'. t, -,:,:' '1
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....DATA
REPORT
OF CURRENT,
TEMPERATURE
AND
PRESSURE
OBSERVATIONS
STRATIFIED
CENTRAL
NORTH
SEA
1980
-
1.982
July
1986
Leo
Maas*
and
Hans
van
Haren*
*Present
adiess:
Introduction
During
springs,
summers
and
autumns
of
1980,1981
and
1982 a
collaborative
study
on
the
seasonal
stratification
of
the
Central
North
Sea
was
performed
by the
Netherlands
Institute
for
Sea
Research,
the
Institute
of
Meteorology
and
Oceanography
Utrecht
and
the
Royal
Netherlands
Meteorological
Institute.
Table
1 lists
mooring
positions
(shown
in fig. 1), local depths, meterdepths, operational periods and
samplingperiods of current meters, pressure gauges and thermistor
chains. Additional current meter datasets on periods not covered in
this datareport exist with the Royal Netherlands Meteorological
Institute, the periods shown here being characterized by the existence
of simultaneous current, temperature and pressure records.
Hydrographic surveys are described by Maas (1981) and van Aken (1981
,19~3a). A description of the meteorological circumstances can be
found in Kleverlaan (1982) and van Aken
(1983b).
The dataprocessing
All instruments were deployed at approximately toe same time (within
one day). A mutual origin of time was adopted,
dictated by the latest
starting instrument. By simple time-averaqing
,
current, pressure and
temperature data were reduced to hourly values, which datasets formed
the basic timeseries to be presented here.
Four types of standard analyses were used to produce
:
1) Low-fre
-quency fields, 2) Tidal Harmonie series, 3) (Tidal band
) residual
signals and 4) Fourier Spectra.
1) Low-frequency fields
In order to produce low-frequency fields we performed a "50 hour
running mean procedure" twice. This procedure is best demonstrated by
focussing on the processing of the temperature signals in
1980.
Consider the original timeseries of the eleven temperature sensors in
fig
.
2a
.
After applying a 50 hour running mean
,
corresponding to
averaging over four semidiurnal periods, figure 2b shows that the
semidiurnal tidal signal is strongly reduced, but still present. A
2
Table
1 Positio
n
s,
de
p
t
h
s,
local
sea
dep
th,
op
e
rat
i
o
n
al
perio
d
s
and
sampl
i
ng
periods
of current
met
e
rs
,
pressure
gauges
and
thermistocha
i
ns
i
n
1980-1982.
CUrrent
met
e
rs
N
A
54°46'
B
54°46'
C
54°41'
D
54°41'
E
54°30'
F
.
54°35 '
G* 54°27'
H
:'
54°28'
'
;
'1
54°30'
::J
~
~
4
°
35,
:K
:5
4°27'
"
L
"54
°
21'
''
'
E
depth
s
(
m_>
" 01-'"3
°
3
8
.
'
"
..
J 6
.
.
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4
1
.
3° 47 ,'
.
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.
14
28,
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4
r
27
0
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.
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3tÇ:'.:
13,19,31;38,45
4
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1
3
-;
2
9"
;
4
S
4°22'
13,29,45
*
4°38'
'2-,
28,
42
4°30'
á~
24,
ClO
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7
1.~
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12,43
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(
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1981
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240-273
24Q-273
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3
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1
9
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dt
(
min)
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4°30'
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4°
30'
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54°30'
r-, :5Q54
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12-32
I
54°30
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4°30'
11-31
K
54°27'
4°22'
11-31
L
54°27'
4°38'
9-29
13
3-155
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I.." •• I.'I ''Figu
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a) Map
o
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fvt
he North S
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Lsob'atih ,
c
e
ntral
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ans
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'
0
'(A)and'1981,1982
(B)
.~ J .:; (
and maaring positians af press~regauges ~
(j=1,2,•••,10)
h) Current meter
(+) and thermistarchain (a) maaring
positians within the areas A and B.
v .•.• " :j :j c' !',i .~.' -', :') "
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00
lil !!! !!~
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198015
=
d
260 ORTNR 26SFigure
2 Temperature
( °C) at the eleven sensors for the original
(a),
filtered
(b) and twice filtered
(c) timeseries. From the
latter graphs inverse inte~pàla
t!
~n g
i
ves timeseries of
I
depths of iso
t
herms (
i
n
°C)
(d).
5
second applicat
i
on of this 50
h
our running mean operation yields
figure 2c, from w
h
ich the tidal signal is virtually absent. This
procedure corresponds to applying a spectr
d
l tr
i
angular Bartlett
....<'.
window
(Jenkins and Watts,
.
1968) to th
~
'
d
ata~ Note t
h
at a 50 hour
ruiming mea
n
'
pzocedtrr
e in pr
i
nciple gives a dat;
a
Loss of 25
h
ours at
bat
h
the
.,p
eginning
and
'~
~d
of the timeser
i
es
.
F
ox t
.
~i
sreaso
n
a
correction procedure was performed over these points in that the first
and last 25 datapoints were subjected to a 25 hour running mean, of
which the first and last 12 points were treated with a
12 hour running
mean, of which, finally, the first and last 6 points were kept
constant.
In
our
op.i.nLon
t,hisstill gives ~
Lnf
ormati.i.o
ns
-
although
I I.
!
the errors introduced will increase towards the endpoints
'
an,d
'
some
I. .
discontinuities result at the matchingpoints
(see fig. 2c).
·,
rf it is
....~.I.
preferred, the reader may.just drop the information conta
l
ned in"the
",
first and last 50 h.ours (50, because of the repeated runni
n
a mean
"j
l.;
procedure) •
"
~
",
.
'.
...
-
'2}
-<ridal
H
'
armonic Ser
i
es
The
·
ö
r
igihá:l
·
times
e
riesof currents and pressp,re
s
were subjected to
a Harmonie Analysis (Dronkers, 1964) with
.
,.
_
]
"
frequencies
(table 2), of
,
,
f
·
Table
2 Tidal and inertial:frequencies used in
t
he harmonic analysis
.
o
The inertial frequency is taken at a latitude 54 30
'N
.
Symbol
frequen
cy
(x10 -4
S-1)
f
1
.
184
0,
0
.
675977
Kl
O
.
792116
;.,,
.N
2
1
.
378797
~2
~
1
.
405189
!';~S2
'
.
454441
.
J' .,M4
2
.
810378
1 .... r:', ~:: '-1.-
-
..
'\ " .~
1
,
,
4.
215
~
;
5J
6
i:.
'
';;;2"" :.~ ·:':'l·q~·r:
»
l!' ~";'_A 16 A 41 B 14
B
28 B 41C
13 C 41o
27o
41E
13E
19 E 31E
38E
45 F 13F
29F
45G
13 G 29H
12 H 28 H 42 1 12 118 I 24 I 30 I 37 1 44 J 12 J 43K
12 K 27K
44 L 12 L 27 L 42 P,1P2
P3 P4 PS P6P7
P8 P9P
l
O
o
1 K6
f S 2 M 4UIpVIp UIpVIp UI/V" UIpV" UI{IV'I UI{IVIp UI{IVIp
u
v
u
v
u
v
u
v
u
v
u
v
u
v
.5 256 1.6 112 1.2 259 1. 5 121 .7 243 1.5 129 .5 230 2.0 121 1. 2 263 1. 2 113 .5 234 2.1 114 1.2 256 1.4 118 .4 255 1.7 124 1. 3 259 1. 6 122 1.2 305 1.8214 1.3 282 1..4 225 1.2 293 1.2 222 1.2 293 1.3 220 1.0 294 1.2 229 .8 324 1.6 211 .6 314 1.6 232 .8 304 1.5 226 .8 341 1.6 214 .6. 310 1.4 231 1.4 321 1.6 204 1.4 286 1.6 241 1.1 317 1.3 231 .63592.1299 .8 13 2.3 299 1.1 27 1.4297 1.0 61 1.5 291 1.2 62 1.7296 1.7571.6300 1.172.2297 1.5 57 1.5 293 .6 11 2.2 302 1.1 64 1.8287 1.6 54 1.3 298 .6 326 2.1 300 1.4 53 2.0 293 1.4 51 1.4 301o
Z(cm) 4.4 3.4 3.7 3.5 6.5 4.1 3.5 4.5 5.2 5.5 .3 67 1.5 247 1.0 38 1.2 262 .5 51 1.3 253 .3 336 1.8 275 .9 37 1.0 264 .4 47 1.7256 .9 44 1.3 266 .3 56 1.8 276 1.0 33 1.5 265 N 2· M 2 1.2 158 1.0225 4.5 126···~~3.i55"_tet98'_194.F.4,).?~._7~~~ 94'1.7 57 .7350.6781.11391.52213.02176.3864.91Ü-2-.-9"·20 .7 177 .5 202 3.8 126 .2 289 20.6 194 2.2 81 7.5 94 1.8 48 .9 307 1.1 68 3.9 104 .4 122 19.9 194 1.8 67 7.3 97 .7 56 .5 329 ';6 60 '''6 139 1.7 3'12.S :217 5'.5"19,,4.4· U,9 2.6 '22 .7155 .8224 3.5 108 .332620.5 193 .9 88 7.4 90 1.7 55 1.0 325 .6 '56 2.0 157'2'.7"'24 15.8 214'6~0 .80''
S.?
·
10?2.~5. 15 .5356 .6 82 4.1123 .5 1118.7202 1.8 73 6.3101 .7 12'" .5·339 .5 64 '2.2 14,1 1.3 ;156.14.32-08 5.6;
'
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.
i
os
h
8
.
.
1
6.
.8 119 1.8281 2.0263 2;0 357. 5.7 l40:2,8 284 23.·9 268,'~O 75 7•.5 ,?7 .4354 1.1 40 1.6 305 1.7 94 1.4 179 5.6 121 .4 218 25.1 2672.3
275' 8.3 98 1~3"
'Ó
$
'
.8 38 1.7 '300 ... 7.73
:103 143 5.6 ·109 .8,45,,25.8472 ",3. ~6 8.3 98 .3276 .9 37 1.9296 .7 68 1.0 173 5.9 113 .4304 2j.6 279 2.9 123 '7.3:'108''';7':ti
..·
.9 38 '~4·298 ",.4 :44 1.0 173,4 •.6 136 1.6,342 '2.7.289~.8
..
14~..<6 •.2 113.1,.4359 .2271.82902.72642.33506.2124.9'234'24.6268 ·."72817;11·02··".7·,0", .9 35 1.9299 1.2 68 1.5 183 5.5 lIS 1.0 134 24.9 273 1.3 145 8.1 102 .8 145 1.0511.2303.6357.11273.91442.4020.42865.51436.2110.9 29 .4 91 1.8 290 2.6274 2.5 347 5.5 124 .3 270 23.9 267 2.0 274 7.0 101 1.2 69 .8 8 1.5 313 2.3 101 2.0 189 8.0 139 1.4250 25.8277 1.4 28 7.9 98 1.1 113 .8 106 1.9289 1.8273 1.5 358 6.9 12'5 .8 261 27.3 270 1.6"'319 8.7 105 1.1 174 1.0 15 1.2 307 1.0 80 1.0 128 6.7 121 .1 314 28.1 272 ';.8' 355 8.8 96 1.5 105 .9 37 1.3 303 .5 63 .4 155 4.7 136 1.3 121.8288 6.3: 1l?4 6.5 119 1.9344 e-._':- "",.. • 2 228 .6 116 .3 250 .6 139 .0 247 .8 95 .2 266 .9 103 .1308 .7144 .3 244 .6 109 .3 203 1.1 122 .3 225 .9 107 .3 226 .7 134 .4 163 .9 239 .0 143 .9 269 .4 193 1.4 294 .3 58 .9 268 .2 91 .9 284 .2 307 .9 284 .0 124 .8 257 • 1 190 1. 1 290 .13221.0274 .6 42 1.2 287 .1192 .9256 .2 103 1.0 259 • 1 270 1.2 302 .4 99 1.4 141 .4 71 1.7 147 .33471.6145 .2 6 1.1 141 .1791.5129 .2 317 1.2 137 • 1 38 1.2 138 .1 16 1.3 91 • 1 156 1. 5 140 .3 68 1.2 120 .22411.1143 .2 118 1.1 118 • 1 28 1.2 122 .3 72 1.3 119 M 4 I{Iz
Z(cm) 1.2 332 2.3 251 1.2 4 2.3 261 .6 47 2.9 256 .2 37 2.5 257 .5162.5256 1.1 211.8254 1.2 352 1.9 248 1. 2 12 1.8 263 1.4 348 2.4 243 .1 322.3261 .9 1 1.9 264 1.3 345 1.4 251 .2 49 2.6 261 1.0 2 1.7 261 K Z(cm) z 218 239 248 225 2.6 2.8 2.4 1.9 2.32'01 1.3 279-',.3:·'l-nS-""-';"if"·J7"23.6l~5':
.8'
285 7.5 80 1.2 9 1.2256 1.4 352 4.4 116 .3,52 23.0 6 1'.4349 8.0 72 1.6 61 1.7353 1.9 84 3.9 117 .6 9424.0 72.0 3 7.7 78 1.1 88 .7 22 1.3 135 4.1 135 .1 17? 25.1 13 1.4 150 8.1 82 .7 154 .777 .914si 3.11441.635222.5132.72207.682.2245 .8 36 .8 116 2.2 13,1 1.3 26 17.2- 25 6.4 25" 6.4 85 1.0 333 2.8 219 1.9290 4.2 122 .5 3{ 22.7 .,"'1.2 317 7.1 80 1.3 39 .7109 .71a6 1.915.81.5 1818.1205.32546.6961.4334 1.7228 1.9 309 2.9 119 1.2 56'22.7 8 2.1 342 7.2 83 1.4 35 2.0 19 1.9 1~1 3.9 123 .5 180 24.3 11 .4 " 7.7 84 .7 70' .6 89 .3,.138 3.0 140 .8 )45 11;.,~ 26-.!I
.
8 ~53 5.9 90 1.7 1 2.3 1S6'·2:·~-Z77-·3':7..t3->r-1':'0'''"23-24-...'6-,·6-·;.2. 58 7.2 78 1.2 83 .L~tO ...9 103 4.512's· .3264 26.6 82.0 103 7.7 75 1.6 72 .4 47 .4 122 2.6 ,;26 1.2 40 19.5 18 5.6245 6.9 90 1.5326 N ,2' '.' '~.'''.:'' M2 S 2 z 4.0 3.8 4.1 5.3 115 158 127 132 300 311 306 268 8.7 5.1 4.6 5.6 Z(clIl) z 53 4.3 4.6 4.4 4.2 331 278 282 268 358 32 329 2 Z(cmT Z(cm) 3.9 5.0 116 138 ':, .z
l~:~..Table
3
Ampl
).
tudes
and
phaae s
from Harmpnic Analysis
of
a)
East
(u)
and Nort
h
(
v
)
veloeities
(cm/s)
b)
surface
elevation
(cm)
17 49 62 40 273 22 300 222 .5 .3 .2 .4 6.6 8.3 7.8 4.8 154 178 168 147 34.3 36.7 34.2 23.7 244 255 239 212 11.3 13.2 11.9 7.3 160 171 151 118 34 44 36 7
,
11.5 7.7 6.6 7.5 .1 .3 .3 .3 192 142 244 182 124 139 131 64 37.2 218 8.6 ~..~.
..
.3 .3 292 19 23 ·10.1. 5.3 6.1 92 155 34.7 317 25 9.4 ·12...·1 , .,t:_-ó.:.
_
•
'
,-,' f,. : ,:..' :'. ; .t t'•7
wh
ich only t
h
e loca
l
inertial frequency is of a non-ti
d
al nature.
Resul
tin
g ampl
i
tude? and p
h
ases have been tabulated
(
table 3),
w
h
e
re
phases ref
e
r to
1 Janua
r
y 00.00 of
t
he correspond
i
ng year.
3
)
'
(t
i
dal b
a
nd
)
r,
e
s
i
duals
i
gnals
,
.
~
he
lów-
f
requency
,
fields a
n
d
,
harmonie t
i
meseri
e
s
(for curren
t a
nd
:
:-
v
·
.
.:'
pr
e
ss
ur
e:
f L
é
Ldä )
a
r
e s
~
bt
~
acted f
,
roin
t.
h
eoriginal timeseries
t
o
.
...
.
.
_
:. ,. " . '.:" .p
r
od
Ü
ce
'
I:
e
si
d
ti
à
l
s
'l'
.
·
l
l'
Fourier spectr
e
:
,
Um
of
s
+
9:n
a
1
~
t
he
~
?
~n
:
d
~
s
~
ed
'
fi
l
ter
:e
d,
with a
this
'
high frequency, no
i
sy
e
os
i
ne hell window
(f
i
g. 3)
i
~~
o
*
po
r
at
i
'
ngth
~
se
m
iq
-t
urnal frequency b
a
nd, w
i
th half width po
i
nts
..
a
i
,'
1
~
'i
2,x
:
1
ö
*~
:
(
.
-
fi
$
~
-
~*
J
.i
'1)
'
and
1
.
•
S
·
SX 10**(
~
:
4
'-
5**
(
-1) •
.
.
.
..
..
,~. .,-~
:~,. I :.;'. .:. :,i
~
.
r
,
L
j. , ,I p: ,(. '::~,,
',
Oi
5
'..
..
..
J ,..Figure 3 Bandpass filter, i.e. aspectral
weighting factor as a
func-tion of frequency. Labels Land
M give the width of the
.
.sLoping:
reg
i
on and
,plateau in units of the fundamental
fre-quency bandwith.
~
..4) Four
:i;;
e
spe
r
_çt
r
a
.')'.
Both the original as well as residua
l
signals we
r
e
Four
ic
rtr
a
nsformed.
'
Th
e
r
av
sp
e
ct
ra
(
2
d
egrees
o
f
f
r
ee
dorn)
a
r
e
presented in the dimensional magnitud
e
s, allowi
n
g a direct
determination of amplitude values
(
i
nstead of giving the power
spectrum,
'
from which the energy contained
iri
'a
frequency bái1d can be
derived) •
Each of the physical fields requires some specif
i
c analyses
w
hich
will now be described:
8
Current
field
a} The low-frequency current vecto
r,
s
-
are presented as stick-plots,
in which the direction corresponds to the obse~ved current direction
and the length of the stick is determined by the key given at the top
of each plot e.g. fig.
10.
b} In
1982 the currentvectors hav~ been proj~c!ed into a specific
direction
(33
T,
the inferred frontal qirection) and a correspondfriq
perpendicular
direction (303
T). I? these pl~ne? velocity contours
(isotachs) have been determined
(e~g. fig. 59).
c} Currentspectra
for V
(North compo~ent}h
,
ay.~_peen displaced two
orders of magnitude for clarity. CUrrents are sometimes better
described by separating the ellipsoidal motion into two counter
rotating circular current components
(fig. 4). The corresponding
timeseries hàve been analyzed
·
to
:
9ive
'-
rotary:speètrà
(e
~
;
~g
'
fig.
.
I"l7).
"
..
'.
-
.."at
-t=O
(If)
;'f" .'+
",
Figure 4 Decomposi tion of tidal current ellipse
(frequency
0- )
specified by the four ellipse parameters
(long axis U,
excentricity e
=
V/U
Iinclination
't
and phase angle
q>
- :- 1 • •~. .'" -: ~_~•• ''_
into two counterrotating circular currents of constant
magnitude
R± and phase angles
e:!:.~
d) The low-frequency current fields, obtained at different vertical
positions, have been separated in a shearing and advecting current
field, a separation suggested by the thermal wind relation
(Holton,1919). Note in figure 5 that th~ separation is not complete in
...A ~..Jo.
t.hes~nse
t.hat;
VIA.
and
-
('\0
-
vI.
'
)do no
t;
allow a reproduction of the
original
V
o
and
"I .
The velocity -<liffeI\ence
.
(v
o
- v )
.\-
has been
'9
COld Worm (a) Cold J. !.-.~-:__"::.', .~
;-_-. ".\~ c ::,.~.--~ .Ta. S
T
;.: Worm (ti) ...--
~
-....
Figure ?
~
Rela
~
ion between turning of geostrophic cur
r
ent
(bottom
Vo
surface ~
) and temperature advection: a) cold advection
\
b) warm a<;lveçtion.
The shearing "thermal" current vector has
warm water
'
at
,
its
·
"
r
ight hand side (on the No
r
thern
Hemisphere) •
.
~ter
Holton (1979).
""
...~
e) The tidal harmonie series of current amplitudes and phases have
been combined into i) current ellipses, e.g. fig. 93, and ii) vertical
_,
graphs showing the vertical profiles of these variables, e.g. fig. 98•
.
,In the latter graphs phases were taken relative to
the surface
"r '
-current meter phase válue of the same mooring.
An
alternative way to
display the information is by forming the amplitude and phase diagrams
of the counter rotating circular velocity components. The physical
advantage and meaning of the theoretical curves in these figures is
discussed in Maas and van Haren (1986).
Pressure field
The pressure fields are converted hydrostatically to elevations.
These, however, have no fixed datum,
'
i.e. the cO'rresponding
'
elevations
are accurate up to an additional constànt
..
This means
'
i
hat
'
an unknown
mean spatial gradient may
'
e>Eist.
10
Temperature field
The observed temperature at each of the sensors of the thermiptorchain
can either be displayed directly as a function of time or as vertical
d
ä
sp.Lecement.s
to which they can be converted.
This conversion
process, performed by an inverse cubic spline interpolation, is
illustrated
in fig. 2c and 2d, applied to the low-pa~sed temperature
observations.
By subtract
i
ng the low-passed temperature
,
field fxo~ t
,
he0HigipaJ_.
data, the temperature fluctuations at the aenso
r
,
.
d~pths are
obt.a
.
i.n
ed
and may be readily compared to the low-passed eLevat.Lon
.
field itself.
.. •: ~'J:
"-;',." r;:..:'
" ..;
'
-:.
Acknowledgements
We are happy to thank captain Blok and his crew, of
R.
V..
~rq;l
.
,
.
.tor
the pleasant cooperation during the hydrographic cruises
~:
in
,
1981and
1982.
Thanks are also due to Oick Riepma of the Royal Netherlands
Meteorological
Institute, to Hendrik van Aken of the Institute for
Meteorology and Oceanography Utrecht and to the Hydrographic Service
of the Royal Navy for providing us with current, temperature and
pressure data respectively.
The financial support from the Netherlands Council of Sea Research
is gratefully acknowledged.
11
Reports
on
the
strat
i
f
i
ed
N
orth
Sea
Pro
j
ec
t
an
d
References
Aken,
H
.M.
van,
19
8
1
.
Project
gelaagde
N
oordzee
CTD-
w
aarne
m
i
n
ge
n
1
9
81
,
IMOU-i
nt
ernal
report
V
81-33.
Ake
n
,
H
.
M
.
van,
1983a. Project "gelaagde
Noordzee 81/82"
CTD-waarne-mingen
1982, IMOU-internal
report V 83-8.
A
kén
,
'
,
H.M. vàn
'
,
'
1983b. Project "gelaagde
Noordzee 81/82"
meteorolo-gische
'
waarnemingen
1982, IMOU-internal report
V 83-18.
'
:
Aken,
'H
.M'.
,
van,
-
1984.
·
A one-dimensional mixed-Iayer model
for
stratified shelf seas with tide- and wind-induced mixing,
ot. Hydrogr.
Z., 37, 3-27
Aken, H.M. van,
1986. The onset of seasonal stratification in shelf
seas
due to differential advection in the presence of a salinity
gradient, Conto Shelf Res., 5, 475-485.
Aken,
H.M.
van, G.J.F. van Heijst and L.R.~1.Maas,
1986. Observations
of fronts in the North Sea (in preparation).
Haren, J.J.M. van,
1985. Verwerking en analyse van getijsignalen in de
seizoensgelaagde centrale Noordzee, IMOU-internal report V 85-7.
Haren, J.J.M. van and L.R.M. Maas,
1986. Temperature and current
fluctuations due to tidal advection of a front (in preparation).
Kleverlaan, E.J.A.,
1982. Meteorologische omstandigheden tijdens
projekt gelaagde Noordzee,
1981, D10U-internal report V 82-20.
Maas, L.R.M.,
1981. Inwendige getijden in de Noordzee & onderzoek
naar overgangsverschijnselen tussen gelaagd en ongelaagd water,
IMOU-internal report V 81-3.
Maas, L.R.M. and J.J.M. van Haren,
1986. Observations on the vertical
'
.
st.ruct\}re
of t.Lda
L
and inertial
currents
i
n the North Sea, submitted
to J. Mar. Res.
Dronkers, J.J., 1964. Tidal computations
in rLvers and coastal waters,
Amsterdam.
Holton, J.R.,
1979.
An
introduction to dynamic meteorology,
Inter-national Geophysics Series, vol.
23, New York.
Jenkins, G.M. and O.G. Watts,
1968. Spectral ~nalysis and its
12
Contents
of
figures
---
Current
fields---1.U
(East)
and
V
(North)
velocity
components
of
hourly
timeseries
of
stations
listed
in
table
2.Low-frequency
stickplots
and
,when
available,
advection
and
shear
graphs
3.Residual
band-passed
U and
V timeseries
4. (Raw)
spectra
of
U and
V
5. (Raw)
rotational
spectra
---
Pressure
fields---
·
--
·
1.Hourly
timeseries
of
surface
elevation
field
at
each
station
2. Low-passed
pressuresignals
3.Residual
band-passed
elevation
series
4.(Raw)
spectra
of
the
elevations
---
Temperature
fields---1.Original
timeseries
2.Low-passed
timeseries
3.Corresponding
low-passed
internal
elevation
field
Figure
1980
1981
19~
,
~
.:
"_._,. : \;
;
6-9
27-
45-1•
31
54
10-
32-
55-11
34
61
-12-15 35-39 62-71
16-17
72-76
"
_-
-
..
,
.
.'.-...-.~
,77
:-
8
"
'2
..
,18
40
83
:-
.
19
41
83
20
41
21
42
84
22
23
23
43
43
89-91
85
.
86,
4.Temperature de:viations (unfiltered and filte
r
ed
'
) 24-2-5
'
,
4
4
'
:
·
:87
....;
88
5.(Raw) spectra of the temperature deviations, the
resulting values being displaced by an order of
magnitude for clarity.
To eompress the bulk of information not all of these
graphs are shown for all stations.
These figures
a
re followed by some
g
rap
h
s showing
eombined information for the three years, sueh as:
4) Current ellipses following from Harmonie Analysis
5) E
l
lipse parameters, of original eurrent ellipses as
weIl as of their rotary eomponents, as a funetion of
depth.
26
93 - 97
98 - 109
1980
D
E
PTH=
16 M
19
8
0
D
E
PTH= 41 M
a
1980
D
E
PTH
=
16 M
1
9
8
0
A
D
E
PTH
=
41 M
b
Figure 6 Timeseries of hourly current veloeities in East (al and
N
orth
(hl direetion at position A,
1980.
N
ot
i
ee
t
he different
1"9
80
+-.,D
EP
TH=
14
M 0B
CD (/) <, :Co (J ::J 0 CD t1
9
8
0
D
EP
TH=
2
8
MB
1
9
80
B
DE
P
TH
=
'itM
Q
lil
t~~t,O~~~2t.~S~~~2~SO~~~~2S~S~~~2i60~~~2~6S~~~2~7no~-L~2d7~S~-L~~-L~~~~~~~-L~~~~~~~-LdD
A
YN
R
oapTlh'
1'1
1'11
980
B
D
E
P
T
H=
2
8
M
>1
9
80
B
D
E
P
T
H
=
4
1
M
>b
Fi
gure 7 As
fig.
6
a
t B.
1980
C
D
E
P
T
H=
13 M
V15
°~~~~~~~~WW~~~~~~~~~ruw~~ww~~
1
9
8
0
C
D
EP
TH=
4
1
M
a
<.1
9
8
0
C
DE
P
T
H
=
1
3 M
>1
980
C
DEP
T
H-=
41
M
b
Figure 8 As f
i
g
.
6 at
c
.
,
,
:-
.. ', !; .-~1980
o
DEPTH=
27 M
lil
I1980
o
DEPTH=
41 M
a
lil
1~~~O~~~~~S~~~~~O~-L~~~S~~~~~O~~~2~6S~~~2~70~~~2d7~S~_L~~-L~~~~~~~-L~~~~~~~~DAYNA
1980
o
DEPTH=
27
M
>1
980
o
DEP
T
H=
41
M
g
1~2+'40~~~2~4S~~~2~S~OLJ-L~25~5~LL~~~O~~~2~65~~~V~OLJ-L~27~5~~~~-L~~~LJ~~~-L~~~LJ~~LL~DAYNA
b
Figure 9 As fig. 6 at D.
16 M
1980 A
.
=
"
,
·
4
10 ClVS "'''"'il
M
24.00 24.50 25.00 25.50 26.00 26.50 27.00OAYN
R
(
..
10
1) 27.50 28.00 28.50 29.00l'i M
28 M
B
es
,J/iIt.w ..iUJiil\\\{« 41 M 24.00 24.50 25.00 25.50 26.00 26.50 27.00 27.50 28.00OAYN
R
(
.<\0
1) 28.50 29.00 29.50 30.00 30.50A
~U
2
'01111 13 Mc
lUl/1/1A
.
""
rlllllfl
JlIII/lUll!!hl/
.tdll!!lfi&.-:
_#
'i
l M
24.00 24.50 25.00 25.50 26.00 ~.50
OAYN
R
(
.. 10
1) 27.00 27.50.
~
27
M
o
11!!!t«e, ,i/I11\\\« 41.M 24.00 24.50 25.00 25.50 26.00 26.50OAYNR
(
"10
1) 27.00 27.50Figure 10 Stick plots of low
-
frequency currents in
1980
.
1980
B
21 M;;
"",
*,,-,
qp
34 M-SHEAA 10••(-21 S.. (-II
24.
00 27.00 27.50 2B.00 OAYNR (,.10 I) 29.00 25.00 25.sa
26.00 26.50 24.501980
B
w
21 M 34 M .""wwlmliliOUIII"! 2B.50 AOVEC 10CM/S 24. 00 25.00 25. <;0 26. 00 26.50 27.00 27.50 2B.00 OAYNR (,.10 1) 2B.sa
24. <;01
980
A
L
=9 M=
4
OEP
TH
=
1
6
M
19
8
0
A
L=
9 M=
4
O
EP
TH
=
41 M
'"
ï~~~O~~~~b5~~~~~~-L~~~5~-L~~~-L~~~~-L~~2~70~~~V~5~OA
Y
NR
1
980
A
L=9 M=4
OEPTH=
16 M
1
980 A
L
=9 M=4
OEP
TH
=
41
M
'"
ï~~~O~~~~b5~~~~~~-L~~~5~-L~~~-L~~~~5~~~V~O~~~2d75~OAYNt\
.
.
Figure
12 Bandpassed semidiurn
a
l residual currents at position A,
1980
.
Labels Land
M refer to their use in fig. 3.
19
8
0 B L=9 M='i
DEPTH=
1'1 M
1980 B L=9 M='i
DEPTH=
2
8
M
1
980 B
L=9
M=
'i
D
EP
TH=
'11
M
111
ï~~~O~~~~~5~~~~~~-L~~~5~~~2~ro~~~~~5~~~2~7~O~-L~~h5~
DAYNR
19
80
B L=9 M='i
DEPTH=
1'1 M
1980 B L=9 M='i
D
EP
TH=
28 M
1
980 B L=9 M='i
D
EPTH=
'11
M Figure
13 As fig.
12 at
B.
111
ïL~~O~~~~~5~~~~~O~-L~~~5~~~2ro~-L~~~*'5~~~2~7zLo~~2~7~S~
1
98
0 C L
=9 M=
'+
OEP
TH
=
1
3
M
~
I
1
980
C
L=
9
M=
'+
O
EP
TH
=
'+1
M
lil
ï
·~~~O~~~
~
~S~~~
2
~SO~~~~d;S~~~
2
~~~~~~~S~~~V~O~~~VdS~
OAYNR
.
1
980
C
L
=9
M
=
'+
O
EPTH=
1
3 M
1
980 C
L
=9 M
='+
OEP
T
H=
'+
1 M
> lilï
~~~O~~~
~
~S~~~
~
~O~~~~~S~~~~~~-L~~d;~~~V~O~~~V;5~
OA
Y
NR
Figure
14 As fig.
12 at C.
1980 0
L
=9 M=
4
DEP
T
H
=
27 M
1
980 0
L=9
M=4
DEPTH=
41
M
OJ'I Î~~~O~~~~~5~~~~~~~~~=5~~~~~~~~~~5~~~~~O~~~2~75~DAYNR
1980 0 L=9 M=4
DEPTH=
27 M
1
980 0 L=9 M=4
DEPTH=
41 M
OJ'I Î~~~O~~~~~5~~~2~~~~~N~~5~~~~~~-L~~~5~~~2d7~O~-L~27~5~OAYNR
F
i
gure
1
5 As f
i
g.
12 at
D.
1980 A 16 tV\
I
I
I
II
I
I I I I1980
A 4
1
m
/
'"
:zo~
o~-
3
~-+3~5~B~
I
~~~
3
~
5
~B~
I
~~I~-
3
~~5~B~
'QO
F
(
CPH
J
r--- ._-._._._-_._-'- --_. 1980 B 14,.",
u
~.t~r--L-~3L_~~~~
I
~~
I
~I~~2--~~3~
1
-L1~~-L1
1
~18~
!'
~I~~I--~--~A~~5~1~1~~UI
\
~O
F
[
CPHI
.._
.
__
..---,
1
980
B 28
..".
u
LIlI
I
'"
zr,
10-3 3 58
IIr2 3 5 8 IIrl 3 58
1
0
0F
[C
PH
I
Figure
17 As fig.
16 at
B.
1
980
i:
....J W :> W ....Ja:::
w (/')1
980
Pi
72'10 250 255 280 285 290 29S 300 30S1980
1
98
0
P3
72'10 2'15 250 25S 260 265 270 27SOAYNR
280 285 290 29S 300 30SF
i
gure
18 Hourly pressure timeseries converted to sea level
x:: c.J
N
_._
~
-.
.
1960
Pl
1960
:c
c.JN
1
980 PI
L
=5 M
=
2
1
980 P
2 L
=9 M=4
O
E
P
T
H
=
50
~iO
E
P
T
H=
50
M
~l_l~~~~~5~LJ~~~~-L~~~5LJ~~2m~-L~~2~~-L~~V*'O~~~V~5~OAYNA
19
80
P
3
L
=
9 M
=4
O
EPT
H
=
50 M
19
80 P
4 L
=9 M
=4
OEPTH
=
50 M
lil ~~~~O~~~~~5~~~~~-L~~~~~~~2~ro~~~~~~-L~~V~O~~~V~5~OAYNA
Figure 20 Bandpassed residual elevation fields. Labels Land
M
refer to their use in fig. 3.
r
~
[
~
~
~:~
Nl
1
1
I
1
';
~
~
""
",,'
~~~
,
"",'
""
"
,,'
I
: :
~
I J . ..L:
~
f
I 1111111 1 J 10- 3 5 10-2 3 5 10-1 J 5 iO0,,_u
3 5 10-3F
(
C
p
H
)
_______ __:__ . .. ...J . _-
-
--
_
-
-
_
.
__
.---
_
.
_
-
-
_
.
_-
--
-
-
-198
0 P
1
•
1
1
~
""
l
I I I I 1111I --1..'--:!1~1_:!1!_'UI~I.!Jd'_;__-L-::_'~1 .1..1,-;''!-W" 3 5 8102
3' 5 810-1 5 8100F
(
C"')
-
---
---
--
-
--
---'
198
0
P3
1980 P2
_j CT') IJ') I ! I Ilitl I 1IIIId 3 5 url 3 5 100:
1
I I1 Ilid .0-4 3 5la-1
980 P4
11
I II!tti I I I! Ilid I I I ! I" d 5 10-5 3 5 "rl 3 5 100F
(
C
P
H
.
_
.
_
---
-
-
-
---
-
-
-
-
T
crr---~
T
--
---
-
~
---
---
---
--,
Figure 22 al Original timeseries of temperatures at
11 sensor depths.
h) Timeseries after applying a 50 hour running mean.
ZIMl
Figure 23 a) Temperature timeseries after applying the 50 hour running
mean twice.
b) Inverse interpolation of
(a) yielding depths of
i
sotherms
T
T
T
T
T
T
T
T
T
T
T
10121012101210121012101210121"12101202Cl
~
0~
UI:g
Dl
UI Cl ::D -< Z::lj :008i
N...
0 N...
UI-
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er
10121012101210121012101210121012101210121012~
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UIFigure 24 Temperature variat
i
ons
(
0Cl at the
11 sensordepths
of A,
12
11 11
I
1111 I 111
•
i
j
ij
"
:
i '
i
'
i'
I
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"
,
I III I 11,1 I I I ~ , , " ", ""I II ~. , I , •• ,11 I 11,1 I I lil I \ 111 1'1 I :111' ,I I I1
1 III I 11,1 II I I I .1. I ',11 .,. I I I I . I ·,11 I :"" ,I: I!
I I I 111 I ",, " I I I I 111 I :""1.
:
I I I I 11. I ,11,' I I I I I I '11 I ~,',I I " ~. , III I IIIIII I'
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t!
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I I" ,I I Ir.
I I 11 ,,: ,,,, ,'
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,:
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'I " '"141
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r
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li
l
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.. I I I •• IZ
(
m)
32
"
I'25Z
254
259
Z60
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Z43
255
256
D
:
P, YNR
:
Z44
24-5
Z4-6
Z47
Z48
Z49
250
251
253
F
i
gu
re 25 Inv
e
rse int
e
r
polat
i
on of th
e
or
i
ginal t
e
mperature timeseri
e
s
in fig. 2
2
a
d
i
r
e
ctly y
i
elds a times
e
ries of the
int
e
rnal
e
l
e
v
a
t
i
on f
i
eld of isotherms
o C).
-
-1980 OT
u
cr:
I-...J W('l'1 Cl /.--/
/
/ I I I !I II
T
«(ph)
I I I I I I I I I II
3
5
8
II
r
2
3
5
3
5
8
100
F
i
gure 26 Spectra of the residual temperature timeseries (
T
-iT
60
o
1 981
DEPTH=
13
M
::::::)-60~~~~~~~rr~~~~~~~~~~
130
1 35
1 40
60
Cf)<,
L
(.)o
60
Cf)<,
L
(.)o
::::J1 45
1 50
155
1 60
DAYNR
165
1
70
1
98
1
.
DEPTH
=
19
M
1 981
DEPTH
= 31
M
1981O
E
P
T
H
=
3
8
M
198LO
E
PTH
=
'15 M
Figure
27 Hourly timeseries of East vel
oe
ities
(u) at p
o
sition E,1981
/"fc>
,
,,,
'
so
OA
Y
NA
>
1
98
t
D
EP
TH
=
1
3 M
1
98
1
DEP
TH
=
19 M
1
98
1
D
EP
T
H=
31
M
1
981
D
E
PTH= 38 M
1
981
D
E
PT
H=
4
5
M
>Figure 28 As fig. 27 for North veloeities
(v). Notice difference in
>
1
981
DEPTH=
13 M
1
98
1
DEPTH=
29
M
1981
DEP
T
H
=
45
M
l::HHDEP
T
H=
13
M
1
98
1
DEPTH=
2
9 M
1
981
DE
P
TH=
45 M
Figure 29 As fig. 27-28 at
F.
OJf'TI1
=
I
J
,.
1
98
1
DEP
TH= 2
9
M
liS
'~13~O~~7.13~5~~~1~40~~~1~4S~~-Ll~5~O~~~~~~~~~~~~~~D
A
YN
R
1
9
81
DEPT
H=
4S
M
1981
D
EP
TH
=
13
M
1981
D
E
PTH
=
29 M
~I
>~t
1
98
1
DEPTH
=
4S M
Figure 30 As fig. 27-2
8
at G.
>~
>1981
DEPTH=
12 M
1
98
1
DEP
T
H=
2
8
M
1
981
DEPTH=
42
M
1
98
1
DEPTH=
12 M
19
8
1
D
EPT
H
=
2
8
M
1
9
8
1
DE
P
TH=
42
M
Figure 31 As fig. 27-28 at H.
1
981
E
AftIllIl.
\
~~\IIWIU
IUlnn".
•
:;:in
7flI\\\~~-la CM/S 13
M
19 M 31 M38
M
4S M ~I 13.30 13.BO 1~.30 14.80 15.30 15.80D
A
Y
N
RI~I
D
I)1
98
1
F
lac
v
s
1981
G
la CM/Srl/dl"
13M
13 M...
~
"
..'
...~~
2
9
M
~
~
%-
W\\\Ul/
wz
d
2
9
M
Ä.~\\\\I\\\l\\\\,\\~h
?\
4S M I I i I I I 1 I I -1 13.BO I~.30 I~.80 15.30 15.80DAYN
R
(
~
l
D
I)Figure
32
St
i
ck plots of low
-
frequcncy currents in
1
9
81
.
_)f/dIIIP I I I I I I' I I I , ) 13.80 14.30 14.80 15.30 15.80
DA
Y
NR
(
"
10
II
198
1
H
~.AIJII!
",
A\\\\~\IIIIl\\
~
,
4$»n;I/1I~
\\'
,.---,r--..,-...,.--.---.----r--~I 13.30 13.80 I~. 30 I~.80DAY
N
R ("
1
0
I)1
98
1
E
_
_
___.
A:
!JJI11
/J1DHIU
IUUH/
J1#l
A
~
,,, '" WMf!""~""-
j
U/!
'!
s»:
"'
»},
,
\\
'II
L..
"-»"»\\\\111,,'m11\\wP
AOVl~ 10LM/S 16 M25
M
3Y MY
I
M
I .----T-13.10 13.80 14.10 14.80 15.10 OAYNR [MlO IJ1
98
1
F
10CM_~"""",p,
~
~III
IIIIIA
~ll
.
~
\IUI
/
.
MIJ/Illil~
r---,---,---,---,----,---,---,-, ,
13.30 13,80 14.30 14.80 15,30
OAYNR ['tl0 I)
F
igu
r
e
33
Stick plots of advection in
1981
.
1
98
1
G
~
I
\
_
'
"
.~ ••
JJ!JI/~
/11
3
'7
,«fAn"
I\\\WAIIIlIUU/lu
,#/
.
IIIM"
AOVEC 10CM/S2
1
M
37 M1
98
1
H
10CI';Ml
A
,
\
&e
JlI!!!!&
~
WA~
.
__
.4-"
,
13.30 13.80 14.30 14.80 15.30 15.80 OAYNR [,,\0 1),
13.80 14.30 14.80 15.30 OAYNR (,,\0 I)1
98
1
E
5'1EAR IO.."!··2J S..../·-I) lG M ,-*,\\\\\\Wm, ,., _ ,..._25
M
- ~. ,.... '<t 34 M~
!m\m!)!!!>.. .&)\\\IIIIlIW&
.A
\
IllJ
~
'11 M,---,---,----,---r---.----, I 13.60 14.30 14.60 15.30
DA
Y
NR
(
'd
O
I)1
98
1
F
5HERR 10••1-21 S'.(-I) <.\.t..(WCC
'/I\~ 21 M \\\\11--. ...""'''~~'''\\\,,,,~37
M
r ---~---,----r---r---r---.--_, 13.30 13.80 14.30 14.80 15.30 15.<DA
Y
NA
(M\0
I)Fig
u
r
e
34 St
i
ck plots o
f
shear
i
n
19
8
1.
1
98
1
G
.
.
~\.\\\\\\\\~..
_
---
-_.-
-
--
-
---Alt....
---SHERR t0,."(-21s...
t...l
21 M3
7 M
r---,---r---r---r---r---r--,r--,,--,r---I 13.30 13.60 14.30 14.80 15.30 15.8DA
Y
NA
(
,.10
I)1
98
1
H
... ",,,, ",\\'1\".. GUl...-IUU
tUIII_IIII!!!!le;;;;;..,
..
____,
,
13.30 13.80 14.30 14.60 15.10DA
Y
NA (MlO
I)1981 L=6 M=2 1981 L=6 M=2 1981 L=6 M=2 DEPTH= 13 M DEPTH= 19 M DEPTH= 31 M
1'18
DAYNR
t5]
1981 L=6 M=2 1981 L=6 M=2,sJ
DEPTH= 38 M OEPTH= 4S MtH
1'13 DA
Y
NR
1
53
Figure 35 Bandpassed
sernidiurnalresidual East veloeities
(u) at
position E,
1981. Labels Land
M refer to their rneaning
1
96
1
L=
6
M=
2
D
EP
TH=
1
3
M
196
1
L=
6
M=2
D
EP
TH=
1
9
M
~
IJl <, :1:0 c.J > U'Ir
1
96
1
L
=
6
M
=
2
DEP
TH=
3
1
M
>{'rl, DA
'f
NR'
5.3
1
96
1
L
=6 M
=
2
DEP
TH=
36 M
~
Vi
<, :1:0 U >~
,
198tL
=6 M=
2
J
EPTH=
45 M
> ,-•A,...
.
'VVV'vv
,
IJl <, :1:0 U /1.(3 Jv
3
D
A'f
NR
15'3 (s-,g
1981 L=6 M=2 1981 L=6 M=2 DEPTH= 29 M DEPTH= 45 M 1981 L=6 M=2 1981 L=6 M=2 1981 L=6 M=2 >
-,Ah'
v v
L..l-L...L. (J) <, :Co u'"
,
/'
13
DEPTH= 13 M DEPTH= 29 MDEPTH= 45 M
Fi
gur
e 37 A
s
f
ig. 35-
3
6 at
F.
1981 L=6 M=2 1981 L=6 M=2 1981 L=6 M=2 DEPTH= 13 M DEPTH= 29 M DEPTH= 45 M 1981 L=6 M=2 1981 L=6 M=2 1981 L=6 M=2 DEPTH= 13 M DEPTH= 29 M DEPTH= 45 M
Figure 38 As fig. 35-36 at G.
1981 L=6 M=2 1981 L=6 M=2 1981 L=6 M=2 DEPTH= 12 M DEPTH= 28 M DEPTH= '12 M I