Institut für

Berichte aus dem

Institut für Meereskunde an der

Christian-Albrechts-Universit~t Kiel

Nr. 51

ESACAN - Data report

by

C. Brockmann, E. Fahrbach and W. Urquizo

ISSN 0341 - 8561 1978

Institut für Meereskunde an der

Christian-Albrechts-Universit~t Kiel Nr. 51

ESACAN - Data report by

C. Brockmann, E. Fahrbach and W. Urquizo

Copies of this report may be obtained on request from:

C. Brockmann and E. Fahrbach Institut für Meereskunde an der Universit~t Kiel Düsternbrooker Weg 20 D-2300 K I E L 1

A Spanish version may be obtained on request from:

W. Urquizo

Instituto deI Mar deI Peru Casilla 3734 - Lima - Peru

ISSN 0341 - 8561

Table of contents

Summary

Zusammenfassung 1. Introduetion 2. Measurements

2.1. Navigation and bathymetry

2.2. Moored instrument measurements 2.3. Shipborne measurements

2.3.1. Hydrographie casts 2.3.2. STD-Sonde

2.3.3. Profiling current meter measurements 2.3.4. Surface mapping

3. Data from land stations ACknowledgements

Page

1 1 2 3 3 7 19 19 19 30 36 38 42

- , ^-

Summary

From March to May 19'7 the joint German-Peruvian investigation of the northern Peruvian upwelling area ESACAN ("Estudio d,l Sistem. de Afloramiento Costero en e1 Ar,. NOTt,") tool< p1aee.

Three eurrent meter moorings were laid on a seetion along 5 S . t depths of o 104 m, 1360 m and 3820 ~, On board the Peruvian re.eareh vaslel "BAP Unanue" hydrographie easts, STD-measurements and current pro!iling measuremente were earried out. Meteorologieal data were eolleeted trom five land stations and two buoys. Data are available from two further land stations: at one the sea-level was reeorded;

at the other the sea-surfaee temperature. The data obtained are presented in this paper.

Zusammenfassung

Von März bis Mai 1977 fand das deutseh-peruanisehe Gemeinschafts- projekt ESACAN ("Estudio deI Sistema de Afloramiento Costero en el Area Norte") zur Untersuchung der nördlichen Auf triebs- region vor der peruanischen Küste statt. Drei Strommesser- verankerungen werden auf einem Schnitt entlang SoS in 10~ m, 1360 mund 3820 m Tiefe ausgelegt. An Bord des peruanischen Forschungsschiffes "RAP Unanue" wurde eine hydrographische

Serienausrüstung, eine STD-Sonde und ein profilierender Strömungs- messer eingesetzt. Meteorologische Daten werden an 5 Land-

stationen und 2 Bojen gewonnen. Die Wasserstandsaufzeichnungen und OberflMchentemperaturmessungen von je einer Landstation

stehen zur Verfügung. Das gesammelte Datenmaterial wird in diesem Band vorgelegt.

- 2 -

1. Introduction

One of the most important upwelling areas is situated off the Peruvian coaat. Four regions are especially prominent. They are lituated at ~o - 6° S, 7⁰ - SO S, 11⁰ - 12⁰ Sand 14° - iSO S.

The most intense upwelling i5 encountered in the le.t area.

In addition to the spatial change, there i8 a time variation with a pronounced annual period. The maximum upwelling is found in the southern hemispheric winter.

Figure 1

The location of ESACAN area

7~

Between March and May 1977 two programmes for the investigation of these phenomena were undertaken: The US-investigation

Joint II MAM 77 within the scope of the "Coastal Upwelling Ecosystem Analysis" (CUEA) programme in the southern area and the Westgerman-Peruvian "Estudio deI Sistema de Afloramiento . Costero en el Area Norte" (ESACAN) in the north. The location of the ESACAN area i5 depicted in Figure 1.

The northern upwelling area is of special interest because there coastal upwelling may interact with features typical of the

equatorial region. tor example the equatorial front and the equatorial undercurrent. Special conditions may be generated

by the fact that the Peru current leava. the coalt in thi. region.

A dramatic chan,. in the whole sYltem oceurs when the "El Nino"

phenomenon takes place. The equatorial front advance. far to the south and coastal upwelling i8 suppressed.

2. Meaa urementa

In the period from March 27 to May 22 1977 stratification mea- aurements were made from the Peruvian research vease1 "BAP Unanue"

in the northern upwe11ing area. These measurements were supple- mented by current meter measurements from a moored array.

2.1. Navigation and bathymetry

On board "BAP Unanue" terrestria1 and astronomica1 navigation were practised. The terrestrial navigation was carried out by

radar and ~ reasonable results (accuracy

!

1 nm) within a distance of 15 nm of the coast. Astromical navigation could on1y yield very crude results, because of the restricted visibility. Further than 15 nm from the coast the position error may be as large as ! 5 nm; the accuracy depends mainly on the number of stations made "'i thout terrestrial navigation.

However, the mooring positions, even those for which no radar fix was possible are exact to within 1 nm. Only the gross

features of the bottom topography of the area under investigation Are known (Fig. 2). A more detailed two-dimensional bathymetric survey did not seem justified during this cruise because of the limited navigational accuracy. However, to get some additional information to that given by existing charts, three bathymetric sections were carried out along 4⁰ 15'S, SO 00' Sand 6⁰ 00' S

(/) o

~

- 4 -

o It') o

<0

Figure 2. Bathymetric chart from Scripps Institution of Oceanography (depth in meters).

s

- G

J 20'

K

40'

L

82"20' ^82"

ESACAN AREA

M Meteorologieal station

• Hydrographie station

C Currentmeter mooring .. STO station

20'

P Currentmeter profi/er station

Figure 3. Location of measurements in the ESACAN area.

~ i

I

!

r-

I

l I

I- I

_i

- 6 -

4°15'8

Om

e5'OO'S

I

_~~_--_.--0 m -; 0

C1 ^Im

e'OO'8

Om

)( position of mooring

1

- ' 1000

I

I

!

I

-- 2000

-j3ooo

I

-14000

--1

⁵⁰⁰⁰

!

81°00'W

Figure 4. Bathymetric sections along 4

0

15'S, 5⁰00'S and 6⁰00'S.

f

(Fig. 4).

The measurements of the eoholound,r wer. oorrected to agree with the depth values obtained from the readings of the press ure

gauges in the moorings combined with the known cable

length. Sound velocity corrections have not been applied because they are muoh smaller than the errors caused by instrumental problems.

2.2. Moored instrument measurementS

Three subsurface moorings with 16 Aanderaa RCM-14 current meters were located at the positions given in Figure 3 and 4. The

moorings were maintained for about 50 days. The sampling interval wal 10 minutes for all instruments. As an example a sohematic representation of the mooring C2 is given in Figure 5.

Figure 5

Schematic representation of mooring C2

V

=

velocity sensor T

=

temperature sensor P

=

pressure sensor

AC.REL

=

acoustic release

~E.~AC~

^{mt: VT}

100f-

! I VTP

&+-e:J VT

~TP

-COATEO .

OO-STEEL ~ VT

5 - 8mmf

:: +- ~VT.AC.REL

1000-

POLYPRO- ANCHOR 700kg

PYLEN ~ 1360

2000' 11mm'

Unfortunately not all of the instruments worked without problems The time series obtained are summarized in Table 1.

Because the aim of the experiment was to study upwelling pheno- mena with low frequency variations the time series of the hourly

- 8 -

means have been filtered by a Lanczos low pass filter with a half power point of 35 hours and 60 weights (Fig. 6).

Figure 6

Response of the applied Lanczos low pass filter

(60 weights).

1.0

LU

r

~0,5f-

~ ⁱ

Cf) :..

~ 0:-

PERIOD-

The results of the current measurements are presented in

Figures 7 - 10. Current measurements are presented in two ways:

as progressive vector diagrams (Fig. 7 and 8) and s,tick-plot diagrams (Fig. 9 and 10). The progressive vector diagrams consist of hourly values. The overall mean currents are

presented in Figure 11. The instrumental accuracy of the Aanderaa current meters is given as

!

2 % of the measured speed and as

! 5 degrees for the direction. In Figure 12 the pressure traces are shown. Quite strong movements of the moorings are indicated in the records. The velocity generated by the movement of the mooring has been calculated for the deepening of C2 on April 30 as 0.16 cm s-l, which is negligible in comparison with the

recorded velocities of 15 cm s-l. The high velocities shown in th, record of mooring C2 in 560 m depth seem rather doubtful. But even the most painstaking inquiry did not reveal an instrumental or data processing error which could explain the surprising

feature.

60m

scala A 0 scala B 0

100m

I I

40 km 80

10 20

N t

235m

195m ^1.4

I I

o ^{40 km 80}

410m

C3

20.

Figure 7. Progressive vector diagrams derived from the current meter time series at moorings Ci and C

3.

The deepest current meter of Ci gave erroneous values at the end of the observation period because the

• 'L - - - - - ~~ . . , "",,",, (hn",...l v mpan values).

1.5.

29.4.

N t

scala A 0 scala 80

1.4.

125m

scale A

I I

80 km 160

20 40

- 10 -

Figure 8. Progressive vector diagrams derived from the current meter time series at li'noring C2 (hourly mean values).

HOORING Cl JEPTH 45 M C~RRENT

~1·itr---.---, -~, iL~, ~

_~~\\% Cld:;;~{ '~7~ 'r~

1'11\\\.

,~ ~

- 1 ~:- ^{I t I I t ! I 1 t ! I I !} t ! . i _ I ! I ! ! ! ! I l I , I I ! I I I I I I ! I I I ! I ! I ...

-1 3.RPR e. ^{13. \8. 23. 28. 3.HIlY} B . ! S . 18.-

D '" MOORING Cl QEP1H 60 M CUR~R~E~N~T ____________________ _

Jlr--~--~-:<-"~~!I;W:---'---~~~~~', ,~,~, ^{,:J,3W5 j}

3.APR 8. 13. 18. 23. :!!. 3.MRY e. ^{13. 18.}

o H

MOORING Cl OEPTH 100 M CURRENT

:11->\-I-{U-I--_~--~~~~'~-~~l'---~/"**

-5 ~":::::'"?'fpl I~

-10 I ! I I , I ! ! ! ! I ! I \ t ! ' ! I I ! ! , ! I ! , ! ! ! I ! I I

8.

• "'""CI

, ! ! I ! I ' I : : 18.

3.RPR 8. 13. \8. 23. 28. 3.MAY 13.

o ^H

CURRENT

OEPTH 235 M CURRENT

30 . MOORING C3

1! I )~\ltI1\\II."

-s :.

-10 :.

-1 s :.

-20 :.

~~~~~I-L!~!-LI~LI~!~!~!~!~I-L!~I~~I-LI~'_-L!~!~!~I~,~,~,~~I~!-L!~'-L!~I~'~!~-L~I~' ~~~I ~'-LJ-~I ^-

3.RPR 8. 13. 18. 23. 28. '.MAY B. 13. 18.

i1 H

Figure 9. Stick-plot diagrams derived from the current meter time series at moorings Cl and C

3• For the deepest current meter of Cl see caption of F igure 7 (low passed values at 6 hour interval). North is unwards.

- 12 -

-s ;:

_ 1 0 0 I ! ! , , I I I I , 1 , ! I ! 1 ! I ! I I t ! ! I I I I , I I ! I I ! ! ! I ! , J !--L...J-..J.,l.L~

3.RPR 8. 13. IB. 23. 28. 3.MRY B. 13. 18.

o H

MOORING C2 OEPTH 125 M CURR~E~N_T ________________ _

::i~~~,'~~!~:~~~~','~~~~~\:I~~,~1

^{I 3.RPR} _{o H} ^{B. 13. IB. 23. 28. 3.MRY fl. 13. 18.}

_____ ~M~O~O~R~IN~G~C~2~~O~EP~T~H~2~O~O __ M ___ C~U __ RRENT _______________ __

30 r- . -

2S

t j

~O -

; 8

~ ^I

~:~i~~~~~~~~=mmm~~~~~llilli~~~~~~~~~~~~

-s ~.

-4

j ..

-10:' - I 5 ~- - 2[1 ~-

-Z'5~1 ,! ^I I , I ! I I I I

3.RPR 8. 13.

I ! ! ! ! I , I I

I I I I I

23.

J !

28. 3.HRY 8.

o ^H

MOORING C2 OEPTH 560 M

---~~~--- CURRENT

=

i

~ ~

-20 :.

-25 :.

-30 :.

-~S '- -40 :.

- 4S ~ -SO -

55 '-

-60 .... 1 I ! I I I ! I I I 1. _ L ! I f I I I ,

1.RPR 8. 13· 18.

! I I L I ! I J I ! !

28. 3.MRY 8.

!) H

o H

f I I

13.

! I I

13.

--:; . ---

I':;

18.

J

_j

-3 -<

-~

I"':;

18.

Figure 10. Stick-plot diagrams derived from the current meter time series at mooring C

2 (low passed values at 6 hour intervals). North 15 unwards.

..

0

I

85m

125 m

t

N

~

I I

I

I

r

I I

560m.

2 I

C2

860m

3 I

t

_N

60m

t

_N

195m

4 5 10 15 cm 5·'

I

I I I

Figure 11. Mean current over the whole observation period (51 days). The record of the instrument at 560 m on C

2 seems doubtful, however, no instrumental or processing error could be found. For the deepest

;~",+"""mt=>n-t nf C. see caption of Figure 7.

- 14 -

MOORING Cl OEPTH 45 M PRESSURE

I

: :-J

^I

^I~

•

! ;: I , ]

! ^{! I} : ; I I I I I I

B. 13. 18. 23. 28. 3.MRV 8. 13.

MOORING Cl DEPTH 60 M PRESSURE

=I:,:J

13. 18. ^{I I :} 23.

_:=:

^I

^f:,

2B. ^{I 1 , :} 3.MRY ^I

I:

8.

^{: I ,}

13.

J

MOORING CI DEPTH 100 M PRESSURE

I , ::L ^,:1

^I

_{i_~" ,} I " : : I

^{I I}

I===]

8. 13. 18. 23. 28. 3.MRY B. 13.

:::,::~r- Mr:N~LrJASURJ IJ

120.00 ' ! ! t ' I I ! I I I I t J--L...- I I I ! ! ! I ! I ! I ! ! ^{! I I I ! ! ! ! !-1}

3.~PR B. 13. IB. 23. 28. 3.M,"Y B. 13.

o ^H

320.00 MOOR H~G C2 OEPTH 305 M PRESSURE

~ ^~:,llJ

310.00

t

^{I ; I I,}

,. I

--~ ~

~ ~

300,00' I I I ! I ! I I I I I I I I I I I I ! ! I I I I ! I ! I ! !

3.~PR B. 13. 18. 23. 28. 3.MRY 8.

I I I I

o ^H 13.

:::'::

-

^~

-

640.00: ! I I I I I I I ! I I I I I --L....-.l.. __ l - - - L - . __ .L~ __ -L-L-..L.L-~-'---L- I I I !

3.RPR 8. 13. 18. 23. 28. 1.MRY 8. 13.

o H

Figure 12. Pressure gauge records

(low passed values at 1 hour intervals).

~i f'

18.50

'e

17.50

J

16.50

r

15.50 I ^{! !} I I 3.~PR B.

I l I I !, ^I

13. 18.

! , ! I I I ! t " J ! , !

23. 28. 3.M~Y 8.

o ^H

MODRING Cl OEPTH 60 M TEMPER~TURE 17.00

I ' ' I

18.00 i I ',' • I! ,i . ; , I " j '

~ , . ! ' ^L

. ; I ' ! ~ -

lS.DO! I I I I ' I I j ' I I I I I ! I I . I I ! ! ! i I I I ! 1 I I I I J..

,!

^{I I}

3.RPR B. 13. 18. 23. 28. 3.M~Y 8. 13.

o H

MOORING Cl OEPTH 100 M TEMPE~HTURE

16.50

~

^{,I , ,: ',!}

^{I :} ~

15.50 i ' , ; ' : . ,

i ' I ,

I ' '

14.50 I ! I I , ' ! I t ! I ! I I J ! I I ^! I « I I I I I ! I I ! ! . I I ' I I I I I

3.RPR 8. 13. 18. 23. 28. 3.MRY B. 13.

o H

MOOR I·NG C3 OEPTH 195 M TEMPERRTURE

1 •• 50

r ^T

^{~: ~!~!}

^I ~I ^{I J}

13.50 I I I I : ! I I I j I I I I I I I ! I I ! I I I I ! 1 I ! I I " I : 1 I I L

3.RPR 8. 13. 18. 23. 28. 3.MRY B. 13.

o ^H

:::::~~

MOORING C3

D~PTH 23~

^M

TEMPERA~URE i "

I j 1 I I

I ^{, I} I 4

, , '

12 .SO: I I I I

3.RPR

o H

I

! I I I

8.

I

\ 3.

I I I I I

\ 8.

, I i ! I , I I I ^{I I I I I} I I I I I I I

23. 28. 3.MRY 8. 13.

TEMPERRTURE MOORING C3

I I

I

~.:I,;

^{; L} _I ^J

-j

OEPTH 410 M

\ 1 .50 r - - -

t

----.---:~~c..::.-

I !

\0.50 l 9 .50 ~

L , 8.50¹ I !

3.RPR

o ^H

, '

I I I I I I I I I I I I I I ! I I

13. 18. 23. 28. 3.t1RY 8. \3.

MOORING C3 OEPTH 650 M TEMPERRTURE

-T-~

7.00 , ! I ,

I , I I I

6.001!111~llllllll'IIII~.

3.RPR 8. 13. \8. 23. 28. 3.MRY 8. 13.

o ^H

Figure 13. Temperature records derived from moorings Ci and C3 (low passed values at 1 hour intervals).

- 16 -

MOORING C2 DEPTH 85 M TEMPERRTURE

".DOr:

^·e

_-!,~,~J

15.00' , , ,

3.~PR 8 I 13. 18. 23 ! ! ! ! ! I ! ! ! ! ! ! ; , ! ! !

• 28. 3.'1QY 9. I'.

o H

HOORING C2 DEPTH 125 M TEMPERRTURE

14.50

I ::=K

13.50 I , " I' I I

I- :

1?50 3. APR I ! ! ! 8 , ! I ! ! ! ! ! ! I . . . I I . . . I I I ^{I ! ! I I I I ! !} I I ,

o ^{H • 13.} 18. 23. 28. 3.MQY 8. 13.

HOORING C2 DEPTH 305 M TEMPE~qTURE 1

~

^.50

f

12.50 ....

I I

I! .SO-

1 Cl .50 ---1. I I ! I ! " I ! ! ! I ! ! !

3. ~PR 8 13 8 ' I I I " " I ' " ,

"1 H • • 1 • 23. 28. 3.MIH B. 13.

HOORING C2 DEPTH 560 M TEMPERATURE

""~='l

G. so

t

j • ^I APR ^{I I I I} 8 ^{I I I , I} 13 ^{I , I I I I , I I i I , I I I I I} I ! ! I I I ^I " ! I ^I I I I I ^I '

o ^{H • .} 18. 23. 28. 3.MRY 8. 13.

:::

4.00 ' I I I ^{I I I I I I I} -...J._-.-L--'---L-.:;;'-'--L..' ...JI--LI ---:;,~I--'-I ....LI ..J.I_~_'='--L..I ...JIL-:--L....JI--LI ...J...I _-'-, ...J...' ..J.I--L-I

13. 18. 23. 28. 3.'1RI 8. 13.

3.~PR 8.

o ^H

Figure 14. Temperature records derived from mooring C2 (low passed va lues at 1 hour intervals).

MOORING Cl OEPTH 45 M SRLINITY

35

.!~

^E

I I I, I .

^!

35.00~--~---4---~---~----~---~---~---~---~

34.50 ' , ,

3.RPR 8.

I 1 ! ! ,

13. 18.

! ! ! ! I !

3.^M,n ^{8. J I}

I I ! I

23. 28. 13.

o ^H

MOORING Cl DEPTH 60 M SRL1NITY

35.50 ~

I

^j

I ' ! 3

35.00 b.~---+---""!---ll---+-t

---r--

ⁱ

1

~

^I

~.' ~ ~_.

34.50~ . ~

3.IOO~"~!~'~~~~~~~7!~'-L' ~!~~'-LJ-~~'~'~I~'~7'~!~J-~'~!~I~'~~~~~~1~~~

3.RPR 8. 13. 18. 23. 28. 3.MRV 8. 13.

o H

MOORING Cl DEPTH 100 M SRLINITY

:: :::[ r--,-"""I-,

^{- I - ,} .:...;:...:::;

,..:.:....:...:.~:

..:-, - I -.:, :::..:::.:-!

,~, ~I ~[ .-.:-~, ~:

^{, ;}

! ,

3.RPR 8. 13. 18. 23. 28. 3.t1RY 8.

:

13.

o ^H

MOORING C3 DEPTH 195 M SRLINITY

::::~~t-::-_.L---~] _-l-l---J,.i--!----+--I _-+---:~

14. sn ~ ^{I , I I I I I I ! j t I 1 -}

3.RPR 8. 13. 1 BI 23. 21'\. 13.

n H

Figure 15. Salinity records

(low passed values at 1 hour intervals).

-1 :. -

_ ? ~...l-L-L , I , « I , I ~.~I_,~!_I~,_,~,~,~I~!~,_,~!~I~I_!~!_,~I_'~'_'~-LI ~!-L' ~!-LI~I-L'~I-Lj~!~1 -

. . 1.RPR A. 13. IR. ::'3. 2A. 3.'1R\ 8. 13. 18.

o '"'

~ _~'--0JlE) NG M2 W I ~O ~

l[;'~"~J~\\~~

" -

-I ~ -

_ 2 t-_L.I...-L...J. I I I 1 - 1 I I 1 I ! I I I I

3.APR B. 13. 18. 23.

o H

Figure 16. Stick-plot diagrams derived from the wind records at M

1 and M 2

(low passed values at 6 hour intervals).

For M -1

1 a constant speed of 3.5 m s is assumed.

tor M -1

2 a constant speed of 3.5 m s is assumed

-~ A _ _ ' : ' ')1'\ ..,..,~" h

- 18 -

FigureI 13 - 15 show the ti1tered temperature and .a1inity records.

The errors in the temperature me.eurement • • mount to

!

O.lo

e.

The .alinity time ser!es haI been adjulted to

Asr.e

with the hydrosraphic casts, takinl in account the well known problems with Aandera4 conductivity cells CH. Peters, personal communi-

cation). The striking decrease of salinity at Cl is due to strong overgroth of the conductivity cells.

The wind speed sensors only tunctioned for apart of the obser- vation period. To use as much of the data as possible, the time series of M2 was completed with the mean speed obtained from the intact record of 22 days. The speed sensor on M1 worked on1y for 3 days. The mean speed wal calculated trom thls reeord and u.ed for the whole time series. The filtered wind records are shown as stick-plot diagrams in Figure 16.

2.3. Shipborne measurements

During the whole experiment the Peruvian research vessel

"BAP Unanue" was in the area. Hydrographie casts, 5TO- and

profil1ng current mealurements were carried out. A quasi-Iynoptic survey from April 30 to May 3 wal uled to produce lurface

maps.

2.3.1. Hydrographie easts

Hydrographie casts were earried out with 13 Nilkin bottles.

Two reversing thermometers were mounted on each bottle. The hydro- graphie winch was equipped with 1000 m of wir ••

Unfortunately the salinometer broke down two weekl befor. the end of the eruise. It may be possible that even apart of the salinities determined earlier are affeeted by a slowly incr.4sing error, although there is no evidence of this. For this reason no estimate can be given of the salinity error.

The reversing thermometers appear to be less accurate than may be generally expected beeause there was no possibility in Peru to reealibrate them. By intercomparison the best ones were selected

+ 0

for near-surface use (aceuracy - 0.03 C) and the poor ones

+ 0

for greater depth (accuracy - 0.1 Cl. The results are presented in temperature and salinity sections (Fig. 17 - 24). The location of the sections is given in Figure 3.

2.3.2. STO-Sonde

A Plessey STD with a 1500 m depth range was on bord. As the in- strument did not work reliably only one STn section has been processed (Fig. 25). The accuracy of the STD- measurements is ~ O.l oC in temperature and ~ 0.05 0/00 in salinity. At eaeh STD-station th~ee Niskin bottles were deployed on the same wire as the STD. The temperature measurements of the STD were

corrected to agree with values measured by the reversing ther~o­

meters. The salinity of these samples was determined by L. COdispoti on board the US research vessel "Melville".

The corrected salinity measurements of the STD agree well with the salinities determined earlier on board the

"BAP Ununue".

St. No. (

Or-~~~--~--~~----~--~--5 & 7 8

-:--~~~~~~~~~

300-:' ----10 ___ _ :"

500-~

-

700-

-

&00-

-

7

100~~_'_-_3_5~

^{____ _}

300'-·---

500---

700,-

I

---

900~~

.":-:':':

Figure 17. Temperature and salinity seetions along 5⁰00'S from hydrographie easts earried out from Mareh 30 to 31 197/

- 22 -

OPERAClON ESACAN

Tlmplroturo (-C) 4-S/Abr/1917 .,. 5-00'S

[S~~2T~~--~2rr ____ ~~r-

__

^~2T~~ __ ~2T(~

__

^~2r~ ____ ~2~r-~~~1~2P~~lf~1~f~~ri~1~r~1~r

___

om~:---jr----~========~~ji--~~--~~~~~~jr10M

80

I

7'OO~

.ooL ,..---

!So

I I

.,.

OPERAClON ESACAN

Sollnidod (,...) 4-8/Abr/ll17 ,.roo's

-100 -toO

lool~---~~~~·---~~~I,oo 2oor~~~O

3001- - - - 3 4 . 9 400

L ---

_i ^34.8

:~~34.1

700~

8oo~ I

900 i I- - - _ _ _ _ - - - - 34.8 - - - _

I - - - - - - ...

1000¹ i I i ...

840 83°

-200

.. hoo

-!400 i

..J i !500

8'oW

Figure 18. Temperature and salinity seetions from hydrographie easts.

ESACAN

OPERAClON • 5.00'S 10/Abr/1977 (j)

T(-c:l ". !8 37 ESr. 41 40" 1 1 1 1 1

0'"

50,

,

IOOf"I~

^{14 _ _}

100 13

_ _ 1 2 _

~11-

400 ⁵⁰⁰

r~'::::::

^{_ _}

eoo 8

100 7 -

40'

ESACAN

O"RACIOM

.roo ' ,

) tO/Atlrl1." • S(.... 40" !8 '7 UT. 42 ~I, 1 1 i

0 .. 1

100

200 ...

!

500-

600- _ _ _ _

~f'~

1000 ! 40' 20'

ESACAN

OPERAClON 1977 , • ~oo's (-Cl 14-15/Abr/ 45 43

Temp. 41 47 1

: ::~~~;;!:::~'=:~'~~'~1

EST. ~' 0",

50:-I

100-"

1 4 - 100- 1 5 - -

1'---____ _

~- :-~---

500-

800- •

100- 100-

Il00- 1.5_______ ~-_ ^81ew

- ---;:-:--,.- 4:' , I 40 I 20'

1000 82-

ESACAN

OIt'UCION . " " . '-00'1 ( .... l 14-15/Abr/1 45 43

Salln. "'. 47 I I

50 4' ... " , EST. =:::5,1_...:i:--~~' ,

0", ,_- - 55.5 , ' ... _----~

, I 50-

:

^\

I \

1

_~,-^{5" ...}

^----

^{I ,}

^(:~5

_35.0 ^{\ ...}

'::.::.:.~'~' -..;."~~~~

^{... __ .}

100 200- 300- 400- 500- 600- 700-

_ _ _ _ _ 34.' _ _ _ _ _ . . - - - - 3 4 . 8 _

800-

C

000

- : ? '

^tJ)'

1000 l . . . 1 - - . - 82-

-

I

81 . .

d salinity

Temp

erature_a~n~~

^______

~~=:~~~~~:

^I

1

9 A talt

Hcl~o'a:'i(

Figure ^{0 •} 'gisdle ns

casts. BIO 0 Blbll.thek

hydrograp hOc 1

from sections

..

-

24

-

OPERAClON ESACAN

Temperatura (OCl 2!S-26/Abr /1977 cp. !S·OO'S EST. Om 88A

,

88

,

87 I 86 I 85

,

84 83 82 81 80 ,

,

I '19'

11 50

----,1

-11

100

1

-

::~

^{,.j !}

400r ^{-10 4}

500~ i

- •

10Or- ^I

'7O°r 1

800f- ^I

I

t00r- 1000

40' 10' 11· 40' 10'

.,·W

OPEftACION ESACAN

Sallnldad (%.) 25-H/Ab,/I977 ,.5·00'S

E~.~H~,A~ ________ ~8r~ __ ~8TT ___ 8~~~ __ ~I~~~8r~~8~~~8~~~~1~8P~ __

Omr---~---r---r---~~

50

100

200'- 34.9 - _ _ _ _ __' .J

300-

--j ,

34.8 _ _ _ _ _ -

400-

_ - - - 3 4 . 7 _

---

....J 500-

600- "" ^,

700-

800- -I i

I

900- ^-I

I

1000

40' 20' 20' 81·W

Figure 20. Temperature and salinity seetions from hydrographie easts.

SI. No. 113 112 111 110 109 107 105 Or-~~~~~----~--~~~~~--- m

~~---

---~-

700

900

l-1----~---

300~ I - - - -_ _ _ _ _ _ _ _ _ _ _ _ _ _ - - - -

500~---

i ~

i

7oo~

900

105

OPERAClON ESACAN

Temp.(-c) S-4/Moy/1977 .-~oo'S

t

IST.· 173 172 '11 170'

'ee

^{167 16&}

0,., i i i i i i I i I

It

_11---- _{_'7-}

'0

,~~--~~;;;;~~~~~~

'!iIO -

---

100- _ _ _ 400- _ _ _

eoo - _____ r . - - - -

100 - _ _ - - - . - 100-

800-

tOO-

_--8----.

Ol""ACION ESACAN

Solln.("') S-4/MoJ/',n

,-e-oo'.

IIT. _Oflft I';' '~I

Ir' rrp '"

_{' f} ^,.1 _{, i} ^"

.e.tj~'

50

... _...

... "', _,

1 0 0 - - -

300- - 3 4 9 - - - -

400- 500-

600~

.oo~

40' 20'

81-W

Figure 21. Temperature and salinity seetions from hydrographie easts along 5⁰00'S earried out at April 29 and

from May 3 to 4 1977.

- 26 -

OPERAClON ESACAN

Temptroturo (·C) 9 -10/Moy/1977 , . ~.OO' s

E;:~~I~~I~~18~13~===~====18~12~==I~~I==;I~~0====11~19=;:11!18:==11ST:I:~~I~TS:=;~

:6~ ;:II--~

50 ~,.

100

_ _

~

^____

~lh.~~

^__

~~~~~

-

100-

.'4 _______

--

300-

400-

-

1 1 = - - - = - -^l:~

'0 --;;::..

-

SOQ- 500- 700-, 800'

40' 20' 40' 20'

OPERAClON ESACAN

Sollnldod (%.) 9-10/Moy/l • .,., •• 5·00'1

UT. 114 183 182 111 180 119 118 171 178 115

i r ⁱ I i i i i i i

omr-~---~---~--~~---­

.-

150

40' 20'

...

---

_{" ,}

-.---

40' 20'

Figure 22. Temperature and salinity seetions from hydrographie easts.

OPERAClON ESACAN

Temperoturo (OC) 13-14/Moy/19n IP. !5-00'S EST. 222 221 220 219 218

-.---~, i i i

om~?/

217 21fS 214

-....---- . '--,rrl -..,...:2:;:'2=--_

150 ~17 _ _ _

~I'

IOC) .

---I~

200-_____

^{14....--.~ " -}

300:- _ _ _ _ _ _ : : : : ~

400- " ₁₀ ___ _{_}

500 - - - .

600- ____ _ . - - - - -

roo - _ - - - -7 - - - -

---

800-

20' 40' 20'

OPERAClON ESACAN

Sollnldod ("IM) 1I-'<4/Mo,/1Wr " . 5-00'1

..J i

I

-; ,

I

J

_I

UT. 122 221 220 21t 218 217 114 112

om~'~~;I~~i::~:I::~'~;::2I::~!;!:~I~~!I~~

50

200 300

400 _ 3 4 . 9 : : : : = _{34.~- ~} ~

34.7~

500 600 700 800

20' 82° 40' 20'

Figure 23. Temperature and salinity seetions from hydrographie easts.

- 28 -

SI. No.243 242 241 240 239 237 235

or-~~~--~--~--~~~~~~~

m

100·-==;::;;::;;;o .... ;;;;;::---i.r+. ..

+ ... + ... ;;;;; ... + ...

^~

....

_ 1S~

/Uitt}(}?M

-- -

500=_=_----

700- <8

900;'"

,

m

50 >35.1

100r---4--~~·~ .. ~ .. ~ ... ~ .. ~ ... ~ ... ~ .. ~ ..

~t----30 ...i I

Figure 24. Temperature and salinity seetions along SOOO'S vom hydrographie easts earried out from May 21 to 22 1977.

SI. No. 211 210 209 208 207 205 204 203 Or-~~~~~--Lr--~~L-~~ ___

100--~~-- ~I;

^____

--~~"

^__

~--~/~~~~~~'

300--- ----... ::::;::::; --

-::::::---- -fO

=-;

100-

"---

roo---

900~

":'TOC .:.

){

... ^" ....

,}

m >35.1

..---^...

I - - - -

I -

500~

~

7001-

900~

I

81'

Figure 25. Temperature and salinity sections along 6⁰00'S from STD measurements carried out from May 12 - 13 1977.

- 3n -

2.3.3. Profiling current meter measurements

At 1~ locations profiling current measurements were carried out with a RCM-4 Aanderaa current meter. At Bome locations the profiles were repeated several times. For detailed informa- tion see table 2. The locations of the measurements are

shown in Figure 3.

The current meter sank along the hydrographie wire from a freely drifting ship (Fig. 26).

Figure 26

Schematic representation of a profiling current measurement.

The ship's drift is determined relative to a moored buoy.

0 m z 100

2CIO

I

i

300:-

400~

+-SHIP'S DRIFT ) )

)

30kg

The drift of the ship was determined every 5 minutes with refe- rence to a special1y 1aid buoy, a meteoro10gica1 buoy or an oi1 rig. trom the instantaneous drift fixes during each profile a mean drift was determined which was added to the velocity measured by the instrument. The mean drift at each location

during severa1 profiles is presented in Figure 27. Table 3 gives the statistics of the va1ues presented. Because in general the drift velocity was significant1y higher (in the order of 50 cm s-1 than the corrected current ve10cities (in the order of 20 cm s-1) the accuracy is very limited. Assuming an error in the drift

of ^+- 10 cm s·l l.'n spee an d d + - 5 0 , l.n d" l.rectl.on, one 0 bt . al.ns an error in the velocity components in the order of ! 10 em s·l.

Taking into aeeount this error which is of the same order as the observed currents, the current profiles agree with the measure- ments of moored eurrent meter. However, it there il only the relative current needed, as far ealeulations of eurrent shear the accuaracy amounts to that one, normally given by Aanderaa.

On the current meter there was a temperature and salinity sensor.

The salinity records are adjusted to agree with the hydrographie casts.

rigure 27

Surface currents deter- mined from shipts drift

me~surements. For more detailed information on time and location see Table 3 and station

list.

s

"0

20'

40'

5°

40'~

110 - '

82"20' '2" ^40' 20' I,.

The results of the two components, temperature and salinity are shown in figures 28 - 31.

NORTH-COMPONENT--- -50 -25 0 cms-¹ 50

I I I I I

~f'

^{200 100}

3OOr- 400;"

&00-

100 200 300

400

&00

400 500

400 500

- 32 -

Figure 28. V (northward) velocity component derived from the profiling current measurements at positions shown on Figure 27.