Abstract＊
Therearemore

than300active

volcanoes

MeteorologicalSatellite（GMS）．Most

accompanied

eruptionbybydetection

ofvolcanic

extentashortandnotin

sufficientintervals

timeforthetheactivetherefore，theeruption

disperse

detection

of

view

volcanoes

occurrence

of

the

small−sized

Geostationary

explosive

ofvolcanic

instantaneous

eruption

the

make

clouds．Generally，emption

quickly，andoffield

emptions

emptions

canbe

cloudschangeofoffield

clouds．But

view

the

their
GMS

isimage−taking

from30minutesto4hours，isveryeffective

indetectingemption

todisperse

inlongerorbit＆lsatellites．The

authorcarefully

photographmaterials

duringlate−1977−1985andclouds

ofGMS，ranging

theofclouds，andmonitored

withinwhich

areGMS

imagesIn

thistoofpaper，many

theseveralandvolcanic

cloudsofvolcanic

image

eruptionsinvestigatedofcould

eruptionofareeruption

withtheGMS

image

detectthermalenergyemptions

arediscussed．The

duringeruptionsfrom23volcanoes．Theismhamperedby

theinintervals

ofdata，mainly

theeruption

cloudsby

aresurrounding

altitude

recentgromd

takingintervals

resolution

rate

image

of

data

view

detection

rateofaretheusual
areeruption

byimage

GMS

Y．Sawada

weatherconsidereddata．It

Seismology

ofisof

GMS

volcanic
onofontheexamined

GMS．There

compiled

emptions

eruptionrisingfutureatclouddataanddispersing

satellite

monitoring

on

basis

theoftheare227emptions

from73

aredetectedin31

eruptionclouds

emptioncloudseruptionsbyofgood−quality

about7％．The

about20km
field

ofbasedforaredetection

cloudsoでinstantaneous

resultsbyof

thecloudsabove−mentioned

cloudsGMS

field

atmosphericoferuption

and

the

taken

analyses

problems

above・mentioned，period，and

about14％，whilelowestreleases

processed．Fmdamental

conducted．Besides，someactivities

cloudsclouds．Observations

also

volcanoes＊Presented

time，compared

areeruptive

imagesofestimations

reported

GMS

short

photographs

mderstanding

volcanoes

emptiontak：enafor23volcanoes．

promoteseverallikelyemptionsmallest

in

the

cloud

data

domainandtheand4km，respectively．Judging

from

theofviewof

theconditions

aroundandovererupting

volcanoes，theto

beupperlimitofdetection

capability

isnot

the

easy

to

GMS

distinguishsensor，theeruptionandVolcanology

Research

Division（Presentstatus：JapanMeteorologicalAgency）

4

image−

cloudsforfromTech．Rep．Meteoro1．Res．Inst．No．22

atmospheric
theGMS

cloudsonly

data，except

somecompared

withemptions

withemption

images，and

the

time

well

monitored

cloudswith

atmospheric

altitudes

variationsofdomains

images．With

estimated

from

their

radio−sounding

eruptions

are

well

on

proposeddatamderstand

data

are

cloudsfromjuvenileejectedmaterials

by

data

strengthorobtained

Conceming
cloudsshow

thefrom

behavior

slightly

eruption

phenomena

may

show

or

opticalcloudsareneeded．

data

resultsareusefulreleasesoferuptionclouds．

than10km

lower

albedovaluesarealmost

explosive

allfoundin

GMS

awidearea

areofvariations

ofof

eruptiondata

air−temperature

profilestimedispersedofcloudsandvolcanoes，theof

that

cloud

in

altitudes

decaysandreactivations

of

are

and

be

equationrecognizedthose

proposedcantheforfromenergies

pIume

betweenestimatedbythermal

thethermalthemass

Yokoyama（1957）．This

estimatedfromriseofshows

dispersing

eruptionthat

eruption

images．

velocities

severalemptioneruptionthanclouds

given

above

show

that

and

effective

for

after

carry

detailedprecisethewind

the

some

analysesvisualof

5

noticedspeed

ateruptionofalso

insidecloud

data

eruption

ofofandcanby

expandincludingthe

dispersing

cloudsrisingaltitudes．

noticed。These

data

emptions，estimating

mechanisms

somerespectivearesources

observational

volcanic

dynamic

was

eruptionsheatobservations

monitoring

investigating

clouds，it

surrounding

hours

andandmethod

emptions，released

applying

data

eruptionsfeatureseruptionsbyofrelation＄hips

dispersing

cloudsmagnitude

theofdispersion．However，more

physicalThe

using

GMS

higheroftheshowaltitudes．However，1arge

estimated

eruption

magnitude

Expansions

duringorBriggs（1969）．Proportional
estimatedcloud

valueseruption

nearbystrength

releases

thealbedosametemperature

theenergy

thatatandjudged．

eruption
byof

to

data

tend

higheranalysessurfacetemperatureclouds

theof

GMS

to

at

cloudsbybasedcloudsbyordersurfaceexamples．Eruption

obtained

In

TBB，namely

1987

eruption

GMS

image

thermalenergyanddispersing』