A D—A0 ’e $ 729 NAVAL OCEANOGRAPHIC OFFICE WASHINGTON 0 C FIG 8110SELECTION OF WATER MASS HISTORY FROM BATHYTHERMOGRA M CHARACTERI——ETC (U)JUN 76 A FISHER
LJNCL.ASSIFILD NOO—TN—3700—Si—76 NL
U
ENDD A T E
2 r78
H__ U ______
1.0 ~~_ _ _ _
~ ~ 3 2
I~III~2
I,’ I~
IIIII~11111’ ~ JIIII~ IIHI~• MICROCOPY RESOUJIION T E S T CHAR I
NAJ IO NAL AUR~ AU 0! ~~~~~ A
/ ‘ ,
I N uou si/ H-T E C H N I C A L N O I E
SELECT ION OF
WATER MASS H I STORY
FROM ~3A THYTHERMOGR A M
CHARACTER I STIC S
by
A L V A N FISHER J ‘ D E~ c~’~~~~~JAN 18 1978
JUNE 1976
~~ U. S. N A V .~ 1 OCEANOGR .~PHIC OFFICE
3 WAS HINGTON, D. C. 20373 j~~~ JtmoN STATEMENT
• Appuov.d foz public rel.oas
SECURITY CLASSI FlC~~~~~~4 ? F ’~~~ S ~~~GE (lThen D.1. Enl.r ~~~7 I%JO ô r ii ~ ~ ~~~~~- ci ~REPORT DOCUMENTATION PAGE ~~~~~~~~~~~~~~~~~~ ‘~~~~~~ BEP ORE COMPLETIN G FORM
I. REPORT NUMBER /
2, GOVT ACCESSION NO 3. RECIPIENT~S CATALOG NUMBER
~~~~~~. Technical Note 3700—51—76 V( ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~ TYPE OF REPORT S PERIOO COVERED
Selection of Water Mass History from Bathythermo f~,)— ~ 7
gram Characteristics. T °eJ in i i~c~ / iQ 1~ j I9 PERFORMING ORG. REPORT ~ W~~ ER
7. AUTHOR(i) S. CONTRACT OR GRANT NUMPER(.)
6Z~I ~~an/Fisher
,?7 ________________________* !~~ NPORMING ORGA NIZA TION NAM E AND AODRE$S to. PROGRAM ELEMENT. PROJ ECT , TASK
-
AR E A & WO RK UNIT NUMBERS
U.S. Naval Oceanographic OfficeWashington,_D.C.__ 20373 ___________________________
II. CONTROLLING OFFICE NAME AND ADDRESS
~~~~~~_ ~~jji1~ —‘7
U.S. Naval Oceanographic Office OF PAGES
Washington, D.C. 20373 19IS. MONITORING AGENCY NAME & AODRESS(I( di ll.omit from ControtUn~ OWe.) IL CLASS. ~of fbi. r.port)
IS., DEc LA9SIFICArl o ti /oo ww o RAoINGSCHEDULE
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ‘I16. DISTRIBUTION STATEMENT (of fbi. R.porf)
Approved for public release; distribution unlimited.
17. DISTRIBUTION STATEMENT (of A. ab.trac t wt.r.d in Sleek 20, Sf dSff.,.nl from R.po rf)
IS. SUPPLEMENTARY NOTES
19. KEY WORDS (Continu. on r.w•,.• .id. U n.c...my aid SdmitSfr by block numib.r)
Oceanography SalinityAtlantic OceanWater TemperatureWater MassesBathythermogram
20. ABST RACT (ConSSnu. on r•v.r•. .Id. if n.c.a . v aid idsnUfr by block ni b.r)
~ Discuses the use of a historical data file based on water mass conceptsto automat ically selec t (by computer program) one of several possiblehistories based on characteristics of the input bathythermogram .~~—
DD ~~~~~~~
1473 EDITION OF I NOV 89 IS OBSOLETE ~,/ ~J~$ L~L_,)~ (t UNCLASSIFIEDS/N 0l02 •014~ 660 1
SECURITY CLA IPICATION OF THIS PAGE (Ilimi S.f. Inisr. ~
• ~~~~ 3700— 5 1—76
ABSTR;cr
A historical data f i le based on the near—sur face w:tt~ r :a3se:~
of ~~~ North Atlantic Ocean is discu3sed. The most ac tr ac t ive fea ture
of the water mass file is tha t the characteristics of the i ~~~~~~
i i L~ytherinogram will obje ctiv~ 1y determine the prooer d~~e~~ history ior
computation of the surface to bottom soun d speed pr o f i I~~. 1
second feature is the adjustment of salinity to the pc~ sence of
temperature inversions ( sound channels) to mainta in ~i stable water
column . Evaluation of the water mass f i l e using sa l ini ty- te~ oerature-
depth (STD) data shows that is is superior to t~’e ~‘ile ~res~ ntiy used
in the Integrated Carrier Antisubmarine ~‘1arfare Prediction System (1C\PS) .
:~~~\: ~~~1:),~
•, 00:
i
~~~~~~ ~~~~~
‘ -— —.— ~~~~~~~ ~ !‘7~~~~ • ‘ ‘ . ‘
. -
-~~ — -- —~ ~. :~~.. — .
ERRATA
Tables 1, 2 , and 3: Columns headings should be changed f rom “RMS
SD ” to “Mean RNS ” .
-: - ~~~~~~~~~~~~~~~~~~
-
• -
:~~-i~ ~~~~~~~~~~~~~
— - --
~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~
—
~~
----
~~
— -
~~~~~~~
II ~~ ~~~~~ ~~~~~~~~
‘~~
‘~~ 3700—51—76
ACKN OWLEDG EMEN TS
Space does not permit recognition of all Lhose who c o et r ih u t ~~ci
to the creation of the water mass f i le since its inceotion :- .~v~~ra1
years ago. Among those providing substant ia l assistance ~ir~
A. U. Ortolano and L. Riley (data processing); N. 1. ~~atty , III
(evaluation) ; and L. A. Defibaugh and A. C. Voorheis (!cmnu~ cript
preparation). The project was funded as part of the Integrated
Carrier Antisubmarine Warfare Predi ction Sys tem (ICAPS) under the
cognizance of the U. S. Naval Oceanogrnphic Office.
ii.
- -~~-~~~~-~ -T T.~ ~ ~~~~~~~~~ •~~~~~~~~~~~~~~ ,, —~—-~~~~~~
:~ 37’~ —~ 1—76
I~ Tf~.ODUcf ION
Sound speed profiles extending from sea ~;~~r f i~~— to o :- • i n floo c ire
a necessary input to sonar range prediction models . R’ au~~~~;~ n~~~-ic
Soun d speed profiles rarely are available to fle-~t cp e r at ing unit s ,
synthetic profiles are constructed either by cornbinin a ~-;yno~~Lic b~ thy—
thermograph •trace with deep historical oceanocj reohic d~~~ i (~~endenha l l;
Faucher , et a1 Ilanssen and Tucker) or by historical d.t~:a alone (Russell;
Pocleszwa) . Each of the several techniques available re l i s on a
d i f fe rent iemethod of generating the surface to bottom :;oiind speed nrofi l~ —~.
• They agree , however , in that they provide a ningle seasonal profi le for
each region ; with each region having fixed boundar ies. Unfortuna t~ ly ,
real-world oceanographic features are constrained oni~ by bathymetric
boundaries , and their position may vary rapidly as in the case of a
Gulf Stream meander or cyclonic eddy . Thus historic f i les t~~ed USOfl a
single regional history frequen tly provide misleading sonar range
predictions. The purpose of this report is to describe a historic
oceanographi c data fi le -— based on wa ter mas~i concepts -- in which the
computer program uses the characteristics of the inPut hathvth-?rrnograph
trace to automatically select one of severa l possible h i~;torii~~. The
file was designed to he incorporated into the Integrated Carrier Anti-
submarine Warfare Prediction System (ICAP S) ~uveloeed under the cognizance
of the U .S . Naval Oceanographic Off ice (NAVO CE ANO)
Two premises were ~.ude while developing the new f i l e : (1) that near
surface water masses can be uniquely ident •i fled by the rmnhaline character ist ics
and (2) the ii re i l cha n.~t e r i , ; t i . cs of riei~~hi~~~:i~~q w ~t c russe:~ ar ~ ;u ~ —
~~ V~~~~ ANO ~4 3700—5 1 — 76
ficiently different so as to peri~it reliable i d e n t i f i ca ti o n from sa
exr~endab1e bathythermograph (x 13T) trace alone . A f t e r id~~~t ifi cat ion of
the applicable deep history , teaoerature v~ 1u~ s of I-he input t rac~ are
merged with deep temoeratures usthy an equation of th~ fozm
— Th~ + K1 (K 1...1AT)
where P . and Th~
are , respectively , estimated and h~ storical temperatures
• at depth 1, K a wei ghing factor, and ~T the diffe rence between tempera ture
at the bottom of the XBT trace and thterpolated historical temp-~rature
at the same depth. The weighing factor , developed from imperi cal
solution for a set of historical data , is determined as a function of the
depth increment between points
• K . = 0 835 (D1—D11) /lO0
At the first symthesized temperature value (i 1), K1_1 equals un i ty .
PROCEDU~~
Because few guidelines for water mass identification are avai lable in
classical oceanographic literature, it was decided that the most objective
method of determining water mass characteristics wi thin a gi1en area was
• to look at original oceanographic data. Two world-wiJ~ data f i les were 4
available for this purpose: (1) an oceanographic station data file of
approximately 491K observations compiled by the National Oceanoqraphic
Data Center (NODC) provided temperature and s a l i n i t y da ta ~t each of 32
standard depths between the sea surface and 7,000 meter.~ (ci ) and (.~) an
expendable bathytherxnograph (~~ T) file of approximately 218K observatL’ns
coripilod from three sources (NAVO cE~NO , NODC, and the ~ leet Numeric al
2
• ~~: ~~~~~~~
—- - . • .
--a- - -- -- -
—
T~J 3700 — 5l —7 h
t A a ther Cee t . er) ~ ro ~‘ LW ’c t t e:i: -~ra t u r data at ~ a i LIL ct. ~re ‘ o i n t over the
d . t h range of the in ;t ru sn e nt ( i ~~ deep ~n ; 760 c i ) . ~ih~ f ol lu~ ing procedure
was used to ~t termins w t t e r mass characteristjc$ in I he ne ar—sur face
layer (0-4u0 c i ) :
A. The classical l i te r at u re wa~; searched for i i l i : i h~.~ deseri )tive
papers . For example , the northern edge of the Gulf St r - ~em is frec~ ent iy
delineated by the 15°C isotherm at 200 ci.
B. The ocean station data fi le was used to provide annual comoosite
• statistical data (me an, standard deviation , n~~~ er of observations) at
each standard depth using all available data within the area of interest.
A plot of the distribution of temperature versus s a l in i ty , plotted at both
200 and 400 in , provided insight as to the number of water masses nresent
and thermohaline variability wi thin each water mass. Fi gure 1 shows a
plot of temperature versus salinity at 200 in in the rectangle 4S 50 50 °N ,
400 to 50°W —— an area where the cold labrador Current meets with t h e warmer
North Atlantic Drift. The presence of water masses with specific thermo-
haline characteristics are clearly recognizable, and t en tat i ve wat ’~r ness
classification has been made . The 200 in level was found to b~ an ideal
depth for classification in that it is generally well below the level of
both diurnal and seasonal changes while being wi thin the depth range of
both XBT and AXBT (airborne deployed XBT) probes. The XPT f i le provided
statistical da ta and his tograms for tempera ture and temperature gradients
at preselected depths to supplement the ocean station datj i when necessary .
C. Flecture points in the temperature versus salinity (T-S) nlot
shown in Figure 1 clearly defined water mass criteria in ~reas where
• different water rnas:;es exist in close proximity . Con id •~b 1e t ’~~~~r a t u r ’
3
• -S--—- ---— --- - - - - • • -- •-- -- —•-• -~~~~~~~~“ — ---
_ _ • •
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SALINIT Y (%~~)
32.00 33 .00 34 .00 35.00 36.00 37 .0018 I I I —
1 7 —
1 6 — -~
1 5 — —
1 4 - -
1 3 - -
- SLOPE 0 --
01 1 — —
0T o - —
_ _ _ _ _ 0
_ _ _ _ _0 9
0
~~ 8 - —
• 0-
LU
6 - SCOTIAN 0
-
• -
3 - —
2 -
LABRADOR -
0 - -
.1 - ALL OBSERVATIONS AT 200 METERS —
—2 1 I I — I I I
Fiqur ’ 1. D i s t r i b ut ion oF temperature verrusen linit:y 4 h O N fo — h O °W
4
~~: L~~~~~~-~~~~~--— ~~~~~~~
11T~• ~v~O I~ 37 00 — 5 1 — 7 h
ve r i .ability also occurs in are ls oueu~ h d by a ~~~~~ w at e ~ m i s s , ~ h tb ly
a ec . a L t of (t .siaoic ev~~I i L ~; such I : , upweli ing . here v a r i~ b Lic .v of t h i s
n a t u re was observed , two L t s s if i c it i oii~ ( ‘ .7 rci ‘ and ‘ cold’ ) we re made
to provide a b.~t t e r m~~c~~ beLwe~~u ~~e1 trace en d h i st o r y .
D. T:snse r i u r ~ ~ils .; at 200 lii wer e d ~vsleaed to distir:guish ecijacenb
water masses i)JSSL1 on in fo rma t~ oa h rf l VO J e i iS ~n I C ~~‘/ L O U 5 n~~5?.
ad jacent water a~~se~ h a t i imilar ~aI i t u r ~~ r. clqe .~t th~ test deoth ,
d iffe rentia t Lori was by e~~cn t n i t io I I of ch te nner a ture g r a d i e n t
between the 200 ari d 300—rn leve l s . For x e n o L s , both th~ t u lt Stream
and the Sargasso Sea are cii iract~~rized hy a t~~nner itur e r an ;e of from
150 to ~t3°C at 200 ci. A near— isothermal layer o~ 18 0 C ~ater is foun d tot
exten d from the bottom of the seasonal thermocline to d ath~ exceeding
300 in in the Sargasso Sea. No such l iver exists in the I lu l f Stream .
Examination of Sargasso water in a reqion well removed ~rc ’n rhe Gulf Stream
(30°—35°N; 60 ° —65 °W) showed tha t 95 percent of Lh~ ob s e r e e tL cn s had a
temperature gradient between 0.0 °/ l0O is arid — l . 6 °C/l00 i i . Thus a gradient
of —1. 6 °C/100 is at the 200—300 ii level is used in the r~~~ion of the f c l f
Stream to d i ffe ren t i a t e Sargasso Water from Stream Water .
E. Mean seasonal temperature and salinity values w~ re then det-~roined
for each depth and water mass (figure 2). where the data are not s u f f i c ien t l y
deep temperature and salinity were extrapolated to the hot toci by cornoarison
with neighboring prof iLes . In con sistencie s in the data —- such is temperature
i nversion at depths below 200 in —— were examined to determine if th~ v area result of statistical processing , data dis tribu tion , or bad data.
5
~~~~ -•. ~~_L_L
~~~~~ ., _J T~~~. ~EE_ . .~~~~~~~~~~ ——
T~7T~E R A T U R E SAL ~~N I 1 Y______
MEAN S.D . NUM M E A N S .D. NW’
0 2~3 • T I 2T 2B~ 6Th 34734 f7fp10 23.10 2.65 682 3’~.55 .97 681)20 21.12 3~7o 682 34.Ri~ ~~~3 6so30 19.142 11.36 683 314.96 .83 679
-
~~~~~~~~~~~~~~~~~~ ~~~~ ?~~~~~~~3 ~~~35. i~ — ___
• 75 14.49 2.86 683 35.41 .55 678100 j 3T 2~~~4 683 ~~~~~~~~~~~~~~~~~ 618125 13.lb- 1.57 6814 35.514 .?8 678
.1 50 12.54 1.311 6814 35.51 .22200 11.21 1.24 684 35.38 .17 67Ei
~~~~~~~~50 9 ~~~~~~ ~ f~~) ~~~4 ~~5 674300 8.68 1.25 682 35.14 .13 674
—
~~~~‘cuo 6T. 37 ri p ~~~~~~~~~~~~~ _57
~500 5.67 .79 551 34.99 .06 54~600 5.03 .52 529 34.98 .05 52~
—
___
700 4.67 .32 518 314.98 .914 514 .~~~~~~~~~~~~~~ 7W3 7~ 4~~~~~ 4 (3 34.97 471
900 ‘4.27 .20 438 34.97 .03 43~~~~~~I p J u ‘V~13 ~~T1 593 .03
1100 4.02 • .15 350 34.96 .04 31451200 j.9~. .13 3J0 54.96 .04 3241300 3.85 .12 322 34.q6 .04 316r~ou 3. (~~ ~~T2 319 34.95 r~~~~31~1500 3.72 .12 315 34.95
•
.04 311270 • g~ ~~1~~~~~~~~~I4~~~~
200 0 3.41 .09 239 34.95 .04 2333.UtT .11 ~ b0 JL4~~9L4 .03 1514
• 30 00 2.59 .16 89 34.92 .03 84-.
••- 2 .26 ----
~--;p7 41 3iv;qu —;112---
~~~~SL0PE—WATER 5~~~ N~~~~~76~i — SUMMER
TEriP RnNGE — 9.00 — 15.01. SAL RANGt 3u.u —Thp .p
Fi gure 2 . Tempera ture and salini ty atstandard depths in Slope Water
6 BEST A~~ h~~fL’ i~~~:[ C~PY
_ L
~
. ~~~~~~~~~~ J • ._ 1_~_~~ ~~~~~~~~~~~~~~~~~
• — ~~~~~~~~~~~~~~~~ . .- , • . - • — •~w•_~ ~~~~~~~~~~~~~
y ;c • , TN 3/ fl ’2 —~ l— 7~
F. A c~u i l i t y control check w e ; w ide by ~ lo tH n. j the u~on it
isa a single plot of t . r i p ec a tur e ver sus sa l i n ity ( f igu r e 3) . Incusni •~ t a r t c i n u
in the data a:a immediately apparent; tc!~perT1 n we? errors a ve r L i e ~~L
spike , sal in i ty ~rrors by a horizontal spike , :ind depth e r r u n s 1 y a eew~ d
s u Lks . Wher ~ da ta were obviously incorrect t e plot ; i s • e s o t ned to ‘on —
f orm wi th surrounding data.
EV~ LUATI0N
The f i le was evaluated by comparing the ns~iejwd prof i le ja rt erat ed by both
the new water mass f i le and the old file —— which is based on a single
seasonal profi le for each 5—degree rectangle — — with oceanographic data .
Test data typical of each water mass within the test areas we re we
from salinity—temperature-depth (STD) observations on f i le at ei ther WODC
or the Coast Guard Oceanographic Unit. Si~ observations car season , d iv ided
• emually among water masses , were selected for each area. The uppermost
portion (0—400 in) of the ~TI) cast was treated as an XBT aad ~he Lernoerature
trace extended to 1,500 ci by merging with both old and new h i st o r y f i L e s .
Salinity was estimated and sound speed computed for all depth s between the
surface and 1,500 m. In the surface layer , estimated sa l i n i t y and soun d
speed values were compared with observed values for each depth on the
simulated XBT trace . In the deep leve r (400—1 ,500 ci) e s tie tt eci b. mperature ,
sa l i n i t y , and sound speed values were compared with observed values at 6
depths : 500 , 600 , 800 , 1000 , 1200, and 1500 ci.
The fi r3 t test wes desi gned to test the premise that ~uali t . controlled
data from a large area —— in this case, a 5 x 10-degree rectangle -- would
co~~,~ r iy favorably with the smaller area without qual i ty ror .trolled data is
u e d to compile the old h i s to ry . Should t h ~ s p i e m i ~~ Os cre rr ’ t h ’ii
7
_ _ _ _ _ _ _ _ _ — ~__~1
SAU N ITY (%~,)
34.00 35.00 36.00 37 .00 38 .0030
2 9 -
26 -
25 —
-
U — 0 WINT E R
• ~o / S P R I N G• / ~~ SUMMER
—— / V AUTUMNa . — —
• 7 — —
1~~~~~~~~~I
Figure 3. Seasonal plots of L ’nip’~ra~ ur~,versw; F ; d l i n i t y , 10—2 O ~ N ~~—5l°s~;
L
B
r~~~~~~~~~~~~~~~~~
NAVO( ’ : ANO TN 3 P)U ~5 —76
considerable reduct ion could be macic in the file size. The area i. clutl jucs
Ocean Weather Station EGiO (44°N ,48°W) was selected because eai;si t r r able
• STD data were available from an area of relatively little ocea~iugran~~~;
variability. The results of the test at O~S ECHO are given in Table I. The
new water mass f i le provided slightly better r . s u l ta i in both L~ e sur~ rice
and deep layers.
The second test was designed to document the abil ity of the n ew ~i1~
to differentiate between mater masses , thereby providing i ncrqed prof ile
superior to that produced by the old file. An area of high ocaanogra~hic
variability seaward of the Virginia Capes (VACZ~~ES) was selected because of
the presence of 3 water masses : Slope Water , Gulf Stream Water , and Sargasso
• Water. Results of this test (Table 2) show that the wate.r ness file estimates
salinity significantly better in the surface layer wi th a correspondin g
increase in the accuracy of sound speed computations. The deep data again
are slightly better when estimated by the water mass f i le than wi th the
old file.
The final test evaluated the ability of the water mass f i le to eljuet
salinity values in a near—surface temperature inversion (soun d channe l) .
Persistence of sound channels for months at a time show that they ar e
stable oceanographic features . Howeve r , use of unadjusted his torical
• salinity values causes an apparent unstable wate r column . Thus historical
saLinities must be reduced by the method given in the appendix if they are
to be realistic.
Salinity adjustment was evaluated in Slope Wri ter in the VACAPES area
whore well—defined inversions occur from Anri.L through October. Salinity
L ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .~~~~~~~~ •-~~~~~~~~~~~~
• ... .~~ ~~~~~~~~~~~~~~~~~
r~ __
I ••) Cj 4.
i C, • .~~ 4 IN
C);•) ., ~~ 4..) ‘P ~) 4 . In(4 44
‘.1 9 3 C) . 4 . 4 0 ri ‘N ‘N Cl (I
0
‘2 Ii) ( 4 C, .. I C, N0 ( 4 1) C) LI Cl 4 ) .1
U (1
C l .-I LI 4 .1 4 1 1) • I ‘3 4•) ~—i is4.4 4 (‘1 II . 4 . 1 .•-1 . 4 V O~~
-~
I.~(•j~~Q 5 4
Ii • .~ 0o 1 In
.4 • 4 • 3 • 3 C l 4.3 ‘1 N P. () — C) - .
‘N.
‘~ ~~ ..~ ..~4.) 0 ( 4 .4 4 0 4.) (.4 4 1 0 C) C) H a
t~11a C)4.~ Q ‘~j.,-
~ Q.l~~- l :o •~~
p. .~ ~ d~ P 0 0(.3 LI IN 4,) .4 • I C i . 1 . 4 . 4 . 4 0 (‘S~~ -•~
• n,,;
~~~~~~~~~~~~~~~~~~~~ 0 0( 40 1 .)
o
e V eo~~ .4 ~~~~~In
‘a @ a4.) ç.~ 1 0o rd ‘a C) 0o 4.) C) ~ I ~-1
U) ~ L . .54 4 ) CI .4 . 4
12 ‘ ‘~~ 1 0 4 )44 .
1;H
4. IIVi 4 . 4 • •~ I.) (‘I 43 C)
.3 o 0 H1,
(.4 CI C) CI 1.4
‘ . 4 C) .44 ‘.3 .4 .3 N ‘3
.4 ~~ ‘. ‘ e
d.4 fl •.) 4 )
I’0
C) ~~ 4.44 ;~ 4 4 .3 4(4 (.3 ‘ I4. ) (3) N 4 .4 C4 444 (.4
‘ 5 4
• Ii 4 J 4 5) C 4, 0 ti 4 ;3 C .1 C 1
. 4 1 i • .144 I s
4 . . •~~ : 1 .1• • • • L .• ‘ 4 4 ) 3 . 4 . . . 4 4 4 ) 4 . • ..
10
~~~~~~ !~! ~~ ~~ r r ir)y.~.,..- .
~ V ‘
~~~~~~~~~~~~~~ tJ~ . . . ~.
4:: 4 . . ‘.~ ‘ .1 .‘ 1)
0’ 1.) 0 4 ‘.1 -~
(4) C’. CS ItS C. ( 4 4 44 5.) 4
4) ‘1 - ‘ (~ , (9 -~
in
4 )
0 0) N ‘ ‘ 3 C) i’ . CI
4.) 44) .4 . 3 ,
~— , 1 ,1 .4 .~ I I
CI
(‘4 C’) 3 4 ) C) - ‘7 1) CS . 4 • ‘ l C)
is (‘1 (‘I C C . 4 Ii .~ ,~~
,,; ,~~
r~1)54 r~S
49 31 I I ‘ 4 1. 4 4 ) 1 0 CI C 4~~~~~~~~~~~~ ’~~ /I) ‘: : ‘-: ‘: ‘~ ‘~ ‘~ ‘~
o ..., c~ CI 0 .‘, CI ~ a . )~ .
3,) 3’) Ci ‘.-l‘0
‘.2 ‘. ~ ‘4,. .~ 4 , . ‘.., ,~, p. p. • 4 3.>
0 ‘- ‘ I’.’ .4 N —~ 4,4 4.4 (4 ,.4 ,.4 II C J Ci ~• • •
~
4.) (3 ~4 4.) 4 ’ ‘ 4 , 7 (3 4 4 (4 :•: .1 .4 Ci(4 . 3.4
4 4 ‘.4 :) - c :4 4 Ci ‘C
4 4 .4 -4 ,• -I3 4 1
i ) ‘0 —4 (( CI Cl ‘1 4 4 , 4 4 1 4 ) Ci —
. 1 (3 . . ,,, , , ‘ ‘ i ’)
Cl ,—l ~; C; . ~ (9 C; 4 .0 • ~~~ C- , C:
Ia ‘ : 4) l i ~~~
(3 1 . . - 4 . > C)
I ) CI .~~ (‘4 (9 ‘ 4 ) . c ,-i i’ :‘ - 0 1 I >.
43) 4 ij ’) 4,7 4 4 I4’l 4”) I . 3 4 ’) 1 . . (•1‘C) “i ‘-4 0 ‘3
r i (‘I IN .1 ( I ~~~~~~~ , 4 , ,,4 4 . ) 4 4 •
- C i C : 4 - ’1~3 ~~~5..
~
.,
~:: ~~U)
ii 4.~ C~C) ‘ ~ ‘ , ~.: ‘: : ~
i i 4 . 1 . 4
4 :.‘~
I..( 4
,~~. •3’ ( 4 4- l i’S
C , , ; , : .; . ;4 )
. 1 .1 I , C
(‘I ’ ? ‘4 4 4 , 7 4 4 -’ ‘ 1(0 4 . 4 . ) ( ‘ 4 . ,
‘4 ’ ) I 4 ’ ) 1, 4 ’’ Ii — ; ‘ I
‘ ‘4 .1 .~. 4 4 4 1 I 4 ,, . * : ‘ I
4, 4 1 4 1 54
• ‘ ‘ ‘ .- ! .~i ‘~ ,; ‘ ‘ .~~ “ 4 , ,
-4. .±~~~~~~~~~~~• ~ =.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
. . -
•
: . .~‘v’ Y::~A:~~~ ~‘N 37 i~ 51~~7~,
Was e:;Li:nat’r’i in ~in UIVerli iofl u sing the -s.ite r ness h Lstor~’ ~hi rs L w i t h and
then without the adjusfteni. rout Lee and co~rC).,t :‘~‘d ., i t I l cu ’ :4o ’ ’.’CtI v~ i ’~ ue~ tram
20 STO drops. R: eelts of the evaluat ion —— JLV CCl in Tth~ ’3 —~~
that adjusted salinity values era clearly su~erior to un idj ~~s1’ .rc1 Vai ’.:es ‘I .e
temperature Inversions .
The new water ness file offers substantial advantages over conventional
oceanographic data files . The major advantage of the Clew file is th~
canability of the system to automatically discern in which Of
possible water nesses an input observation was taken,. th ss providinc for
variable water mass boundaries. An evaluation of ‘the water mass selection
ce’i~bi li~ y showed that significantly better results were realized b” its
utilization. A second feature of the new file is salinity adjustment wi th in
a temperat ure inversion. A test of this capability showed that is provided
a realistic estimate of salinity in an inversion . Finally , the c1Ual~~tV
control procedure to which the Crater mass file is subjected permits the use
of large areas without loss of accuracy .
Several recommendations are warrented based on the evalestion of the
water mass file ;
A. The water mass file ehould be expanded to include th~ i n thaz i and
North Pacific Oceans.
B. That the water risss file replace the 5—degree his tcCy i ’ l~ c~se;it1.y
u3°d in ICAPS.
C. That the water mass file should be adopted as the a tvv ‘wt de
oceanographic history tile for on—scene applications.
12
- -
“.. ;,~~~4—- -~~~~~ -- .
- _ _4__4~~ _~~~~~~ - .,-•- ---• .‘~~ hA
- ; T ~~~~’~ ~~~~~~~~~~~~~~~~
4’.
a-‘4’.-F.-- 0 0’)
C-’)0 C)
1’~114(1) ~0 ,--I
(‘ CCl 1-~ 0 H
3,4o(I) ‘ C O
(1 ‘Ci C)~:‘ .i-~ ~I-I ‘—I C)
‘Ci Is .0C
C .0 ‘Cl ~0 C C )C) 5 2 4O S SC) 04 ) 35~ :~ •a‘i - c a4-) .0 U)—I CC> ~~‘C S C~i S
O H (I)C) ,-I 41 ~~.4 4i~~~~14 4J
0 C c ) U)(S 0) s-I i .d ’CJ Ci
~J’ 10(4 til l • •
0 C)
H co si-i w m CO .1_i c: fl-I C)
C’F.). C) 0to
m
CI‘—4
E’
CCI N NCd’) IC)
‘ciCI
‘ci 45C) U)45 CiU)Ci ‘C
C‘U 5,: :
~~,
13
-. L:.~~ . ~~ — ~:‘.. — ~~~~~~~~~~~~~ -~~~ - -~~~~~~~~~~~~~~~ —
::TT—’TT:II-’
‘ .C )~;( ’C A N & ) TN 37OO- -l— ~J6
• D. Sal ,i nity in the ro~-oa- ~d f L i e is d e t e r C l i n , .-d IaCi a Le ect i on of ‘ i a t er
I I . ’ ~a , Season , and k11,Ith . In f u t u re ‘.-? , i L~ C C’) IsIs f iles it: is r ’seo> ::tuend ,e t t i i ~~I:
;;~ liitity 110 determined as a ‘ func t ion of water mass, ce:laaIrciture , (I’CL’ Ldl ,
5 1(3 I sSdsOf l t~ take advantaije of td~ unique th ’ r re>oh ,i l ine • ‘ ‘lationships which
h~’ :!a ci n it ion , id’.’ritify any LJ ,v ‘ i t w i t-s r 1’)(11;., Ci~4 L f l~~~ a L C C i S n . L c U e s i m i l a r to
that used 111 the western North ‘i t an t i c Ocean by i- ’iS ’n e r .
E. Because the e f f e l l t of aver ’lqing masks CC- a l f~’s1ILCI rss , i t is
recommended that an ancillary file containinq dirjiti~ ed x:c.t’ t races Ly : ical
of each water mass on a monthly bcts Ls he constructed to t ?:ov’dO users with
in formation vital to realist ic planning of future f leet oneration s .
~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~ -
‘-
~~~~~~~~~~~~~~~~
-
—~~~~~~~~. .~~~-
-.- ~~~~~~~. - . _1
~~ -~~~~~~~~~~
r’w ~~~~~~~~~~~~~~~~ —
~~~~ -
~~---—----
~~~ - —
___- -
C . ’~~VO 1 . 4 . 4 - ~~ J7 - ) — 5 J - ‘ge
iT’,SI is.’hCr , K. A . , J .0. ~,‘uq h , and 0. V . Il~ r’d’)s ln , ~ouitd 1/IS u- ’.: I Lv ~ ro~,’
synthes is t ’.cchn ictues “or t i t~ Aces:; ti~~ I~~4 ) l ( ’ 1 L 4~l(1d L ( ’> .1 01) S~’a tell)
( ‘~ L~S) , N > vt ! T c 4 t~ - l ~~~~~~ I t 0 ‘0.. !
— ~~~ >~~ ~~:
‘~
1973.
P1 :;lter , A. , Es t itnat ing sa.Lini ty ru t SoUnd Ciisee .‘ Jr>’eI l t ’ C t b u s , In Lt er
t:o the editor, US~J_J. of_Undec’w, c r acous ’..., 2 4 ( 2 ) , ~~
271-276 ,. 19’14.
Hanasen , G. L. :uici W . Ci. Tucker, .[ E l , .L oLe r im I else r i L e d (Ca r rj e r Ieit —
:;ubmarine Warfare Prediction ~~~~~~~ (IC~P~ ) i ’0U ’)Ua l, (cP e42— ~
Computer System) (Li) , Nwa 0cnano~~~~~h L c O f t ~ cs , ~le~ ’ ,’r wct i
Publication 10 , Washing ton , l0Opp, 107’i . (‘u ’d’1Dr ~NT L\L
~1endenhall , B. 1~. , Desi ’~n of a s t ructure ztrame L~’ ri :C, i t t on 1 5 ’t t > O ( I ‘ or
,)4))lkcatiorl to the three—dimensional, analys is o ’~ o;~. C’) L L m ~ l r ’ n t H l- ~
Lieteorology International Incor[)oratod , I’L l> ,’)1 .ICC ’ ) ’)rL , I’ r ( S j -’ I t 5~~~ 5” )
Monterey, 57 PP~ 1970.
Podeszwa , E .C-1 . , Sound ~psed profiles for the North decific Ocean ,
Noval 1esr~,ater Svstoms Ce n t-er , T1’shuica ’L !) eciun er i t 5271 , Nt ’~ Lon ’lon ,
1H4~j o , 1976.
isI; 1 : 1 ’ H , J.~1. , A tschn ~ue to sL~~marise sound >s ’4’.’ecl da t .i tron t h e sea
CL ’ l iC It . i 0 >) ill acc,ustic p ( ’Oj45 ( 1 .’1t~~Ofl loss mod - ‘Is ,
C’ t ’) h, r r , ‘~~ 14:hnLCaL r~oLe ~~~~ C. ~n l ) i i w ~o , ~s’~4p, I9 ’/S.
. 1 1’r~’~•
.
.
.
I ~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~ ~TT . T ~~~~~~
-. :i’,.~~~. — -~~~~~~~ - .
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
APPEND IX
S2\LINITY ; Jus’I’Nr :NT
Oceanographic stability is a prime requisite for persistence of near-
surface temperature inversions, for unstable conditions :-:oul-1 de~ troy an
inversion through mixing in a relatively short period. In ~t1y5~ Cd1
oceanography, stabili ty is quantif ied by the change in density with rnsp ->ct
to change in depth ; stable condi tions being denoted by a >‘o~ it iv~ gradient .
Bccause density is a function of both temperature and salinity , it follows
a priori that a salinity inversion must coincide with a temp erature invers ion
if stability is to be maintained. Historical sa],inities , by definition,
represent me an conditions and thus cannot cope with an anomalous condition
socC’i as an inversion. This appendix describes a method of adj u s t i n g
sa l in i ty as estimated from an historical file to provide a stable wet er
column . In order to allow for minor instabilities frecuentlv in Arctic
wa ters , the correction is only applied where a temperature inversion exceeds
0.25°C.
The equation used to adjust historical salinity was derived from steowise
reqression of density as a function of salinity (30 to 40 °/ o o ) ~md constant
t’emp’~rature (10°C)
p —1. 26584x10 l+7 .72412x10
l5~ 4~ 22003xi.0
85 (1)
Differentiation of equation (1) to give change of d ’ > n si t . v w i th respect
to change in salinity yields , after rearrangement , addition ‘~f a ‘-‘orrection
term to assure stability within the inversion , 1 1 > 1 1 c~~ ’f l V ~r s i a ’l of don s i t y to
•
: ,
~~~~~~~~~~~~~~~~~~~~~~ T-~~~_ _ .~~ z’L’: J
3700 5 1—7 6
the maca conventional sigma—t yields
~~ t”Ci (2)•
—
O.7724+l.68SOxiO 7S~~
.;;‘t-sr-e AGt the difference between ~t at adjacent points,
Cj, : the corrective term , and
S0 : original historical salinity at point i
The in itial step in applying equation (2) is the computation of sigma-h
as a function of depth and temperature as input ‘from the XBT and interpolated
historical salinity . The XBT is scanned from bottom to top and salinity
values adj usted for all points wi th in temperature inversions that are more
than 0 .2 5 °C loss then the temperature maximuii at the lower boundary of the
inversion. The corrective term is increased by 0.01 sigma-t units
per depth incremen t ‘to assure stability within the inversion . Adjusted
historical salinity (S1) is now computed using the equation
s1~ = s 0 +As 1 (3)
A-2
-_~~~~~~~~~~ ..~~i: -~ — -‘ -~~~~~~~~~~
