Northeast Fisheries Science Center Reference Document 93-10

Test and Evaluation of the SBE 19 Seacat Profiler

by

Tamara Holzwarth-Davis

NOAAfNational Marine Fisheries Service Northeast Fisheries Science Center Environmental Processes Division

Woods Hole, MA 02543-1097

June 1993

The Northeast Fisheries Science Center Reference Document are a series of informal reports produced by the Center for timely transmission of results obtained through work at the various NEFSC labs. The douments are reviewed internally before publication, but are not considered formal literature. The National Marine Fisheries Service does not endorse any proprietary material, process, or product mentioned in these reports.

Page iii

Table of Contents

Abstract ................................................................................................................................ 1 Introduction .......................................................................................................................... 1 DeSCription of Profller ..................................................................................................................... 1 Methods ................................................................................................................................ 2 Results .................................................................................................................................. 5 Discussion ............................................................................................................................ 5

list of figures

Figure 1. Vertical profIles of temperature and salinity showing dats comparison of CID and Profller during tandem casts .............................................. 6

Figure 2. Vertical profIles of temperature and salinity showing dats comparison of CID and Profller during cast vs tow ....... , ......................................... 8

Figure 3. Vertical profIles of temperature and salinity comparing Profller data collected during down and up casts during bongo tows ................................. 10

Figure 4. TIme history of tow showing time vs depth, Profller data ....................................... 12 Figure 5. Station plot of DE8909 I showing various station operations ................................. 14 Figure 6. Contour plots of surface and bottom temperature and salinity

data taken with Profller ............................................................................................... 15 Figure 7. Contour plots of surface and bottom temperature and salinity

data taken with CID ............................................................................................ 16

list of Tables

Table 1. Station operations for DE8909 I ............................................................................. 2 Table 2. Difference in maximum recorded pressure between Pro.ft1er

and CID during tandem casts ................................................................................ 4 Table 3. Mean temperature and salinity differences between the CID

and the Pro.ft1er for the two cast groups, T: tandem and CVT: cast vs tow, at 0 and 1 m offsets ............................................................................ 4

Table 4. The mean temperature and salinity difference between the down and the up casts of the Profller for both cast groups, no pressure offsets ................................................................................................. 5

Page 1

ABSTRACT

An SBE Model 19 SeacatProfllerwas purchased to obtain temperature, salinity, and pressure data during plankton tows. A test and an evaluation of the Profller were conducted aboard the R/V Delaware II during Pari I of the DEL8909 Larval Herring/Sand Lance Study, November 27 through December 12, 1989. An SBE Model 9 Seabird CTD was used as a standard for comparison. Data collected with the Profllerwere compared with those taken with the crD during two methods of operation: 1) "Tandem" casts as the two instruments made simultaneous vertical profiles; and 2) vertical CTD only casts followed by double oblique Profller casts with a bongo net. The down and up casts from the Profller were also compared. Ease of operation and feasibility during plankton tows were also evaluated.

The Profiler collected data of good quality and compared well to the crD.

INTRODUCTION

Since May of 1987, hydrographic data have been collected by the N ortbeast Fisheries Science Center primarily with an SBE Model 9 Seabird conductivity, temperature, and depth (COT) in­ternally recording device. This CTD is manufac­tured by Seabird Electronics of Bellevue, Wash­ington. It has been a reliable instrument with good data quality.

ACTD cast can take up to half an hour at deep (200 m) stations. At the time of this test and evaluation, certain cruises (e.g., bottom trawl surveys) did not allow for this extra time in their cruise operations. An expendable bathythermo­graph (XBT) was used to obtain temperature data throughout the water colunm. The XBT does not require extra station time as it can be launched while the ship is under way. Although the XBT is faster, it measures fewer data than a crD and can be costly because the probes are non-retriev­able.

An SBE Model 19 Seacat Profller was pur­chased to obtain salinity, temperature, and pres­sure data during plankton tows. Bydeploylngthe instrument with bongo nets, no additional time is needed for hydrographic data collection.

The Profiler was tested aboard the R/V Dela­ware II during the DEL8909 I Larval Herring/ Sand Lance Study. This report presents an evaluation of the instrument's data quality and suitability for use on plankton tows.

DESCRIPTION OF PROFILER

The Profller measures 736.6 mm (29 in) long with a diameter of99 mm (3.9in). It weighs 5 kg (11 lb). The pressure housing is made of Celcon plastic and is capable of withstanding pressure

up to 600 m in depth. The SBE-3 thermometer, SBE-4 conductivity meter, and precision semi­conductor strain-gauge pressure transducer are the same sensors as those on the CTD. The manufacturer claims the follOwing sensor accu­racies:

Temperature: Conductivity: Pressure:

0.01'/6 months 0.0001 Siemans/m/month 0.5% of full scale range (approx. 3 m).

The Profller is powered by 6 D-cell alkaline batteries that can provide up to 48 hr of continu-0us data operation and a 2 year data retention reserve. The memory of 64K bytes permits 1.5hr of recording. The sampling rate is two scans per second (the crD rate is eight scans per second). The Profiler does not have a submersible pump as does the crD; therefore, the conductivity cell is "free flushing".

Data retrieval for both instruments is via an RS-232link to an IBM-PC compatible computer. Seabird Electronics provides software that can communicate with the instrument's memory, retrieve, plot, and store the data. This software also derives salinity values and can average the data into specified depth intervals. Although the pressure sensor actually measures pressure and the data are recorded as decibars, it is common to refer to the pressure as depth and to substitute meters for decibars. This substitution is accu­rate to approximately 0.5%.

In order to attach the Profuerto the wire above the bongo nets, a few modifications were made to the Profuer. Two blocks of PVC with a slot cut in the side to accommodate the wire and a notched screw with a wing nut were taken off Niskin bottles and hose-clamped to the Profuer housing. For safety purposes, a snap shackle was at­tached to an eyelet in each endcap on the Profuer.

Page 2

Table 1. Station operations for DE8909 I

Standard Consecutive Bongo TueofWork Tandem salt Comment Station tt Station # Profller

1 1 x 2 2 x 3 3 x x 4 4 x x 5 5 x 6 6 x 7 7 x 8 8 x 9 9 x

10 10 x 11 II x x 12 12 x x 13 13 x 14 14 x 15 15 x x 16 16 x x 17 17 x x 18 18 x x

144 19 x x 19 20 x x

145 21 x x 20 22 x x 21 23 x x 22 24 x x 23 25 x x 24 26 x x 26 27 x x 25 28 x x 27 29 x x 28 30 x x 30 31 x 33 32 x x 34 33 x x 35 34 x x 36 35 x x

METHODS

DEPLOYMENT

Both the ern and the Profiler are designed for use as vertical pro filers with optimal data collec­tion occurring on the downcast. For this test, the Profllerwas deployed In two ways: I) attached as a vertical pro filer to the cage of the cro and, 2) mounted above the bongo net and towed ob­liquely through the water column.

During part I of the cruise, the cro was used on 63 of the 72 stations (see Table 1). On nine of these cro casts, the Profller was also used. The Profiler was shackled to the cage with its sensors directed down. This placed the sensors of both instruments at the same sampling depth and less than half a meter apart. Both Instruments were attached to the wire while on deck. A Niskin

CTD

x x x x x x x x x x x x x x em data lost x x ProJller data lost x Profller data lost x x x x x x x x x x x x x x x x x x x x x x x

No Profller upcast data

bottle was clamped to the wire directly above the ern after placing the units over the side of the ship. This "tandem" castwas lowered and stopped within 5 m of the bottom, then a "messenger" was sent down the wire to trip the Niskin bottle and collect a water sample. Water samples are used to calibrate the conductivity sensor on each Instrument. The wire was brought up and the Niskin bottle removed. Then the ern and Profller were swung onto the deck and removed from the wire.

The Profller also was used on 47 plankton tows. Thirty-six of the tows were preceded by a ern cast. These 36 "cast vs tow" stations provided another method for comparison. Tow procedures began by attaching a 45 kg ball beneath the bongo frame. A bathykymograph (BKG) was placed above the bongo. The Profller was clamped and shackled to the wire directly above the BKG with its sensors directed up. This was all done on deck. The entire assemblage was

Page 3

Table 1. Continued

Standard Consecutive Bongo Tme of Work Tandem Salt Comment Station # Station # Profiler

37 36 x x 38 37 x x 39 38 x x 40 39 x x 41 40 x x

123 41 x 124 42 x x 125 43 x 126 44 x 127 45 x 128 46 x 129 47 x 130 48 x x 132 49 x x 133 50 x x 134 51 x x 135 52 x x 136 53 x x 131 54 x x 137 55 x x 138 56 x x 139 57 x x 42 58 x x 43 59 x x 44 60 x x 46 61 x 45 62 x 47 63 x 48 64 x 49 65 x x 32 66 x x 50 67 x x 52 68 x 54 69 x 53 70 x 55 71 x 56 72 x x

then placed over the side of the ship and lowered. A double oblique sampling protocol was followed. In order to obtain an optimum sampling of the water column, wire angle and wire speeds in and out were carefully monitored. Tow speed of the ship was 1.5 knots.

Mter the cruise, standard data processing steps were applied. Salinity corrections of +0.043 practical salinity units (PSU) for the CTD and +0.014 PSU for the Profl1er were determined by comparing the water-sample salinity to the cor­responding in situ salinity. Data were stored in files containing station infonnation and I-m averaged data values. These data were obtained from the downcasts.

DATA ANALYSIS

To detennine the quality of the data obtained from the Profl1er, the Profl1er data were compared

CTD

x x x x x x

x x Bad ProJller data x x

x x x x x x x x

x x x

x x

x x x x x x x x x x

x x x x x x x x

x x x x x x x x x CID data lost

with the CTD data. The mean temperature and salinity differences between the two instruments were found for each station where both instru­ments were used. These mean differences were then divided into two groups, tandem data and cast vs tow data (Projller station 123 within the tandem group contained bad data and was not used in any further analysis). The group mean temperature and salinity differences were then calculated by averaging the eight tandem values and the 36 cast vs tow values. Using this group mean 2:2 standard deviations, individual outliers within each group were discarded and the group means recalculated. The mean of the standard deviations associated within each group were also calculated.

To account for a possible discrepancy in the pressure sensors of the two instruments, various pressure offsets were applied to the data before detenuining the individual station mean differ­ences. The group means were then determined in

Page 4

the same manner as described previously. The pressure offsets originally ranged from -3 to 6 m in one-meter increments. These offsets had the effect of shifting the Profller data up or down in the water column. It was later determined that the Profller showed a consistent difference of -I m compared with the em (see Table 2). Data values portrayed in this report will show values obtained from the direct comparison as well as data in which the + 1 m correction was applied to the Profller.

Table 2.

Tandem Station #

123 126 127 128 129 46 45 47 48

Difference in maximum recorded pressure between Profller and em during tandem casts

Maximum Depth (m) Difference l

Profiler CTD

48 49 -1 28 29 -I 40 41 -I II 15 -4 21 23 -2

140 141 -I 161 162 -I 149 150 -I 126 127 -1

Vertical plots at selected stations were gener­ated using Tell-A-Graf. These plots compare the temperature and salinity values recorded by the two instruments, no pressure offsets were ap­plied.

Another method of data comparison was used to test the capabilities of the Profller itself. This involved comparing the downcasts and the upcasts for each station where the Profller was deployed. Agaln these data were divided Into two groups, tandem data and cast vs tow data. Mean temperature and salirllty differences were deter­mined in the same way as described for the CTD versus Profller comparison. No pressure offsets were attempted. Tell-A-Grafwas again used to generate vertical plots of selected stations to compare the downcast and the upcast data taken

I Pmfller minus CID

with the Projller. Horizontal contour plots were generated us­

ing Surface !II commands on the VAX computer. Plots were made of surface and bottom tempera­ture and salinity for both the CTD and the Profller. A station plot was mapped out showing the various station activities.

Plots showing a time history (time versus depth) of the tow were generated for selected bongo/Projller stations.

Table 3. Mean temperature and salinity differences between the CTD and the Profiler for the two cast groups, T: tandem and CVT: cast vs tow, at 0 and 1 m offsets

Offset

o o

+Im +lm

o o

+Im +Im

Group , Observations 1

T CVT

T CVT

T CVT

T CVT

8 33

8 33

8 34

8 34

TEMPERATURE (OC)

+0.029 +0.020

+0.016 +0.020

SAIlNI1Y (PSU)

-0.014 -0.019

-0.01l -0.015

Standard" Mean" Deviation Standard deviation

+0.022 +0.024

+0.014 +0.024

+0.026 +0.018

+0.024 +0.020

+0.016 +0.031

+0.015 +0.031

+0.032 +0.052

+0.032 +0.049

1 The number of Individual station means that were Included In the final statistical analysis 2 The standard deviation of the station mean dilIerences that were used to determine the overall mean difference,

x; 3 The mean of the individual station standard deviations.

Page 5

Table 4. The mean temperature and salinity difference between the down and the up casts of the Profiler for both cast groups {refer to Table 3, no pressure offsets}

Group #Observations Standard Mean Deviation Standard Deviation

TEMPERATURE (OC)

T CVT

8 44

-0.014 +0.004

+0.037 +0.019

+0.077 +0.030

SALINTIY (PSU)

T CVT

8 44

RESULTS

+0.035 +0.002

By directly comparing the maximum pres­sure values for both instruments during the tandem casts, it was clear that there was a pressure discrepancy between the two (see Table 2). The Profller was nearly consistent in showing a recorded value I m shallower than the GrD, while both pressure sensors were at the same level. The group mean temperature and salinity differences did decrease slightly by applying the I-m pressure offset (see Table 3).

The downcast versus upcast comparison showed smaller mean differences during the bongo tows than during the tandem casts (see Table 4).

Figures I and 2, depicting the vertical plots of temperature and salinity data obtained at se­lected tandem and cast vs tow stations, show comparable measurements between two mea­surements.

The upcast data contained bad records for the near-surface values. Before performing the statistical analysis, as much as I to 5 m of data had to be deleted. The vertical plots show data readings that make it appear as though the Profllerwas out of the water, although the pres­sure sensor indicates below surface pressures (see Figure 3). The data throughout the rest of the water column, however, were very sim.ilar for downcasts and upcasts. This problem also oc­curs with the SBE 9 GrD on some casts and is believed associated with the strain gauge pres­sure sensor used on both instruments.

The time history of the tow shows depth versus time characteristics of the tow (see Figure 4) for three different stations. These stations range in depths of approximately 50, 100, and 200 m.

+0.028 +0.020

+0.042 +0.034

Figure 5 shows the locations of all stations during Part I of the cruise.

The contour plots were generated using data from Parts I and II of the cruise to give better coverage of the study area (see Figures 6 and 7). Plots depict surface and bottom temperatures and salinities as collected from each instrument. Differences in the contours are due primarily to the different station locations for the data from the two instruments.

DISCUSSION

The results from this test show that the Profller compares well to the GrD. The mean differences between the GrD and the Profllerwere small and no correction was needed for the Profller data. The pressure offset of I m is within the 3 m range of manufacturer specifications for the pressure sensor.

It was noted that when the -3 to 6 m offsets were applied to the Profller data, the mean tem­perature differences did not change for the cast vs tow group but remained at +0.020°C. This can be accounted for by the relative unifOrmity of the water column during the winter months.

In regard to the mean salinity difference, both instruments were calibrated to an external stan­dard before analysis, so any further difference between the two instruments would be due to "noise" in the water column as the sensor moves through it. The small mean differences (tandem: -0.011 PSU, cast us tow: -0.015 PSU) at the 1 m offset indicate good dynamiC response of the sensor. Some salinity spikes were visible on the plots where the Profzler passed through thermo­clines. This is to be expected from a free-flushing conductivity cell.

Page 6

STATION 126 STATION 127

TEMPERATURE (DEG C) TEMPERATURE {DEG C} , " "

, ,., " " • .. , " ,

" " ,

" ,

" " w 0 o .

1 " "

" " Vi' Vi'

~ ~

~ 20 ~ " ill U U w w 8 Q :=; 25 w" ~

~

" " ~ ~ ~ ~

" ~ 30 w ~ ~ ~

: " '"

" " ! '-' "

" " SALINITY (P5U) SALINITY (psu)

3'.S ,. " 3O.' " ",5 " 31.5 " "'S " ".5 "

,. 3~,5 " '~,5 " 31.5 " ".5 " 0 0

~

" "

" " Vi' Vi' ~ ~

~

" ~ " ill ill

U U w w 8 8

" w " w ~ ~

" " ~ ~ ~ ~

" w " w ~ ~ ~ ~

" "

" " Legend Legend

" ~ " ""------!,139f~L_[.F_ !,139fLL_E.F_

" "

Figure 1. Vertical profIles of temperature and salinity showing data comparison of CTD and Prof1ler during tandem casts.

0

" " " " " " " fj

" " " Vi' 65

~ 70

m " 8 80 .s. as

w" ~ " ~ Vl 100 ~ 105

[ 110

'" '" '" ,;0

m

'" '" '" '" '" '" '" n'

0 , " " " " ;0

" " " " " Vi' " x " « " ro

" 8 " 8 "' w " X

" ~ ~ '" ~ '" w ~ '" ~

'" '" '" ';0 m

'" "' '" '" '" '" '" '"

, "

" '"

Figure 1. Continued.

STATION 046

TEMPERATURE (DEG C) 65775885

SALINITY (PSU)

" '" " '" " '" \

95 10

Legend

~

~~9f1JJ.R..

Vi' ~ «

'" Oi 8 w ~ ~ ~ ~ w ~ ~

Vi' ~

« m U w 8 w ~ ~ ~ ~ w ~ ~

" " " " " " " fj

" " " " " " " " " " '" '" no

'" '" '" no m

'" '" '" '" '" '" '" n,

0 , " " " " 30

" " " " " " " " " " "' " " '" '" '" '" '" '" BO

'" '" '" '" '" '" '" no

'"

"

STATION 045

TEMPERATURE (DEG C) Ii 5 7 7,5 a 65

SALINITY (PSU)

9.5 10

JO~ JI "5 31 ,l5 3J ,'5 " "5 35

Legend ~

f'B9HlJ:.!'_

Page 7

Page 8

'" " '" " '" " '" " " " " " Vi' ~~ ~

< " m " 8 90

o " '--"" 100 W 105

~ 110 Vl 115 ~ 120 Ct: 125 0... 130

m

"" '" '" '" '" '" "" '" "" '" '"

STATION 138

TEMPERATURE (DEG C) 65775H!!5 S.5 10

;66;L----'------------'

SALINITY (PSU)

"·',"~"'"C'C-"'-'-O"C'C-'C'-"'O'O'ci'C',c"C'C-O'·--'C·C'__i" , )/

'" " '" " '" " '" " " " " " '" Vi' 75

~ M

~ 85

8 ;; 8.- 100 W 105 0::: 110

~ 115 Vl 120 tt! 125 0... 130

''" '" '" '" "" '" "" '" "" '" ""

Legend

~ E~9fll_[_R_

'" ,"""-----------------------"------'

'" " '" " '" " '" " '" " " " --;-::;- 70

iY 75

< '" m " U 90

W " 2- 100 W 105

~ 110 Vl 115 t:} 120

~ "' 0... 130

'" "" '" '" '" "" '" "" '" "" '"

"

STATION 042

TEMPERATURE (DEG C) 6.5 -: 7.5 a ~.5 9.5 10

"" '" 'CO' "-------------------------------

SALINITY (PSU)

";'"~c'"C'"-~'C'-'''C'~'"'-"'~'c'~','-'''t'~"'·~,'·C'~'', -~

'" " '" " '" " '" " '" " " --;-::;- 65 iY 70

< " m " 8 :~ 8. 95

~ 100 ~ 105 tn 110

:-:J 115 n:: 120 0... 125

"" m

"" "' "" '" "" '" "" '" "" '" '"

Legend

=--­!:'89f~l_[~_

;6~,JL ________________________ ~ ____ ___

Figure 2. Vertical prollles oftemperature and salinity showing data comparlson ofCTD and Profl1er during cast vs tow.

Page 9

STATION 130 STATION 050

TEMPERATURE (DEG C) TEMPERATURE (DEG C) , " "

, "

, " " " 0

55 657751!B~ QS10 0t-~~~~-L~~~~~'

,

W

" Vi' ~ -< rn " U w 2-w " ~ =0 ~ ~ w " ~ ~

" "

" ,j <0

" "

" "

SALINITy (PSU) 30 305 3, 315 32 325 53 JJ5 J' 3'5 35

o y-----'-~"--"-:-l---"-----'~~'-i

t " '"

SALINITY (PSU)

" '" " '" " H.' " ".5 " 0

(;

w

" Vi' ~

" -< rn U w 2-

" w ~ =0 ~ ~ 30 w ~ ~

"

" " Legend Legend

" ~

~~9EL_EK " I ~ f~9f~L_E_R_

" "

Figure 2, Continued,

Page 10

w

" '" " " " " " " " " " Vl 70

~ " ., "' rn " 8 90

8- 1~~ ~ 105 ::> 110 VJ 115 t:l 120 0::: 125 Q 130

'" '" '" '" '" '" '" '" '" ,eo

'"

STATION 138

TEMPERATURE (OEG C) ~5175~1l~ 95 10

190 I d~~1_ ____ -J ________________________ -J

SALINITY (PSU) 30 3~ 3' ".5 " ".5 " 3l.5 ~ ~,5 ~ ,

Legend "_P ____ _ 99~t:!

w

" " " " " " " " " " " " Vl 7S

~ "' ;Jj 85

8 ~~ 8100 W 105 0::: 110

~ 115 Vl 120

1i 125 Q 130

'" '" '" '" '" '" '" '" '" ,eo

STATION 042

TEMPERATURE (OEG c) 657758BS ~ 5 10

'"' '" '" "'1-______________________________ -J

SALIN!!,\, (PSU) ,0 ,05 ,. 315 " "5 H J,5 " ,'5 ,< ,

W lOS

'5 110 til 115

~ 120 0:: 125 Q 130

'" '" '" '" '" '" '" '" "' ,eo

'" '"

Legend

"_P----­DOWN

~;;1-------____________________ ~

Figure 3. Vertical profiles of temperature and salinity comparing Pro.JUer data collected during down and up casts during bongo tows.

Page 11

STATION 130 STATION 050

TEMPERATURE (DEG C) 555 6577:;B1I5 9510 Ot--L~--~~~~~~~~-,"

, "

TEMPERATURE (DEG C) 6577Sal!S " "0

0

I "

" in ~

< " ~

u w a ~" w ~

" ~ t:3 JO ~ ~

·1 "

"

" ,oJ-__________________________ -1

" SALINITY (psu)

" ,,,

" '" " ,,,

" '" ,< 1._5 <, 0

,+-----------~ ,

" 1

" " ", Legend Legend

" U_P ___ " ~-p----

DOWN !J9_~~_

" "

Figure 3. Continued.

Page 12

TIME (SECONDS)

'" '" '" '" '" '" '" "" '" .00 '" no ," '<0 '"' 960 1020 lOHO 1140 1200 1260 1320

0

L/ 10 ~

20 (f) 30

"" 40 « 50 ill 60 U 70 w 80 0 90 ~

100 w 110

"" 120 ::J 130 (f) (f) 140 w 150

"" 160 "- 170

180 190 station 33

200 210

TIME (SECONDS)

" '" HlO '" ,eo "" '" "" '" '00 '" no m ,., '" '" 1020 IOHO n .. o 120() 1160 1320

0 10

~ 20 (f) 30

"" 40 « 50 ill 60 U 70 ·w 80 0 90 ~

w 100

"" 110 ::J 120 (f) 130 (f) 140 w 150

"" 160 "- 170 180 station 145 190 200 210

TIME (SECONDS)

'" '" '" '" '00 '" '" "" 0 '" .00 ... no '" ... '" 960 1020 10110 1140 1200 1260 1320

10 ~

20 (f) 30

"" 40 « 50 ill 60 U 70 w 80 0 90 ~

100 w 110

"" 120 ::J 130 (f) (f) 140 w 150

"" 160 "- 170

180 station 190 138

200 210

Figure 4. TIme history of tow showing time vs depth. Profiler data.

Comparison of the downcasts and the upcasts did show some pressure sensor problems during the upcast. The mismatch of surface pressure values could not be corrected by a discrete 1 or 2 meter offset. As expected, the Profller performed slightly better on the upcast during an oblique tow than on the upcast during a tsmdem cast. This is due to the placement (upside down) of the ProJUer above the bongo nets so that the conduc­tivity cell always encounters undisturbed water during the tow.

The time versus depth plots show that time histories of the tow could have useful applica­tions. There is the possibility of using time histories during real time data collection to help maintain optimum towing angle by monitoring the speed of the wire out and in.

The at-sea operations involved no modifica­tion to the bongo itself. The Profllerwas attached while waiting for the ship to position itself on station. It detached qUickly and could be carried by one person.

Although data extraction from the unit's memory Is quick (5 minutes or less), multiple casts could be stored if time or personnel short­ages were a problem. Even someone with little or no experience can be trained in less than an hour to use the computer. The six batteries placed in the Profller lasted the entire cruise, approxi­mately two hours total recording time, without being changed.

Page 13

CONCLUSION

The Profller performed well within its limits of sensor accuracy and compared favorably with the CTD in terms of data quality.

Using the Profller during bongo tows saved time when compared with doing a CTD cast and a bongo tow, and did not interfere with the bongo net operations.

Since this test, the Northeast Fisheries Sci­ence Center has purchased three more SBE 19 Seacat Profllers which, in addition to Pro.fU.er #360, have successfully completed more than 4,000 stations in just three years (1990, 1991. and 1992). Since April of 1991, these instru­ments have been used routinely in the real-time mode, saving time because data are stored by the computer asltis collected. This real-time use has also Simplified bongo tows by allowing the opera­tor to know the exact depth of the instrument during deployment.

ACKNOWLEDGMENTS

The author would like to thank Dr. David Mountain for providing suggestions and com­ments during the writing of this report and for overseeing its progress. Thanks also to the crew and scientists who cooperated with the instru­ment testing aboard the R/V Delaware II.

"U

~ ~ ..

• ~ f

Figure 5. Station plot of DE8909 I showing various station operations.

'1300

000

'1100

nOD

"00

"00

i

&

·~i

i

~

§ ~ ~ i ~ ~

~ ~ - - -,

>.:J

"~ ,.~ "r~ [(-- ,: '--. ' 8~ "'-.; "

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! § § i ~ ~

- - - - -,

~~\))\~ ' .. ~~, I B\'( "p '·d -'"---,,, / \8J

C" g~ " ~ ~~8j~\ ( ,.,' ::~ ,\ •.. , .... ' .•. \. "OO," .. '''",AAW",

.=

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lJJ - ~

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~ "ec5 V..,'"

~J25~ 330/

/. '. , "

~ : .. , :';.. BOTTOM_SALlNITi ~ ,', "-J , ~o , ;'

Figure 6, Contour plots of surface and bottom temperature and salinity data taken with Profller.

'U

~ <n

8 § ~ § ~ § ~

~300

i

t~~QD mp"~:" ,Ij< &") .,- '.d \7 ( t ... r~'l~~ .iJ;-~J n . ' ..

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