Introduction＊The

climatesystemlithosphereandthebiomass，Ithasupper

limitofthepredictable

periodlargestone

istheearthspan

isoftime−scale，ourpresent

fragmentary．As

is

the

composedknowledge

repeatedly

ofvarious

theatmosphere，theocean，thetlme−scales

of

in

the

short−range

ageitself，

Even

if

understandingof

theirsandstatedinsense

theofvariation．The

istheweatherforecastipg．

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ourselvestothecharacteristics

arestill

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cryosphere，thelimitof

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present

knowledge

succeeded

inOf

theResearchismodels

realcharacteristics

arestill

far

For

model

is

from

ofvariations

of

the

itselfand

thus

for

theconducted、suchastudy．They・integratedfor

understanding

model

Hahn（1981）first

circulation

climate

model

with

rhomboidal

analyzed

the15−yeardata。

Theirreproduced

without

year−to−yearchanges

furthersurveyedatmosphere．

RecentlyLauyear−to−yearchangesoftheSST

overvarianceofthe200mb

heightinthequantityinthelatitudes．At‡heOSU＊Pr6pared

areOregontwo−layer

bymuchState

SST

less

the

realshowinthatthqrunrunthemodelsthethehaveatmosphere．

systematic

biases

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byeffective

SST

a・factorinandT．Tokioka，K．Yamazaki

of

sea

一3一

real

a

model

atmosphere

improvement

rμn

the

the

generalyears，andof

theincluding

in

has
ais

that

the

model

ob串erved

thetemporalcorresponding

tropics；．whereas・the

integration

fortemperature（SST）．Lau

thanvariability

studiedasmodel．

spectralvariations

largerwellthe．extratropics

basin．Heミhowed

is

the

atmosphere

asof

a

integrationsof2−60verthein

surfすcelong−term

Pacific

enhancing

A．Kitoh．

variations．of

considervariability

Esbensen（1985）haveandstillmostUniversity（OSU）a10−year

GCM。Kushnir

canwavenumber15for18model

15−yeartropicalyet，weatprescribedtwo

perturbed

atmospherelong−term

characteristics（1985）has

climatologicalfluctuations

the

the

truncation

results（1981）、has

SST

TokiokaθヵαZ．（1985）forof

usefulandof

show

Study

therefore

Manabeatmospheres

th￠latteLofthecirculations

toanalogueof

globalcirculation

identical

goodunderstanding

thegeneral

MRI・GCM−1）．
nottheofcomplete．Model

example，seeatheasthem．Atmosphericbasicmodel（thetheoftheatmosphefe。

InstituteAlthoughformerunderstanding

reproducing

course，thefromandmiddle

been

and

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subseasonal

samewith

varia炉ility

fornorthemhemisphere

winterwith

Recently，a12−yeartheuseintegration

ofhasInstitute（MRI）with

the5−layer

SST．Thistechnical

reportispresented

MRI・GCM−I

based

on

the12−yearoftheanddiscussions

nearfuture。

〃of

the

MRI・GCM−I

results

aresimulatedfornotbeendata。

performedatwithout

prescribing

theof

purposerun．Thereforeincluded。They

theyear−to−yearshowingdetailed

will

MeteorologicalbetheResearchchangesmeaninthestatisticalmaps

descriptions，interpretations

publishedinseparate

papersinfive−layer

grid

04θZ

model

Themodel（theMRI・GCM−1）used

with

lts

at100mb．The

Physical
bytop

processes

Arakawa

andincludedforvariationaretheSchubert（1974）and

There

are

notemperatureice

asandαム（1984）forinasinterannual

thedistributions

presented

well

theof

the

inplanetary

penetrative

boundarywith

the

model

detailsof

thesolarinsolation

cumulusonconvection

Randall（1976），

isincluded

Theinthemodel．

conditions，乞．召。，thesea

surfaceand

theshownandlongitude．

hydrology（Katayama，1978）．

aremode1．Januaryand5。inbased

surfaceusedandlayersea

topography

Kitohtheandprescribed

togethertropospherlcofboundaryprescribedalatitudeofcoverages．The

isis40in

variation

ice

Tokiokaθ孟αZ．（1986）and

resolution

thermodynamics

seasonalvarlations

study

parameterizations

sea

furtherpresent

horizontal

radiation（．Katayama，1972），grounddiumalthetemperaturein

Fig．0．See

July、performances

of

sea

Tokiokaθ診

the

model

areMarch100ZofTokioka（1986）．

翫Pθ7伽傭The

wasstartedatJanuary100Z

year13．The

initialconditi6nof

thelbysimulation

withproducedrunanotherofyearlandwas

continu6drun

was

taken

from

the

atmosphericconditionon

Januaryadifferent

versionofthe

Excluding

the

first

model．

until

tw・．m・nths・fthesimulati・n・the12−yearsi血ulateddataareanalyzedlnthisrep・rt。Data
wereoriginally

but

on

mean

the

sampledforevery6hours．In

report，maps

the10−day

mean

and

the

monthlymean

Chapter

describes

thehorizontal

distributions

lquantities。Chapter2showsmonthlymonthly

this

mean

mean

thequantlties、

horizontal

based

not

on

the

origlnal

averageofthemonthlydata。

of

distributions

Chapter3shows

quantities．Chapter4describes

are

the

thethe12−yearof

theyear−to−year

latitude−helght

mean・annual

一4一variation

crossinvariationsections
theofofthelatitude．time

crossseρtions．Finally，Chapter5shows

Both

the

mean

annualvariation

and

the

longitude−timeyear−to−yearcrgssvarlations

一5一

are

sections
lncluded．

atselected

latitudes。