEK all exhibited little or no correlation with
winds and tides. The flows were all generally southerly;
their averages agreed with previous measurements made with
the GEK. This direction of flow was opposite to the gener-
alizations of Scott and possibly agreed with those of Pirie,
depending upon the placement of one of his eddies. The
k-factor for the GEK could not be determined because currents
measured directly in the thermocline were found to be not
correlated with the GEK measurements. However, the average
current speeds were in reasonable agreement with currents
measured at other times in Monterey Bay, leading to the con-
clusion that k cannot be much greater than the assumed value
of 1.0.

DD Form 1473

1 Jan 73 Ilnr 1 n^^ifipfl .

S/N 0102-014-GG01 0 SECURITY CL*SSiriC*TION OF THIS P»CEr»1"n D.I. F"'«""»

Apparent Surface Currents over the
Monterey Submarine Canyon
Measured by the Method of
Towed Electrodes

by

Karl Arthur Mahumed
Lieutenant, United States Navy
B.S., U.S. Naval Academy, 1968

Submitted in partial fulfillment of the
requirements for the degree of

MASTER OF SCIENCE IN OCEANOGRAPHY

from the
NAVAL POSTGRADUATE SCHOOL

ABSTRACT

Five data cruises were taken on board R/V ACANIA to study
the effect on the Geomagnetic Electrokinetograph (GEK) of
various environmental factors, including winds, tides, and
internal waves, over the Monterey Submarine Canyon. An in
situ current meter was used successfully on one occasion to
obtain data to establish a k-factor for the GEK in the Sub-
marine Canyon, and to directly measure the particle velocities
of internal waves. The observed surface currents measured
with the GEK all exhibited little or no correlation with winds
and tides. The flows were all generally southerly; their
averages agreed with previous measurements made with the GEK.
This direction of flow was opposite to the generalizations of
Scott and possibly agreed with those of Pirie, depending upon
the placement of one of his eddies. The k-factor for the GEK
could not be determined because currents measured directly in
the thermocline were found to be not correlated with the GEK
measurements. However, the average current speeds were in
reasonable agreement with currents measured at other times
in Monterey Bay, leading to the conclusion that k cannot be
much greater than the assumed value of 1.0.

TABLE OF CONTENTS

I. INTRODUCTION 10

A. THE PROBLEM 10

B. USE OF THE GEK IN THIS STUDY 12

C. ADDITIONAL PARAMETERS USED 12

D. PREVIOUS STUDIES IN MONTEREY BAY 13

II. THEORY 20

A. GEOMAGNETIC ELECTROKINETOGRAPH (GEK) 20

1. Theory 20

2. Errors 23

B. INTERNAL WAVES 24

III. PROCEDURE 28

A. CRUISE PLAN 28

B. CURRENT METER EMPLOYMENT 30

IV. CRUISE SYNOPSES 33

A. RUN ONE 34

B. RUN TWO 39

C. RUN THREE 44

D. RUN FOUR 51

E. RUN FIVE 56

V. DISCUSSION OF RESULTS 61

A. VALIDITY OF THE MEASUREMENTS 61

B. SUMMARY OF DATA 62

APPENDIX A: PROGRAM AND DATA TABLES 64

BI BLI OGRAPHY 78

INITIAL DISTRIBUTION LIST 80

5

LIST OF TABLES

I.
II.

III.

IV.
A-I.
A-II.
A-III.
A-IV.
A-V.
A-VI.
A-VII.
A-VIII.
A-IX.
A-X.
A-XI.

Geomagnetic Activity

Fix Determination

Cruise Durations

Averaged Data

24
29
30
62

Run 1
Run 1
Run 2
Run 2
Run 3
Run 3
Run 3
Run 4
Run 4
Run 5
Run 5

GEK Data 65

Wind Data 66

GEK Data 67

Wind Data 68

GEK Data 69

Current Meter Data 70

Wind Data 73

GEK Data 74

Wind Data 75

GEK Data 76

Wind Data 77

LIST OF FIGURES

1. Area of the Present Study 11

2. GEK Pattern of McKay [1970] 14

3. GEK Pattern of Smith [1972] 15

4. Generalized Upwelling Circulation Pattern 17

5. Generalized Oceanic Circulation Pattern 18

6. Generalized Davidson Circulation Pattern 19

7. Simple Internal Wave 25

8. GEK Pattern 28

9. Current Meter Anchoring 32

10. Run 1, North-Setting Components 35

11. Run 1, East-Setting Components 36

12. Run 1, Vector Scatter Diagram 37

13. Progressive Vector Diagram 38

14. Run 2, North-Setting Components 40

15. Run 2, East-Setting Components 41

16. Run 2, Vector Scatter Diagram 42

17. Run 2, Progressive Vector Diagram 43

18. Run 3, North-Setting Components 45

19. Run 3, East-Setting Components 46

20. Run 3, North-Setting Components, GEK and

Current Meter 47

21. Run 3, East-Setting Components, GEK and

Current Meter 48

22. Run 3, Vector Scatter Diagram ^9

23. Run 3, Progressive Vector Diagram 50

24. Run 4, North-Setting Components 52

7

25. Run 4, East Setting Components 53

26. Run 4, Vector Scatter Diagram 54

27. Run 4, Progressive Vector Diagram 55

28. Run 5, North-Setting Components 57

29. Run 5, East-Setting Components 58

30. Run 5, Vector Scatter Diagram 59

31. Run 5, Progressive Vector Diagram 60

A-l. Program KAMGEEK 64

ACKNOWLEDGEMENTS

There are several people who had a part in this undertaking
without whose assistance nothing could have been accomplished.
First and foremost, my gratitude to Dr. R. G. Paquette for
initiating this thesis and for counselling, advising and when
necessary, prodding me along. Woody Reynolds and the entire
crew of R/V ACANIA made data collection both profitable and
enjoyable; their selfless help is gratefully noted. Lt . John
Hollister provided the means by which I was able to communicate
with the IBM 360 and receive output. P02 John Fanning of the
Oceanography Staff assisted in on-loading and off-loading
equipment, even when off duty. Last but not least, my family
deserves a commendation. They were my "crew" for several
cruises, and throughout the project have supported all my
efforts in a manner which eased the burden of this study. To
one and all, a most heartfelt thanks.

I. INTRODUCTION

A. THE PROBLEM

This study was undertaken in an attempt to examine
phenomena observed twice previously during experiments with
the Geomagnetic Electrokinetograph (GEK) above the Monterey
Submarine Canyon. Anomalously high apparent velocities were
recorded by the GEK in studies by Howton [1972] and later
during a student demonstration cruise. It was believed that
these high values could be the results of internal wave activ-
ity in the Canyon. Lipparelli and Beardsley [1971] postulated
such an effect and computed its magnitude for frequencies as
low as 1.8 x 10 hertz.

Howton' s study had no method for detecting and recording
the presence of internal waves, so no GEK-internal wave cor-
relation could be made. The present study involved the use
of the GEK, expendable bathythermograph (XBT) , and an iri situ
current meter, together with wind and tide data.

Five data collection runs were taken on R/V ACANIA. The
location of each run is shown in Figure 1. All five runs
involved the use of the GEK and measurement of the winds and
tides. Runs Two through Five involved the added use of XBT's
and an In situ current meter, although the current meter
functioned properly only once, on Run Three.

It was hoped that the same anomalous apparent values
could again be observed and correlated. If the anomalies

10

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Figure 1. Area of the Present Study

11

were not observed, the present study hoped to widen the data
base on environmental influences on surface currents over the
Submarine Canyon, together with an estimate of a likely k-factor
for submarine canyons.

B. USE OF THE GEK IN THIS STUDY

As employed in the present study, the GEK is capable of
measuring apparent surface current velocities in the vicinity
of a point, from an underway platform. Section II provides a
general discussion of the theory associated with the GEK,
together with its shortcomings.

C. ADDITIONAL PARAMETERS USED

1. Winds

Wind vectors were obtained from the Pacific Gas and
Electric Power Station at Moss Landing, California. The
anemometer is mounted on a 75- foot staff and is well away
from obstructions which might perturb the wind field. The
vectors are assumed to be representative of the winds in the
vicinity of the data collection point. Winds were recorded
hourly and are plotted as north and east components in Sec-
tion IV.

2 . Tides

Tides were recorded at the Naval Postgraduate School
tide station and are presented, in Section IV, as heights
above mean lower low water.

12

3 . Thermocline

Thermocline depths were traced by the use of XBT drops
taken periodically during Runs Two through Five. Thermocline
depth and the depth of the 10°C isotherm are plotted in Sec-
tion IV.

4 . Geomagnetic Activity

Geomagnetic indices, A^, were obtained from the Space
Environmental Support Center, Boulder, Colorado. Values tab-
ulated in Table I of Section II are daily averages of the
geomagnetic activity as measured at Tucson, Arizona.

D. PREVIOUS STUDIES IN MONTEREY BAY

1. Stevenson [1964]

Stevenson conducted his experiment in southern Monterey
Bay using drogues at three depths. He attempted to determine
the wind-dependence of surface currents in the Bay. He deduced
a close wind-dependence when the wind speed exceeded five
knots; he found no correlation with winds and tides. Steven-
son's drogues drifted to the right of the wind direction with
little time lag in the rotation. He did observe one anomaly;
for northwest winds, drogues drifted to the left of the wind
direction.

2. Garcia [1971]

Garcia utilized totally numerical methods to model
circulation in the Bay. He postulated that the major off-
shore currents, the California, flowing south, and the
Davidson, flowing north, were the driving forces for a closed
circulation system in the Bay. He noted the effect of the

13

Canyon in dividing the closed system into two or three dis
tistinct gyres or eddies.
3. McKay [1970]

McKay used the GEK in studying surface currents in
the vicinity of the Canyon. No attempt was made during his
cruises to make a time-series measurement of currents at a
point. He used a variation of cruise plan A2 from Von Arx
[1950] which provides current determinations along a track,
as shown in Fig. 2.

h

Figure 2. GEK Pattern of McKay [1970]

McKay examined the dependence of wind, sea, and tides
on the apparent surface currents. He arrived at tidal depend-
ence as the predominant result, but lacked sufficient data to
adequately understand the nature of the dependence.
4. Smith [1972]

Smith used the GEK, together with tides and isotherm
surfaces to attempt to correlate apparent surface currents
above the Canyon. His cruise plan was a variation of McKay's,
as shown in Fig. 3. He postulated a dynamic set of circulation

14

patterns but made no clear conclusion of any environmental
influence on apparent surface currents.

1

a V

u

Figure 3. GEK Pattern of Smith [1972]

5. Howton [1972]

Howton used wind and tides to attempt a correlation
with apparent surface currents as recorded by the GEK. He
used cruise plan C-l from Von Arx [1950], the complete tra-
versal of a square, in order to collect time-series data at
a point. He conducted six cruises at a point over the Canyon.
He concluded that there are both diurnal and semi-diurnal
components of the apparent surface currents which demonstrate
a consistent phase relationship with the Sun and Moon. His
statistical efforts showed indirect coupling of the apparent
surface current with the semi-diurnal tide.

6. Pirie, et al . [1974]

In a study for the Goddard Spaceflight Center, Green-
belt, Maryland, Pirie et al. made a site study of Monterey Bay

15

with the emphasis placed on the applicability of remote
sensors for surface current studies. His efforts were pri-
marily to summarize all the previous work done in surface
current determination in the Bay. The end product from his
study is represented by generalized circulation patterns by
oceanic season; Monterey Bay experiencing three climatic
seasons, the Oceanic, Upwelling, and Davidson Current periods.

Figure 4 shows the generalized circulation for the
Upwelling period from mid-February to late August, as proposed
by Pirie et al. Four of the author's runs were taken in this
period.

Figure 5 shows the generalized circulation for the
Oceanic period, from September to mid-November, as proposed
by Pirie et al. One of the author's runs was taken in this
period.

Figure 6 is the generalized circulation in the Davidson
Current period. No runs by the author were taken in this
period.

Pirie concluded that the dominant driving force of the
Bay's circulation is the offshore currents, with secondary
influence from the wind.

16

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Figure 4. Generalized Upwelling Period Circulation

17

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18

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Figure 6. Generalized Davidson Current Period
Circulation

19

II. THEORY

A. GEOMAGNETIC ELECTROKINETOGRAPH (GEK)
1 . Theory

Apparent surface currents are measured by the method
of towed electrodes by using the GEK. The GEK consists of a
pair of non-polarized electrodes, usually silver-silver
chloride, connected to a recording potentiometer by a
neutrally-buoyant, two-conductor cable. The electrodes are
normally 100 meters apart, each connected to an individual
conductor. The use of neutrally-buoyant cable eliminates
any cable droop which might degrade measurements. The elec-
trodes must be towed far enough astern of the towing ship to
be free of ship- induced electromagnetic effects (usually two
to three ship lengths). Von Arx [1950] and Longuet-Higgins ,
Stern and Stommel [1954] are the sources of detailed descrip
tion and derivation of towed-electrode theory.

Faraday, in 1832, proposed the induction of an
electro-magnetic force (e.m.f.) in water moving through the
earth's magnetic field. Equation (1) permits a quantitative
calculation of this e.m.f., E.

E = vxH x 10"8 volt (1)

z

E = induced e.m.f. (directed perpendicular to current
vector)

v = horizontal current velocity (cm/sec)

x = distance over which v is measured (cm)

H = vertical component of earth's magnetic field (gauss)

20

If the water everywhere is not moving at the same
velocity, electrical currents will flow because of the po-
tential differences. The generated potentials are decreased
by the resistive potential difference due to the current flow.
Generally, a space integral of E - ir is required to find the
potential field and the distribution of current density, i,
given the resistivity, r.

Ideally, the velocity maximum is at the surface, and
there exists beneath this surface layer a thick layer of
essentially static water, which acts as a low-resistance shunt
upon the resistive voltage generators near the surface, bring-
ing the potential gradient to near zero. If then, two identical
electrodes are towed through the water, they themselves are
at equal potential. But the single length of wire between the
electrodes is being carried transversely through the vertical
components of the Earth's magnetic field by the athwartship
component of the surface current, which affects both cable
and ship. The voltage recorded aboard the ship then is gen-
erated in this wire according to equation (1) . A thick,
conductive bottom could serve the same purpose as a static
water layer.

If there is not a static layer below the surface
layer and the bottom is more or less insulating, the voltage
in the sea between the electrodes will not be zero and the
signal due to the surface currents will be altered. If the
current were the same at all depths, no voltage would be
measured. If there were a reversed rapid flow near the

21

bottom, the voltage at the surface might be augmented. If
rapid flow was present at mid-depth and the cross-section of
the static conducting path were not great enough to dissipate
it, its influence would be felt at the surface. Thus, surges
and internal waves can affect the voltage measured by the GEK
if the particle motion reaches the surface. The effect may
still be felt if the water is not too deep, if the motions
extend to near the bottom, or if the motion does not reach
the surface. The resulting anomaly may either add to or
subtract from the signal otherwise present at the surface,
depending upon the relative direction of the flow.

The precise calculation of the effects of such a
phenomenon presents considerable difficulty involving three-
dimensional integration (probably by numerical methods) and
requiring a knowledge of the water velocity at all points in
the volume. For this reason, the treatment of the phenomenon
in this study is only semi-quantitative.

Since Monterey Canyon is of moderate depth, it was
anticipated that it might approximate an ideal case when
surges are absent and that the degeneration which results
in the necessity of raising the k-factor to above unity is
fairly small. Part of the objectives of this study was to
test this hypothesis by comparing the GEK-measured surface
currents with directly measured currents. However, as will
be seen, a current meter in the thermocline exhibited little
correlation with currents at the surface.

22

2 . Errors

There are several sources of significant errors in
the measurement of apparent surface currents by the GEK:

a. Deep currents or the effects of depth which result
in a k-factor change, as discussed above. This results in an
error in magnitude only, if the degeneration is an effect of
an insufficient static layer. The sides of the canyon may
also distort the electric field.

b. Geomagnetic disturbances can disrupt the Earth's
magnetic field. According to Longuet-Higgins , Stern, and
Stommel , variations equivalent to 0.1 knot can be expected
over long-term measurements, with maximum errors of 5 knots
possible during major solar storms. Bennett and Filloux
[1975], in a month of data collected in the deep Atlantic,
rarely observed electrical fields in excess of 0.25 mv/100 m,
equivalent to 0.13 knot; apparently Longuet-Higgins1 5-knot
variations are not realistic, at least in deep water.

Table I lists the geomagnetic activity for the days
on which data was collected. It will be seen that the stormy
conditions of 11 November 1974 coincide with the GEK records
for that date, and may account for the observed high apparent
values at that time.

23

TABLE I
Geomagnetic Activity

Run

]

Date

Geomagnetic Ind

ex Condition

1

10
11

Nov
Nov

74
74

6
31

Quiet
Minor Storm

2

26

27

Feb
Feb

75
75

6

5

Quiet
Quiet

3

3

4

Apr
Apr

75
75

5
5

Quiet
Quiet

4

21

22

Apr
Apr

75
75

12
13

Unsettled
Unsettled

5

1

2

May
May

75
75

6
15

Quiet
Active

C. Zero-point drift of the electrodes can result in
errors. This drift can be the result of electrode deterior-
ation or cable leaks. Drifts in the present study were either
controlled or were slow enough to be negligible.

d. It should be noted that over the submarine canyon
Howton found the currents on opposite sides of his square
significantly different so that the zero derived by comparing
tows on reciprocal courses has an element of uncertainty.
This error was minimized in this study by using the L-shaped
tow pattern in which the reciprocal courses are close together
in both time and space. Section III discusses the tow plan.

B. INTERNAL WAVES

We will first consider a simple, two-layer system, as
shown in Fig. 7. In this system, internal waves are those
waves within the water mass and on the interfacial boundary.

24

If the wave shown is progressive, from left to right,
particles in the cell A-B-C will orbit in a clockwise manner
while particles in the C-D-E cell will orbit in a counter-
clockwise manner.

-< D

Figure 7. Simple Internal Wave

If the apparent surface current is also moving from left
to right, it can be seen that the apparent surface current
will alternately experience degradation and enhancement as
the internal wave progresses past the point of measurement.
Motions in the lower layer also will contribute to the
potentials measured.

These simple internal waves are the only ones possible
in the two-layer model discussed above. The ocean is not
two-layered, and there are an infinite number of possible
internal waves which can occur in the continuous density
gradients in a given water mass anywhere in the ocean.

25

Since the tidal character of internal waves is so prom-
inent, tides were for some time considered to be the only
cause of internal waves by forcing a tidal oscillation of
the density boundary, either near shore or in deep water.

Internal waves need not be clearly periodic. Aperiodic
characteristics, such as wind-induced surges, are also possible
The effect of an onshore wind into a semi-enclosed basin can
cause these aperiodic internal waves by building up surface
water at the coastline, depressing the boundary, and setting
the boundary in motion.

There is reason to expect internal waves in the Monterey
Submarine Canyon. McClelland [1972] obtained fragmentary
records of internal waves in the Canyon. He noted a 90-meter
movement of the 7°C isotherm in a period of 3 hours. Motion
of that order was not seen in any of the data for the present
study; most of the internal waves observed were of the order
of 20-30 meters.

Shepard [1974] observed internal waves in the Canyon to
be moving up-canyon at speeds of 25-88 cm/sec. In other
experiments off San Diego, Shepard observed the passage of
the same internal wave over the shelf and in a canyon. His
results showed that the canyon-confined wave propagated faster
than the wave over the shelf, suggesting that the constriction
of the canyon walls tends to increase propagation speed.

The work of Lipparelli [1971] suggested that the effects
of internal waves on the GEK might be important. He computed
the effect of short-period, idealized, free internal waves on

26

GEK signals. He modelled a two-layer ocean and limited his
study to free internal waves which would form on the inter-
face. The concern in the present study is with a wave forced
at semi-diurnal frequency and with a wave number of lO^m"1 .
Extrapolation of Lipparelli's results to such wave numbers
and to a 12.4 hour period for depths and densities appropriate
to the canyon yields a signal of about 10 mv/100 m, correspond-
ing to 5 knots. This must be regarded as an order of magnitude
only, since the canyon is far more complex than Lipparelli's
model. The calculations do suggest that sizeable effects of
internal waves may be expected.

The length of time-series was limited by practical con-
siderations to periods of a little less than 24 hours (see
Section III for details). With this length of series, it
would be possible to extract a 12.4 hour periodic component
reliably only if the data were relatively free of other fre-
quencies and noise. As will be seen, this latter property
did not prevail and neither tidal components nor any other
characteristic period could be extracted with certainty.

27

III. PROCEDURE

A. CRUISE PLAN

Sailing plan C-2 from Von Arx [1950] was chosen for this
study (see Figure 8) . The dogleg plan has advantages over
the previously discussed square plan used by Howton [1972].
Howton's fixes were obtained by summing reciprocal courses
on opposite sides of the square. The sum resulted in a zero-
point for that pair of courses and the apparent velocity
perpendicular to that course could then be determined as the
difference to the right or left of a zero-point. One circuit
of the square resulted in two pairs of two differences. Using
successive vector sums, apparent current velocity could be
calculated twice per circuit of the square.

Figure 8. GEK Pattern

28

The dogleg plan used in the present study essentially
"folds" the square in half diagonally. This results in re-
ciprocal courses being transited on (ideally) the same track.
Howton's reciprocals were separated by the width of the sail-
ing plan. Fixes for the present study were calculated in the
same manner as Howton, by using a leapfrog scheme wherein
each value of apparent current is used for two separate cal-
culations. Table II shows the sequence of obtaining a fix.

TABLE II
Fix Determination

Fix No. Track Segment E/S Track Segment N/S

1

A,

" *i

Bi

- c,

2

B2

- A2

c,

" B2

3

A2

" B3

B3

- c2

4

B„

" A3

c2

" B,

At a speed of six knots, a complete traversal of the track
took about forty minutes, so a fix was obtained about every
twenty minutes. At each end of the track, Williamson turns
were executed to maintain the proper track. Occasional vari-
ation of the track was necessitated by fishing boats, fishing
buoys, or mechanical problems of the ship. During these devi-
ations from the track, no data was recorded until the track
had been reestablished. With the exception of a two hour
break in the data for Run Three, no data gaps exceeded thirty

minutes .

29

It had originally been planned to make all data collection
in 24-hour periods, but ship commitments or equipment mal-
functions prevented this. Table III lists run durations.

TABLE III
Run Duration

Run No.

Duration

(hrs)

1

20

2

23.5

3

19.5

4

20.5

5

21

Although no cruises lasted as long as had been planned,
lengths of records were long enough to give a reasonable
probability of encountering anomalous events and correlating
between tides, winds, and directly-measured currents, provided
such correlations were strong.

Program KAMGEEK, Figure A-l, was used to calculate the
apparent current vectors. The program computed resultant
vectors from the north and east components read from the strip
chart of the recording potentiometer.

B. CURRENT METER EMPLOYMENT

The Hydro Products Model 502 current meter was used as

the in situ meter for Runs Two through Five. However, the

meter worked properly only on Run Three. Data was read at

fifteen minute intervals from the strip chart output of the

current meter for reduction; the components are listed in

Table A-VI.

30

Figure 9 shows the anchoring scheme used for the current
meter. The subsurface float was intended to support the array
vertically with 150 pounds net buoyancy. The surface float,
also of 150 pounds net buoyancy, the spar buoy, of 100 pounds
buoyancy, and the surface marker were intended to provide
about 200 percent of the total array weight in buoyancy in
order to prevent the array from sinking should the anchor slip
into deeper water. One-half inch braided nylon was used to
connect the current meter to the anchor: three- eighths inch
polypropylene line was used for the remainder of the array.

The array was deployed in reverse order; marker, surface
float, subsurface float, current meter, and anchor line. Once
the proper position had been reached, the anchor was released,
and the array sank. After it had been determined that the
anchor was stationary, the spar buoy, with strobe lights and
radar reflector, was attached to the marker. The position of
the array was then established as Point B in the cruise plan.

31

RADAR

reflector'

STROBE *~^

LIGHT """*'U

SURFACE FLOAT

MARKER

SPAR BUOY

-V^AA^^

100«

COUNTERWEIGHT

O

SUBSURFACE FLOAT

6 m

HYDRO PRODUCTS 502
CURRENT METER

600i

-CONCRETE ANCHOR(150 lb)

BOTTOM

Figure 9. Current Meter Anchoring

32

IV. CRUISE SYNOPSES

The data are presented in several different graphical
forms in Figures 10 through 31, grouped by runs. The dif-
ferent forms of presentation are discussed below.

For each data collection run, GEK and wind data are
graphically presented in north and east components versus
time; the tide height and depth of the 10°C isotherm and
thermocline are also shown. Wind speeds are divided by 10
relative to the speed scale. The current meter data are
added in Run Three and they have been multiplied by 5 in
order to provide resolution in the north- sett ing components
(Figure 18) . In order to permit comparison of the GEK and
the current meter on the same scale, Figures 20 and 21 are
included.

Vector scatter diagrams were drawn manually from GEK
components. Progressive vector diagrams were drawn using
the VECTORDRAW program of Hollister [1975]. Note that the
scales are different on individual diagrams.

33

A. RUN ONE

Date: 1200, 10 November 1974 - 1200, 11 November 1974

Coordinates :

A- 36° - 46.7'N, 121° - 54.9'W

B- 36° - 46.7'N, 121° - 56.0'W

C- 36° - 47.5'N, 121° - 56.0'W

65 Data Points

Vector Average: 9.39 cm/sec @ 152. 5°T

Note: No temperature data was available for this run
due to the lack of XBT's on R/V ACANIA.

34

Tide Height(ft. above WLLW)
en r^ in to

A
to

•H
0)

•x.

o

VO

O

*3

C-4

o

o

o

CVJ

<?

VD

1

1

1

3
•H

(38S/0I3) p8GdS pUT(Yl/^USJjn3

35

Tide Height(ft. above ItlLLUl)
ct* r*- in to

o

o

CM

o

o

o

CM

-<*

\D

1

1

1

(oes/wo) paeds puini/^uej jr»3

u

DO
•H

36

Figure 12. Run 1, Vector Scatter Diagram

37

Figure 13. Run 1, Progressive Vector Diagram

38

B. RUN TWO

Date: 1000, 26 February 1975 - 0900, 27 February 1975

Coordinates :

A- 36° - 46.9'N, 121° - 53.9'W

B- 36° - 46.9'N, 121° - 54.9'W

C- 36° - 47.75'N, 121° - 54.9'W

49 Data Points

Vector Average: 7.47 cm/sec @ 226°T

Note: The low number of data points was due to a slower
speed on this run made necessary by loss of one
engine on R/V ACANIA.

39

Depth (m)

o □ o
o «~ cm tn

Tide Height(ft. above MLLW)

CD
CN

<-J O o

(oes/iua) paeds puTfn/^uejjn^

id

6

o

■M

• H 0

•^ C/l

I— I

a} o
o

« .-I
W

o

CO

c

O

c

c

•H

T3
nj
<D
U

CD
i— I
oj
<J
to

t/i

S

o ^c

txOUn t3
Q

+-»

p, *
0) 13
Q O

•H
+->
+J
<U
CO

,c

V

•P T)

a

>H

C

to

O

0}

2

T3

*»

C

•*

+->

•H

(SI

S

G

•H

^

3

o

O

CC X U,

•H

40

Depth (m)
o

o o

CM tO

Tide Heiqht(ft. above MLLW)
an i*- in tn

o

o

a

r~

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00

O

0)

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TO 4->

C O

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^ rH 00

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c

o

13! C_J -H

Co ^
rto fl

o

rH O

o

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W no

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C3 rH

o

m rt

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(/) -H

r-

PH !fl

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a

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o

r-

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m t3

CM

CuO O as

c o

a

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CO

ID OO

V"

C/3 Q O
i o

o

+-> -a p.

o

t/> C t/i

U3

rt 03

r"

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•> +-> -H

o

cm ,rs ;s

<3

oO

C -H Jh

POO

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o

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•

r—

rH

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o

rH

(oes/Luo) peeds puifYi/^uejanQ

D
DO
•H
Ph

41

N

CanV

on

I — i

10 cm/sec

Figure 16. Run 2, Vector Scatter Diagram

42

-9

-6

-3

Km East

EN3

.c
-♦->
£-6.

E

-9 —

Figure 17. Run 2, Progressive Vector Diagram

43

C. RUN THREE

Date: 1000, 3 April 1975 - 0900, 4 April 1975

Coordinates :

A- 36° - 47.0'N, 121° - 53.75MV

B- 36° - 47.0'N, 121° - 54.7'W

C- 36° - 47.75'N, 121° - 54.7'W

58 Data Points

Vector Average: .69 cm/sec @ 180°T

Note: During this run the cable and electrodes had to
be reeled in to resolder a leaking electrode.
This resulted in a two-hour gap in the data.

44

Depth (m)
o

Tide Height(ft. above MLLUl)

o

o

CM

o

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I

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CO

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c

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•> -H

r-

5-. ID

<D cti

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4-> ID CD CD

o

(DCHlH

CO

2 tf oj

o

u o

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C c rt

CD

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O

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VD

u o e

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U E P\

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■Q-

^XlHTJ

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CJJ nD <U

m rt 5-i

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m-i o a>

CD

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CM

X TD

o

(/)+-> •> CD

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o

e cd cd a,

o

(DP O «

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CM ^_^

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o< c cu

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CD Ol

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CM

bOX 4->

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g *

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4-> O Ph Vl

a h

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CD 3

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(oas/ujo) peads puTfry^uajjn^

45

Tide Heiqht(ft. above MLLUJ)

00

o

c

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CD

M

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u

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a3
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rH U

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CD £,

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cn

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46

(3as/w3) psads quajjn3

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3

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to
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0)

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to

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N

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on **is

M

^

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10 cm/sec

s

La CftrqcK* I

■a— —»?■■*■ iraatpaaai

Figure 22. Run 3, Vector Scatter Diagram

48

-4

-3

Figure 23. Run 3, Progressive Vector Diagram

50

D. RUN FOUR

Date: 0900, 21 April 1975 - 0900, 22 April 1975

Coordinates :

A- 36° - 47.1'N, 121° - 53.7'W

B- 36° - 47.1'N, 121° - 54.8'W

C- 36° - 47.8'N, 121° - 54.8'W
54 Data Points
Vector Average: 9.79 cm/sec @ 158. 5°T

51

Depth

Tide Height(ft. above MLLUl)
cr> Is- in ro

T

CD

CD

a

o
o

CO

o

CD
O
v£>
CD

CD
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<J
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a

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(O

o

n

CM

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n

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o

h-

CM

o

CD

CO

CD
O
VO

a

D

CD
CD
CM

D

CD

a

CD

M3

•H

•

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*

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ID X

C

+->

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j£

en

•

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to

T3

c

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CTj

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T3

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« 1-

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m

C3 tH

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to

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to

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rH

co

cu

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+->

6

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+-> rC

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ex:

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3

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(oes/wo) peeds puT(Yi/^uej jn^

52

Depth

(

m)

o a

r- CM

o

Tide Height(ft. above PflLLUl)
en r- in to

o

CD

CD

x—

O

o

co

a>

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<D

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53

N

1 1

5 10 cm/sec

1

Figure 26. Run 4, Vector Scatter Diagram

54

Figure 27. Run 4, Progressive Vector Diagram

55

E. RUN FIVE

Date: 0900, 1 May 1975 - 0900, 2 May 1975

Coordinates :

A- 36° - 47.1'N, 121° - 53.3MV
B- 36° - 47.1'N, 121° - 54.2'W
C- 36° - 47.9'N, 121° - 54.2'W

61 Data Points

Vector Average: 13.68 cm/sec @ 175.75°T

56

Depth (m)

o

CM

a

to

Tide Height(ft. above ItiLLUl)

CO V£) ^J-

o

D

O

T_

CD

o

T3

o

•H •

CO

o

o

X) jC

o

C 4->

UD

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O

3= c/> •

O
O

13 C
C U -H

03 o 13
o as

o

o

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C CD

CM

4-1 Ct! rH

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to C t/i

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CD
CM

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CU >h -P

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a

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CM

O rC O

CM'

U H rH

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CD
O
CM

E

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CO tfl
•H CD

+-> +->
<d cl, «

O

CO CD Tj

O

i Q CD

CO

,C CD

r-

+-> x) p<

5h C <s>

O
O

o a

r-

O

c: -h ?h

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3 CD o

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r-

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CO
CM

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r-

CD

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3

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DO

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ti.

(oes/iuD) paads pui^/^usaino

57

Depth (m)

a o o

o «~ cm ro

Tide Heiqht(ft. above NLLW)

o

o

o

r~

D
O
CO

CD
T3 •

O

•h e

E- P

CD

o

M __£

o

n3 P

VO

C O

O

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O
O

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i—l CD

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o

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MH r3

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o

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P i— 1 10

C U CD

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CD

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oa.

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a, CD

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C CD

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C -H P

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O

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p

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3

o

DO

P-,

(oas/iuo) peeds puT/Yi/iuejjn;]

58

N

-W

on

fv*is

E

I 1

10 cm/sec

Figure 30. Run 5, Vector Scatter Diagram

59

Km East

Figure 31. Run 5, Progressive Vector Diagram

60

V. DISCUSSION OF RESULTS

A. VALIDITY OF THE MEASUREMENTS

The apparent disparity in magnitudes of the surface and
subsurface currents as recorded during Run Three provoked
some doubt about the validity of the GEK records. The re-
corder was not in appreciable error; recalibration showed
it to read 5 percent low. Two conclusions are possible.
Either the currents measured in the thermocline are poorly
correlated with surface currents, or the GEK measurements
are poorly correlated with surface currents, or both. In
principle, the flow in the thermocline need not be well-
correlated with surface currents because of the low eddy
viscosity at the top of the thermocline.

The mean flows obtained by three workers [McKay, 1970,
Smith, 1972, and Howton, 1972] obtained with the GEK over
the canyon range from 11 to 13 cm/sec and are generally
southerly. These results agree satisfactorily with those
of the present work shown in Table IV, considering the var-
iations of day and season. Therefore, the present data are
comparable with the GEK data of the past, and no error
peculiar to the present series seems likely.

Scott [1973], quoting the data of AMBAG (Association of
Monterey Bay Area Governments) personnel obtained with drogues,
shows average currents of 7-10 cm/sec over and near the canyon
in June. This agrees approximately with the present data and

61

suggests that no large k-factor is necessary to convert the
data. Thus, although no precise k-factor can be assigned,
it seems justifiable to speak of the GEK measurements as
"currents" and to assume that k equals 1.0 pending a more
precise determination.

TABLE IV
Averaged Data

Run

Speeds

(cm/sec)

Avg Dir (°T)

Avg N

Avg E

Avg Magn

1

-8.33

4.33

9.39

152. 5

2

-5.37

-5.19

7.47

226.0

3

-0.69

-0.02

.69

180.0

4

-9.10

3.61

9.79

155.5

5

-13.64

1.02

13.68

175.75

B. DISCUSSION OF DATA

The various composite graphs were examined visually for
evidence of correlation between parameters. As was mentioned
previously, such short data sets could not be analyzed sta-
tistically for periods approximating half the length of time-
series with any validity unless the signal-to-noise ratio
were large. This is equivalent to saying that the correlation
would be obvious to visual examination. Although the par-
ameters contain components of the order of a 12-hour period,
it is clear that none of them is correlated.

The probable influence of magnetic storms on Run 1 was
discussed in Section II. The effects of these storms appear

62

smaller than those predicted theoretically. The likelihood
that the apparent currents represented real surface currents
was discussed in Section V-A. It was concluded that they
are less than real currents, on the average, by a factor
between one and two. The average currents agree reasonably
well with previous measurements in the area with the GEK.

63

APPENDIX A
PROGRAMS AND DATA TABLES

C PROGRAM KAMGEEK

C

C CONVERTS CURRENTS IN N AND E COMPONENTS TO VECTOR FORM

C AND TIME TO DECIMAL FORM CONTINUOUS OVER THE

C 0000-2400 BOUNDARY

C

DIMENSION TIME1(4),TIME2(4),V(4),U(4),TIME(4) ,XMAG(4) »
*DIR<4)
K = 4

PI=3. 14592
RAD=180./PI
TP=0.
ADD=0.
XK = 60.
N = 0

WRITE(6,200)
WRITE<6,300)

1 READ(5,5) (TIMEK J ) tTIME2( JJ ,V( J) ,U(J) , J=l,4)

5 F0RMAT(4(2F2.0,2F7.1) )
DO 15 J=lfK

1F(TIME1( J) .EQ.99JG0 TO 6
IF(TIME2U).EQ.0.)TIME2(J) = l.E-5

2 TIME( J)=T1ME1( J)+TIME2( J)/XK
IF((TP-TIME< J) ) .GT.20. J ADD=24.
TIMEC J)=TIME( J) +ADD

IF(TIMEU).oT.24.) T I ME( J ) =T I ME < J) -24.
TP=TIME1( J)

XMAG( J)=SQKT(UU)*U(J)+V(J)*V(J))
IF(XMAG( J) .E^.d. )XMAG( J) = l.E-5
DIR(J)=ABS(ARSIN (U(J)/XMAG( J) ) )
IFCUC J) •GT.0..AMO.VU1 .GT.O.)DIR( J)-DIR( J)
IF(U(J).LT.O..A\ID.V(J).GT.0.)DIR(J)=2.*PI-OIR(J)
IF(U(J).LT.3..A\ID.V(J).LT.0.)DIR(J) = 1.*PH-DIR(J)
IF(U(J).GT.O..AnD.V(J).LT.O.)DIR(J)=l.*PI-DIR(J)
JJ = J

DIR( J)=DIR( J)*RAD
15 CONTINUE
GO TO 25

6 JJ=JJ-1

100 FORMAT ( 24X,F5.2,3X,F5.1t£X,F4.0)

2 00 FORMAT ( 24X,' TIME' , 7X , • MAGN I TUDE ■ ,4X , • DI RECT ION' )
300 FORMAT! 23X,' (L3CAL) ' ,6X, ■ (CM/SEC) « ,3X,' ( DEG TRUEPt/)
WRITE(6t100)(TIMt(J) ,XMAG( J),DIR(J),J=1TJJ)
WRITE (7» 100) ITHEI J) ,XMAG( J),DIRU),J = lfJJ)
GO TO 45
25 WRITE(6,100) ( T I ME ( J ) t XMAG ( J ) , D I R( J) , J = l » 4)
WRITE (7, 100) ( TIME( J),XMAG( J),DIR(J),J=1,4)
30 GO TO 1
45 CONTINUE
STOP
END

Figure A-l. Program KAM GEEK

64

TABLE A- I

Run 1. GEK Data

TIME MAGNITUDE iSISE5SiIip,|

(LOCAL) (CM/SEC) (Dt& TRUE)

15 75 52.1 189.

16 03 41.4 l9k'
16 37 40.6 2-

6^ ?2.3 0.

I6-98 £°/£ 150.

17.28 41.6 £53;

IB-Jo 40.0 41;

18-48 \ht 128.

18-77 ?£*£ 132.

I9-05 It'l 133.

I9*33 4n"§ L24l

19-65 ?8'o 115.

19.95 22*2 125.

20.23 45.6 i|g.

20-52 43.0 1^-

20- 83 36.5 \ }£•

Ba !1 :

22.33 20.8 ''•

22.67 20.3 86

?•? ofl 20 .3 ,0

^'?n 25.2 12o.

23.30 ir a 163-

11:11 lJ:J !

?:8oi it-s 1:

1^5 9.0 *■?•

U67 29.2 4.

2/?0 7.*3 146*.

?#A0 7.0 209.

S-62 8.1 205.

7.6 209.

2.92 8.1 205.

till 9l0 193.

f 83 19-1 ?*?'

4.15 20.4 2^6.

4 45 11.8 1|J.

4 83 36.0 |56.

^ 1 a 38.4 3^v.

1:1! tl a 338.

i 79 34.7 343.

*'°i ?!:g 192:

M8 37:2 ibI:

§•58 2i*J 187.

7'i? 7.3 292.

7* 52 1 7 q 279.

7»80 I7*8 \)X\

8-12 1%'t 351.

!•*! 11:5 Hi:

SlI8 lj:i 25,.

Q40 41.2 *■ °X

73 40.6 0.

I0-00 45.4 u.

10.30 45.7 l|'«

10.62 \*'% \%\\

10.83 12.9 l^i.

11.15 i3-5 3?§;

11.47 l3-^ X
65

TABLE

A-II

Run 1,

Wind Data

TIME

DIRECTION

SPEEDS (CM/SEC)

PDT

O rp

SCALAR
89.4

EAST COMPONENT NO]
-68.48

nri COMPONENT

1000

130

57.48

1100

120

89.4

-77.42

44.7

1200

073

223.5

-65.26

-213.67

1300

293

357.6

328.99

139.82

1400

314

312.9

224.98

-217.47

1500

308

268. 2

211.34

-165.21

1600

316

312.9

224.98

-217.47

1700

230

268.2

172.45

205.44

1800

062

447.0

-209.64

-394.70

1900

069

491. 7

-176.03

-459.25

2000

074

491.7

-155.71

-472.52

2100

072

357.6

-110.50

-340.08

2200

060

670.5

-535. 25

-580.65

2300

066

536.4

-218.31

-490. 27

2400

076

402.3

-97.36

-390.23

0100

081

357.6

-55.79

-353.31

0200

094

402.3

-401.50

28.16

0300

083

491.7

-59.99

-488.26

0400

089

402.3

-6.84

-401.90

0500

078

357.6

-74.38

-349.73

0600

088

268.2

-9.39

-267.93

0700

096

268.2

-266.86

28.16

0800

098

223.5

-221.27

31.07

0900

108

268.2

-255.06

82.87

1000

103

134.1

-130.61

30.17

1100

088

223.5

-7.82

-223.28

1200

125

134.1

-109.83

76.97

66

TABLE A- III

Run 2, GEK Data

TIME

MAGNITUDE

DIRECTION

(LOCAL)

(CM/SEC)

(JEG TRUE)

10.45

2.0

33.

10.92

17.0

276.

11.38

16.9

90.

11.78

20.3

90.

12.22

24.4

3 04.

12.65

16.0

323.

13.03

32.1

345.

13.55

33.0

340.

13.97

22.8

330.

14.42

20.0

3.

14. 85

8.9

18.

15.37

14.1

53.

16.07

12.6

64.

16. 78

10.2

57.

17.22

32.1

165.

17.73

32.1

165.

18.23

45.9

169.

19.03

45.4

173.

19.42

42.7

172.

19.88

43.1

191.

20.33

26.8

162.

20.78

27.8

204.

21.30

22.8

210.

21. 77

28.0

225.

22.25

24.3

234.

22.72

24.3

234.

23. 18

20.6

286.

23.65

26.0

2 83.

C.13

30.5

304.

0.58

30.5

304.

1.07

29.1

299.

1.55

24.3

306.

2.02

24.3

306.

2.53

19.9

315.

3.02

16.4

239.

3.52

18.9

243.

3.98

17.8

252.

4.43

10.2

237.

4.88

12.0

225.

5.35

10.2

213.

5. 75

7.9

225.

6. 17

10.2

123.

6.57

14.1

143.

7.03

27.8

114.

7.50

32.2

128.

7.87

26.0

140.

8.43

22.0

130.

8.98

15.2

153.

9.37

12.6

154.

67

TABLE

A-IV

Run 2, W

ind Data

TIME

DIRECTION

SPEEDS (CM/SEC)

PDT

o >-p

SCALAR
178.8

EAST COMPONENT NOF
-167.54

ITH COMPONENT

1000

110

61.15

1100

168

89.4

-18.60

87.43

1200

130

134.1

-86.23

102.72

1300

277

312.9

310.71

-38.13

1400

294

402.3

367.70

-163.74

1500

273

357.6

357.11

-18.60

1600

255

357.6

345.44

92.62

1700

170

223.5

-38.89

220.15

1800

187

312.9

38.17

310. 71

1900

178

134.1

-4.69

133.97

2000

118

178.8

-157.88

83.86

2100

156

89.4

-36.39

81.71

3300

184

44.7

3.13

44.61

2300

110

134.1

-126.05

45.86

2400

177

178.8

-9.30

178.44

0100

331

402.3

195.12

-352.01

0200

221

223.5

146.62

168.74

0300

131

89.4

-67.50

58.65

0400

100

178.8

-168.07

61.15

0500

095

223. 5

-22 2.61

19.44

0600

139

44.7

-29.32

33.75

0700

093

268.2

-267.93

13.95

0800

095

312.9

-311.65

27.22

0900

081

223. 5

-220.82

-34.87

1000

206

44.7

19.58

40.19

1100

252

44.7

42. 51

13.81

1200

274

89.4

89.22

-6.26

68

TABLE A-V
Run 3, GEK Data

TIME

MAGNITUDE

DIRECTION

LOCAL)

(CM/SEC)

(DEG TRUE)

12.30

22.9

164.

12.62

21.8

163.

12.90

21.0

174.

13. 18

17.1

172.

13.47

17.2

191.

13.77

7.6

207.

14.07

7.0

166.

14.33

2.4

45.

14.65

2.9

53.

14.97

6.1

22.

15. 27

5.6

0.

15.58

3.4

0.

15. 87

5.2

311.

16. 17

5.2

311.

16.47

7.1

299.

16.73

6.8

246.

17.02

13.3

258.

17.35

13.1

262.

17.65

14.2

263.

17.95

16.2

241.

18.22

15.6

240.

18.53

16.6

235.

16.82

14.0

227.

19. 10

10.5

257.

19.47

7.7

252.

19.77

15.3

208.

20.02

13.7

170.

20. 25

4.1

146.

20.52

3.4

0.

20. 75

3.4

0.

20.98

5.6

127.

21.23

6.4

45.

21.47

5.3

32.

21.68

5.3

32.

21.95

4.5

0.

22. 17

3.4

0.

22.42

5.6

127.

22.67

4.6

104.

22.88

3.0

112.

23. 10

4.0

135.

23.33

2.8

0.

23.53

5.6

0.

2.25

9.6

135.

2.48

8.8

130.

2.75

7.9

135.

3.03

7.9

45.

3.32

5.6

0.

3.55

3.4

0.

3.75

3.4

0.

3.97

11.9

0.

4. 20

12.7

21.

4.45

9.6

28.

4. 83

8.5

0.

5.05

14.1

0.

5.35

18.1

39.

5.57

21.3

32.

5.80

19.3

21.

O.05

11.3

37.

69

TABLE A-VI
Current Meter Data

TIME
(PST)

CURRENT METER READING
MAGN (cm/sec)/DIR (°T)

COMPONENT
E (cm/sec)

SPEED
N(cm/sec)

1300

2.6

/

056

2.2

1.4

1315

2.6

/

061

2. 2

1.3

1330

5.2

/

061

4.5

2.5

1345

6.2

/

076

6.0

1.5

1400

10.2

/

106

9.8

-2.9

1415

18.0

/

131

13.6

-11.8

1430

12.9

/

126

10.5

-7.6

1445

15.5

/

106

14.8

-4.3

1500

18.0

/

086

17.8

1.3

1515

15. 5

/

081

15.2

2.5

1530

12.9

/

076

12.5

3.1

1545

15.5

/

086

15.3

1.1

1600

12.9

/

081

12.6

2.1

1615

15. 5

/

101

15.2

-2.9

1630

18.0

/

126

14.6

-10.6

1645

15.5

/

106

14.9

-4.3

1700

15. 5

/

106

14.9

-4.3

1715

15. 5

/

106

14.9

-4.3

1730

10.3

/

116

9.3

-4.5

1745

15.5

/

106

14.9

-4.3

1800

15. 5

/

116

13.9

-6.8

1815

10.3

/

086

10.2

0.7

1830

7.7

/

106

7.4

-2.2

1845

5.1

/

101

5.0

-1.0

1900

7.7

/

131

5.8

-5.0

1915

7.7

/

086

7.6

0.5

1930

5.1

/

081

5.0

0.8

1945

7.7

/

076 •

7.5

1.8

2000

10.3

/

086

10.2

0.7

2015

12.9

/

126

10.4

-7.6

70

TABLE A-VI (continued)

2030 15.5 / 126

2045 18.0 / 136

2100 12.9 / 131

2115 12.9 / 131

2130 12.9 / 126

2145 10.3 / 096

2200 12.9 / 106

2215 12.9 / 111

2230 20.6 / 126

2245 15.5 / 146

2300 15.5 / 141

2315 15. 5 / 136

2330 18.0 / 126

2345 18.0 / 126

2400 12.9 / 086

0015 15.5 / 091

0030 18.0 / 096

0045 15.5 / 101

0100 15. 5 / 096

0115 15.5 / 106

0130 18.0 / 101

0145 15.5 / 106

0200 20.6 / 106

0215 15.5 / 096

0230 15.5 / 091

0245 18.0 / 081

0300 18.0 / 086

0315 18.0 / 076

0330 15. 5 / 076

0345 18.0 / 076

0400 15.5 / 071

0415 15.5 / 081

0430 18.0 / 081

0445 15.5 / 081

12.6

-9.1

12.4

-13.0

9.7

-8.5

9.7

-8.5

10.4

-7.6

10.2

-1.0

12.4

-3.6

12.0

-4.6

16.7

-12.2

8.7

-12.9

9.8

-12.1

10.7

-10.8

14.6

-10.6

14.6

-10.6

12.7

0.9

15.3

-0.3

17.8

-1.8

15.2

-2.9

15.3

-1.6

14.9

-4.3

17.6

-3.4

14.9

-4.3

19.8

-5.8

15.3

-1.6

15.3

-0.3

17.6

2.9

17.8

1.3

17.5

4.3

15.0

3.6

17.5

4.3

14.7

5.1

15.2

2.5

17.6

2.9

15.2

2.5

71

TABLE A-VI (continued)

0500 15.5 / 081 15.2 2.5

0515 15.5 / 081 15.2 2.5

0530 15.5 / 086 15.3 1.1

0545 15. 5 / 086 15.3 1.1

0600 12.9 / 096 12.7 -1.3

0615 15.9 / 101 15.2 -2.9

0630 15. 5/106 14.9 -4.3

0645 15.5 / 126 12.6 -9.1

0700 18.0 / 116 16.2 -7.9

72

TABLE

A-VII

Run 3, Wind Data

TIME

DIRECTION

SPEEDS (CM/SEC)

PDT

o *r

SCALAR
134.1

EAST COMPONENT NOF
-32.45

TH COMPONENT

1000

166

130.08

1100

213

402.3

219.25

337.53

1200

307

402.3

321.44

-242.18

1300

256

402.3

390. 23

97.36

1400

243

536.4

477.93

243.53

1500

244

491.7

442.04

215.36

1600

238

357.6

303.24

189.53

1700

240

402.3

348.38

201.15

1800

241

402.3

352.01

195.12

1900

243

536.4

477.93

243.53

2000

253

536.4

512.80

156.63

2100

273

402.3

401.50

-20.92

2200

272

312.9

312. 59

-10.95

2300

257

312.9

304.76

70.40

2400

251

312.9

295.69

102.00

0100

240

312.9

270.97

156.45

0200

222

312.9

209.33

232.48

0300

192

178.8

37.19

174.87

0400

188

178.8

24.85

177.01

0500

192

89.4

18.60

87.43

0600

154

89.4

-39.16

80.37

0700

227

491.7

359.43

335.34

0800

227

491.7

359.43

335.34

0900

232

223.5

176.12

137.68

1000

162

178.8

-55.25

170.04

1100

181

268.2

4.57

267.93

1200

220

357.6

229.94

273.92

73

TABLE A-VIII

Run 4, GEK Data

TIME

MAGNITUDE

DIRECTION

(LOCAL)

(CM/SEC)

( DEG TRUE)

12. 13

22.8

150.

12.4b

27.8

156.

12.78

27.8

156.

13.15

14.1

127.

13.57

21.5

113.

13.88

22.8

120.

14.35

20.3

124.

14.72

26.0

140.

15. 15

20.6

164.

15. 50

10.2

147.

15.63

12.0

135.

16. 18

14.1

143.

16.65

18.1

129.

16. 97

14.4

101.

17.25

4.0

135.

17.63

11.6

166.

18.03

11.3

0.

18.30

19.8

0.

18.73

20.6

196.

19.07

10.2

213.

19.60

10.2

213.

20.05

5.6

90.

20.45

0.0

0.

20.82

16.9

0.

21.18

17.8

193.

21.55

28.8

191.

21. 92

28.3

186.

22.28

11.6

194.

22.63

14.1

217.

22.97

29.5

343.

23.35

28.8

191.

23.67

6.3

243.

0.05

2.8

0.

0.43

25.4

0.

1.13

26.0

163.

1.72

10.2

147.

2.07

8.9

162.

2.40

6.3

27.

2.77

12.6

64.

3.10

18.1

39.

3.40

16.5

31.

3.72

18.9

153.

4.08

18.9

153.

4.45

14.1

143.

4. 75

12.6

154.

5.07

10.2

147.

5.33

10.2

147.

5.67

5.6

90.

6.40

2.8

0.

c.72

2.8

0.

7.02

4.0

315.

7.35

8.9

342.

7.68

8.5

0.

8.00

8.5

0.

74

TABLE

A-IX

Run 4, W

ind Data

TIME

DIRECTION

SPEEDS (CM/SEC)

PDT

0 H"*

SCALAR
89.4

EAST COMPONENT NOI
-48.72

UH COMPONENT

1000

147

75.01

1100

263

89.4

88.77

10.91

1200

256

312.9

303.51

75.75

1300

283

581.1

565.99

-130.75

1400

267

402.3

401.50

20.92

1500

253

536.4

512.80

156.63

1600

244

581.1

531.13

236. 51

1700

234

536.4

433.95

315.40

1800

236

581.1

481.73

324.83

1900

229

715.2

539.98

469.17

2000

232

849.3

669.25

523.17

2100

243

581.4

517.76

263.82

2200

240

491.7

425.81

245.85

2300

218

402.3

247.82

317.01

2400

270

312.9

312.9

0

0100

274

312.9

311.96

-21.90

0200

248

312.9

290.06

117.34

0300

275

491.7

489.73

-42.78

0400

288

491.7

467.61

-151.94

0500

297

357.6

318.62

-162.35

0600

301

447.0

383.08

-230.21

0700

300

268.2

232.26

-134.1

0800

307

89.4

71.43

-53.82

0900

240

178.8

154.84

89.4

1000

230

134.1

102.72

86.23

1100

230

223.5

171.20

143.71

1200

258

268.2

262.30

55.79

75

TABLE A-X

Run 5, GEK Data

TIME

MAGNITUDE

DIRECTION

(LOCAL)

(CM/SEC)

(DEG TRUE)

11.80

21.5

23.

12. 10

12.0

135.

12.43

16.5

121.

12. 78

19.9

135.

13. li

18.1

141.

13.48

12.6

116.

13.87

5.6

0.

14.15

16.9

0.

14.50

17.1

171.

14.85

6.3

153.

15.20

6.3

153.

15.57

6.3

153.

15.92

7.9

135.

lb. 25

12.6

154.

16.58

11.3

0.

16.88

22.6

0.

17.25

23.3

194.

17.55

31.5

190.

17.88

31.5

190.

18.17

34.4

189.

18. 53

35.7

198.

18.83

30.4

202.

19.18

32.9

211.

19. 50

32.9

211.

19.90

32.9

211.

20.18

22.0

230.

20.58

24.3

234.

20. 90

24.3

234.

21.25

16.5

211.

21. 58

10.2

303.

21.93

6.3

27.

22.22

14.4

169.

22.55

18.1

141.

11. 83

14.1

53.

23. 18

14.1

53.

23.48

11.6

76.

23.83

8.9

72.

0. 18

10.2

123.

0.57

12.6

116.

0.90

10.1

141.

1.25

14.4

169.

1.60

14.4

169.

2.00

15.2

158.

2.30

15.2

158.

2.62

16.5

149.

2.97

12.0

135.

3.32

8.9

162.

3.63

4.0

135.

3.98

6.3

117.

4.30

15.2

158.

4.65

15.2

158.

5.00

12.6

154.

5.32

12.6

154.

5.68

7.9

135.

6.03

5.6

0.

6.37

25.4

0.

6.75

25.4

0.

7.07

28.2

0.

7.42

28.8

191.

7.78

28.8

191.

8. 17

28.8

191.

76

TABLE

A-XI

Run 5, W:

ind Data

TIME

DIRECTION

SPEEDS (CM/SEC)

PDT

O rp

SCALAR
268.2

EAST COMPONENT NOP
268.2

LTH COMPONENT

1000

270

0

1100

242

223.5

197.35

105.05

1200

243

268.2

238.97

121.76

1300

239

312.9

268.16

161.14

1400

254

402.3

386.61

111.03

1500

261

402.3

397.47

62.76

1600

249

402.3

375.75

144.02

1700

257

402.3

391.84

90.52

1800

258

447.0

437.17

92.98

1900

248

491.7

455.81

184.39

2000

219

536.4

337.40

416.78

2100

211

491.7

253.22

421.39

2200

178

223.5

-7.82

223. 28

2300

135

178.8

-126.41

126.41

2400

132

178.8

-132.85

119.62

0100

180

44.7

0

44.7

0200

202

44.7

16.76

41.44

0300

284

312.9

303.51

-75.72

0400

283

223.5

217.69

-50.29

0500

283

223.5

217.69

-50.29

0600

239

312.9

268.16

161.14

0700

296

312.9

281.30

-137.05

0800

291

312.9

292. 25

-112.02

0900

282

178.8

174.87

-37.19

1000

274

223. 5

223.05

-15.65

1100

280

268.2

264.18

-46.67

1200

261

312.9

309.15

48.81

77

BIBLIOGRAPHY

1. Bennett, D.J. and Filloux, J.H., "Magnetotelluric Deep
Electrical Sounding and Resistivity," Reviews of Geophysics
and Space Physics, Vol. 13, No. 3, p. 197-203, July 1975.

2. Garcia, R.A. , Numerical Simulation of Currents in Monterey
Bay , M.S. Thesis, Naval Postgraduate School, Monterey, 1971

3. Hollister, J.E., Currents in Monterey Submarine Canyon,
M.S. Thesis, Naval Postgraduate School, Monterey, 1975.

4. Howton, H.M., A Study of Time Variability of Surface
Currents at a Point in Monterey Bay, M.S. Thesis, Naval
Postgraduate School, Monterey, 1972.

5. Lipparelli, M. , The GEK Signal of Lowest Mode Internal
Waves , Ph.D. Thesis, Oregon State University, Corvallis,
1971.

6. Longet-Higgins , M.S., Stern, M.E., Stommel, H. , The Elec-
trical Field Induced by Ocean Currents and Waves, with
Applications to the Method of Towed Electrodes, MIT and
WHOI , Papers in Physical Oceanography and Meteorology,
XIII(l), 1954.

7. McClelland, J.J., An Oceanographic Investigation of Thermal
Changes in Monterey Bay, California, September 1971-
January 1972, M.S. Thesis, Naval Postgraduate School,
Monterey, 1972.

8. McKay, D.A. , A Determination of Surface Currents in the
Vicinity of the Monterey Submarine Canyon by the Electro-
magnetic Method, M.S. Thesis, Naval Postgraduate School,
Monterey, 1970.

9. Pirie, D.M. and Steller, D.D., California Coast Nearshore
Processes Study Final Report - ERTS- 1 Experiment #088,
Goddard Space Flight Center, Greenbelt, Maryland, 1974.

10. Scott, D.A. , AMBAG Oceanographic Survey, Oceanographic
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V-7m, 1973.

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'"Internal Waves' Advancing along Submarine Canyons,"
Science, v. 183, p. 195-198, 18 January 1974.

12. Smith, T.D., GEK Measurements of Surface Currents in
Monterey Bay, 1971, M.S. Thesis, Naval Postgraduate
School, Monterey, 1972.

78

13. Stevenson, CD., A Study of Currents in Southern Monterey
Bay, M.S. Thesis, Naval Postgraduate School, Monterey,
1964.

14. Von Arx , IV. S., An Electromagnetic Method for Measuring
the Velocities of Ocean Currents from a Ship Underway,
MIT and WHOI , Papers in Physical Oceanography and
Meteorology, XI(3), 1950.

79

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MONTEMY, CALIFORNIA Ml

Thesis
M27718
c.2

Mahumed

Apparent surface
currents over the

Monterey Submarine
Canyon measured by the
method of towed elec-
trodes.

Mahumed

Apparent surface
currents over the
Monterey Submarine
Canyon measured by the
method of towed elec-
trodes.

thesM27718

Apparent surface currents over the Monte

i iiiii iiiii 111

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