NOAA Data Report ERL PMEL-67

TOGA-TAO Shipboard ADCP Data Report,

1991–1995

Eric S. Johnson1 and Patricia E. Plimpton2

1Earth and Space Research

1910 Fairview Ave.E.

Seattle, WA 98102

2NOAA/Pacific Marine Environmental Laboratory

7600 Sand Point Way NE

Seattle, WA 98115

May 1999

Contribution 2086 from NOAA/Pacific Marine Environmental Laboratory
NOTICE

Mention of a commercial company or product does not constitute an endorsement by

NOAA/ERL.Use of information from this publication concerning proprietary products or the

tests of such products for publicity or advertising purposes is not authorized.

Contribution No.2086 from NOAA/Pacific Marine Environmental Laboratory

For sale by the National Technical Information Service, 5285 Port Royal Road

Springfield, VA 22161

ii
Contents iii

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. Data Preparation . . . . . . . . . . . . . . . . . . . . . . . . . 2

3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 3

5. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figures and Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

List of Figures

1a Figures 1a–f show the locations of fully navigated ADCP data for

each cruise by latitude and longitude .................. 7

1b Same as Figure 1a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1c Same as Figure 1a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1d Same as Figure 1a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1e Same as Figure 1a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1f Same as Figure 1a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2a Figures 2a-k show sections of zonal and meridional velocity from each

roughly meridional section of cruise track ............... 13

2b Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2c Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2d Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2e Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2f Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2g Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2h Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2i Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2j Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2k Same as Figure 2a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

List of Tables

1 The dates (day-month-year) of the southernmost, equatorial, and

northernmost data included in each plotted section. ......... 6
iv Contents
TOGA-TAO Shipboard ADCP Data Report, 1991–1995

Eric S. Johnson1 and Patricia E. Plimpton2

1. Introduction

Since 1979 the variability of the tropical Pacific Ocean has been studied using

arrays of moored instruments.The several equatorial moorings of the Equatorial Pacific Ocean Climate Studies (EPOCS) program grew into a tropical

array during the Tropical Ocean Global Atmosphere (TOGA) program, and

most recently into the larger Tropical Atmosphere Ocean (TAO) array of the

El Ni ̃no/Southern Oscillation (ENSO) observing System.The present array,

consisting of nearly 70 moorings spanning the width of the Pacific from 8◦N

to 8◦S, is designed to provide atmospheric data and oceanic temperature and

current velocity data which resolve the large-scale variability of the tropical climate system, both as a means of increasing our understanding of the

physics involved and to enable successful modeling and prediction of the interannual variability related to ENSO.While the array itself cannot resolve

smaller-scale processes, some of which (e.g., tropical instability waves) contribute significantly to the larger-scale physics, it nevertheless provides the

background against which more detailed investigations can be undertaken.

In addition, the TAO array is periodically maintained by ship, and these

repeat cruises form an ideal vehicle for collecting ancillary data sets such as

the acoustic Doppler current profiler (ADCP) data discussed in this report.

The shipboard ADCP data provide a direct measure of the velocity field over

a significant portion of the basin.Moreover, the fine vertical and horizontal

scales of the ADCP velocity profiles provide a powerful tool for investigating

smaller-scale phenomena.

Briefly, the ADCP instrument uses acoustic pulses to measure the horizontal velocity of the water below the hull of a ship as a function of depth.

Since the instrument functions continuously with very little oversight, it

inexpensively collects a large amount of data covering all spatial scales as

the ship transits from mooring to mooring.The ADCP velocities are measured relative to the ship itself rather than to the earth; thus for the ADCP

velocities to be useful, additional data must be collected from which the

ship’s velocity can be determined and then subtracted from the ADCP relative velocities to give absolute velocities.A fuller treatment of ADCP data

preparation can be found in Luther and Johnson (1990).

The present data consist of approximately twice-yearly cruises by the

NOAA ship Discoverer along each of the instrumented longitudes in the

tropical Pacific, generally from 8◦S to 8◦N, together with transit legs to and

from various ports (Figure 1a–f).The first usable data were collected in

1991 along a few longitudes, with the number of sampled longitudes grow1Earth and Space Research, 1910 Fairview Ave. E., Seattle, WA 98102

2NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle,

WA 98115
2 Johnson and Plimpton

ing through the years along with the TAO array (e.g., McPhaden et al.,

1998).Depth coverage extends from 19 m down to around 300 m, depending on acoustic conditions.Navigation data consist of Global Positioning

System (GPS) fixes and gyrocompass headings.The ADCP installation

on the Discover was plagued by interference from bubbles entrained in the

ship’s boundary layer at higher speeds.Installation of a fairing to divert the

boundary layer around the transducer reduced the problem to an intermittent nuisance.

2. Data Preparation

Preparation of the PMEL data consists of three stages: the timing adjustment, the navigation of the data, and the calibration of the ADCP.Each

1-minute ADCP ensemble is recorded with a GMT timing mark, but these

times are derived from the recording computer’s internal clock, which is

subject to a constant drift and to operator resets.The ADCP time marks

are corrected to true GMT using the integrally recorded GPS navigational

fixes that include accurate GMT time.At the same time the measured relative velocities are corrected for the true speed of sound at the transducer,

determined using the water temperature as measured by the instrument’s

thermistor and an assumed salinity of 35 psu.In situations where the thermistor was not working the speed-of-sound correction cannot be carried out,

but its cruise-averaged value and the broadest scales of its spatial variability

are necessarily incorporated in the time-dependent instrument calibration

detailed below.

After the ADCP time marks are corrected the ship’s velocity is determined using the ancillary GPS fixes.The resulting ship’s velocities are

subtracted from the ADCP relative velocities to give absolute water velocities in a deep reference layer (139–195 m), chosen to minimize the expected

spatial variability of currents without severely taxing the instrument’s depth

range.Both computer and hand editing of the resulting velocities are used

to eliminate obviously bad fixes, whereupon the data is renavigated until

results are satisfactory.

The resulting reference layer velocities are used to calibrate the ADCP

instrument for heading offsets and gain errors.The data are searched by

computer for hour-long intervals containing large variations in ship’s velocity.These intervals are used to estimate the heading bias and gain error of

the instrument as in Joyce (1989).The calibrations are edited for obvious

outliers, filtered heavily in time to remove time scales shorter than 1.6 days,

and fed back into a final, clean navigation of the data.

Routine navigational noise is then further reduced by time filtering the

clean reference velocities to eliminate periods shorter than 2 hours (time

scales shorter than 20 minutes), corresponding to space scales shorter than

8 km when the ship is underway at 12 knots.Note that this filtering cannot

be done at any earlier stage of data preparation since the ADCP relative

velocities and ship velocities contain large, rapidly varying signals associated with ship maneuvers.Filtering such maneuvers would aliase differences
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 3

in sampling rate and coverage between the ADCP and the GPS data into

spurious velocities, as well as eliminating the possibility of instrument calibration.Once the filtered reference level velocity is determined the velocities

at other depths are built up using the observed shears in each profile; the

results are the ADCP absolute velocities.

Some cleaning of the data takes place during the navigational process:

data that cannot produce reasonable reference layer velocities are flagged as

unnavigable.However, additional sources of noise and error, such as the bubbles while underway and lowered instruments while on station, are present

in the data.Users must be aware of such potential limitations and test for

those that might affect their particular analysis.The data are archived in

original depth bins rather than re-gridded, so depths are not corrected for

the small (∼2%) difference between nominal and local speed of sound.Velocity, AGC, and percent good are recorded at all depths: the shallowest bin

is centered at 19 m depth, with each succeeding bin located 8 m deeper.The

combination of 8 m bin width and 8 m pulse length results in a triangular

response function spanning 16 m depth.Thus the response functions of the

successive depth bins overlap by 50%.

Roughly meridional sections of velocity data are shown in Figure 2.Sections are presented in chronological order; each comprises about a week of

data (Table 1).

3. Conclusion

The collection and processing of shipboard ADCP data from equatorial

cruises by the NOAA ship Discoverer have produced 41 meridional sections of absolute velocities for zonal and meridional currents.The sections

were along eight different longitudes in the Pacific Ocean between 95◦W and

165◦E during the period from 1991 to 1995.The sections have been incorporated into the NODC data base of shipboard ADCP measurements located

at the University of Hawaii.

4. Acknowledgments

We would like to thank the Pacific Marine Center engineers who installed and

maintained the ADCP on the NOAA ship Discoverer.We also appreciate the

diligent work of the Discoverer’s officers and survey technicians, who oversaw the

ADCP operation during the cruises.This work was supported by NASA grant

NAGW-5035 and by the TAO Project Office.

5. References

Joyce, T.M. (1989): On in situ “calibration” of shipboard ADCPs. J. Atmos.

Oceanic Tech., 6, 169–172.

Luther, D.S., and E.S. Johnson (1990): Eddy energetics in the upper equatorial

Pacific during the Hawaii-to-Tahiti Shuttle Experiment. J. Phys. Oceanogr.,

20, 913–944.
4 Johnson and Plimpton

McPhaden, M.J., A.J. Busalacchi, R. Cheney, J.R. Donguy, K.S. Gage, D. Halpern,

M.Ji, P.Julian, G.Meyers, G.T.Mitchum, P.P.Niiler, J.Picaut, R.W.

Reynolds, N.Smith, and K.Takeuchi (1998): The Tropical Ocean Global Atmosphere observing system: a decade of progress. J. Geophys. Res., 103(C7),

14,169–14,240.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 5

FIGURES AND TABLES
6 Johnson and Plimpton

Table 1: The dates (day-month-year) of the southernmost, equatorial, and northernmost data included in each plotted section.

Cruise and Latitude Southern Equatorial Northern

TOGA91 155◦W 22-07-91 19-07-91 14-07-91

TOGA91 160◦W 22-07-91 24-07-91 26-07-91

EP391 110◦W 31-10-91 28-10-91 22-10-91

EP491 140◦W 28-11-91 26-11-91 20-11-91

EP491 125◦W 03-12-91 03-12-91 09-12-91

TOGA92 155◦W 13-03-92 06-03-92 01-03-92

TOGA92 170◦W 14-03-92 16-03-92 20-03-92

TOGA292 155◦W 16-08-92 14-08-92 08-08-92

TOGA292 170◦W 20-08-92 22-08-92 27-08-92

EP592 140◦W 18-09-92 14-09-92 08-09-92

EP592 125◦W 21-09-92 26-09-92 04-10-92

EP692 110◦W 09-11-92 05-11-92 30-10-92

EP792 95◦W 28-11-92 01-12-92 04-12-92

TG193 155◦W 04-03-93 02-03-93 27-02-93

TG193 170◦W 14-03-93 10-03-93 09-03-93

TG293 180◦W 22-03-93 25-03-93 28-03-93

TG293 170◦W 02-04-93 02-04-93 06-04-93

EP393 95◦W 04-09-93 01-09-93 27-08-93

EP393 110◦W 07-09-93 09-09-93 15-09-93

EP493 125◦W 06-10-93 02-10-93 29-09-93

EP493 140◦W 10-10-93 12-10-93 19-10-93

EP593 155◦W 04-11-93 31-10-93 27-10-93

EP593 170◦W 14-11-93 11-11-93 09-11-93

EP693 180◦W 21-11-93 25-11-93 01-12-93

TG194 155◦W 26-05-94 22-05-94 17-05-94

TG194 180◦W 04-06-94 07-06-94 10-06-94

TG194 170◦W 02-06-94 30-05-94 17-06-94

TG294 140◦W 13-10-94 11-10-94 07-10-94

TG294 155◦W 17-10-94 20-10-94 25-10-94

TG394 170◦W 10-11-94 06-11-94 02-11-94

TG394 180◦W 14-11-94 16-11-94 22-11-94

GP195 95◦W 18-02-95 15-02-95 09-02-95

GP195 110◦W 22-02-95 24-02-95 27-02-95

GP295 125◦W 17-03-95 14-03-95 10-03-95

GP295 140◦W 18-03-95 21-03-95 26-03-95

GP395 155◦W 11-04-95 09-04-95 05-04-95

GP395 170◦W 12-04-95 15-04-95 20-04-95

GP495 195◦W 06-05-95 30-04-95 25-04-95

GP495 180◦W 06-05-95 08-05-95 13-05-95

GS95 125◦W 06-09-95 03-09-95 29-08-95

GS95 140◦W 06-09-95 10-09-95 15-09-95
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 7

Figure 1a: Figures 1a–f show the locations of fully navigated ADCP data for each cruise by latitude and

longitude: each cross represents one hour of data.Regions of sparser coverage were generally due to data

loss through bubble interference.
8 Johnson and Plimpton

Figure 1b: Same as Figure 1a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 9

Figure 1c: Same as Figure 1a.
10 Johnson and Plimpton

Figure 1d: Same as Figure 1a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 11

Figure 1e: Same as Figure 1a.
12 Johnson and Plimpton

Figure 1f: Same as Figure 1a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 13

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA91 155 oW; 7/91

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA91 155 oW; 7/91

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA91 160 oW; 7/91

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA91 160 oW; 7/91

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP391 110 oW; 10/91

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP391 110 oW; 10/91

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP491 140 oW; 11/91

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP491 140 oW; 11/91

−100

−50

0

50

100

Figure 2a: Figures 2a-k show sections of zonal and meridional velocity from each roughly meridional section

of cruise track.The original ADCP data were averaged into bins of 0.1◦ latitude and 16 m depth, and plotted

with interpolated (10 cm/s banded) shading.
14 Johnson and Plimpton

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP491 125 oW; 12/91

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP491 125 oW; 12/91

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA92 155 oW; 3/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA92 155 oW; 3/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA92 170 oW; 3/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA92 170 oW; 3/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA292 155 oW; 8/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA292 155 oW; 8/92

−100

−50

0

50

100

Figure 2b: Same as Figure 2a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 15

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TOGA292 170 oW; 8/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TOGA292 170 oW; 8/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP592 140 oW; 9/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP592 140 oW; 9/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP592 125 oW; 9/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP592 125 oW; 9/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP692 110 oW; 11/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP692 110 oW; 11/92

−100

−50

0

50

100

Figure 2c: Same as Figure 2a.
16 Johnson and Plimpton

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP792 95 oW; 12/92

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP792 95 oW; 12/92

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG193 155 oW; 3/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG193 155 oW; 3/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG193 170 oW; 3/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG193 170 oW; 3/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG293 180 oW; 3/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG293 180 oW; 3/93

−100

−50

0

50

100

Figure 2d: Same as Figure 2a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 17

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG293 170 oW; 4/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG293 170 oW; 4/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP393 95 oW; 9/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP393 95 oW; 9/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP393 110 oW; 9/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP393 110 oW; 9/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP493 125 oW; 10/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP493 125 oW; 10/93

−100

−50

0

50

100

Figure 2e: Same as Figure 2a.
18 Johnson and Plimpton

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP493 140 oW; 10/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP493 140 oW; 10/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP593 155 oW; 10/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP593 155 oW; 10/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP593 170 oW; 11/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP593 170 oW; 11/93

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, EP693 180 oW; 11/93

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, EP693 180 oW; 11/93

−100

−50

0

50

100

Figure 2f: Same as Figure 2a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 19

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG194 155 oW; 5/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG194 155 oW; 5/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG194 180 oW; 6/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG194 180 oW; 6/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG194 170 oW; 6/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG194 170 oW; 6/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG294 140 oW; 10/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG294 140 oW; 10/94

−100

−50

0

50

100

Figure 2g: Same as Figure 2a.
20 Johnson and Plimpton

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG294 155 oW; 10/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG294 155 oW; 10/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG394 170 oW; 11/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG394 170 oW; 11/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, TG394 180 oW; 11/94

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, TG394 180 oW; 11/94

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP195 95 oW; 2/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP195 95 oW; 2/95

−100

−50

0

50

100

Figure 2h: Same as Figure 2a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 21

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP195 110 oW; 2/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP195 110 oW; 2/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP295 125 oW; 3/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP295 125 oW; 3/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP295 140 oW; 3/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP295 140 oW; 3/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP395 155 oW; 4/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP395 155 oW; 4/95

−100

−50

0

50

100

Figure 2i: Same as Figure 2a.
22 Johnson and Plimpton

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP395 170 oW; 4/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP395 170 oW; 4/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP495 195 oW; 4/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP495 195 oW; 4/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GP495 180 oW; 5/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GP495 180 oW; 5/95

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GS95 125 oW; 9/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GS95 125 oW; 9/95

−100

−50

0

50

100

Figure 2j: Same as Figure 2a.
TOGA-TAO Shipboard ADCP Data Report, 1991–1995 23

−5 0 5 10 15

0

100

200

300

Zonal Velocity, GS95 140 oW; 9/95

Depth, m

−100

−50

0

50

100

−5 0 5 10 15

0

100

200

300

Meridional Velocity, GS95 140 oW; 9/95

−100

−50

0

50

100

Figure 2k: Same as Figure 2a.