Acoustic Doppler Current Profiler observations during the

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L+i ' -.
Acoustic Doppler Current Profiler observations during the
Coastal Mixing and Optics experiment: R/V Endeavor cruises from
14 August to 1 September 1996 and 25 April to 15 May 1997
Stephen D. Pierce
John A. Barth
P. Michael Kosro
College of Oceanic and Atmospheric Sciences
Oregon State University
Corvallis, Oregon 97331-5503
Data Report 169
Reference 98-2
December 1998
http://diana. oce. orst. edu/cmoweb
We present velocity observations from a shipboard acoustic Doppler current profiler (ADCP) on
RN Endeavor during cruises E9608 (14 August to 1 September 1996) and E9704 (25 April to
15 May 1997). The cruises were conducted as part of the Office of Naval Research Coastal
Mixing and Optics Accelerated Research Initiative. The objective was to rapidly survey a region
in the Middle Atlantic Bight south of Cape Cod, Massachusetts. The ADCP was an RD Instruments hull-mounted 307-kHz unit. Data were collected nearly continuously during both cruises,
in a region about 80 km square around 40.5°N, 70.5°W. Vertical bin length was 4 m and the typical depth range in open water was 200 m. To reference the velocities to earth coordinates, we
used bottom-tracking supplemented by differential global positioning system (GPS) navigation.
A GPS attitude system was also used, in combination with the ship's gyrocompass, to determine
heading. This report describes the ADCP processing steps and presents the observed velocities.
In addition, we apply an empirical tidal model to estimate and then remove the barotropic tidal
currents, and we present the resulting subtidal velocities. An online version of this report is
available at http://diana.oce.orst.edu/cmoweb.
Table of Contents
Introduction
Editing
Calibration
Navigation
Synopsis of uncertainties ...................................................................................................................
Determination of subtidal flow ..........................................................................................................
Data presentation ...............................................................................................................................
Acknowledgments ..............................................................................................................................
References
E9608 observed and subtidal velocity vectors at standard depths ..............................................
E9608 subtidal east and north velocity sections ............................................................................
E9608 soliton sections ......................................................................................................................
E9704 observed and subtidal velocity vectors at standard depths ..............................................
E9704 subtidal east and north velocity sections ............................................................................
INTRODUCTION
This report presents observations of velocity from a shipboard acoustic Doppler current profiler
(ADCP) on the R/V Endeavor during cruises E9608 (14 August to 1 September 1996) and E9704 (25
April to 15 May 1997). The cruises were conducted as part of the Office of Naval Research Coastal Mixing and Optics Accelerated Research Initiative. The objective was to rapidly survey a region in the Middle Atlantic Bight using both ADCP and SeaSoar tows, where a set of moorings and a stationary research
vessel were also collecting data (Figure 1). The first cruise was in the summer season, a period of strong
stratification of the water column, while the second cruise was in the spring, a period of re-stratification
42
Corners of Big Box
Corners of Small Box
41.5
40.5
40
-72
-71.5
-70.5
Longitude (°W)
-71
-70
-69.5
Fig. 1. Map of the study region in the Middle Atlantic Bight. Bottom topography in meters.
1
e9608.cnf
AD, SI, HUNDREDTHS
AD, NB, WHOLE
150.00 Sampling interval
AD,BL,WHOLE
75 Number of Depth Bins
2 Bin Length
AD, PL,WHOLE
AD, BK, TENTHS
AD, PE,WHOLE
4 Pulse Length
2.0 Blank Beyond Transmit
1 Pings Per Ensemble
AD, PC, HUNDREDTHS
AD. PG,WHOLE
XX,PD2,WHOLE
XX,TE,HUNDREDTHS
AD,US,BOOLE
DP,TR,BOOLE
DP,TP,BOOLE
DP,TH,BOOLE
SS,OP,TENTHS
SS,ZR,TENTHS
SS,OT,HUNDREDTHS
SS,ST,HUNDREDTHS
SS,SL,HUNDREDTHS
1.00 Pulse Cycle Time
25 Percent Pings Good Threshold
5 [SYSTEM DEFAULT. OD21
0.00 [SYSTEM DEFAULT, TE]
'4
YES Use Direct Commands on Startup
NO
Toggle roll compensation
DP , VS, BOOLE
NO
YES
YES
Toggle Pitch compensation
Toggle Heading compensation
Calculate Sound Velocity from TEMP/Salinity
DP,UR, BOOLE
YES
Use Reference Layer
DP, FR, WHOLE
DP,LR, WHOLE
DP, BT, BOOLE
DP, B3, BOOLE
YES
YES
Use Bottom Track
Use 3 Beam Solutions
/* [for E9704
DP, EV, BOOLE
DP, WE, TENTHS
DR,RD,BOOLE
DR, RX, BOOLE
DR,RY,BOOLE
DR,RZ,BOOLE
DR,RE,BOOLE
DR, RB, BOOLE
DR, RP, BOOLE
DR, RA, BOOLE
DR, RN, BOOLE
DR,AP,BOOLE
XX,LDR,TRI
XX,RB2,WHOLE
DR,RC,BOOLE
XX, FB,WHOLE
XX, PU, BOOLE
3 First Bin for reference Layer
6 Last Bin for reference Layer
no
NO
1
NO
1
1
SG, PPE, BOOLE
SG, PMD, BOOLE
SG,PSW,BOOLE
SG. PAV, BOOLE
SG, PPG, BOOLE
SG, PDI, BOOLE
SG, PD2, BOOLE
SG, PD3, BOOLE
SG. PD4, BOOLE
SG,PWI, BOOLE
SG, PW2, BOOLE
SG, PW3, BOOLE
SG, PW4, BOOLE
SG, PAI, BOOLE
SG, PA2, BOOLE
SG, PA3, BOOLE
SG, PA4, BOOLE
SG. PP3, BOOLE
Recording on disk
Record N/S (FORE/AFT) Vel
Record E/W (FORT/STBD) Vel.
Record Ancillary data
Auto-ping on start-up
Record CTD data
[SYSTEM DEFAULT, FBI
[SYSTEM DEFAULT, PU]
DISPLAY (NO/GRAPH/TAB)
ZERO VELOCITY REFERENCE (S/B/M/L)
HIGHES T VELOCITY ON GRA:PH
LOWEST DEPTHS ON GRAPH
HIGHEST DEPTHS ON GRAPH
SET D SPTHS WINDOW TO T..NCLUDE ALL BINS
MINIMU M PERCENT GOOD TO: PLOT
L.
PLOT NORTH/SOUTH
PLOT EAST/WEST VEL.
PLOT VERTICAL VET..
PLOT 'ERROR VEL.
PLOT PERCENT ERROR
PLOT MAG AND DIR
PLOT AVERAGE SP, RJ..
PLOT AVERAGE AGC.
NO
NO
PLOT PERCENT GOOD.'
PLOT DOPPLER 1
PLOT DOPPLER 2
NO
NO
NO
PLOT DOPPLER 3
PLOT DOPPLER 4
PLOT SP. W. 1
NO
PLOT
YES
NO
NO
YES
YES
YES
YES
NO
PLOT
PLOT
PLOT
PLOT
PLOT
PLOT
PLOT
SP. W.
2,
'SP. W.
4,
SP. w. 3
.AGC I
ADO '2
AGC 3
AGC 4
3-BEAM $$UT-ION
YES
NO
2
1
64
6
YES
NO
0
3
1
DP,PX,BOOLE
SS,LC,TENTHS
SS,OH,TENTHS
NO
5.0
0.5
2
NO
YES
YES
NO
0
3
YES
YES
SS,VSC,TRI
0
AD,DM,BOOLE
TB,SC,BOOLE
AD,CW,BOOLE
DR,RW,BOOLE
DR,RRD,BOOLE
DR,RRA,BOOLE
YES
YES
DR,RRW,BOOLE
NO
NO
NO
NO
YES
DR,RD,BOOLE
DR,RBS,BOOLE
XX,STD,BOOLE
LR,HB, HUNDREDTHS
LR 1 SPECIAL
for Depth
Offset for Heading'
Offset for Pitch:
Offset for Roll
OffSet FOR temp
Scale for Temp
Salinity (PTT),
Toggle UP/DCPNN
Toggle concave/Convex
trahsducerhea d
[SYSTEM DEFAULT, GPI
1.0 (SYSTEM DEFAULT, DD)
DR,PDDWHOLE
SL,1,ARRAY5
SL,2,ARRAY5
SL,3,ARRAY5
SL,4,ARRAY5
SL,5,ARRAY5
SL,6,ARRAY5
DU,1,ARRAY6
DU,2,ARRAY6
DU,3,ARRAY6
DU,4,ARRAY6
DU,5,ARRAY6
DU,6,ARRAY6
DU,7,ARRAY6
DU,B,ARRAY6
DU,9,ARRAY6
DU,10,ARRAY6
DC,I,SPECIAL
DC.2,SPECIAL
DC,3,SPECIAL
1 SPECIAL
Offset
30.0 Mounting angle for transducers.
1500.00 Speed of Sound (m/sec)
DR,SD,WHOLE
AD,PS,BOOLE
XX,LNN,BOOLE
XX,BM,BOOLE
XX,RSD,BOOLE
XX,DRV,WHOLE
XX,PBD,WHOLE
TB,RS,BOOLE
UX,EE,BOOLE
Record Percent good
Record average AGC/Bin
NO
TB,FP,WHOLE
TB,LP,WHOLE
TB,SK,WHOLE
TB,DT,BOOLE
DU,TD,BOOLE
XX,PN,WHOLE
GC,GG,TRI
Bytes of user prog. buffer
YES
XX,TU,TRI
Record error Good
-50 LOWEST VELOCITY ON GRAPH
50
0
500
YES
25
YES
YES
YES
YES
YES
NO
NO
NO
SS,UD,BOOLE
SS,CV,BOOLE
SS,MA,TENTHS
SS,SS,HUNDREDTHS
XX,GP,BOOLE
XX,DD,TENTHS
XX,PT,BOOLE
Record vertical vel.
[SYSTEM DEFAULT, LDR]
192 [SYSTEM DEFAULT, RB21
GC, ZV,WHOLE
GC, VL,WHOLE
CG,VH,WHOLE
GC,DL, WHOLE
GC,DH,WHOLE
GC,SW, BOOLE
GC,MP,WHOLE
SG, PNS, BOOLE
So,PEV, BOOLE
for depths < 200 m /
for depths a 110 m
3
GC,TG,TRI
SG, PEW, BOOLE
SG, PVT, BOOLE
/`
/*
3 beam solutions are used] "/
YES Use Error Velocity as Percent Good Criterion
100.0 Max. Error Velocity for Valid Data (cm/sec)
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
5.0
45.0
0.0
0.0
45.00
50.00
33.50
SS,OD,WHOLE
SS,OH,TENTHS
NO
YES
NO
[SYSTEM DEFAULT, PT)
(SYSTEM DEFAULT, TUI
'FIRST BINS TO PRINT
LAST BIN TO PRINT
SKIP INTERVAL BETWEEN BINS:
DIAGNOSTIC TAB MODE
TOGGLE USE OF DUMMY DATA
'[SYSTEM DEFAULT, PN)
Second recording drive
First recording drive (1=n:,28:: ;,,
Profiler does XYZE transform
Limit of Knots change
Weight of new knots of value
GRAPHICS CONTROL O=LO RES. 1=HI RES. 2=ENHANCED
YES=SERIAL/NO=PARALLEL Profiler Link
[SYSTEM DEFAULT, LNN)
(SYSTEM DEFAULT, BMI
RECORD STANDARD DEVIATION OF VELOCIT IES PER BIN
[SYSTEM. DEFAULT, DRV)
[SYSTEM DEFAULT, PRD)
SHOW RHPT STATISTIC
ENABLE EXIT TO EXTERNAL PROGRAM
Velocity scale adjustment
USE DMA
SHOW CTD DATA
Collect spectral width
Record average SP.W./Bin
Record last
raw dopplerA
Record last raw AGO
Record last SP.W.
Record average 3-Beam solutions.
Record beam statistic
(SYSTEM DEFAULT. STD[
0.00 Heading Bias
8
NONE
NONE
NONE
NONE
19200
1200
1200
1200
8
8
NONE
NONE
1200
1200
0
0
1
8
1
8
0
0
1
8
1
0
0
1
1
PROFILER
LORAN RECEIVER
REMOTE DISPLAY
ENSEMBLE OUTPUT
AUX 1
AUX 2
0.00
0.00 YES 01
0.00 YES 02
0.00
100 00
-100 00
100.00
-100.00
60.00
60 00
200.00
-200.00
200.00
-200.00
60 00
60.00
0.00
0.00
0.00 YES D3
0.00 YES D4
200.00
19.00
60.00
0.00
0.00 YES AGC
0 00
0 00
0.00
60.00
0.00
0.00 NO
SP. W.
0.00
0.00
0.00
60.00
60 00
0.00
0.00
0.00 NO
0.00 NO
ROLL
PITCH
0.00
0.00
60.00
0.00
0.00 NO
HEADING
0 00
"FH00001' MACRO 1
"E0004020099" MACRO
"B009001" MACRO 3
Coastal Mixing and
..
60ri:00
0.00
2
/*
0.00
0.00 NO
TEMPERATURE
E9704 case does not include this */
Optics" CRUISE ID GOES HERE
LORAN FILE NAME GOES HERE
tollowing the winter mixing season.
The cruises were organized around the collection of CTD data from a towed undulating vehicle, the
SeaSoar, in two areas: a small box pattern covering about a 25 by 30 km area and a big box pattern covering about 70 by 80 km (Figure 1). Each of these boxes was sampled repeatedly during each cruise. In
addition to the CTD, the SeaSoar was equipped with a nine-wavelength light absorption and attenuation
meter (WETLABS ac-9) and a new microstructure instrument developed at Oregon State University
(MicroSoar). The water column was generally sampled by the SeaSoar from the surface to within 5-7 m
of the bottom. Between SeaSoar tows, conventional CTD/rosette casts were also made. ADCP and
underway surface temperature, salinity, and meteorological measurements were made continuously (Figure 2).
For a full description of the SeaSoar and conventional CTD data and cruise narratives for the two
surveys, see O'Malley et al. (1998). For descriptions of the spectral light absorption and attenuation measurements, see Barth and Bogucki (1999) and Barth et al. (1999). For descriptions of the microstructure
observations, see Erofeev et al. (1998). Also, online data reports for all data sets are available at
http: //diana. oce. orst. edu/cmoweb.
The reader unfamiliar with basic ADCP principles and terminology used in this report is referred to
the helpful Practical Primer, RDI (1989). The ADCP was an RD Instruments hull-mounted narrow-band
model, with 4 beams oriented 30° from vertical. To achieve higher vertical resolution, the Endeavor's
standard 153-kHz transducer was replaced with a 307-kHz model borrowed from Oregon State University
(OSU). Spool pieces to adapt the OSU transducer to the Endeavor's hull opening were fabricated out of
0.5" steel by Modern Heat Inc., Gloucester, Massachusetts.
The ADCP transducer was at a depth of 5 in. We set up the instrument with a pulse length of 4 m, a
bin width of 4 in, a blanking interval of 2 in, and an ensemble averaging time of 2.5 min. Bottom-tracking was turned on (off) automatically when the bottom depth was less than (greater than) 200 in. This
was accomplished by a watchdog program running on the data acquisition system (DAS) PC, which tog-
gled the bottom-tracking parameter within the configuration file (Table 1) and restarted data acquisition
when the 200 in isobath was crossed (C. Flagg, personal communication). Good quality bottom-tracking
was available during 92% of the E9608 cruise and 93% of the E9704 cruise. The average number of
pings per ensemble was 116. The error velocity threshold for raw pings during data collection was 1 m/s.
No corrections for pitch and roll were made; errors associated with these are likely to be small (Kosro,
1985). Additional configuration details can be found in Table 1, a copy of the file used to configure the
DAS.
During E9608, one of the 4 ADCP beams had unusually low backscatter amplitudes (Figure 3).
This was probably a problem within the #4 transducer head itself. Between the two cruises, the transducer unit was returned to RD Instruments for testing/repair. The problem did not occur during E9704
(Figure 3). RD Instruments provided no explanation of repairs made. The weak beam during E9608
resulted in slightly reduced depth range, although the problem was to some extent remedied by allowing
3-beam solutions when the bottom depth was greater than 110 in (which occurred about 12% of the time
226
228
230
232
234
236
238
240
242
244
246
Shortwave
1200
900
I
600
300
11
0
40
30
E
°c 20
10
0
15 Aug
-30 Aug
25 Aug
'20 Aug
,mar=I
180
90
CO)
a)
CD
M
0
a)
a
-90
-180
ADCP-T (5m)
0025
ITS
15
226
228
230
232
234
236
238
240
242
244
246
Year day 1996
Fig. 2a. Solar radiation, wind speed, wind direction, and 5-m water temperature at the ADCP transducer,
during E9608.
4
114
116
118
120
122
124
126
128
E
132
134
Shortwave
1200
N
130
900
600
300
0
40
30
CA
4-
c 20
10
0
15 May
25 Apr
180
90
-90
-180
10
U
ADCP-T (5m)
9
a)
8
7
E
a>
F-
6
114
116
118
120
122
124
126
128
130
132
134
Year Day 1997
Fig. 2b. Solar radiation, wind speed, wind direction, and 5-m water temperature at the ADCP transducer,
during E9704.
5:
0
1L
,0,
23
1.234
'50:
E 100
150 --
200.-
II
E9704
0
50
iT
I
d
100
150
200
250
Mean Raw Beam AGC
50
100
150
200
250
Mean Raw Beam AGC
Fig. 3. Mean AGC vs. depth for E9608 (left) and E9704 (right).
during E9608).
During E9608, the shallowest available depth bin was centered at 10 m. During E9704, however,
the top two depth bins were judged bad and usually rejected internally by the DAS. The shallowest avail-
able depth is thus 18 m. We attempted to remedy this by experimentation with several different ping-toping tracking control "E" direct commands, but the changes had no apparent effect.
The ADCP operated continuously except for breakdowns usually caused by DAS-PC "freezes" and
planned short interruptions to change system parameters or diskettes. Overall, good data were collected
95% of the time during the E9608 and E9704 cruises. The occasional DAS PC freezes were apparently
caused by ship's electrical noise infecting one of the serial communication lines. The source of this noise
was investigated but never identified. A hardware watchdog reset program installed on the DAS PC limited these "freeze" gaps to 5 min in most cases. The largest gap was 95 min on year day 234 (Figure 6a),
during E9608 Big Box 2 Line Cl. This was caused by the failure of a circuit board within the ADCP
deck unit. A replacement board was installed and tested successfully. The section was repeated (E9608
Big Box 2 Line C2) in order to obtain a clean section without a gap. The beam-average backscatter
amplitude (Figure 4) and percentage-good-pings per ensemble (Figure 5) diagnostics appear reasonable
y
over both cruises. More discussion of these is in the EDITING section below.
The ADCP data were initially processed and displayed in real-time by the RD Instruments program
running on the DAS PC. Additional shipboard and shore processing were accomplished using some components of the Common Oceanographic Data Access System (CODAS) software package made available
by the University of Hawaii (Firing et al., 1995), running on a Sun Sparc 10. Using the user exit 4 (ue4)
program running on the DAS PC, each profile was sent serially to the Sun workstation where a second
copy of the raw data was collected by the monserv program. Parts of the CODAS software required the
Matlab language, and the figures for this report were made using the Gri package (Kelley, 1995).
For position, differential GPS with the U.S. Coast Guard corrective radio broadcasts using a Trimble
NavTrac XL receiver were integrated into the ADCP data stream at the end of each 2.5-min ensemble by
the ue4 program. Differential GPS data quality was excellent throughout both cruises. Ship's heading
was by a combination of Sperry gyro compass and Trimble TANS vector attitude GPS, which were both
recorded at 1 Hz on the Sun workstation. The Trimble TANS vector unit experienced occasional crashes
(1-2 a day) which required human intervention and resulted in gaps of about 10 min. The cause of these
crashes was unknown. Some software developed at the University of Hawaii to work with Ashtech attitude data (eg. decash) was modified and used with the Trimble data. The attitude data were edited and
averaged into 2.5 min intervals to match the ADCP ensemble times. More details regarding these steps
are discussed below in the CALIBRATION section.
EDITING
As data quality decreases with depth, we must decide on the deepest usable bin for each 2.5 min
ensemble. In addition, the data are edited for interference with the sea floor in shallow water and for
occasional interference from the CTD hydrographic wire and other objects. To flag and remove suspect
data points, several methods were used in combination during post-processing, as recommended by Firing et al. (1995) and others:
The percentage-good-pings per ensemble cutoff was set to 30%; below this point data were not used.
The %-good-pings is a record of the proportion of raw pings within the 2.5 min ensemble which are
judged good internally by the RDI firmware and subsequently included in the ensemble average.
The automatic gain control (AGC) gives an indication of the echo return signal strength, scaled such that
1 AGC count corresponds to about a 0.45 dB change in signal power. The AGC decreases with bin depth
in general. A small increase with depth may simply indicate the presence of a strong scattering layer due
to a large zooplankton population, while a larger increase is probably a reflection off of the sea floor.
Individual ensembles were scanned for increases of AGC >30 counts, and the deepest subsequent bin
where a local maximum is reached was taken as an indication of sea floor location.
In the deep water case, where no sea floor echo is detected, the AGC will eventually stop decreasing
with depth and become constant. This constant level is the noise floor; the signal of interest is no longer
present. We use a noise margin of 10, retaining bins which have AGC greater than 10 above the noise
floor.
7
200
50
AGC
E 100
4-
Q
0
200
233
234
235
236
237
I
I
1
1
200
1
238
239
240
241
242
245
246
247
100-H
200 HI
1
243
I
244
Year day 1996
Fig. 4a. Backscatter amplitude (automatic gain control) vs. time and depth, during E9608.
8
250
0
50
100
150
200
250
AGC
0
E
100
CL
a)
0
200
120-
118,
0
1
100
200
123
124
0
-IN III mpg 1,
100
200
126
127
128
129
130
131
132
133
134
135
0
100
200
Year day 1997
Fig. 4b. Backscatter amplitude (automatic gain control) vs. time and depth, during E9704.
9
80
Percent good
0
0
200
0
100
200
0
100
200
238
239
240
241
242
243
244
245
246
247
0
100
200
Year day 1996
Fig. 5a. Percentage-good-pings vs. time and depth, during E9608.
10
20
Percent good
L
80
40
1
0
200
117
118
119
120
0
100
200
125
0
100
200 -1
1
126
127
128
129
1
130
131
132
133
Year day 1997
134
135
0
100
200
Fig. 5b. Percentage-good-pings vs. time and depth, during E9704.
11
Since the ADCP initially measures velocity along the axes of four beams, which are then transformed to
the 3-dimensional components u, v, and w, there is redundancy in the scheme. This redundancy is used
within the RDI firmware to make two distinct estimates of the vertical velocity w. The difference between
these two estimates is called the error velocity and is a useful data quality indicator. A large error velocity
indicates an inconsistency among the oceanic velocities sampled by each of the 4 beams. Thus it is
another way of detecting interference with one of the beams caused by an object. We reject individual
bins which have an error velocity above 10 cm/s, a relatively conservative choice; the results are not very
sensitive to the choice.
The second differences with respect to depth of the horizontal velocities (denoted d2uv) and the second
differences of the vertical velocities (d2w) were calculated for each profile. If d2uv or d2w exceeded
cruise-long 2 standard deviation thresholds, the bin was rejected.
If the standard deviation of w calculated over an entire profile exceeded a cruise-long 3 standard deviation threshold, the profile was rejected.
The result of the editing is shown in Figure 6, where good data points are plotted and missing points
appear as white space. Many of the minor blank regions correspond to SeaSoar deployments, recoveries,
or CTD stations, where the object in the water interfered briefly with one or more of the four ADCP
beams.
CALIBRATION
Sound speed
The system was configured to use sound speed calculated from the ADCP's own thermistor and an
assumed constant salinity. The ADCP thermistor (at 5 m depth) was checked against SeaSoar temperatures (from 4.5-5.5 m) when available. This revealed a mean difference of 0.44°C with no apparent
trend; the ADCP sound speeds were corrected in post-processing using this constant offset. No correction
was applied for salinity, since the largest deviation from the assumed constant salinity and the 4.5-5.5 m
SeaSoar salinities was 2.3 psu, corresponding to only a 0.2% change in sound speed. Associated uncertainties in ADCP velocity connected with temperature and salinity are negligible (<1 cm/s) compared to
other sources of error.
Attitude GPS
When bottom-tracking is not available, accurate heading information is needed to rotate ADCP
velocities from transducer to earth coordinates. The ship's gyro compass usually provides an accurate
heading in a long-term sense, but it can experience short-term drifts on the order of 1°. The largest form
of error is known as the Schuler oscillation, which tends to be excited by ship accelerations in the northsouth sense (Bowditch, 1977).
In recent years, attitude GPS receivers have been developed. These make use of phase differences
between a reference antenna and three other antennae to yield a ship's heading, pitch, and roll with poten-
tial accuracies of 0.06° (King and Cooper, 1993). Although the attitude GPS receivers are not yet reliable
12
-11
\=/
A.r-,
E 100
0
200
228
229
100
230
232
231
A
200
_:i2
t
jL
234
233
235
237
963
0
A
100
A
A
A
A
200
:001
8EZ
6£Z
£Z
i7jZ
Oi3l
It
ZZ
9.Z.
LIZ
Z
H
245
Year day 1996
Fig. 6a. ADCP ensembles remaining after editing, for E9608. Bottom depth is also shown.
El
0
E
100
a)
0
200
-
-
116
117
118
119
120
121
122
123
124
125
0
100
200
0
\-i
100
VVV
200
I0
126
127
128
129
130
131
132
133
134
135
-k
100
200
Year day 1997
Fig. 6b. ADCP ensembles remaining after editing, for E9704. Bottom depth is also shown.
14
enough to depend upon completely, in combination with the gyrocompass they are very useful. Initially
each ADCP profile uses the gyrocompass heading, as input directly into the DAS PC during data collection. Ultimately, we correct the data set by applying a set of rotation angles, one for each ensemble, based
on the difference dh between the attitude GPS and gyro headings.
The 1 Hz dh (GPS - gyro) data were edited to remove occasional noisy values in the following manner, as suggested by Firing et al. (1995): if a dh exceeded a running mean of 20 samples by more than 1°,
it was rejected. The dh as well as the GPS pitch and roll data were then averaged into 2.5 min blocks, to
match the ADCP ensemble times. Prior to using these 2.5 min average heading corrections, they were
subject to the following additional tests: the dh can not exceed 3°, the pitch can not exceed 5°, the roll can
not exceed 7°, and each 2.5 min mean must have been formed from at least 10 raw 1 Hz data points.
Gaps in the dh were filled using linear interpolation. The resulting series of heading corrections for the
two cruises are shown in Figures 7a and 7b, with interpolated values plotted as plus symbols. The dh
swings are probably associated with the numerous north-south ship accelerations experienced during
these surveys, but in a complex way. Note that the dh corrections only affect the final data set when bottom-tracking is not available. During these cruises, we had good bottom-tracking 92% of the time (indicated by the gray lines of Figure 7).
Sensitivity and Alignment
We use the bottom-track method to determine and correct for the sensitivity error /3 and the
ADCP/gyro misalignment angle a, following Joyce (1989). We assume that the bottom track velocity for
each ensemble should be equal and opposite to the ship velocity from navigation. The degree to which
this is not true provides values for a and /3.
Following some of the recommendations of Trump and Marmorino (1997), for calibration purposes
we reject cases where either the ship speed was below 1 m/s or the ship was turning significantly (if the
2.5 min mean ship heading and the momentary heading differed by more than 2°). We also apply a simple median rejection criterion to exclude outliers among the raw a and /3 estimates. For E9608, we find /3
= 0.982±0.001 and a = -1.9±0.1°. For E9704, we find /3 = 0.985±0.001 and a = -1.8±0.1°. The actual
rotation of the ADCP database velocities is complicated by the heading offset corrections. The CODAS
program rotate is used to incorporate both the dh corrections for each profile and the cruise-long a and /3.
The a values actually used for the rotate runs were -2.2° for E9608 and -2.7° for E9704, since we must
correct for both the regular a (ADCP/gyro misalignment) and the cruise-long gyro/GPS misalignments
(0.3° and 0.9° for E9608 and E9704 respectively). As a check on the processing steps, the entire calibration procedure was repeated without using the attitude GPS data, and identical results were obtained for
the ADCP/gyro calibration parameters.
At worst (at highest ship speed of 5.5 m/s), the /3 uncertainty implies an unknown bias of 0.5 cm/s
in velocity measurement, while the a uncertainty implies an unknown bias of 0.9 cm/s.
15
.228.
'229
231
:230
L
.IIuJ
Lk
f-AW
I
A1Ii
"W
w
1
I
232,
1
I
233
234
235
236
237
238
239
240
241
242
246
247
.h
Ai.A.I iI naf.41
243
244
,I
jl
W 11 19 "MINTYINI
7 TW
245
Year day 1996
Fig. 7a. Attitude GPS - gyro heading dh, for E9608. Interpolated values are plotted as plus symbols (+).
Periods of good bottom-tracking are indicated by the gray line.
16
121
122
126
127
123
124
125
129
130
134
135
`1.
131
r
Ti
132
133
Year day 1997
Fig. 7b. Attitude GPS - gyro heading dh, for E9704. Interpolated values are plotted as plus symbols (+).
Periods of good bottom-tracking are indicated by the gray line.
LT
NAVIGATION
To reference the ADCP velocities to absolute (earth) coordinates, ship velocity is determined by bot-
tom-tracking where possible; elsewhere it must be determined from navigation. In the latter case, the
uncertainty in ship velocity is the largest source of ADCP error.
Using a 16-32 m reference layer, we transfer the problem of smoothing ship velocity into the problem of smoothing reference layer velocity. We combine the smoothed ship velocity data and measured
ADCP layer velocities relative to the ship to calculate absolute motion of the reference layer (Kosro,
1985; Wilson and Leetmaa, 1988; Firing et al., 1995). The advantage of this step is that our noisy signal
is now relatively stationary; conventional linear filtering techniques are now appropriate, and we low-pass
window:
filter
in
a
robust manner
in
the
time
domain with a Blackman
w(t) = 0.42 - 0.5 cos(2,rt/T) + 0.08 cos(4nt/T), using a filter width T of 20 min. The resulting
smoothed velocities are also integrated back to obtain a new consistent and smooth set of ship positions.
This step uses the smoothr routine in the CODAS package. After this, the shear profile for each ensemble
is added to the reference layer to determine absolute velocities at all depths.
SYNOPSIS OF UNCERTAINTIES
The inherent short-term random uncertainty in an ADCP velocity for a 2.5 min ensemble and 4 m
bin is 1.2 cm/s (RDI, 1989) This form of error is reduced with further averaging. For the typical case of
5 min data, the short-term random uncertainty is reduced to 0.9 cm/s.
If bottom-tracking is available, the absolute ADCP velocity may have an unknown bias of 1 cm/s
(due to inherent limitations of the bottom-track method, RDI (1989)). If bottom-tracking is not available,
the absolute ADCP velocity may have an unknown bias of 1.4 cm/s (combination of sensitivity and alignment errors). In addition, the absolute velocity has a random error due to navigational uncertainty of ±3
cm/s and is low-pass filtered to suppress motions with time scales of less than 20 min (for features present
throughout the 16-32 m reference layer).
DETERMINATION OF SUBTIDAL FLOW
Introduction
In this region of the Mid-Atlantic Bight, we expect observed velocities to be significantly affected
by tides (Moody et al., 1984). In order to unmask the subtidal flow field, which may be of particular
interest, we estimate and then remove barotropic tidal currents from the data sets. We estimate tidal currents in the region using an empirical model fit to both the present ADCP shipboard data sets and a few
selected current meter records. A least-squares harmonic method is applied, where the tidal parameters
are fit in time and also allowed to vary spatially through polynomial surface trend interpolation. The
method is similar to the one applied to a different data set in Chapter 2 of Pierce (1998), and it is a variation on the one introduced by Candela et al. (1992).
18
For the tidal estimation, we use the velocity data sets (depth-averaged):
Name
Type
Location(s)
Time Period
Data source
E9608
Shipboard ADCP
70.03-71.42W, 39.69-41.54N
14-Aug-96 to 1-Sep-96
authors
E9704
Shipboard ADCP
69.90-70.87W, 39.81-40.90N
25-Apr-97 to 15-May-97
authors
OSU Main
Mooring
70.51 W, 40.49N
10-Jul-96 to 26-Sep-96
M. Levine/T. Boyd*
Primer
Mooring
70.10W, 40.14N
5-Dec-96 to 15-Feb-97
R. Pickart
Primer
Mooring
71.17W, 40.13N
25-Jul-96 to 4-Aug-96
R. Beardsley
*Boyd et al. (1997)
The moored records provide relatively accurate tidal information at three locations (Figure 8). The
shipboard ADCP provides less information in a temporal sense, but provides important spatial informa-
tion to the tidal solution.
Method
A least-squares harmonic method was first used in a tidal estimation problem by Horn (1960), using
a room-sized computer. By now such methods applied to stationary current meter data are routine. The
method represents the tide in the form:
N
u(t) = u0 + J[bi cos(wit) + ci sin(wit)]
(1)
i=i
where wi is the frequency of the i1h tidal constituent. Observed currents are then regressed onto (1) using
and ci which minimize the residuals. The other component, v(t), is treated similarly. We use the five primary tidal constituents [N = 5 in (1)]:
M2, S2, KI, 01, and N2. From the Moody et al. (1984) analysis of tidal records in the region, these five
constituents account for 93% of the total tidal variance.
least-squares methods to find the coefficients bi
Candela et al. (1992) recognized the inherent flexibility of least-squares methods when they suggested that bi, ci in (1) need not be constants. Tidal spatial variability can be modeled by allowing bi, ci
to be spatially-varying functions, whose unknown coefficients are determined by regression onto the
observations, as before. The specific form of the functions might reflect some dynamical knowledge of
how the tidal currents vary in space, or they might be sets of arbitrary functions which will hopefully do
well at fitting themselves to the spatial structure at hand. Candela et al. (1992) successfully use a combi-
nation of these two approaches, since they make use of arbitrary polynomials and splines but they also
normalize by 1/H, where H(x, y) is a local bottom depth. This normalization is appropriate in the shallow East China Sea and Amazon Basin (they also estimate the subtidal mean flow, by simultaneous least-
squares fitting to spatial functions with no time dependence; we fit only to the tidal flow).
19
40.8
40.7
V_._Mtra,...-.':+wi_3}'rz..-..--___tiM.FY_xe+..:-,"_dn'ri:':t; s
40.6
40.5
z
°
40.4
40.2
40.1
40.0
r.:wi.....
39.9
c.
-71.0
-70.8
-70.6
-70.4
Longitude (°W)
-70.2
.
i
39.8
-71.2
-70.0
-69.8
I
Fig. 8. Data sets used in the tidal estimation: shipboard ADCP (small dots) and moorings (filled trianales). The blue shading denotes the 50, 100, 200, 500, and 1000 m isobaths.
As in Pierce (1998), we take a similar approach but normalize u and v by
x,IH, where x, is the x-
distance from the observation to the coast and the y-axis points towards 270°T, approximately alongshore.
The Battisti and Clarke (1982) model solutions for u and v contain these terms as well, a first-order
approximation for the way a tidal Kelvin wave is modified by depth changes.
The surface-fitting polynomials take the form:
M1
+m2X+m3y+m4Xy+m5x2 +m6y2 +...
(2)
We expand b;, c; in these and then solve (1) for each velocity component u and v. Tidal ellipse parameters are then calculated from u, v using standard methods, e.g. Rosenfeld (1987). The number of terms of
(2) which can be included and successfully determined will in general vary depending on the structure
and quality of the data. We use the diagnostics provided by the singular value decomposition (SVD) to
help determine how many unknown terms we are able to solve for (e.g. Press et al., 1992). In our case,
we use the first four terms (bilinear) of the sequence (2) for M2 and K 1 and only the first term (constant)
for the other constituents. Some experimentation with adding higher degree terms led to non-physical
solutions which were also difficult for the solution machinery to produce (solution was rank-deficient).
Different from Candela et al. (1992), we estimate uncertainties for each of our data sources prior to
the least-squares calculation. These uncertainties are used to weight the different data sets appropriately
and they help determine resulting model uncertainties. For a 5-min shipboard ADCP depth-averaged
velocity, we assume apriori uncertainties of ±1 cm/s when bottom-tracking is available and ±3 cm/s when
it is not. For hourly depth-averaged current meter data we use ±1 cm/s.
Results
As expected, the M2 (12.42 hour) tidal component is the dominant one; 72% of the total tidal variance is contained here. The size of the M2 varies strongly across the region, with semi-major axes of 30
cm/s at the northeast corner of our survey region but decreasing to 2 cm/s in the southwest corner (Figure
9a). The rapid increase in tidal currents towards the northeast is consistent with previous observations;
tidal currents continue to increase to the east of our region, reaching a maximum of about 100 cm/s in the
vicinity of Georges Bank (Moody et al., 1984). The ellipses are relatively circular in our region, indicated
by the similarity in size of the semi-major and semi-minor axes (Figure 9a). The standard errors from the
least-squares calculation for the semi-major/minor axes vary from 1-3 cm/s.
The K1 (23.93 hour) component, with 16% of the tidal variance, has semi-major axes which vary
from 14 cm/s at the northeast corner to 2 cm/s at the southwest (Figure 10a). The eccentricity is more
pronounced than in the M2 case, particularly in the northeast corner.
When tidal ellipses are relatively circular, determining orientation and other angular information is
more difficult. We only present angular results where standard errors are less than 20° (Figures 9b and
10b). M2 orientation does not vary too much, while the K1 has an increasingly alongshore orientation
moving onto the shelf.
21
4U. ti
35
40.7
30
40.6
10
40.5
z
40.4
20-
°
-5
40.2
40.1
40.0
39.9
39.8
-71.0
-70.6
-70.2
-70.4
Longitude (°W)
Fig. 9a. M2 tidal ellipse semi-major (solid) and semi-minor axes (dashed), cm/s.
77
40.8
i
.60'
70
40.7
//
40.6
50
40.5
z°
/
/
if
.40'
I
40.4
-30'
r .40
-20
40.3
40.2
40.1
40.0
39.9
-50
39.8
71.0
-70.8
-70.6
-70.2
-70.4
Longitude (°W)
-70.0
-69.8
Fig. 9b. M2 tidal ellipse orientation (solid) and relative phase (dashed), °CW from alongshore. The rotation of4 the tidal ellipse is CW. Contours are only shown where the standard error is less than 20°.
40.8
40.7
40.6
40.5
II
o-I
z
40.4
0
40.2
40.1
b
40.0
11
39.9
39.8
-71.0
-70.8
-70.6
-70.4
-70.2
Longitude (°W)
-70.0
-69.8
11
Fig. 10a. K 1 tidal ellipse semi-major (solid) and semi-minor axes (dashed), cm/s.
9
24
40.8
t
`
t'
t
80
V. t t t t t
t
t l t
t
t
40.7
t
c
t
t
ta
%
'%
r _
t
t
40.6
G
40.5
z
1
40.4
S
%
'
%
%
%
%
ft
J
130
%
%%
.%
%
,
s
%
-
120
RS
40.2
40.1
40.0
39.9
39.8
0'LL-
8'0L-
-70.6
-70.2
-70.4
Longitude (°W)
0'0L-
8"69-
Fig. 10b. K 1 tidal ellipse orientation (solid) and relative phase (dashed), °CW from alongshore. The rotation of the tidal ellipse is CW. Contours are only shown where the standard error is less than 200.
SZ
40.8
40.7
40.6
40.5
z°
40.4
20 cm/s
40.2
40.1
40.0
39.9
39.8
-71.0
-70.8
-70.6
-70.4
-70.2
Longitude (°W)
-70.0
-69.8
x:0
Fig. 11. M2 tidal ellipse sizes and orientations from the Moody et al. (1984) atlas (grayshade) and the
present study (solid).
26
Results for the other three tidal constituents are much smaller, as expected for this region
,these constituents were assumed to be spatially constant by the model):
Period
% tidal
Semi-major(minor) axes
Orientation
Phase
(hours)
variance
(cm/s)
(°CW from alongshore)
(°CW)
N2
12.66
7
3.2(3.0)
-18
13
01
25.82
4
2.8(1.8)
40
48
S2
12.00
1
1.6(0.9)
51
16
Name
All of our tidal results are generally consistent with the available tidal analyses of historical current
meter records as compiled in the Moody et al. (1984) atlas. Among the comparisons shown in Figure 11,
et al. (1984) results. This level of
the M2 semi-major results have a 2 cm/s rms difference from Moody
uncertainty is consistent with the error level predicted by the least-squares machinery (1-3 cm/s), which
is a good check that our model and assumptions are reasonable.
DATA PRESENTATION
Maps
Maps of ADCP vectors at approximately 10 in increments are presented for E9608 (pp. 31-75) and
E9704 (pp. 131-165). The 4-m depth bins selected are the closest available ones to the depths of the SeaSoar property maps (5, 15, 25, ... dbar) in O'Malley et al. (1998). Each vector is a 2 km horizontal spatial
average of either the observed (grayshade) or subtidal (solid) velocity. Each map is labeled at the top with
a survey name and time period (UTC). The blue shading denotes the 50, 100, 200, 500, and 1000 in isobaths.
Sections
Vertical sections of east and north subtidal velocity are shown for E9608 (pp. 77-116) and E9704
(pp. 167-215). For contouring, we use a Barnes objective analysis scheme with 3 iterations (Daley, 1991).
The horizontal (vertical) grid spacings are 2 km (4 m), and the successive smoothing length scales are
5 km (10 m), 3.2 km (6.3 m), and 2 km (4 m). Velocity contour units are cm/s, and positive regions are
shaded. Each page includes the time period (UTC) and a small map showing the location of the section.
Soliton sections
During E9608 on 28 August 1996, approximately 24 hours was devoted to special SeaSoar/ADCP
sampling aimed at capturing internal solitary wave packets (solitons) as they propagated through the
region. During this period, the ADCP ensemble averaging time was set to just 10 s, yielding high spatial
resolution horizontally (60 m) but with larger inherent short-term uncertainty (±6 cm/s). Sections of
observed velocities during this special period appear on pp. 117-129.
The data described here are publicly available from either the online version of this report
(http://diana.oce.orst.edu/cmoweb/adcp/) or from the National Oceanographic Data Center Joint Archive
for
Shipboard
ADCP (JASADCP).
The JASADCP
27
is
accessible
through
the
web
at
http://ilikai. soest. hawaii. edu/sadcp/.
ACKNOWLEDGMENTS
We thank the crew of the R/V Endeavor for superb work under difficult conditions, in a region with
considerable ship traffic and fishing activity. We thank Marc Willis and the URI Marine Technicians for
assistance with the adaptation and installation of the 307-kHz transducer borrowed from the R/V Wecoma.
This work was supported by the Office of Naval Research Grant N00014-95-1-0382.
28
REFERENCES
Barth, J. A. and D. J. Bogucki, 1999: Spectral light absorption and attenuation measurements from a
towed undulating vehicle. Deep-Sea Res.. [submitted.]
Barth, J. A., D. J. Bogucki, A. Y. Erofeev, and J. Simeon, 1999: SeaSoar spectral light absorption and
attenuation observations during the Coastal Mixing and Optics experiment: R/V Endeavor cruises
from 14-Aug to 1-Sep 1996 and 25-Apr to 15-May 1997, Data Rep., Coll. of Oceanic and Atm.
Sci., Oregon State Univ. in preparation
Battisti, D. S. and A. J. Clarke, 1982: A simple method for estimating barotropic tidal currents on conti-
nental margins with specific application to the M2 tide off the Atlantic and Pacific coasts of the
United States. J. Phys. Oceanogr., 12, 8-16.
Bowditch, N., 1977: American Practical Navigator, Defense Mapping Agency Hydrographic Center.
Boyd, T., M. D. Levine, and S. R. Gard, 1997: Mooring observations from the Mid-Atlantic Bight, JulySeptember 1996, Data Rep. 164, Ref. 97-2, Coll. of Oceanic and Atm. Sci., Oregon State Univ.
Candela, J., R. C. Beardsley, and R. Limeburner, 1992: Separation of tidal and subtidal currents in shipmounted acoustic doppler current profiler observations. J. Geophys. Res., 97, 769-788.
Daley, R., 1991: Atmospheric data analysis, Cambridge University Press.
Erofeev, A. Y., T. M. Dillon, J. A. Barth, and G. H. May, 1998: MicroSoar microstructure observations
during the Coastal Mixing and Optics experiment: R/V Endeavor cruise from 25-Apr to 15-May
1997, Data Rep. 170, Ref. 98-3, Coll. of Oceanic and Atm. Sci., Oregon State Univ. Also available
on-line at http://diana.oce.orst.edu/cmoweb/micro/main.html
Firing, E., J. Ranada, and P. Caldwell, 1995: Processing ADCP data with the CODAS software system
version 3.1, user's manual, University of Hawaii. Manual and software available electronically at
ftp://noio.soest.hawaii.edu/pub/codas3
Horn, W., 1960: Some recent approaches to tidal problems. Int. Hydrogr. Rev., 38, 28-105.
Joyce, T. M., 1989: On in situ "calibration" of shipboard ADCPs. J. Atmos. Oceanic Technol., 6, 169-172.
Kelley, D., 1995: Gri - a program to make science graphs, user's manual, Dalhousie University. Available on-line at http://phys.ocean.dal.ca/-kelley/gri/gril.html
King, B. A. and E. B. Cooper, 1993: Comparison of ship's heading determined from an array of GPS
antennae with heading from conventional gyrocompass measurements. Deep-Sea Res., 40,
2207-2216.
29
Kosro, P. M., 1985: Shipboard acoustic current profiling during the Coastal Ocean Dynamics Experiment.,
UCSD Ph.D. thesis, SIO Ref. No. 85-8, University of California, La Jolla, Ca..
Moody, J. A., B. Butman, R. C. Beardsley, W. S. Brown, P. Daifuku, J. D. Irish, D. A. Mayer, H. O. Mofjeld, B. Petrie, S. Ramp, P. Smith, and W. R. Wright, 1984: American continental shelf, Bulletin
1611, U.S. Geological Survey.
O'Malley, R., J. A. Barth, A. Y. Erofeev, J. Fleischbein, P. M. Kosro, and S. D. Pierce, 1998: SeaSoar
CTD observations during the Coastal Mixing and Optics experiment: R/V Endeavor cruises from
14-Aug to 1-Sep 1996 and 25-Apr to 15-May 1997, Data Rep. 168, Ref. 98-1, Coll. of Oceanic and
Atm.
Oregon
State
Univ.
http://diana.oce.orst.edu/cmoweb/csr/main.html
Sci.,
Also
available
on-line
at
Pierce, S. D., 1998: Equatorward jets and poleward undercurrents along the eastern boundary of the midlatitude North Pacific, COAS Ph.D. thesis, Oregon State University, Corvallis, OR.
Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1992: Numerical Recipes, 2nd edition,
Cambridge University Press.
RDI, 1989: Acoustic Doppler current profilers principles of operation: a practical primer, RD Instruments, San Diego, Ca..
Rosenfeld, L. K., 1987: Tidal Band Current Variability Over the Northern California Continental Shelf.
WHOI Tech. Report, 87-11.
Trump, C. L. and G. O. Marmorino, 1997: Calibrating a gyrocompass using ADCP and DGPS data. J.
Atmos. Oceanic Technol., 14, 211-214.
Wilson, D. and A. Leetmaa, 1988: Acoustic doppler current profiling in the equatorial Pacific in 1984. J.
Geophys. Res., 93, 13947-13966.
30
31
E9608 Small box 1
subtidal
26 m
fir ///V
0
i
z
V
0
A
70.5
70.4
. 40.5
I
J
J
ct,
I
ct,
40.4
Iwl
40.4
Y.a
70.4
70.6
70.3
z
O)
0
40.6
z
0
0
40.5
-°0 40.5
i
p
}e!.
J
J
co
ct,
40.4
40.4
70.3
cN
70.4
Longitude (°W)
70.5"
70.4
66m
54m
70.6
70.5
70.3
I
a 40.5
!icrt I 1\\J
z°
/
z
°
70.5
dd
0
/
40.6
70.6
70.3
46 m
A
0
TA
ffr
Jca
0
c
VW
Q) 40.5
vvv Vii
ZilIi!zt
40.6
4 /1"t't
o4
i
0
0
14 m
\1
25 cm/s
t t 7 t7?
observed
15-Aug-96 23:20 to 16-Aug-96 15:27 (228.9124-229.b4d9)
C.
E9608 Big box 1
14 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
4/11,
70.2
70.4
Longitude (°W)
L
0, low .
SvVYC,avv.,
Ilk
FYI
JIIPPlIII11 /ll/f9dv«<< Lf11(12/
I
N
T
vM
C
observes
subtidal
E9608 Big box 1
26 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
0 )SOOIV0(+.
v 141 v v V1,
rrni
,. -*
70.2
70.4
Longitude (°W)
A'N
11111\l.
Vr\
I \'*'\ \ . -,,
,/// / ,o -...
/////l%I'IIl
0
11?tt 1` 1If"l'I1/li
O
-P,
O
_Pk
,.-
-06
0
I-S
25 cm/s
E9608 Big box 1
34 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
observed
subtidal
O
I
I
777
1\ I 11111 i I I 1 d rA , vm v`tV'Jvu
n\
O
N
/l1 I t I
r
rt'r
11` 1
_s
-
"It
25 cm/s
70.8
70.6
70.4
70.2
Longitude (°W)
70.0
E9608 Big box 1
46 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
subtidal
25 cm/s
I
40.6
.
Al
it
D
xl j
ti
h
40.4
It
%
3
II
40.2
1
j
40
70.8
70.6
.
70.2
70.4
Longitude (°W)
70.0
It
E9608 Big box 1
54 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
observed
l .I \\I /111rrvaasa
O
O
O
O
subtidal
70.2
70.4
Longitude (°W)
E9608 Big box 1
66 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
observed
0
70.2
70.4
Longitude (°W)
O
O
V
O
O
O
N
II/l11 i,it
T
A
O
subtidal
11I
E9608 Big box 1
x
I'
74 m ADCP, 17-Aug-96
01:59 to 18-Aug-96
09:07 (230.0833-231.3804)
observed
subtidal
i
II
40.6
I
40..4
I
I
r
40.2
Zm=
III
la,
40
70.8.
70..6
70.2
70.4
Longitude (°W)
140,
70.0
E9608 Big box 1
i
86 m
to 18-Aug-96 09:07 (230.0833-231.3804)
IR ADCP, 17-Aug-96 01:59
,observed
subtidal
I
is
i
25 cm/s
40.6
40.4
40.2
r
40
\ \\
L
70.8
70.6
70.2
70.4
Longitude (°W)
I
4
70.0
E9608 Big box 1
94 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
observed
subtidal
40.6
40.4
40.2
40
I
I
70.8
70.6
I
70.2
70.4
Longitude (°W)
42
70.0
E9608 Big box 1
106 m ADCP, 17-Aug-96 01:59 to 18-Aug-96 09:07 (230.0833-231.3804)
observed
subtidal
25 cm/s
1
40.6
40.4
40.2
40
III
70.8
70.6
70.2
70.4
Longitude (°W)
43
70.0
18-Aug-96 09:35 to 19-Aug-96 03:08 (231.3995-232.1310)
25 cm/s
0
40.5
I
z°
. 40.5
p
lI/l f
f
a
40.6
l-1fYYl
z
<<t t 1 l l
rn
40.
I
/ f rid
14 m
40.4
r
ti
70.6
70.5
70.4
70.6
70.3
70.5
70.4
70.3
J
0
cT
co
f
40.4
I
1\
fj
40.4
V\4 \1
J
ill It, I
I
40.5
VVVAMV
z
;rr
I" "..a- P PAX-rVooov
1
fl v\t,l
40.5
40.6
V
z°
t{ 1f .,wf
40.6
\\ti tit.c.L.L.
46 m
li
70.4
70.6
W
70.5
0
70.6
70.4
70.3
66m
54m
40.6
T
40.6
70.5
z
°
z°
- 40.5
70.6
70.5
70.4
Longitude (°W)
ca
40.4
70.3
70.6
A
40.4
J
I
cu
[ VM A
J
E
t%1tt 11
40.5
70.4
70.5
Longitude (°W)
70.3
9608 Small box 3
observed subtidal
0
At
1
r'
a) 40.5
r, ////
_ :- .,..
v vv
; l G Gr
}VU
. - -4. r t V
z
J
40.4
Iii
40.4
144
CO
40.6
4
J
ti
40.5
26 m
At
z
ttI,, \,,%ZL..-.
40.6
1A rr
tip.--- _
25 cm/s
20-Aug-96 01:39 to 20-Aug-96 14:40 (233.0691-233.6113)
70.6
70.5
70.4
70.6
70.3
70.5
i
40.4
70.5
70.4
j
t
S1
70.6
70.3
1JJVvv-
.1
ca
t
t
irI
J
tVvyZ1tV,
v
70.6
40
i i,%f x7`77)
40.4
rt 1t
ca
z°
.
J
40.6
_
40.5
`Mr1vVV
z
°
70.3
46 m
34 m
40.6
70.4
70.5
70.4
70.3
66m
40.6
I
40.6
z
z
0
0
I
54m
. 40 5
Q) 40.5
_0
i
l
40.4
70.6
70.5
70.4
70.3
Longitude (°W)
J
ca
40.4
I
ca
'Ju 11
i
J
I
N V,
.
70.6
70.5
70.4
Longitude (°W)
70.3
E9608 Big box 2
14 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
f.1s I1\-r
subtidal
70.2
70.4
Longitude (°W)
E9608 Big box 2
26 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
subtidal
25 cm/s
——
i
T
/
S
S
S
40.4
z
0
ti
-.-
40.2
/
40 r
70.8
70.6
70.2
70.4
Longitude (°W)
47
70.0
E9608 Big box 2
34 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
subtidal
11
IL%
lrro,1
cD
O
!e
N
O
_
,
fqIi
IT
0
cq*,
0
0
70.2
70.4
Longitude (°W)
E9608 Big box 2
46 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
1
r1>A"
, ,C'
r
70.2
70.4
Longitude (°W)
O
O
O
OD
f
{
U
O
-n
I
I
O
N
'" .: 1
1, ae
O
.
1
07
O
subtidal
E9608 Big box 2
54 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
O)
OD
O
,,- -
O
O
subtidal
70.2
70.4
Longitude (°W)
E9608 Big box 2
66 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
subtidal
25 cm/s
40.6
-pM
40.4
q
}
4
P
40.2
i
xti
f
40
All
70.8
70.6
70.2
70.4
Longitude (°W)
-51
70.0
E9608 Big box 2
74 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
0)
771
I
O
70.2
70.4
Longitude (°W)
v0
0
fl.
N\\\\
(1
O
N
JAIL /111.lidvrb
n
A
O
A
O
-N
d
subtidal
E9608 Big box 2
86 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
observed
-fl
C.
subtidal
71
11
25 cm/s
40.6
40.4
z
0
ILA
r
41
J
-30
40.2
r
H
a
L
11
70.8
70.6
70.2
70.4
#y (°W)
Longitude
1
53
70.0
E9608 Big box 2
94 m ADCP, 20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
1'
11
observed
subtidal
Jr-
Yr
rl-
V
40.6
40:4
40.2
40
-J
,r
70.8
70:6'
,1
j-
70.4
70.2
Longitude (°W)
-54
-J
70.0'
I
E9608 Big box 2
106 m ADCP,
20-Aug-96 17:03 to 21-Aug-96 21:58 (233.7107-234.9158)
I
fill Ip
Im
observed'
subtidal
25 cm/s
IL
1
40.6
I7,
1.
P
40.4
40.2
4a-
r
r
!
Ia-
C
40
70.8
70.6
70.2
70.4
Longitude (°W)
!55
70.0
E9608 Small box 4
observed subtidal
24-AUg-9(i 20:01 to 25-AUg-9b 11:34 (LO /.b i4b-2itS.4bZb)
ail
25 cm/s
26 m
17
0
II
0
(No) apnl!le-1
0
Cl?
70.6
0
70.4
N
70.5
70.5
70.3
70.4
46 m
34 m
lp
0
0
U,
a)
0
v0
(No) epnl!lal
z
r-.
J
v0
0
N-
70.5
70.4
70.3
70.6
70.3
40.
T
o
It
!
Mil
I1
0
v
-1
40.
70.3
:c I
fl
70.5
70.4
Longitude (°W)
70.4
66 m
54 m
70.6
70.5
70.6
70.5
70.4
Longitude (°W)
70.3
25-Aug-96 11:34 to 26-Aug-96 03:11 (238.4826-239.1331)
I
I
I
I
J
1
40.4
t
cu
f.
40.4
4-
I
cu
t 11 1
r
J
40.5
1Jlfir(
-3-A
V
Z
.
40.5
40.6 -
z°
r
z
°
26m
14m
t rzeLt.r_.
40.6
x 6N > > 11
25 cm/s
70.6
70.5
70.4
70.6
70.5
70.3
70.4
46m
%.!
rl
11y1
40.4
Aw*
4-4
?
40.5
/ // 'i
V
%
`
I
40.4
z°
I
'rr
ii cat
40.5
40.6
/
z
°
I IAA IT]/'
`
40.6
)(r(r
I
34m
I
^n
70.6
70.5
70.6
70.4
70.5
70.4
70.3
66 m
54 m
40.6
40.6
z°
70.6
I
40.5
J
Co
I
40.4
i l
1
co
,ell / 4
J
//'' fi'/
-°a 40.5
t
'
z°
40.4
70.6
70.5
70.4
70.3
Longitude (°W)
57
70.5
70.4
Longitude (°W)
70.3
26-Aug-96 03:11 to 26-Aug-96 16:53 (239.1331-239.7038)
25 cm/s
40.6
N
14 m
40.6
z
z
40.5
}
I
a
J
ca
J
c0
40.4
40.4
70.6
70.5
70.4
70.6
70.3
70.5
z°
/111,/I/I
O
40.6
O
U1
z°
. 40.5
p
01
70.4
O
70.5
CA)
70.6
0
O
40.4
66m
T
40.5
,
z°
C3
O
A
40.6
1
54m
V
70.3
46 m
34 m
z
°
70.4
W
a) 40.5
0
_'p
O
0
J
J
cu
A
0
O)
V
40.4
O
A
O
ca
70.6
70.5
70.4
Longitude (°W)
70.3
I
E9608 Butterfly 1
.1
9
subtidal
t
observed
26-Aug-96 23:59 to 27-Aug-96 11:12 (239.9998-240.4669)
40.6
r
X40.5
_0(D 40.5
40.4
40.4
70.6
70.5
70.4
70.3
70.5
70.6
70.4
70.3
46 m
34 m
40.6
40.6
z
z°
- 40.5
40.5
:3
:3
40.4
70.6
70.5
70.4
70.3
70.5
70.6
54 m
70.3
70.4
66 m
11
CD
Q
it
40.6
z
z
40.5
40.5
J
co
40.4
i]
40.4
y
V
f
70.6
70.5
70.4
70.3
Longitude (°W)
70.6
59
70.5
70.4
Longitude (°W)
70.3
27-Aug-96 11:12 to 27-Aug-96 21:28 (240.4669-240.8951)
25 cm/s
26m
14m
40.6
z
40.6
;
0
°'a 40.5
z
,I
0
40.5
R
2
J
J
cc
cz
40.4
70.6
70.5
70.4
70.3
70.5
70.6
70.4
70.3
46m
34m
40.6
z
z°
(D 40.5
(D 40.5
0
4-
4-
J
J
ca
co
40.4
40.4
70.5
70.4
70.3
70.5
70.6
70.4
70.3
66 m
54 m
40.6
40.6
z°
z
°' 40.5
J
J
ca
40.4
1
40.4
I
0
Q) 40.5
70.6
70.5
70.4
Longitude (°W)
70.3
70.6
70.5
70.4
Longitude (°W)
70.3
E9608 Butterfly 3
observed
27-Aug-96 23:52 to 28-Aug-96 08:51 (240.9946-241.3692)
subtidal
z°
z°
40.5
(D 40.5
J
J
40.4
40.4
70.6
70.5
70.4
70.3
70.6
70.5
70.4
70.3
46m
34m
40.6
40.6
z°
z°
a) 40.5
40.4
70.6
70.5
70.4
70.3
70.6
70.4
70.5
70.3
66m
54m
40.6
14
z
°
1
40.6
z°
. 40.5
40.
J
J
ca
co
40.4
40.4
TI
-li
70.5
70.4
Longitude (°W)
70.3
49
70.6
70.6
70.4
70.5
Longitude (°W)
70.3
E9608 Butterfly 4
0hsPrver+.
28-Aug-96 09:41 to 28-Aug-96 17:09 (241.4038-241.7152)
subtidal
ti
40.6
-40.6'
z
z
0
0
-°'0 40.5
. 40.5
J
J
W\T,\%-\
w
La
p
ca
ca
40.4
40.4
70.6
70.5
70.4
70.3
70.5
70.
70.3
70.4
11
46 m
34 m
40.6
40.6
z°
I
z
0
40.5
40.5
J
J
cu
//
0-1
40.4
70.
70.5
,r
40.4
70.4
70.3
70.4
70.3
66 m
54 m
I
40.6
-
40.6
z°
z°
- 40.5
40.5
p
J
J
co
co
40.4
40.4
I
15
70.6
70.5
70.4
70.3
Longitude (°W)
70.6
.62
'1
..
-
11
i
70.5
70.4
Longitude (°W)
t70.3
p
E9608 Small box 7
observed subtidal
25 cm/s
29-Aug-96 04:00 to 29-Aug-96 21:17 (242.1667-242.8872)
14 m
z
z
40.5
J
J
co
3
ca
J
40.6
z°
r
40.5
r-
44-
J
ca
40.4
31,
66 m
T
40.6
z
z°
0
a)
40.5
D
N14- I-tA-A N
4-
0
J
4-
J
co
40.
70.6
70.5
70.4
Longitude (°W)
70.3
Q.
29-Aug-96 21:17 to 30-Aug-96 12:10 (242.8872-243.5076)
25 cm/s
N
rn
14m
3
CD
CD
0
cy,
E9608 Small box 8
subtidal
z°
z
°
J
J
Z-z ''
i
-o
i
"
40.
co
-
ca
70.6
70.5
70.4
70.3
70.5
70.6
70.4
70.3
46m
34m
40.6
z
0
z°
(D40.5
X40.5
:3
i
=3
40.4
70.6
70.5
70.4
70.3
70.6
70.5
70.4
70.3
66 m
54 m
40.6
a
(D 40.5
i
I
z°
i
z°
T
40.6
J
J
co
i
40.4
lt
f t
A
70.6
70.5
70.4
Longitude (°W)
70.3
70.6
64
70.4
70.5
Longitude (°W)
70.3
30-Aug-96 14:52 to 31-Aug-96 05:49 (243.6196-244.2424)
25 cm/s
26m
14m
40.6
40.6
z°
z°
40.5
40.5
+-.
J
J
Co
Co
40.4
40.4
70.6
70.5
70.4
{
40.5
J
CO
-l°
40.4
70.6
70.5
z°
- 40.5
+-.
J
Co
40.4
70.4
I
it/ll1
wurilll
40.6
\N UV
4 i H1u/1f/ii -
z°
70.3
46 m
34 m
40.6
70.4
70.5
70.6
70.3
70.4
70.5
70.6
70.3
70.3
66m
54m
40.6
40.6
z°
z°
40.5
40.5
4-
J
J
co
1
I'Al-
I
/
40.4
ti
CO
70.5
70.4
70.3
Longitude (°W)
70.6
70.4
70.5
Longitude (°W)
70.3
E9608 Big box 3
14 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
11
n
,)[)served
subtidal
40.6
A'Q,:4
.40.2
Ii
v
40
r
r
A
i
70.8
70.6
70.4
70.2
Longitude (°W)
66
70.0
E9608 Big box 3
26 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
subtidal
II
I
25 cm/s
40.6
ti
r
4
40.4
T-
z°
I
40.2
40
I
A
4
70.8
70.6
70.2
70.4
Longitude (°W)
70.0
4i
E9608 Big box 3
34 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
I
1
subtidal
40.6
7
17
5
C
i
V
70.6
70.4
70.2
Longitude (°W)
I
70.8
I
40
4
40.2
I
'IN
40.4
70.0
E9608 Big box 3
46 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
subtidal
it
tL AWL
j
fi-o
0
It
N
O
O
h
0N-
70.2
70.4
Longitude (°W)
E9608 Big box 3
54 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
L-
I
b
p
N
i
I
I
11
subtidal
70.2
70.4
Longitude (°W)
E9608 Big box 3
66 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
subtidal
CO
O
ct
O
O
'N
O
d
71
0
70.2
70.4
Longitude (°W)
E9608 Big box 3
74 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
subtidal
I
r
(0
I
I V/
n=-
11
T
\\\ \ \ \
I
N-
70.4
70.2
Longitude (°W)
1V
It
E9608 Big box 3
86 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
subtidal
25 cm/s
Fs=
40.6
40.4
40.2
V,
N
40
70.8
70.6
70.2
70.4
Longitude (°W)
73
70.0
E9608 Big box 3
94 m ADCP, 31 -Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
. _r
r//rte.
1\tt,1 l
1
70.4
70.2
Longitude (°W)
v
O
,
F
\\
\_,.-1 /flt
O)
O
O
subtidal
E9608 Big box 3
106 m ADCP, 31-Aug-96 05:49 to 01-Sep-96 11:08 (244.2424-245.4640)
observed
subtidal
40.6
40.4
40.2
40
70.8
70.6
70.2
70.4
Longitude (°W)
75
70.0
77
E9608 Small Box 1
Line 1
Line 2
(km)
0
10
20
10
1
1
Line 3
(km)
0
1
50 -
100 -I
100 --
41
41
70.48 °W
70.56 °W
150-1
150 -I
40
40
70
71
200 -
East
50
Longitude (°W)
East (cm/s)
subtidal
I
0
50
50 -
100
100 -I
I
i
D
100
150
15-Aug-96 23:20 to
150-1
16-Aug-96 02:39 to
16-Aug-96 04:44 to
16-Aug-96 07:01
16-Aug-96 04:19
16-Aug-96 01:59
(228.9724-229.0833)
(229.1111-229.1799)
(229.1979-229.2928)
2.7 hours
1.7 hours
2.3 hours
200
200 -
200
40.6
70
71
200 -
subtidal
0
150 -
70
Longitude (°W)
East (cm/s)
subtidal
a
10
20
50 -
70.63°W
Longitude (°W)
(km)
0
North (cm/s)
North (cm/s
North (cm/s)
subtidal
subtidal
subtidal
40.5
Latitude (°N)
%R
40.4
40.5
Latitude (°N)
79
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 1
Line 4
10
20
50 -
Line 6
Line 5
(km)
0
20
(km)
0
10
50 -
100-i
100 -
41
41
41
10
20
50 -
(km)
0
70.27 °W
70.35 °W
70.41 °W
150 J
71
200 -
40-i
40 -
40 --
70
Longitude (°W)
71
200
70
Longitude (°W)
Longitude ("W)
East (cm/s)
East (cm/s)
East (cm/s)
subtidal
subtidal
subtidal
50 -
50 -
100 -
100 -
150 -
70
71
200 -
16-Aug-96 07:31 to
16-Aug-96 11:13 to
16-Aug-9610:35
16-Aug-96 13:10
150
-
16-Aug-96 13:38 to
16-Aug-96 15:27
(229.3132-229.4416)'_
(229.4680-229.5488)
(229.5681-229.6439)
3.1 hours
1.9 hours
1.8 hours
200
200
subtidal
40.5
Latitude (°N)
North (cr»/s)
North (cm/s)
North
Tim
subtidal
sUbtidal
40.4
40.4
40.5
Latitude (ON)
80
40.6
40.5
Latitude (°N)
.
.40:4
E9605 Big BOX 7
Line B
70
60,
50
.40
30'
:20
I
I
I
I
I-
d
I
50-
100
i{
am
:41
®
70.62.6W
z
150
-1 v
&'7
71
200
70
Longitude (°W)
East (cm/s)
subtid4
0
50
100
150
18-Aug-96 01:28 to
18-Aug-96 07:21
(231.0613-231.3068)
5.9 hours
200 -
North '(cm/s)
subtidal
40. &.
40.7
40.6:
40.5
Latitude (°N)
40.4
Si
40.3.
40:2
E9608 Big Box 1
Line C
(km)
i6`
30
40
E 100
am
0
41
70.48 °W
z
150
v
J
40 -
71
70
Longitude (°W)
17-Aug-96 20:12 to
18-Aug-96 00:36
(230.8417-231.0255)
4.4 hours
40.6
40.5
40.4
Latitude (°N)
40.3
4022
82
E9608 Big Box 1
Line D
.8A
60
70
50
(km)
40
30
20
10
17-Aug-9613:42 to
17-Aug-96 19:24
(230.5715-230.8085)
5.7 hours
North (c(n/s)
subtidal
40..6
40.5
-40.4
40.1Latitude (°N)
83.
40:2:
.40:1
40.0
0
E9608 Big Box 1
Line E
80'
70
40
50
60
(km)
30
20
10
0
70.20 *W
n
'17-Aug-96 07:00 to
17-Aug-96 12:42
(230.2919-230.5292)
5.7 hours
North (cm/s)
I
.
-
-
a,
'40.6
40.5
40.4,,
aubtidal_
40.3
Latitude (°N)
8.4
40.2.
40:1
4,0.0
E9608 Big Box 1
Line F
60
50
l
I
40
30
20
10
(km)
0
1
41
70.06 °W
40 71
70
Longitude (°W)
17-Aug-96 01:59 to
17-Aug-96 06:10
(230.0833-230.2575)
4.2 hours
40.6
40.5
40.4
Latitude (°N)
40.3
40.2
85
E9608 Small Box 2
Line 1
10
20
(km)
0
Line 2
20
Line 3
(km)
0
10
71
70
Longitude (°W)'
East (cm/s)
'East (cm/s)'
subtidal
subtidal
18-Aug-96 09:35 to
18-Aug-96 11:59 to
18-Aug-96 11:31
18'--`Aug-9613:44
0
70.48 °W
70.55 °W
70
Longitude (°W)
(km)
10
20
70
Longitude (°W)
East (cm/s)
suttidal
18-Aug-96 14:12 to
18-Aug-96 16:05
(231.3995-231.4801)
(231.4994-231.5725)
(231.5923-231.6708)
1.9 hours
1.8 hours
1.9. hours
North (cm/s
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
86
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 2
Line 4
1
20
0
10
20
Line 5
(km)
(km)
0
10
20
0
10
50-1
50
Line 6
(km)
50'
100
41
41
150 -
150 -
70.27 °W
70.35 °W
70.41 °W
150
v
Jm
.40
40
70
71
200 -
200 -
Longitude (°W)
East (cm/s)
subtidal
i
i
0
i
50 -
50 -
50 -
100 -
150-i
100
100 -1
150
18-Aug-96:18:02 to
150 -
S-Aug-96 21:06 to
18-Aug-96 19:42
1
1.7 hours
200 -1
19-Aug-96 01:45
(31.8797-231.9667)
(231.9909-232.0732)
2.1 hours
2.0 hours
20'0
subtidal
40.5
Latitude (°N)
18-Aug-96 23:46 to
X18-Aug-96 23:12
(231.7515-231.8211)
North (cm/s
200
East (cm/s)
subtidal
0
70
71
Longitude (°W)
T
40.4
200 -
North (cm/s
North (cm/s).'
subtidal
40.5
Latitude (°N)
87
--T40.4
40.6
subtidal
1
40.5
Latitude (°N)
40.4
E9608 Small Box 3
Line 1
20
Line 2
(km)
10
20
0
Line 3
(km)
20
0
10
(km)
0
10
0
50
50-
50 -
100 -
100-.
41
41
70.63 °W
70.48 °W
70.55 °W
z
150 -
m
f 150 - am
150 -
Jcu
Jco
40 -
40
71
200 -
70
Lo ng itud e (°W )
40 -
71
200 -
70
Longitude (°W)
200
-
71
70
Longitude (°W)
East (cm/s)
East (cm/s)
East (cm/s)
subtidal `-
subtidal
subtidal
0
0
50 -i
100 -
150 -
100 -
100-1
14-40",
150-i
X20-Aug-96 10:30 to
20-Aug-96 08 k17 to
20-Aug-96 10:05
20-Aug-96 12:13
(233.5335-233.6113)
(233.4376-233.5096)
(233.3453-233.4203)
1.9 hours
1.7 hours
1.8 hours
200 -
40.6
50 -
150-i
20-Aug-96 12:48 ,to
20-Aug-96 14:40
50
200 -i
200 -
North (curs)
North (curls)
North (cm/s)
subtidal
subtidal
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
88
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 3
Line 4
0
10
20
Line 5
(km)
50 -I
20
Line 6
(km)
0
10
20
(km)
10
0
50 -
100 -
I
41
I
41
150-I
70.27 °W
70.35 °W
70.41 °W
C
150 -I
J
40 -I
40 -
I
70
71
200 -
71
Longitude (°W)
200 -
70
Longitude (°W)
East (cm/s)
East (cm/s)
subtidal
subtidal
Longitude (°W)
50 -
100 -
150 -
06:04 to
20-Aug-96 01:39 to
20-Aug-96 03:56 to
20-Aug-96 03:27
20-Au 96 05:40
20-Aug-96 07:51
(233.2530-233.3273)
(233.1642-233.2363)
(233.0691-233.1440)
1.8 hours
1.7 hours
1.8 hours
200 -
North (cm/s)
North
subtidal
subtidal
T
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
89
40.4
40.5
Latitude (°N)
40.4
E9608 Big Box 2
Line A
70
.
50
'60
30'
40
70:
Al
70.77 OW
East (cm/s)
subtidal
ai
20-Aug-96 17:03 to
20-Aug-96 22:18
(233:7107-233.29,7
5.3 hours
North (cm/s)
subtldal
40.3
40.2
Latitude (°N)
90
E9608 Big Box 2
Line B
80
40
(km)
0
10
30
100
s
a
m
0
70.63 °W
.71
200
70
Longitude (°W)
East (cm/s)
subtidal
0
......
20-Aug-96 23:06 to
21-Aug-96 04:53
(233.9627-234.2035)
5.8 hours
North (cm/s)
subtidal
40.6
40.5
40.4
40.3
Latitude (°N)
91
40.2
40.1
40.0
E9608 Big Box 2
Line Cl
70
60
50
20
30
40
10
(km)
0
70.48
200
0
21-Aug-96 05:43 to
21-Aug-96 11:11
(234.2384-234.4660)
5.5 hours
North (cm/s)
subtidal
40.6
40.5
40.4
40.3
Latitude (°N)
40.2
92
40.1
40.0
E9608 Big Box 2
Line C2
70
50
60
40
20
30
E 100
a
a>
0
150
21-Aug-96 13:01 to
21-Aug-96 19:35
(234.5424-234.8163)
6.6 hours
40.6
40.5
40.4
40.2
40.3
Latitude (°N)
93
10
(km)
0
E9608 Big Box 2
Line D
20
.0 L
10
(km)
0
I
::50-
41
70.35 °W
z
1-50 -{
40
73
200 -
7O
Longitude (°W)
East (cm/s)
subtidal
0
50
-
100 -
1'50 -a
21-Aug-96 20:23 to
21-Aug-96 21:58
(234.8498-234.9158)
1.6 hours
North (cm/s)
ubtiaal
40.5
40.6
Latitude (°N)
94
E9608 Small Box 4
Line 1
Line 2
(km)
20
0
10
(km)
0
10
Line 3
(km)
0
10
100
s
CL
I
41
70.63 °W
4
I
70
Longitude (°W)
70
71
70.48 °W
70.55 °W
Longitude (°W)
200
Longitude (°W)
East (cm/s)
subtidal
25-Aug-96 07:30 to
25-Aug-96 09:21
25-Aug-96 03:01 t.
25-Aug-96 05:18 to
25-Aug-96 04:55
25-Aug-96 07:07
(238.3127-238.3899)
(238.2215-238.2966)
(238.1258-238.2052)
1.9 hours
1.8 hours
1.9 hours
North (cm/s)
Imo
subtidal
40.5
Latitude (°N)
40.5
Latitude (°N)
95
I
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 4
Line 4
Line 5
(km)
20
0
10
Line 6
(km)
10
(km)
10
0
0
100'-i
70.27'°W
70.35 °W
------ .r
70
Longitude (°W)
71
70
Longitude (°W)
200
70
Longitude ('W)
East (cm/s)
East (cm/s)
East (cm/s)
subtidal
subtidal
subtidal
``'
-
25-Aug-96 00:51 to
24-Aug-96 20:01 to
24-Aug-96 22:42 to
24-Aug-96 22:14
25-Aug-96 00:27
25-Aug-96 02:37
(238.0358-238.1093)
(237.9461-238.0192)
(237.8345-237.9264)
1.8 hours
1.8 hours
2.2 hours
200 -1
40.5
Latitude (°N)
40.4
North (cm/s
North (cm/s)
subtidal
subtidal
40.5
Latitude (°N)
96
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 5
Line 1
.20
Line 2
(km)
10
20
0
Line 3
(km)
20
J"
10
(
(km)
10
0
0
'50 -
w
r
100
t
100 -1
F
,4J
41
4.1
70.62 °W
70.48 °W
70.55 °W
Z
1:50-{
Z
m
v
1'50
150
a
m
J
40-
.40 -
71
200
7.0'
40 70
71
Longitude (°W)
200
71
Longitude (°W)
East (cm/s)
tzi
subtidal
200
East (cm/s)
70
Longitude (°W)
° East (cm/s)
subtidal
k
subtidal
.0
50
50
100
150
50
1-0.0-
150
25-Aug-96 23:14 to
100
1-50 -
25-Aug-96 20.51 to
26-Aug-96 01:05
25-Aug-96 18:38 to
25-Aug-96 20:24;
25-Aug-96 22:48
,(238.9686-239.0458)
(238.8690-238.9505)
(238.7766-238.8505)
1.9 hours
2.0 hours
1.8 hours
200
'200
-I
2b0 -#
North (cm/s)
North (cm/s)
North (cm/s)
subtidal
stjbtidal
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
97
40.4
40.5
Latitude (°N)
V
40.4
1
E9608 Small Box 5
Line 4
20
Line 5
(km)
20
0
10
Line 6
(km)
L
1
2
50-1
0
10
20
0
10
(km)
50-1
100 -
100 -i
41
41
41
70.35 °W
70.41 °W
0
r
150
150 -
R
J
J
40-
40
40
70
71
200 -I
150 -
a)
71
200
Longitude (°W)
East (cm/s)
g.,
_.:.
70
Longitude (°W)
70
Longitude (°W)
71
200
East (cm/s)
East (cm/s)
subtidal
subtidal
subtidal
i
1
1
v
50-i
50
100-4
150-i
100
150-1
25-Aug-96 16:17 to
25-Aug-96
25-Aug-96 13:59 to
25-Aug-96 13:31
25-Aug-96 15:52
25-Aug-96 18:14
(238.6786-238.7604)
(238.5828-238.6616)
(238.4826-238.5637)
2.0 hours
1.9 hours
1.9 hours
200 -
200
North (cm/s)
North (cm/s)
subtidal
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
98
No
.
(c
s)
subtidal
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 6
Line 1
20
20
0
10
Line 3
Line 2
(km)
(km)
0
10
(km)
0
10
1,0:0 -
70.63 °W
70.48 °W
70.55 °W
1'50 -
40
0
70
Longitude (°W)
71
200 ,r
I
70
71
2001
Longitude (°W)
'East (culls)
East (cm/s)
subtidal
subtidal
f
i
50 -
, 100'--
100 -
150-1
26-Aug-96 14:4& to
26-Aug-96 16:53
26-Aug-96 12:14 to
6=Aug-96 09:57 to
26=Aug-96 14:21
[email protected]:48
(239.6169-239.7038)
(239.5100-239.5981)
(239.4148-239.4919)
2.1 hours
2.1 hours)
1.9 hours
200
200
North (cmis)
North (cm/s)
subqaf
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
99
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 6
Line 4
20
0
10
20
Line 5
(km)
0
10
100 -
100 -
41
41
41
70.27 °W
70.35 °W
70.41 °W
150-
(km)
0
10
20
50-I
50
50 -
Line 6
(km)
50 -'r v
1504'-'
m
150 -
C
m
J
J
40
71
200 -
0
70
Longitude (°W)
70
Longitude (°W)
71
200 -i
East (cm/s)
East {cmis )
subtidal
subtidal
1
71
200
70
Longitude (°W)
East (cm/s)
W
subtidal
1
50 -i
50 -
100 -
150 --1
40 -
40 -
50
100-1
100 -
26-Aug-98 0
150-
to
I
150-i
26-Aug-96 05:20 to
26-Aug-96 04:55
26-Aug-96 07:08
26-Au -96 O r 3O.
(239.1331-239.2053)
(239.2224-239.2979)
(239.3134-239.3964)
1.7 hours
"1.8 hours
4'2.0 hours
200 -
200 -
200 -1
North (cm/s)
North (cm/s)
subtidal
subtidal
I
40.5
Latitude (°N)
40.4
26-Aug-96 03:11 to
40.5
Latitude (°N)
100
North (cm/s)
subtidal
I
40.4
40.5
Latitude (°N)
40.4
E9608 Butterfly 1
NS
10
20
I
1
0
(km)
0
50 -I
41
70.49 °W
150 -
40 -I
71
200 -
70
Longitude (°W)
East (cm/s)
subtidal
27-Aug-96 07:16 to
27-Aug-96 09:46
(240.3029-240.4072)
2.5 hours
40.6
40.5
Latitude (°N)
101
E9608 Butterfly 2
NS
30
20
(km)
0
10
1
0
50
41
70.49 °W
o150 -
40 71
200 -
70
Longitude (°W)
East (cm/s)
subtidal
0
C
50 -
100 -
150-i
27-Aug-96 17:31 to
27-Aug-96 20:00
(240.7299-240.8335)
2.5 hours
200 -I
North (cm/s)
--F40.6
subtidal
40.5
Latitude (°N)
40.4
102
E9608 Butterfly 3
NS
(km)
20
30
0
10
41
70.49 °W
.11
150 -
40
71
200 -
70
Longitude (°W)
East (cm/s)
subtkial
0
11
-100
I
150 -
28-Aug-96 04:49 to
28-Aug-96 07:19
(241.2007-241.3052)
2.5 hours
200 -
North (dalNs)
subtidal
40.6
40.5
Latitude (°N)
'4,0:4
.103,
E9608 Butterfly 4
NS line 1
10
NS line 2
(km)
0
10
20
(km)
0
50 -
70.56'W
150 -{
yl
70
Longitude (°W)
East (cm/s)
subtidal
28-Aug-96 14:53 to
28-Aug-96 17:09
(241.6202-241.7152)
2.3 hours
200 -
North
°._
40.4
Latitude (°N)
40.2
104
40.4
40.3
Latitude (°N)
40.2
E9608 Small Box 7
Line 1
20
Line 2
(km)
0
10
20
Line 3
(km)
10
'20
(
(km)
10
0
0:-
.50 -
'50
50
-
t.
100
100 -
41
41
41.
70.63 °W
150 -
-
150
150
CD
70.48 °W
70.55 °W
J
J
40 -=
71
.200
40
40
70
Longitude ('W)
71
200 -1
70
Longitude (°W)'
7.1
.20:0
1-=East (crim/s)
East (cm/s)
.e subtidal
East (cna/s)
subtidal
70
Longitude (°W)
subtidal
0
0
0
50
50
50-
100
1.00 -
1°00 -t
150-I
150 -
i
r
C
}
29-Aug-96 16:42 to
29-Aug-9618:0,.
150-i
29-Aug-9614:18 to
29-Aug-96' 12:00 to
29-Aug-96 13:52
29-Aug-96 16:14
(242.6960-242.7851)1
(242.5963-242.6770)
(242:5000-242.5783)
2.1 hours
1.9 hours,
1.9 hours
200-,
200 -
North
subtidal
40.5
Latitude (°N)
40.4
2100
North (cm/s)'
North (cm/s)
subllial',
subtidal
40.5
Latitude (°N)
inc
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 7
Line 4
0
10
20
Line 5
(km)
20
Line 6
(km)
10
l
50 -
50-
50 -
100-1
100-i
41
41
41
70.27 °W
70.35 °W
70.41 °W
150-I
150 - a)
(km)
0
10
20
J-
(
r
150 -I
J
1
71
200 -1
40
40 -1
40
70
Longitude (°W)
71
200 -
70
Longitude (°W)
71
200
70
Longitude (°W)
East (cm/s)
East (cm/s)
East (cm/s)
subtidal
subtidal
subtidal
0 -t
50 -
50 -1
50 -
100 -
100 -
100 -i
150-1
150-1
29-Aug-96 09:28 to
150 -I
29-Aug-96 06:55 to
29-Aug-9605:53
29-Aug-96 09:03
29-Aug-96 11:33
29-Aug-96 04:00 to
(242.3946-242.4815)
(242.2884242.3775)
(242.1667-242.2454)
2.1 hours
2.1 hours
1.9 hours
200 -1
200 -
200 -
North (cm/s)
North (cmls)
subtidal
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
106
North (cmls)
subtidal
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 8
Line 1
10
20
(km)
0
Line 2
20
Line 3
(km)
10
(km)
0
10
20
50
41
70.47 °W
70.55 °W
70.63
150
40 70
Longitude (°W)
70
Longitude (°W)
200
70
71
Longitude (°W)
East (crrn/s)
East (cm/s)
subtidal
subtidal
50
100
150
30-Aug-96 04:38 to
30-Aug-96 10:06 to:,
-y
30-Aug-96 12:10 =::
30-Aug-96 06:52
(243.4210-243.50766)
(243.1932-2412862
2.1 hours
2.2 hours
200
40.6
North (cm/s)
North (cm/s
subtidal
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
107
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 8
Line 4
20
Line 5
(km)
20
0
10
50 -
10
-
(km)
0
10
20
(1
i
.50
Line 6
(km)
.
50-
100-I
loo-
41
'41
41
70.27 °W
70.35 °W
70.41 °W
z
150 Ji
150 -
150 -
J
40
40 -
70'
71
200 -
71
Longitude (°W)
200
40
70
Longitude (°W):
71
200
70
Longitude (°W)
Eas (cm/s)
--East (cm/s)
-Era "t (CM/S)
subtidal
subtidal
subtidal
0
100-I
100
1,00, -1
150-i
.50 -
50 -
5
150 -
30-Aug-96 02:09 to
150 -
29-Aug-96 23:53 to
29-Aug-96 23:24
30-Aug-96' 01:43
30-Aug-96 04:11
29-Aug-96 21:17 to
(243.0900-243.1743)
(242.9953-243.0722)
(242.8872-242.9753)
2.0 hours
1.8 hours
2.1 hours
200 -
2.00-1
'200'
North' (mils).,
North (cm/s)
subtidal -
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)'
1108
North (ctnls)
subGdal__
404
40.5
Latitude (°N)
40.4
E9608 Small Box 9
Line 1
Line 2
(km)
0
10
20
-7.1
70
Longitude (°W)
0
70.49
70.55 °W
70
Longitude (°W)
(km)
10
0
10
70.63'°W
Line 3
(km)
71`
70
Longitude (°W)
:East (cm/s)
East (cm/s)
East (cm/s)
subtidal
subtidal
subtidal
100 -
31-Aug-96 02:56 to
30-Aug-96 22:08 to
31-Aug-96 00:26 to
31-Aug-96 04:53
30-Aug-96 23:59
31-Aug-96 0229
(244.1229-244.2039)
(244.0182-244.1036)
(243.9229-243.9996)
1.9 hours
2.0 hours
1.8 hours
North (cm/s)
subtidal
40.5
Latitude (°N)
40.4
40.5
Latitude (°N)
109
40.4
40.5
Latitude (°N)
40.4
E9608 Small Box 9
Line 4
Line 5
(km)
0
10
20
_i11
b
Line 6
(km)
10
0
10
(km)
0
II
100 -,
70.27 °W
70.35 °W
70.41 °W
z
.150
J
40
.71
200 -
70
Longitude (°W)'
7Q
70
71
200
200 -1
Longitude (°W)
East (cm/s)
East (cm/s)
subtidal
subtidal
Longitude (°W)
East `(cim/s)' subtidal
0
vi
50.-
..50-Y
'50 -
100 -
100 - .
100 -
30-Aug-96 19:53 to
t50, -
1;50 -j
30-Aug-96 17:19 to
30-Aug-96 16:51
3q Aug-96 19:23
30-Aug-96 21:45
30-AUg-9614:52 to
4
(243,8285-243.9064)
(243;7216-243.8080)
1.9 hours
2.1 hours
(2416196-243.7022)
2.0 hours
26o4
North (cm/s)
,subtidalI
40.5
40.4
Latitude (°N)
200. -
North (d
North
subtidal
subticfa)
'40.5
Latitude (°N')
110
40.4
40.5
Latitude (°N)
40.4
E9608 Big Box;]
Line CO
20
10
(km)
0
50 -
41
70.47 °W
z
150-1
CD
V
J
03
40
71
200
70
Longitude (°W)
31 -Aug-96 05:49 to
31-Aug-96 08:02
(244.2424-244.3352)
2.2 hours
40.4
40.5
Latitude (°N)
111
E9608 Big Box 3
Line Cl
70
60
I
I
40
50
30
20
10
(km)
0
I
E 100
70.48
71
200
70
Longitude (°W)
0
31-Aug-96 09:00 to
31-Aug-96 14:28
(244.3755-244.6034)
5.5 hours
North (cn
subtidal
40.3
40.2
40.1
40.0
Latitude (°N)
39.9
112
39.8
39.7
E9608 Big Box 3
Line C2
20
(km)
0
10
41
70.49 °W
40 -I
71
70
Longitude (°W)
100-I
150-
01-Sep-96 08:32 to
01-Sep-96 11:08
(245.3560-245.4640)
2.6 hours
200 -I
North (cm/s)
subt.itlal
40.6
40.5
Latitude (°N)
40.4
113
E9608 Big Box 3
Line Ds
40
30
20
10
(km)
0
1
41
70.35 °W
J
40 71
70
Longitude (°W)
31-Aug-96 15:23 to
31-Aug-96 19:00
(244.6415-244.7923)
3.6 hours
40.1
40.0
39.9
Latitude (°N)
39.8
114
E9608 Big Box 3
Line Es
40i
10
(km)
0
41
70.20 °W
40-i
71
70
Longitude (°W)
31-Aug-96 20:06 to
31-Aug-96 23:29
(244.8379-244.9790)
3.4 hours
40.0
39.9
Latitude (°N)
115
E9608 Big Box 3
Line F
60
50
40
30
10
20
(km)
0
i
41
70.06 °W
40
71
70
Longitude (°W)
01-Sep-96 00:21 to
01-Sep-96 04:46
(245.0152-245.1987)
4.4 hours
40.3
40.2
40.1
40.0
Latitude (°N)
39.9
116
39.8
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