Observations of colour index, secchi disk depth and total suspended matter in the Skagerak.

OBSERVATIONS OF COLOUR INDEX, SECCHI DISK DEPfH AND TOTAL SUSPENDED MATTER

IN THE SKAGERRAK

Eyvind Aas, Jo !Wkedal, Marit Nyborg and Kai Serensen

INSTITUTT FOR GEOFYSIKK

UNIVERSITETET I OSLO

ITN§TllTUTE ~IEIPO~T SE~ITES

OBSERVATIONS OF COLOUR INDEX, SECCHI DISK DEPTH AND TOTAL SUSPENDED MATTER

IN THE SKAGERRAK

Eyvind Aas, Jo H0kedal, Marit Nyborg and Kai S0rensen

Abstract

Observations of colour index, Secchi disk depth, total suspended matter, temperature and salinity from the years 1988-92 are presented. No simple relations are found, although the bluest waters always will have a salinity above average. The greener waters, on the other hand, may have any salinity. According to our observations, the waters are not signifi- cantly bluer during the winter season, and the Secchi disk depths are not larger. The highest values of the total suspended matter are always found in the greenest waters, but no constant relationship between the total suspended matter and the colour exists.

E. Aas is with the University of Oslo.

J. H0kedal is with the Norwegian Polar Institute.

M. Nyborg is with the Swedish Meteorological and Hydrological Institute.

K. S0rensen is with the Norwegian Institute for Water Research.

1. INTRODUCTION

In 1988 and 1989 the Department of Geophysics at the University of Oslo participated in a project led by the State Pollution Control Authority of Norway, related to the eutrophi- cation of the outer Oslofjord (Andresen et al., 1989, S0rensen et al. 1990). The aim of the department's project was to investigate the relations between the colour index and other quantities like the depth of the euphotic zone (the 1% PAR depth), and the particle and chlorophyll contents. The results have been presented in the two reports refered above, and in the cand.scient. thesis by Andresen (1991).

During the project it became clear that central Skagerrak water represented the clear water end of the relations, while the turbid water end was taken care of by the waters of the river Glomma and the surrounding Hvaler archipelago. It was decided to make more extensive measurements in the Skagerrak, and several cruises were made during the sum- mer of 1989 onboard the research vessel G. M. Dannevig from the F10devigen Marine Research Station in Arendal (S0rensen et al. 1990). In 1990 observations were made in the northern part of Skagerrak as a part of the SKAGEX project, onboard the R/V Trygve Braarud from the University of Oslo.

After a preliminary analysis it was concluded that it would have been interesting to have observations from the winter situation as well, since the algal production is less during this season, and the water possibly clearer and more blue.

Fortunately the Nordic Council for Physical Oceanography was able to support such measurements. These took place from the late autumn of 1991 to the spring of 1992 in the Torungen-Hirtshals section, as a part of the council's Skagerrak project. This paper presents the observations. In order to make a more complete collection, the observations from 1989 and 1990 have been included. The measurements in 1989 were made by Terje Leyning, and in 1990 by Lars Asplin.

2. INSTRUMENTS AND OBSERVED QUANTITIES 2.1. Colour index

The colour index meter has been described in detail elsewhere (Aas, 1993). The under- water part consists of a cylinder which looks downward and observes the radiance L from nadir at the wavelengths 445, 514 and 546 nm. The colour indices F_{1 ,} F_{2 ,} and F₃ are defined as

L(445) L(514)

(1)

F = L(445)

2 L(546)

F = -Fz =

3 F

1

L(514) L(546)

(2)

(3)

The observations were made at 0.14, 1 and 2 meters depth. Their values may be denoted F(O.l4), F(l), and F(2), respectively. The value of the colour index F(O) at the surface may be estimated from

or

2.2. Secchi disk depth

1

F(O) = F(l) (F(0.14))o.s6 F(l)

F(O) = F(l) F(l) F(2)

(4)

(5)

The threshold depth of observation for the Secchi disk (diameter 30 em) has been measured with the naked eye (S₀^{) ,} through the blue BG12 filter (Sb), through the green VG9 filter (Sg), and through the red RG1 filter (Sr).

2.3. Total suspended matter

The total suspended matter (TSM) was measured by filtering a surface sample through a preweighted Nucleopore filter (0.4 pm), rinsing the filter with distilled water, and weighting the filter at-a Sartorius micro balance.

2.4. Temperature and salinity

The temperature and salinity were at all cruises measured with Neil Brown CTD profilers.

3. OBSERVATIONS

3.1. Observations 1989

The locations of the stations in the sections Torungen-Hirtshals and Tjom-Skagen- Jomfruland are shown in Figure 1, and their positions are presented in Table 1 and 2.

The observed quantities are given in the Tables 4-11. 3.2. Observations 1990

The locations of the stations in the sections in the northern Skagerrak, taken during the SKAGEX project, are shown in Figure 1, and their positions are presented in Table 3.

The observed quantities are given in the Tables 12-23.

3.3. Observations 1991-92

During this period the observations were restricted to the Torungen-Hirtshals section. The observed quantities are presented in the Tables 24-31.

4. DISCUSSION

4.1. The sections

No extensive analyses will be made here, but a few features shall be pointed out. In the Skagerrak waters the colour will be mainly influenced by the contents of algae and yellow substance. The yellow substance may be related to the salinity, but the algal content will probably depend more on the available nutrients. The result is that while the higher colour indices usually are found with the higher salinities (Figures 2-4), the positions of the extreme values do not necessarily coincide. The waters were not significantly bluer during the winter season, nor were the Secchi disk depths larger.

The correlation between the total suspended matter and the colour index was very low, although the highest values always seem to be found in the greenest waters.

4.2. The statistical distributions

Figure 5 illustrates how the highest values of F₁ usually is followed by the highest values of F₃, and high values of salinity. The smallest values of F₁ is similarly followed by the smallest values of F_{3 ,} and small values for the salinity. But it is also seen that small values of F₁ and F₃ may appear for high salinities as well. This means that the bluest waters (F₁ > 0. 7) will always have a salinity above average (S > 28), while the greener and the greenest waters may have any salinity.

Figure 6 presents histograms of the three colour indices. From the modes of the distri- butions it can be judged that on an average both L(445) and L(546) will be smaller than L(514), and that L(445) will be smaller than L(546).

Acknowledgements

The field work in 1989 was supported by the State Pollution Control Authority of Norway, and the work in 1990 by the Norwegian Council for Science and the Humani- ties. The Nordic Council for Physical Oceanography fmanced the measurements in 1991 and 92. We are also due thanks to the scientific staff and the crew onboard the G. M.

Dannevig for their assistance during the measurements, and to the Fl0devigen Marine Research Station for the opportunity to make these observations.

References

Aas, E., 1993. Calibration of a marine radiance and colour index meter. Rep. Univ.

Oslo, Dep. Geophys., 87, 24 pp.

Andresen, T., 1991. Anvendelse av fargeindeksmeteret i Oslofjorden. Hovedfagsoppgave, Inst. geofys., Univ. Oslo, 121 pp.

Andresen, T., Leyning, T., S0rgard, E. og Aas, E., 1989. Eutrofisituasjonen i Ytre Oslofjord. Delprosjekt 3. 7: Optiske observasjoner - Overflatevannets kvalitet sett ut fra observasjoner i overflatelaget. SFT-rapport 388/90, 50 pp.

Smed, J., 1979. Manual on ICES oceanographic punch cards. Fourth edition. Cons. Int.

Explor. Mer, 37 pp.

S0rensen, K., Aas, E. og Lindell, T., 1990. Eutrofisituasjonen i Ytre Oslofjord 1989.

Delprosjekt 4.6a: Optiske malinger. SFT-rapport 405/90, 50 pp.

Figure 1. Locations of the sections and stations in the Skagerrak.

0 1 0 20 30 40 50 Km

14A 13A 12A 0

321 0 320

4A 11A

...

OS 6 7

Torungen

.t:J

1e 23.

319 0

0 318 0 317

4. 316°

u..

X w

0

z

a:

:J

0

_J

0

MAY 1989

s•

s•

go

11.

12e

35

/ · ... 33 F · - - · ""

>-

0.6 -

~

. , _~ ~·-· _~.

/

z

" __ cf

'q, .., ... .o... /p-

b---0"'

-a___ //

--

s

0.4 0.2

/

/ _J

29 <C

(f)

27

o~-L--~-L~----~--~-L~--~~25

1 2 3 4 5 6 7 8 9 10 11 12

TORUNGEN HIRTSHALS

314°

313°

312° 0 3~8

0 0 309 311 310

Figure 2. Surface salinity and colour index in May 1989, along the section Tor- ungen-Hirtshals.

1.0

JULY 1989

u:- ) ...

X 0.8 \ •

LU • )).., / '

0 .~ . - - - . ~.~· ^{I '} ..q ',

.

Z 0.6 e / ^I b. .D.. /

/ --..0. ,' --o--o.. __ ^'(Y__ --cf

a: ,,' ',

s

::J 9" 'o----d

0 0.4 /

_ j I

o I

0 0.2 , p

"

0 1 0 20 30 40 50 Km

35

33

>-

31 1-

z

_ j

29 <(

C/)

27

o~~~L--L~--~~~~~~~~~~~~25

322 320 318 316 314 312 310 308 306

JOMFRULAND SKAGEN T JORN

Figure 3. Surface salinity and colour index in July 1989, along the section Jomfruland- Skagen-Tjom.

1.0 MARCH 1992

/.

----o

\ s'

..-- _\

lL

/7J' • \

X 0.8

LU

~·/

""

^>-

0 0.6 ~---- F1 31 1-

z _• z

-

""'·

0

_J ,J:r'

-

0

0 ^0.2 _I ^{I 27}

I I

0 25

1 2 3 4 5 6 7 8 9 10 11 12

TORUNGEN HIRTSHALS

Figure 4. Surface salinity and colour index in March 1992, along the section Torungen- Hirtshals.

1.0 ^{I I I I I I}

0

•

0.9 ₀ ⁰

0

o·

0.8

..

• •

0 0

Figure 5. The colour • •

index FiO) as a func- 0.7

• 0

c.

T""" •

LL • •

..

tion of the surface salinity.

Large open circles are values where

FiO)> 1.2,

large black circles are values where

Fi0)<0.9,

and small black circles are values where 0.9<Fi0)< 1.2.

CJ) 40

0 z

~ > _a:

w ₂₅

CJ)

co 0

LL

0

a:

co

:J

z

X w 0.6 0

z - a:

:J

0

0

0.5- 0.4- 0.3- 0.2 ~

0.1 ^1- 0 18

,-----

' ' -----1 '

•

I

---.

,----

' ' ^{' ' '} ' ' '

•

I I

20

•

•

• • ^••• •

• •••••

. ..

'·

^•

•

, .

• •

.•'

•

•

• •

I I I I I I 1 _j

22 24 26 28 SALINITY

1--,

I I I I I I I I l _____ l

I I

:-

- - ·-' I - - -

00 0.2 0.4 0.6 0.8 1.2 1.4 1.6 COLOUR INDEX

• • ^{• I}

• • •

• •

• •• •

•

• • •

_j_ I ^I

30 32 34

Figure 6. Histo- grams of the colour indices FiO) (solid line), FiO) (thin dashed

line), and F₃(0) (thick dashed line).

-

-

- - -

-

36

TABLES

Quantities which have not been explained in the text are:

Time:

Wdir:

Wsp:

Wea:

Clo:

Sea:

hs:

S:

TSM:

GMT

wind direction in 10 ^o wind speed in knots

weather according to the ICES (Smed, 1979) or WMO code cloud amount in eighths

state of sea according to the ICES or WMO code solar altitude in o

depth in meters concentration in mg/1

TABLE 1 Torungen-Hirtshals TABLE 2. Tjom- Skagen- Jomfruland

Location no. Position Station no. Position

--------

58°24'N 08°46'E 306 58°00'N 11 °20'E

2 58°23'N 08°50'E 307 57°58'N ll⁰12'E

3 58°20'N 08°58'E 308 57°55'N 11 °03'E

4 58°16'N 08°59'E 309 57"52'N l0°52'E

5 58°l2'N 09°05'E 310 57°49'N l0°4l'E

6 58°08'N 09°ll'E 311 57°49'N l0°32'E

7 58°00'N 09°2l'E 312 57"54'N l0°27'E

8 57"56'N 09°27'E 313 57"58'N l0°24'E

9 57°5l'N 09°34'E 314 58°03'N 10° 19'E

10 57"48'N 09°40'E 315 58°09'N 10° 14'E

11 57°42'N 09°47'E 316 58° 16'N 10°08'E

12 57°39'N 09a52'E 317 58°23'N l0°00'E

318 58°29'N 09°55'E

319 58°36'N 09°49'E

320 58°4l'N 09°45'E

321 58°45'N 09°40'E

322 58°49'N 09°36'E

---

TABLE 3 Northern Skagerrak Location no. Position ---

Dl 58°56'N 09a49'E

D2 58°52'N 09°56'E

03 58°48'N l0°02'E

04 58°44'N l0°09'E

D5 58°40'N l0°15'E

06 58°40'N 10°25'E

07 58°40'N 10°35'E

DB 58°40'N 10°45'E

09 58°40'N l0°55'E

DlO 58°40'N 11 °05'E

011 58°44'N 10°20'E

012 58°48'N 10°26'E

013 58°52'N l0°31'E

014 58°56'N l0°36'E

015 59°00'N l0°42'E

016 59°01'N 10a54'E

---

TABLE 4. 1989, May 18-19. Torungen- Hirtshals

---

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

18 0755 20 8 2 2 8.68 29.54

2 18 0900 20 8 3 3 9.51 28.49

3 18 0945 20 8 2 4 9.72 27.61

4 18 1050 21 8 3 4 9.94 27.65

5 18 1220 21 8 3 4 10.13 28.40

6 18 1335 21 8 5 4 10.15 27.64

7 18 1550 21 4 3 4 10.48 27.02

8 18 1730 21 3 3 3 10.60 28.52

9 18 1840 21 4 6 3 10.23 29.03

10 19 1205 22 5 3 3 10.58 30.53

11 19 1025 22 6 4 8 3 10.47 30.74

12 19 0930 22 4 4 8 3 10.10 29.99

---

TABLE 5. 1989, May 18-19. Torungen- Hirtshals

---

No. h, F 1(0) F1(1) F 1(2) Fz{O) F₂(1) F2(2) so sb ss s, TSM

---

1 36 0.61 0.55 0.45 0.61 0.52 0.43 7.5 4 7 3 0.7

2 44 0.59 0.50 0.45 0.56 0.48 0.43 7 3.5 3 1.1

3 47 0.52 0.50 0.42 0.55 0.49 0.40 7 3 5 2.5 1.3

4 52 0.57 0.48 0.36 0.55 0.36 0.33 7 1.5

5 50 0.57 0.46 0.37 0.59 0.47 0.37 10 4.5 7 4 1.6

6 46 0.52 0.48 0.34 0.46 0.45 0.30 7 3.5 5.5 3 1.3

7 28 0.64 0.52 0.46 0.61 0.52 0.45 11 6 9 4.5 0.9

8 16 0.67 0.63 0.54 0.71 0.67 0.57 11 6 8 5 1.0

9 9 0.69 0.62 0.55 0.81 0.73 0.66 10 5 6.5 5 0.7

10 50 0.81 0.69 0.66 0.98 0.77 0.75 11 7 10 6 1.7

11 50 0.72 0.67 0.60 0.84 0.73 0.67 II 6.5 8 5 1.4

12 50 0.65 0.59 0.52 0.68 0.60 0.54 8 4 6 3 2.3

---

TABLE 6. 1989, June 14. Torungen- Hirtshals

------

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

--------

14 0715 05 12 3 2 13.78 25.31

2 14 0800 05 12 3 2 15.79 27.17

3 14 0910 05 16 3 3 15.62 25.42

4 14 1050 05 17 3 3 15.82 25.19

5 14 1200 05 16 3 3 15.82 25.01

6 14 1435 07 16 2 3 14.95 26.17

7 14 1600 08 14 3 3 16.00 26.35

8 14 1715 09 12 3 3 15.41 29.91

9 14 1800 09 10 4 3 14.99 30.09

10 14 1920 09 10 5 3 15.32 29.76

11 12

TABLE 7. 1989, June 14. Torungen- Hirtshals

------

No. h, F1(0) F,(l) F1(2) Fz(O) F2(1) Fz(2) So s, s, s, TSM

---

1 33 0.54 0.42 0.31 0.54 0.37 0.30 5 3 4

2 38 0.50 0.46 0.42 0.53 0.49 0.45 4

3 47 3.5

4 55 0.39 0.33 0.28 0.40 0.31 0.24 4.5

5 53 0.28 0.26 0.25 0.26 0.22 0.22 7 4 5 3

6 42 0.52 0.42 0.34 0.48 0.42 0.37 8 5 7 4

7 31 0.58 0.52 0.47 0.71 0.60 0.51 6 4.5 5 4

8 21 0.73 0.66 0.59 0.84 0.76 0.70 4.5 3.5 4 3

9 15 0.68 0.63 0.56 0.78 0.73 0.66 4 3 4 3

10 7 0.59 0.55 0.50 0.67 0.61 0.55 3.5 2.5 3 3

11 12

TABLE 8. 1989, July 17-18. Torungen-Hirtshals

---

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

------

17 0920 21 8 2 7 2 16.29 23.98

2 17 1020 21 10 2 7 2 16.43 25.52

3 17 1125 22 12 2 7 3 16.54 24.64

4 17 1245 22 12 2 7 3 16.07 26.07

5 17 1330 24 12 2 7 3 15.05 28.97

6 17 1430 24 12 2 7 3 14.46 28.42

7 17 1645 24 16 2 7 4 15.74 27.08

8 17 1832 24 18 2 7 4 15.73 27.36

9 17 1915 25 16 2 7 4 14.92 29.68

10 18 1830 29 8 2 3 15.47 31.75

11 18 1705 29 10 3 15.59 31.76

12 18 1610 29 12 3 15.57 31.54

---

TABLE 9. 1989, July 17-18. Torungen- Hirtshals

---

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

17 0920 21 8 2 7 2 16.29 23.98

2 17 1020 21 10 2 7 2 16.43 25.52

3 17 1125 22 12 2 7 3 16.54 24.64

4 17 1245 22 12 2 7 3 16.07 26.07

5 17 1330 24 12 2 7 3 15.05 28.97

6 17 1430 24 12 2 7 3 14.46 28.42

7 17 1645 24 16 2 7 4 15.74 27.08

8 17 1832 24 18 2 7 4 15.73 27.36

9 17 1915 25 16 2 7 4 14.92 29.68

10 18 1830 29 8 2 3 15.47 31.75

11 18 1705 29 10 1 3 15.59 31.76

12 18 1610 29 12 3 15.57 31.54

------

TABLE 10. 1989, July 19-21. Tj6rn- Skagen- Jomfruland St.

306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322

Day 19 19 19 19 19 20 20 20 20 20 20 20 20 20 20 21 21

Time 0410 0550 0720 0915 1145 0830 1025 1125 1245 1420 1550 1735 1845 2034 0450 0610 0745

Wdir 12 12 27 25 25 01 01 01 01 01 21 21

21 25 25 25

Wsp

2 4 3 2 2 2 2 2 2 2

2

Wea

TABLE 11. 1989, July 19-21. Tj6rn - Skagen- Jomfruland St.

306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322

h, 8 20 32 45 52 40 48 51 50 41 32 19 9 0 12 22 33

0.93 0.73 0.79 0.66 0.87 0.89 0.85 0.93 0.70 0.65 0.71 0.74 1.05 0.61 0.60 0.60

0.86 0.68 0.75 0.63 0.83 0.88 0.85 0.90 0.64 0.60 0.67 0.71 0.94 0.63 0.58 0.54

0.79 0.59 0.76 0.56 0.81 0.84 0.86 0.89 0.58 0.55 0.64 0.67 0.86 0.62 0.52 0.46

F,(O) 1.37 0.93 1.07 0.76 1.15 1.16 1.12 1.26 0.81 0.77 0.99 0.85 1.52 0.74 0.62 0.62

Clo 2 2 4 4 5 4 3 3 2

2

2 2

F,(1) 1.31 0.92 1.06 0.69 1.13 1.16 1.10 1.21 0.72 0.72 0.92 0.85 1.34 0.76 0.63 0.55

Sea 2 2 2 2 2

1 2 2

F₂(2) 1.15 0.86 1.13 0.61 1.09 1.10 1.16 1.16 0.66 0.66 0.88 0.85 1.22 0.77 0.58 0.49

Temp 14.94 15.35 14.98 15.71 15.09 15.74 16.12 14.38 14.53 13.95 15.79 16.23 15.29 16.15 16.26 16.19 16.32

12 14 16 9.5 15

16 15 12 14 18 16 14 14 14 14

Sal 31.51 30.36 30.65 30.20 30.54 30.46 30.81 31.83 31.70 32.29 29.46 29.41 30.36 29.64 26.81 25.81

s,

6.5 10 10 6.5 10

12.5 11 9 8.5 12.5 11 9 9 8.5 8.5

s.

8 12 12 8 11

14 12 10 11 16 14 12

12 12 11

s,

4.5 5 5 5.5 7

9 6 5.5 4 5 6 5 6 6 7

TSM

TABLE 12. 1990, June 8. SKAGEX, Northern Skagerrak

---

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

D3 8 0715 09 22 2 8 4 14.89 24.41

D5 8 0920 06 26 2 8 4 15.05 23.93

D7 8 1105 06 18 6 3 14.46 26.19

D8 8 1200 09 18 2 8 3 14.68 28.87

D9 8 1315 09 18 2 7 3 14.21 26.40

D10 8 1410 09 14 2 7 3 13.58 28.18

TABLE 13. 1990, June 8. SKAGEX, Northern Skagerrak

No. h, FI(O) F1(1) F1(2) F,(O) F2(1) F,(2) s, s. s, s, TSM

---

D3 33 0.56 0.47 0.39 0.52 0.45 0.36 8

D5 48 0.54 0.45 0.39 0.52 0.45 0.40 8

D7 54 0.66 0.59 0.54 0.70 0.63 0.58 7

D8 54 0.75 0.67 0.63 0.75 0.72 0.69 8

D9 50 0.56 0.51 0.46 0.52 0.51 0.42 5

D10 44 0.66 0.64 0.54 0.73 0.66 0.55 7

TABLE 14. 1990, June 10. SKAGEX, No!them Skagerrak

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

D5 10 1450 0 0 17.43 24.15

Dll 10 1330 0 6 15.81 25.48

D12 10 1230 0 0 16.44 21.74

D13 10 1105 0 6 16.16 22.66

D14 10 0950 31 10 15.54 26.65

D15 10 0725 31 10 2 15.22 25.48

D16 10 0545 0 0 3 15.12 24.19

TABLE 15. 1990, June 10. SKAGEX, No!them Skagerrak

No. h, F1(0) F1(1) F1(2) F2⁽⁰⁾ F2(1) F2(2) so sb s, ^{s, TSM}

---

D5 40 0.58 0.52 0.47 0.60 0.54 0.46 12

D11 49 0.68 0.59 0.54 0.73 0.61 0.55 11

D12 52 0.63 0.58 0.52 0.63 0.57 0.52 8.5

D13 54 0.62 0.55 0.51 0.61 0.55 0.49 7.5

D14 50 0.63 0.60 0.58 0.66 0.64 0.61 10.5

Dl5 35 0.62 0.56 0.48 0.61 0.55 0.48 10.5

D16 21 0.50 0.22 0.18 0.36 0.19 0.15 9

TABLE 16. 1990, June 11. SKAGEX, Northern Skagerrak

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

D3 11 0625 31 6 16.66 24.75

D4 11 0800 0 0 4 16.61 24.37

D5 11 0905 0 0 3 16.59 24.28

D6 11 1035 0 0 2 16.55 24.03

D7 11 1150 21 6 2 16.90 18.81

D8 11 1320 20 8 2 16.42 23.97

D9 11 1410 26 8 2 16.72 23.53

D10 11 1510 26 10 2 16.53 25.96

TABLE 17. 1990, June 11. SKAGEX, NorthemSkagerrak

---

No. h, F1(0) F1(1) F1(2) FiO) Fil) F₂(2) so sb s, s, TSM

---

D3 27 0.62 0.59 0.52 0.66 0.63 0.55 10

D4 39 0.55 0.52 0.47 0.60 0.54 0.48 12

D5 46 0.62 0.54 0.50 0.63 0.55 0.49 12

D6 53 0.62 0.55 0.51 0.60 0.57 0.52 11

D7 53 0.59 0.53 0.47 0.54 0.51 0.43 8

D8 49 0.64 0.56 0.51 0.58 0.50 0.45 6

D9 45 0.63 0.53 0.48 0.61 0.54 0.48 7

DIO 36 0.66 0.59 0.52 0.63 0.60 0.54 9

TABLE 18. 1990, June 14. Skagex, Northern Skagerrak

---~---

No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

D3 14 0630 05 22 2 8 3 16.56 20.15

D4 14 0735 05 24 2 8 3 16.50 21.63

D5 14 0840 05 26 2 8 4 16.47 23.18

D6 14 0940 05 18 2 8 4 14.32 28.75

D8 14 1200 09 10 2 7 3 16.52 21.19

D9 14 1310 09 4 5 3 16.82 21.17

D10 14 1405 09 3 2 2 17.64 23.69

TABLE 19. 1990, June 14. SKAGEX, Northern Skagerrak

---

No. h, F1(0) F,(l) F,(2) F2(0) F2(1) F2(2) So s. s, s, TSM

---

D3 27 0.52 0.51 0.41 0.52 0.45 0.36 6

D4 36 0.55 0.54 0.46 0.55 0.43 0.38 6

D5 42 0.67 0.59 0.56 0.67 0.58 0.52 7

D6 50 0.59 0.56 0.55 0.63 0.60 0.58 7

D8 53 0.55 0.52 0.45 0.54 0.48 0.42 8

D9 50 0.59 0.59 0.50 0.58 0.55 0.45 7

DlO 46 0.66 0.60 0.54 0.64 0.57 0.51 8

TABLE20. 1990, June I6. SKAGEX, Northern Skagerrak

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No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

D5 I6 1130 3 16 5 3 15.71 I6.46

Dll 16 1025 3 19 6 3 15.58 22.38

D12 16 0920 3 19 6 3 16.62 22.09

DI3 16 0830 3 I9 6 3 I5.26 15.99

DI4 16 0640 3 I4 6 2 I6.46 24.07

DIS I6 0455 3 I6 6 2 I5.28 5.70

DI6 I6 0400 3 10 6 2 I7.4I 20.74

TABLE 2I. I990, June I6. SKAGEX, Northern Skagerrak

No. h, F₂(0) F₂(I) F,(2) s. s. s, TSM

D5 54 7.5

DI1 53 7.5

DI2 48 6.5

DI3 42 7.5

DI4 30 8

DIS 15 8.5

DI6 8 5.5

TABLE 22. 1990,June17. SKAGEX, Northern Skagerrak

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No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---

·o1 17 0330 07 16 6 8 2 16.55 23.04

D2 17 0515 03 24 7 3 16.46 22.74

D3 17 0620 03 27 6 3 16.71 24.22

D5 17 0850 03 16 3 3 16.67 24.40

D6 17 1020 03 16 6 3 15.23 18.79

D7 17 1130 03 13 6 3 16.89 24.80

D8 17 1250 03 11 7 3 16.96 24.83

D9 17 1340 03 13 2 8 3 16.58 24.07

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TABLE 23. 1990, June 17. SKAGEX, Northern Skagerrak

No. h, ^F2(0) F,(1) F2(2) s, s. ^{s, TSM}

D1 5 6

D2 18 6.5

D3 26 8.5

D5 43 10

D6 53 9

D7 54 9

D8 52 9

D9 47 10

TABLE24. 1991, November 18-19. Torungen- Hirtshals

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No. Day Time Wdir Wsp Wea Clo Sea Temp Sal

---...\.------

18 0723 31 6 2 7 2 7.40 26.23

2 18 0800 31 18 2 8 3 8.38 28.72

3 18 0846 5 20 2 8 4 8.96 31.74

4 18 0947 5 16 2 8 4 8.55 32.92

5 18 1103 5 20 2 8 4 8.33 31.51

6 18 1237 5 22 2 8 4 8.40 31.48

7 18 1434 5 20 2 8 4 8.58 31.88

8 19 1400 5 18 3 8.78 32.38

9 19 1305 5 18 3 9.36 33.85

10 19 1226 4 18 3 9.04 33.77

11 19 1123 5 18 2 3 9.21 33.64

12 19 1029 5 18 3 9.32 34.01

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TABLE 25. 1991, November 18-19. Torungen- Hirtshals No. h,

1 0

2 4

3 7

4 11

5 13

6 10

7 2

8 4 0.55 0.55 0.55 0.70

9 9 0.61 0.58 0.55 0.64

10 10 0.58 0.52 0.47 0.57

11 13 0.58 0.52 0.47 0.62

12 12 0.54 0.47 0.41 0.52

F,(l)

0.64

0.63 0.57 0.61 0.58 0.54 0.51 0.55 0.49 0.42 0.34

8.5 9 8 8

8 5 6 6 5 3

3.5 5

4.5 3 3.5 3 3.5 2.5

5.5 5

5.5 4 4 5 4.5 2.5

s,

2.5 2.5

2.5 2.5 3 4 3 1.5

TSM

0.30

0.28 1.21