A magnetic survey of Ireland for Epoch 1959 5

•

U.o.c.

~50. 36 536. 71

METEOROLOGICAL SERVICE

A MAGNETIC SURVEY OF IRELAND

FOR EPOCH 1959.5

BY

J.

McWILLIAMS, B.Sc. and

J.

BYRNE, B.

A.

•

OOIlTENTS

1.

Introduction

2.

Selection and Marking

oC

Sites

J.

Procodure

4.

Instruments used

5.

Azimuth ldeaBuroments

6.

Control

C~ntre

7.

Calibration oC the SUMO), Instl'Ulllonts

8.

Reduction

oC

the Obsorvations

9.

Nonaal ValuoB

oC

tho Klements

10.

Anolll4liea

11.

CompariBon of Normal faluos

Cor

1959

and

1950

Table

1.

Location of StationB u80d during the Surve),

Table

2. Obsorved and Computed Value.

oC

the Magno tic Eloments

Table

J.

Computed Values of the Klomonts Cor

1959

and

1950

Survo)'s

r!Q!!:

To simpUf), reproduotIon, the lottor )' haa boon used

throughon~

tho text to signify

~.

rage

1

1

1

2

2

J

"-5

6

6

9

10

1. Introduction

A detuilod JIlA~netic survey of a countl,., evon a8 slIIall as II'olwHl, l~

n major oporation, involvin:; considerable organisation, timo lllld expenso.

Tho rosult is that such survoys are not llUldo aa frequently a8 io dcsiraLlo.

To ovorcome this difficulty, tho Irish ~oteorelogical Sorvico docidod to

sot up a limitod numbor of Magnetic Survoy str.tions, which would pl'ovido an

olwcrvution netwoI'k, conforming 01060 ly to that recommondod by tho JAr-A Committeo No.5 on World Magnotio Survoy, and at which marrn('tio ,,1.1'\'CY

obsorvations could be conveniontly mado at froquont intorvalJ.

Advantago IIa8 takon or tho faot that the r.letoorolodcal Sorvico

llirolldy had undor its oontrol a notwol'l, of synoptio reporting stations wldeh

are woll situatod for tho purpose in mind, and that an officor of tho

Serdce on inspeotion du ty visits thoso stations at rogular intorVllls.

Aocordiagly, dUI'ing un inspootion tour of tho rcporting stationo in 19:;8,

ono of us (Mr. J. Dyrno) solootod sitos for tho !-Jagnetio Survoy

olJsorvations 01080 to or II!thin tho grounds of each of tho oleven synoptic

stations, lUld theso together with VAlentia Observatory form tho sUI'vcy

netllork of twelvo stations, IIhieh are listod in Tablo 1.

During tho next inspeotion tour of synoptio stations in 1259 tho

neoossary Dagnotio equipment (seo para. 4 lJeloll) lias carried and tho

sunoy complo ted.

2. Solnntion and Marking

or

Sit08

Tho oxaot site of oacb obsorving station was chosen so as to uo fl'eo

Crom all possible disturbing magnetic inCluonoos, could lJe oxpoctod to

remain freo from Buch influencos in tho CoresoealJle futuN) and at which

Il suitable pel'!lllUlont roCereneo

tho Declination obsol"Vationa.

objoot

Figs.

or "azimuth murk" was availlllJlu for

7 - 17

abow tho positions of tho Gitos with reference to their surroundings 8Jld tho metoorological station.

Th" ohosen site was ma!'lcod lJy moans of a concrete slab, buried about

IS in. lJolow tho mJrface of th" ground. A small holo in tho contre of the

slab WaS used to provide an oxact location.

A full description of tho loeation of this conorete slalJ, includi~

measured distances from well defined roCoronoe points, IIao preparod so as to

facl1itato discoyory on all futuro oocasions. Disoovory was also

facilitatod by means of a IIoodon pog drivon into tho ground so thAt ito top

was) ovol with tho BUrfaoo and vortically oyor the holo in tho slab.

Tho survor lias oompleted during the period Juno 2nd to July 2nd, 1959.

•

2

-The tour began at the control station - Valontia Obsorvatory - whero

oontrol obsorvations wore mado with each et tho instruments.

outstations wore thou visitod and the tour endod at the starli~l: point,

whor1) control obsorvations wore again mado with oach ol tbo instruIaOn~B.

Tbis schodulo all01l'0d about two days At each stai-ion, during .. hich timo at

loast two and gonerally throe or tour BotS

at

observations wore cOVlplotod

with each instrument.

4. Inst,,,monts used

The instruments used tor the IJIllgnotic obsorvations woro al<

[o11olls:

(a) Doolination and 1I0rizontul Intond ty •• , •••••• QlIM No. 186

(b) Vortical Intensity •...•.••••••••••••.••••.•.• ImZ No. 112

A socond QlIM (No. 184) was also oarried, but tho susponsion of this

iustruVlent broke oarly in tho survoy, so tho tour was completod with ono

\lmlonly. 1I0wover, this did not atreot tho survoy as the two QlllJ's were

carriod mainly to provido for such a contingency,

A full description of the QlIM instl"Ument IUld its use lor 1I0rizontal intonsi ty IDOasurements is given in

[1].

A desoription

at

tho mothod uscd

lor moasuring Doolination .. ith this instrument is givon in

[2].

A full doscription of tho DMZ instrumont IUld its uso for Vertical

intonsity obsorvations is givon in

[3].

Othol' eljuipruont, oarriod on tho survoy, oonsisted oC a Wild ~urvo)'or'~

theodolito (kindly lont to tho }'(oteorological Sorvico by tho Irish Ordnanco

Survey) for Azimuth detenninations, two aoourately ratod pockot w"tchus and

two stop wAtohos, and finally a l'1lotangular tont, speoially dcsigned fol'

lI:D.gnotio fiold work.

5.

Azimuth M08Buromonts

To dofino tho azi~th for Declination observations, I'1lCeronoo objeots

vore choson which it WAS oonsidered would remain pormanont and in oloar vi ow

from the sito lor magnetia obsorvations in the foreseeable future. Tho

mothod usod for tho dotennination of azimuths was a variation of that

doscribed in pages

56 - 59

of

[4].

The Wild theodolite lont by Irish Ordnanco Survoy was usod tor tho observAtions. At Bomo stations tho

azimuths of tho roforonoo objoots wore not detonnined during tho noturl

survoy tour, duo to tho sun not boing visible. In BUch oaBes tho necossary

observations 1fOre oarriod out dUring a subsoquont visit to the stations

6. Contl~1 Centro

Tho control centre, to which all the survey olJsorvatiolia 1'01'0

reCorr'ed and at which continuous recurds 1';el"O availablo to provido

instantaneous deviations Crom tho moan valuos at oach particular timo or

ousel'vation, was Valontin Ousorvntory.

The magnetic recording oquipwont avnilablo nt this station

consi6ts oC:

(n) 11 standard La Cour I; nun recordor, with a sot

ot

La Cour

n, D, nnd Z Variollleturs.

(b) n La Cour 180 nu:r (Quick-llun) recorder with a seo)ont.l sot of

Ln Cour n, D and Z variomotors.

A tull doscription oC thoso instrumonts and the I'ooordors will be

fouud in (5J, [6J and

[7],

whilo 11 dosodption of the sito and tho absolute

and variomotor huts will bo found in [8J.

Tho instrumonts usod for baso lino detonninations during 19;9

wcro:

Declination and norizontnl Intensity •••• Iluska Obs. Idagnotometer No.5917

Vertical Intonsi t.y ••••••••••••••••••••••••••••••••• IJdZ No. 66.

7. Cnlihrntion or tho Survoy Instrumonts

Tae magnotic instruments used during the survoy (parn. 4 nbove) ,

Cor'n part of tho equipl:.ont. "hich is used reGularly at Valentia Obsorvato ry,

in addition to tho baso lino instruments, reforred to in para. 6 above.

A regular cOJ'parison is therofore available, showing tho agreoment botween

tho data as obsorvod by tho survey instrumonts and tho Valentia base line instl'llmonts. Tho following tablo shows the orror in the

with reforenoe to tho oorresponding Variomotor baso lino

bog inning and at tho end

ot

the survey tour.

survey instruments

instl'Ulllont at tho

Corroction to roduoo to tho

Elemont

Declination

lIorizontal Intons·tty

Vertical Intensity

Survey

Instrument

QUM No.186

QlIM No.186

fNZ No. 112

valu9. givon bl:: bllse

At beginning of SUMel:: Tour

+ J.'O

+

2.21

+ I.Oy

Ii no ins t I'Umon t At end

ot

SUMOl:: Tour

0:0

+ J.Oy

4

-The Valentia

bADII

line inst('UJJl(lnts have also !.Jeon compared wHh othor

obsOM'atory standards as tolln·al

nuz

No,66, This instrument has boo4 compared nnnually with tho Dte Cvil ,

originally installed at Abinger

will

noll' installed at

lIartlnnd Magnetic Station,

In JlI.nu!1ry.

1959, the rosult

ot

thio camparioQQ showed that tha

~fZ

Nc,66

WAD

givina rBsults,

..-hich

were

5,4y higher thllJl tho /lartl1md Dye Coil.

Tho

eon stant

ot

mz

No.66 was theN/orc' adjuatc': to bring the

result. into agreomont with the Dye Ooil valuoa.

In february, 19bO,

INZ 110.66

was again comparflc'

.;-i t:l .he

Hartland Dyo

Coll I:.lld

tho result showod that

lho Il},(Z 'Ui8

reading only

0,5y hig~or

than the Dye Coil.

T

hu

s.

durh1!i

the poriod

ot

the I;unoy. the Valentia bas" line standard for

Z may bo taken as being

ill

agreomont with the I/artbnd standard.

RuEka ObHonatory IIIl;rnetolloter:

During tho poriod 19/6/59 to 2/10/59, this instrumont was

compared with three QIIM instl"Ulllents, receivod from Coponha.gon

and usod

AD

travelling standards

by

tho Committee on

Comparison of Magnetic StllJldarda

ot

the IAGA.

The mean dHterence betwoon the rosults obtained with the

Rusk,. Ilagnetometor and thoso ohtained !.Jy the threo

QWl

travolling standardB were as follows:

Ruska - QllK No.

90

-

+ 1 • 2 0 tlIIImDo

•

QllloI

No • 91

-

+ 0.6

•

..

Q1!!1

No • 92

-

+

0.9

..

is these three QIlII's were cali!.Jrated at Rudo Skov O!.Jsorvatory,

immediately prior to dispatch to Valentia, tbo

valuo~

9btainod

'l'ith them may be taken

AS

representing the Rudo Skoy 3tlLDdar,!.

8.

Reduction or the Observations

The values, obtained

by

tbo survey

inst~entB,

were tirst

oC

nIl

corrected to agree ..-ith the Valentia base line

inBtl~~onts,

using the

maan of tho dirteroncos as tound at the bo;;inning and at tho end or tho

SIIrvey tour. (See para.

7

abel-e).

Vor each individual timo

ot

obsorvation at the survey 8tation. the value of tho instantanoouB

deviation

ot

the magnotic elemont trom tho base lino valuo WaS computed

trom the Valentia magnetogrAmS Cor the corresponding local timo,

Combining tbis instantaneous doviation with the base line value, gavo

9.

Tho Annual Mean Value (COl' all days) for 1959 (K ) Was computod

Dl

from the hourly mOMS valuos, tabulated from tho magnotogrll.1HJ.

Tho value for the survoy station reduced to opoch 19'~.5 ',;,,6 then

obtainod from tho oquation:

Elemont for Survoy Station at 1959.5 D Es - Ev + Kill •

This method of roduction doos not allow (or tho ChangOS in tllo diurnal

variation with latitudo, Lut in a small country liko Irplantl, lho 01'1'01' BO

involvetl is small. _{A chock on tho lIla{;1litude of this 01'101' wa~ outainod Ly}

making at loast two observations IUld genora11y three 01' four lOl' _'llcb

elemont, on difforent clays and nt difforent timos. Tho ""cult of this

chock showod that even thou,;h the instantanoous deviatioas i:1 tho olC/ocnts,

as recorded at Valentia, varied ovor quite a witle ran/jo, tho moen 01'1';)1'8 in

the reduced valuos for the s'Urvoy stations were quito omall.

valuos "ore as

follows:-Tho 110 tual

(a) For tho four stations in tho Northorn halt

ot

tho country

(Malin Hoad, Dolmullot, Clonos IIlId CIaremorris)

(b)

... ormal

Doolination - mOM 01'1'01' ~

t.

1:0

Ilorizontal Intensity

Vertical Intonsity

For tho seven stations

Declination

-Ho ri zan tal In tonsity

Vertioal Intonsity

Valuos

ot

tho Elements •

•

•

in tho

mOM

•

•

•

- <;. 4.3 y

•

- :. 3.0 y

Sou thorn halt

ot

01'1'01' = :. O~ 9

•

D <;.

3.5

y

•

a:'

5.3

y

tho oouut ry

For tho purposo of comparioon with a more dotailod surv"y :llulo

tor

epoch 1950.5 [9J, the oquation tor AIIeh

at

tho olomonts, AS a (uHotion

ot

tho latitude and longi tudo of the station, waa oomputed, Each of the elemonts may bo reprosentod Ly an equation in the form:

K .. A (If - 50) + D

(.:t -

5) + C

whore

A

is the longitude 1Iest and

1/

the latitudo North in dogreos and A, D and 0 are constants.

Using tho method of loa6t 8quare~, tho equations obtained yore:

DO .. 0.343 (11- 50) + 0.584

(,A. -

5) + 9.776 ... (1)

I1Y .. -459.6 (11- 50) - 10.5

(A -

5) + 19118 ... (2)

6

-In tho oaso

oC

Doolination, which is measured positlvo towarde tho West,

the valuo obtainod Cor Dirr was obviously much

too

low

in

eo~pariBon with tho Cour stations Sbannon Airport, Claremorris, llullingILr • ..nd 7.ll1<onny,

. whioh Corm an al"Oa

oC

whioh Dirr ib the approximAto eon tro. 'rho valuo ohtainod Cor Dirr, thOI'OCOI'O, was not used in tho computation oC tho

nOmAl "'Iuation Cor l)oo11nation, nor in <.ll'~.wing tho tl'UO isogonals in

Fig.

1.

'fho60 throe oquations givo t1l0 nOI'lllal values DC tl,o ""'Gnetio

olf.),.ents and tho isogonals and ir.<ldynn:.ic linos, dorivod from thalli arA

8"0_11 on lI'igo. 1 -

J.

Similar oquations for tho 1:1)0 Survey givon in [9]

'fore:-DO _ 0.248

«(1 -

50) + 0.5J5

(A. -

5) + 11.21 ... (4) IIY a -472 ()f - 50) - 47.8 (

A -

5) + 19011 ••••••••••••• (5)

Zy = 448

(~

- 50) + 6:;

(A. -

5)

~

,;2909 ...••••.•••••.. (6)

For comparison purposes, the IRogonal and ioodynamic linos, derive'!

from both sets

oC

equations havo b~on drawn in Viga.

4 -

6.

In tho cILeo of all throo olelUcots, tho 1'61"O"lOont is as 010S9 .... 8

could be ol.pectod, "onddoring that tho [orm oC tho oquations is so

dopondont on tho values obtained at tho individual stations, .hero looal

anomalios are 1ikoly to exist, and in no caBO vaB a station, usad in tho

19:;0 sul'Vey, I"O-occupied during tho 1959 DUrvOY.

10. A •• cmlll i08

The valu08 of the elomonts, observod at oach oC tha Dtationij, aro

givon in TAble 2. .U •• , ginn in this tablo, are tho normal values for

OMh atation, as computod CroCI equatioGs (I) - O)aOO1'O. Tho differenoes botween th~ obsorvod and calculated ~orCl81) values are given in tho third column

oC

tho tabla. 'rhosa difterenc08 aro gonerally considel"Od nS

t1eaBUI"OB oC tho wanou:alios w at tho stations, lut thla is only in a vary

general WAY, A8 thoy dopond 00 ~oh on the tit

oC

the oquations.

1'ha valuos oC these 110 caHod "anolLlllioll" hnvo boon plotted in

riga. 1 -

J,

tho valuo Appropriato to oach 'Jtat10n having been plotted to

tho right

at

the atation cirole, ~d the obaorvod value to tho leCt oC the

otation airalo.

The

true ino1ine8, Thioh tAko account

ot

th080 AUogajie8,

LAve boon drawn on rigs. 1 -

J.

11.

CQ~~rinon

oC

N0r-a!

ValuoR tor 19~2 and

1250

In 1&ble J

Are

given tho normal TAluas

oC

the threo olomouts Cor tlol:' 19.50 &arvo1, AS com~tod Croll equations (4)-(6)Cer oaoh

oC

th" stations

.le802t, during the nine rearM,

hAv~

alae boon tahulatud in

T~blo

J.

JrQm lh~ae

ohAnges, the rollowing

uar

be

dodueodl

(a)

~alinatlon

hAa dooroauvd

~

aa

Aver~o

or

59.' ovor thJ

wholo oountry.

Tho

rate

~t

dooreA38 wao grsutost in

~~o

Bouth

&nd dc~rcaQod

to tho Harth

~~d

lost.

The Qquntion

lor

the ohAnge ann bo obtained

by

Eubtraatlng equations

(l»)gd

,,),gLTing

a roloUlt:

D1959 - Dl'J50

.!f.O'J5('/ - 50) +

0'.049(A.-

5) -

1..~'.4

...

(7)

Jor VAlontiA

Obsorvo.LoI'j',

tho eOllpatod ohat:tlo

(or

tIlIl ..

".~

yoara gives

a dea~~8o or

60:2.

The aotual

Oh:"l~~,

baood on

the

annual uoau valuoA at thio atation, was n

d~nraaoo

or

62!6.

(b)

Uorizontal Intensity

in" ... ~auLd by &Il avor~6

ot

260y ovei'

the

lrholo oount""

til"

rat .. o( inaroace bein!; greatost in the

Vost and North and least in the KaAt

and

Bouth.

The equation

tor the chAago

oan

bo obtnJ:l0d

(rom

equations C!)ll.Dd (>),ghing:

111959 -11₁₉₅₀ - 12.4 (If - 50) + J7.3

(A -

5) + 107 ... (8)

Jar Yaleutia Obuorvatory,

tld o~putod

ohango tor tho nine reara

~iles an i~l~a6e

ot

J27 g~.

The

actu ..

l ohAngo. basod on

the annUAl goan

vnlu~s

Cor the »tation ahawo

AD

inoroaco o(

JOlr.

(0)

Tertianl Intensitr increased

br

4n

AVO rage o( IlJy OTer the

Whole a1l\l.Dl",.

Tho rala of ohange inoreased

tram

South

to

ftorth.

Tho oquation Cor lho ohange oan be obtained

trom

equations O)=d

~'and

giTcs:-Zl959 - Z1950 - 24.5 (11- 50) -

2.2.

(A -

5)

+

41 ... (9)

Jar Talentia Obuervllolory, the oarputed ohango Cor tho nino

years giTes

~

inoreaso

ot

76y.

The aolual chango, baaod on

tho annUAl

Roen

vlloluila At tho ataUoll

r

6110.e an increane at

lot.

Tho agreement in thia

CL£a

ia not as good as tor tho

other two elemnts,

f·flIbz.!llr

in

(:Art

due to the taat that

prior to

1954 tho oolr Vortical Inton8itr data aTailable tor

Talentia wu

eO!l:~t8d

fNIl lIorhont41 IntelUlitr

lUll!

tho Dip

. . 88/l1l1lred

br

_ana of

110

dip .,irol0.

H

IlCIlt be I"CJlCIlIbered, honTer. thlit

~quationa

(7)

,(S)and (9)Ar8 unlikelr to

proTO Te",

roliablo, ir applied ouhit.!o tho llUM'ey aroa,

&8

in a survey

or

tMI

trpe,

ClQnUaed to a

T'3",

narrow rAllgo

.c fI

and

A ,

tho

coerriuien~1I

ot

fI

!:lld

i\.

d~end

verT lIDoh

011

tho rona

.c

tho oquation usod and

tho

hul

~o=alio8

at the indiTidllA1 etations, and

&8

praTtously stated, in no caoe

8

-Uoforencos

[1]

Communications Magnotiquos No.

15

Lo Quartz Mugnotomotro _{by D. Lu Cour.} (.!11M (Quartz Horizontal Forco Magnotomoter)

(Publishod lly Dot Dansko Mcteorolo;;iUco Inntitut)

[2] On tho Dotormination of D by monns of QWJ.

(Publishod in C;oophysica, Vol. 5, No.2) Dy K. Thiosen.

[3 ]

_{Cormrunicnt ions Magno tillUCS No. 9}

Tho Mn;;notometric Zcro Dnlnneo, tho IWZ. Dy D.

La Cour. O'ublishod by Dot Dansko Moteorologisko InstHut)

[4] Dil'octiolls for Magnotic Moasurements by D.L. Hazard. (U.S. Coast and Goodetic Survoy Publication N". 1(;6)

[5]

[6]

COI:l.lIlunicntions Mllgnoti(lUOB No. t)

La DaiMco do GodlIllVII. Dy D. La Cour. (Publishod b\' Dot Dansko Motcorolo,:isko

COIIlf,lunications MIlt:llotiquos No. 11

La Yariomotro do Coponhag'uo. l;y D. La (Pub! hhod lly Do t Danske Motooro logi ske

OhS~l"Vutions Fllitos A Thu!e

Premioro Partio: Magnotismo Terrestro. (Publishod lly Dot Dunsko Uotoorolog'iako

Ins titut)

Cour Md V. Laurson. Institut)

fly Y. LlLUrson. Institut)

[~]

Magnotic ObsOM'ations at Valontia Obsorvatory

1954.

(Pub! ishod I.Jy tho II'ish Metoorological Sorvico)

[9] Geophysical Memoirs No. 4

Tho Magnotic SUl"Voy oC Irolnnd Cor tho Epoch

1950.5.

Dy Thomas Murphy. (Puul iol1Ud by Dubl in Inst Huto fo r Advancod Studies, School of

Table 1 Location or Stations used during tho Survey

Goographic Co-ordinates _{Geomagnotio Co-ordinatos}

Station

Latitudo (N) Longitude (If ) _Latitude (N) Longitude

(m)

)/alin !load ₅₅Q 22' 07Q 20' _{59?3 7S?7}

Dolmullet _{54° 14' 10° 00' 5&?S}

75?1

Clones 54° 11' 07Q 14' 5S?2 78?0

Claromorris 53° 43' 09°

00'

_{5S?1 75?9}

lIullingar _{53° 31 ' 07° 21' 57?6}

77?5

Daldonnol 53° IS' 060 26' _{57?2 7S?3}

Dirr 53° 05' 070 54' 57?3 76?6

Shannon Airport 520 42' OSo 56' _57?l

75?3

Kilkonny 52° 40' 07° 16' _{56?S 77?0}

RosslaN 52° 15' 060 20' 56?2 77?S

Valentia 51°

_56'

lOQ 15' _{56~6 n?5}

[image:11.576.45.544.90.496.2]

- - -

-Tahle 2

Observed and computed values of the Magnetic Eler.ent.

DECLINATION

HORIZONTAL INTENSITY

VEIH rCAl,

INTESSITY

Station

_Observed

_Calculated

(0) - (C)

Observed

Calculated

(0) - (C)

Observed

Calculated

(0 ) - (C)

(0 )

(C)

(0)

(C)

(0 )

(C)

0 0 _'1 Y Y Y Y Y

Malin Head

12 40.8

12 58.1

- 17.)

16661

16626

)5

45687

456J)

54

~lmu11et

14 25.4

14 08.2

17.2

17019

17122

-10J

45209

45262

-5)

Clones

12 J3.J

12 JO.l

03.2

17148

17174

-26

44944

45065

-121

Cl •. "morris

13 12.6

IJ 22.7

- 10.1

17J59

17J66

-7

45072

44959

11J

Mullingar

12 28.1

12 20.7

07.4

17529

17476

53

44764

44761

J

Baldonnel

11

49.J

11

44.0

05.J

17644

17587

57

44550

44599

-49

Birr

12 06.8

12 Jl.0

- 24.2

1764)

17672

-29

446)2

44587

45

....

0

SbllJlIlon Airport

12 54.7

12 59.2

- 04.5

1787J

178J6

J7

44452

44472

-20

Kilkenny

12 03.8

12 00.5

OJ.J

17892

17667

25

44JlO

1.4354

-44

Besslare

11

15.4

11 18.9

- 0).5

17976

18070

-94

44204

44096

108

Valentin

13 22.9

13 29.6

- 06.7

18252

18176

76

44215

44191

24

nfCLINATION

HORIZONTAl,

INTEKSITY

VERTICAL IIfI'K'fSITY

Stllt.on

1959

1950

Ch811ge

1959

1950

Change

1959

1950

Change

1959-1950

1959-1950

1959-1950

•

•

_•

'1 '1 Y '1

r

'1

Mill in Head

12

0

58.1

13

0

47.3

o -49.2

16626

16365

261

45633

45466

167

BolJ:wlle t

14 08.2

14 56.0

-47.8

17122

16775

347

45262

45129

133

Clones

12 30.1

13 26.4

-56.3

17174

16931

243

45065

44927

138

C1arenorris

13 22.7

14 16.4

-53.7

17366

17064

302

44959

44836

123

Mullingar

12

20.7 1)

_20.4

_-59.7

₁₇₄₇₆

₁₇₂₃₇

₂₃₉

₄₄₇₆₁

₄₄₆₃₉

₁₂₂

Baldonnel

II

44.0

12 47.4

-1 03.4

17587

17385

202

44599

44480

119

_....

Birr

12 31.0

13 31.6

-1 00.6

17672

17419

253

44587

44477

110

....

Shannon Airport

12 59.2

13 58.9

-59.7

17836

17549

287

44472

44374

098

Kilkenny

12 00.5

13 05.2

-1 04.7

17867

17642

225

44354

44253

101

Rcss1are

11

18.9

12 28.8

-1 09.9

18070

17885

185

44096

44003

093

Valentia

13

29.6

14 29.8

-1 00.2

18176

17849

327

44191

44115

076

[image:13.937.85.846.160.484.2]

10° 90

IRELAND

55°--Scale \0 0 10 20 Mil . .

l..oJ.l . . . . o < ! . - L . - J

o

.0

:t

8

o

.'"

!:( 80

....

•

·

_.

:

·

•

.

(', '., _.'

...

~' ,

.

(

.'

• J 7" , ,

" 0

1 .0

"

'....

.

_.

:

~

,

_:

' _.,

.

.. _---(

~

________

~~

______ -+ __

~

______

+-__

1-+ ______

~~~~~----54°

5JO--- -- t---~~:~----.J4~---~~---~~---~0

t'

•

o

1~~--_+----~----~~~~---4_--~:~---t_----52°

'.

Fig. 1. Declination (West),

- - - True Isogonals. Observd

Computed

volue of Declinotion is given "Anomoly"

is

given on right

~

7" ~.

. ... Computed Isogonals. on left of eoch stotion circle,

[image:14.577.43.546.75.848.2]

IRELAND

55°--ScaJe lO 0 10 20 Mllea

, " II

... . . .

,

... .

17359

'

..

,J

:1.:-"'4=-::';"'---...;.;-.

"1 oooy

17000'" .. ~ . . .

-.

. .

. .

.

.

. . . .

.

. .

,

.

loremorri,

·7

... .

Birr 1764 • - 29

. .

Mull'

• •

_•

•

_•

...

,

•

_•

:

..

_

...

,-.

.

.

. .

.

.

.

. . .

.~2.9 .•••. ~J ... . 'i7500Y

5 3 ° - - - - t - - - - )

_{----~---~---~~~r_----~~~---\~~~5J.}

. 17750Y

..

--?~~~--...f--

... .

'y:--. • ...

.

.

.

. . . .

.

. .

. .

.

.

.

.

..

.

... .

Kilkenn 17692.'25

17750Y

ooy

"--~"'"osIIQ e 1600 y

----~---~~~L----+_---1_---52·

10·

_a"

7"

FI'g. 2, Horizontal Intensity.

10° 9"

IRELAND

55°---$cUlt 10 0 10 20 Milea

I

452S0~

8"

,

-" .' .

"','

/ .

.

.

'

..

..

,

..

' 7° 250), 45250y 4~OOOY

•

45209

4S250y .. • •• -t;4944 P'-12

\.. ',.-,Clon

• _•

•

... , .. 45000

,."

..

'

..

'

..

'

..

'

... 'C'I~~cmorril . 45072 .113

..

'

..

,

..

'

..

' . '

..

Bir,. 44632 \:1.45

.' . y., .' .•. t ... /

.'

.

..

'

..

'

..

' 445500-49 Baldonn.' 1----54° 4750Y

_-~:4:i"'

_..

4450ey

,

..

'

I---~---~----~.~

..

~~~---~----~.

44

..

'

10· _8"

Fig. 3. Vertical Intensity.

[image:16.579.45.549.64.820.2]

Kilkcnn 443100-4

..

, . '

.

....

...

.

'

..

.' . .. 44250Y

... 4',,10Y

Jv---i----

52 •

7" _~"

- - - T r u e Isadynam·lcs ...•.•.•... ',. Computed Isadyncrnics.

Ob"erved value of Vertical Intensity IS given on left of each station circle.

IRELAND

55° _ _

Scale 10 0 10 20

1_ ... ' _--'

Mile.

I

.

_•

_-.

• ,

t!

°M .

o al.n

,

:!

-

...

.

_.

\

.. -

...

~ ...

.

_.

• _•

_,

• _•

'",

....

_,

,

,

55·

'''---.

H - - - ;--IL...+----,:.-I--I~--l-+~~l---54°

53°_ ..

_-Mullingo

•

Baldonnel

..

_o

,

r:!

.: _ _ _ 53°

_~~;_--+-~~~,~~~---t_--52·

"

o

~

b

70°

Fig. 4. Declination (WesH

s·

..

_o

,0

!:}

computed Isogonals for 1959.5 ... Computed Isogonals for 1950.5

[image:17.579.51.557.62.821.2]

10° 9° SO _7°

Mol'l" Head

IRELAND

55° _ _ _{L--~---r----·--55°}

Sccl. 10 0 10 20 Mil . .

....

...

[image:18.575.55.551.64.808.2]

c.-...-.;.:.:.-..

.... ..

'

'. '. . .1anoy

17000 y ~:"..f--,k"'>~.::.7

..

:-=.7 ••

,...-1""" . .;..

17000y

.

_.'

~". " I

.

o

.'

"

.' ···\:·1···· ....

. .. : ' ...

...

""

,.

'

...

, ' ... '-...' Cion .~ , ...• ~:~:::~.:

..

'

....

.

'

..

..

' Claremorri.

..

'

.

. .

.

.' ... -~'-'-­

....

.

...

Mullinga ...••.

1.

~~~~

________

~----~~~~f.7

_...

..

~.~--~.J.l.~·~··~·t··-·-·---:~17500y

...

.

.

'

.

53°···-"---... 53°···-"---...

_Ia

Boldonn.1

~C> ~'" .. ' .17500y

Q/----+---+---~~"~~·~··~·~··-··-·----~t_~.-~·

_..

'

77 ':>0

y_~----~----.::.:_:

.. :-:.:C .. -:".""

~+",",.",.

,:,,;".:.' :':' '.:.' :,:".:,:' ':':"-'

--i---Jr

177 ':> 0 Y

..

'

Kilkenn

o

....

..

' .•• 1

7~Oy

y.

~~~---~~~~~~.-:".~

_..

..

~_t~~.:.:

.. .:..:.: ..

~.~.·-·--t_---~~--16

ooy

'

....

..

' . "

I

I 70°

..

'

...

....

....

.

" ,

....

gO

Fig. 5. Hor'lzontol Intensity.

....

....

'

.

__ ~~---r_---52°

... 111 ooy .. ' 16 ':>oy

7°

Scal~ ,

I

Scale 1000

I I

'M,,~

o

I

Fig. 7. Molin Head and surroundings.

1000

I

(heights are given in feet above Iri'h Ordnance Datum)

A indicates lite of Meteorological Station.

[image:19.577.75.525.90.719.2]

Scal. I

!

'00

I:,:,

o

- T o 8'

' n9harnst

_own

SAND IS MUD

Scale 100

a

t ""!IIIII

100

!

Fig, 8. Belmullet and surroundings.

,

;00

I

2 Mlln

A

To 8elrnUl/e

t

300

!

400

!

600 Fut

I

(heights are given in feet above Irllh Ordnance Datum)

A Indicates .ite of Meteorolo;J°lcal Station.

B indicates aite 01 Magnetic Station.

"'0

~

~

Seal. ,

a

I , I , I , I I I

)

,

I

2 Miles I

Scale tOO 0 tOO 200 300 400 500 Fe .. t

I"!I.!!!!I I I I I I

Fig. 9. Clones and surroundings.

(heights ore given in feet above Irish Ordnance Datum)

A indicates lite of Meteor-olog'lccl Station.

[image:21.579.96.542.82.717.2]

SCQI~

o

"': '

Scale 100

o

100 200

W. 111" . . 1

"-;g. 10 Clarc:morris and surroundings.

/

'. ' _. . _".

I

/

' .

2 Miles

. . "Go: "::",

_Q..,

300 400 SOO Feet

(tlej~hl. are given in feet above Iri.h Ordnance Datum)

A indicates lile of Meleor-olog'lcal Station.

S indicales ~ite 01 Magnetic Station.

' ..

A,... 9

a

2 Niles

...

,;;,

Sea/It 100

a

100 200 300 ~oo 500 F<J"t

'"It!",,1

Fig. 11 MuUingar and surroundings.

(height. ore given in feet above Irl.h Ordnance Datum)

A indicates lite of Meteorological Station.

[image:23.594.83.531.79.710.2]

Scat. I

_a

I I

AO

Seal" 700 a lOa

I,,'I"!!.!

Fig. 12 Boldonnel ond surroundings.

I

I

o

Control

Tower

200 300

I I

. 9

400

2 Miles

I

>-~

X

~

~

0

ct

a.

<f

f-.

(/)

t1

500 Feet

(height. are given in fut above irish Ordnance Datum)

[image:24.574.86.532.74.695.2]

Scale

B

•

Scale 100

o

I,,""III!

o

100

I

200 300 400

Came or

2101iln

I

500 Feet

Fl'g, 13 Birr and surroundings.

(height. are given in feet above Iriah Ordnance Datum)

A indicates .ite of Meteorolog'lcal Station. B indicates site 01 Magnetic Station.

, ~. ;.e_r __ _

B

•

n

•

o

Scale '00

l..u..u.u..U.' I

o

o

1lJO

L _

s

n

200

on

on~A",,"

_ _ _ _

)

;--"-',

-2 Miles

I

----,<.

\J

---=:.====---

_--

---.:==.-300 400 500 Feet

d surroundin:;J5. A' port on

Shannon Ir

~c".

kbh

Fig, 14 given In fe.t 0 . I Instrument

. hh are oroJoJtca

( hel

9 'te of Met. • $\otlon.

A I

_nd(Cotes,~

,

t.1a~netlc

.

Datum)

Ordnance

Enclosure.

•

I

Scale 100

o

100 200 300 400 500 F •• I

( .. "III,,!

Fig. 15 Kilkenny and surroundings.

(heights are given in feet above Iri.h Ordnance Datum)

A Indicates .it. of Meteoroloy'lcal Station .

[image:27.574.91.540.81.701.2]

•

50

Fig. 16

•

Sea" too

o

too

111!!IP",1

ROSSLAfIE OR

SOUTH BAY

200 300 400

. S

urroundlOg . Datum) R

osslare and S Irish Ordnance

. t above

given n fee I. I Office.

( h I

f'lht. ore teorolog (;0 •

e • Ito of M. . StatIon.

A indicates I't of Magnetic

t S 51 e

a

indlce e

Gr •• nOl'd

rdnt

2 Miles

600 Fut

[image:28.574.88.536.72.704.2]

,

•

•

I

CORK HARBOUR

,

I J

Ro<;he's

POint

o

Fig. 17 Roche's Point and surroundings.

(height. are given in feet above Irl.h Ordnance Datum)

A Indicates lite of Meteorological Station.

B indicates site of Magnetic Station.

2 Miles

I

robolgon

kt..

HouS"

2000 FtIIt

I

[image:29.585.94.538.81.716.2]