Chapter 5 Discussi。nf。r further investigati。n

Chapter5
5。1
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is
the
the
from
optical
10ud
is
eruption
taken
in
personal
clouds
taken
LANDSAT
of
MSS
image
pale
in
bands
cloud
on
November14，1979，the
the
of
sea
an
shows
be
result
emption
ground
eruption
as
plot
noted
that
cloud
at
obtained
cloud
was
surface，so
in
in
thin
it
was
clouds，LANDSAT
MSS
one．
processing．The
data
used
are
Jamary30，0ctober9，November14and
on
October12，1983．Generally，
clear−toned
Nos．6and7（Tanaka
images
一74一
must
atmospheric
atmospheric
computer
on
the
same
and
of
data
temperature−albedo
Sakurajima
features
through
a
in％）than
in℃）．This
problem
in
M：SS
July29，1985．It
value（ordinate
eruption
on
are
on：LANI）SAT
February24and
temperature（abscissa，TBB
clearly
Nos。4and5，but
thermal
eruption
in
and
Q
energy．
than，often
in
juvenile
ejected
on
atmospheric
Sakurajima
Sakurajima
eruption
by
ejected
shown
bright−toned
be60minutes，the
estimated
December20，1979，March19，1980，March23，1981，and
the
to
small
required．
Eruption
eruption
by
that
so
relatively
the1984September−October
energy
indicate
show
eruption
thermal
the
showed
juvenile
eruption．To
characteristics
the
many
not
throughout
the
clouds
by
an
Physical
Fig．5−3for
section
data
is
indicates
the
and（1id
individual
clouds
abscissa）is
T．E．（CLOUD），there
intensity
of
of
of
energy
in
estimated
gaps
（EJECTA）．This
this
smaller
release
less
almost99．6％of
in
ejecta（T．E．・（EJECTA）in
the
eruption
thermal
period，eruption
or
time
at7．9×1022ergs，while
of1024ergs．The
thermal
this
watts
duration
September23−24accomted
The
during
1987
et
brightness
in
al．，1981）．However，in
obtained
were
almost
bands
the
identical
of
case
in
Tech．Rep．MeteoroL
all
of
the4bands
after
image・enchancement
radiation
brightness
was
Sakurajima
eruption
cloud
band
assigned
showed
decreasing
towards
The
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bands
cloud，sea
images
on
area
thin
ones
spreading
over
with
those
over
ground
anddecreases
towards
clouds
sea
and
radiation
middle
the
level
of
a
All
the
wide
of
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individual
eruption
showed
a
high
edges
or
in
clouds
of
correspond
with
those
5−7showed
a
similar
7band
approximately
higher
The
high
pattems
radiation
results
may
droplets
or
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or
than
bome
both
inside
at
least
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with
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was
intensity
radiation
of
brightness
comparatively
of
compared
of
emption
in
ofthe
present
level
high
the
of
in
the
No．4
simple
cloud，atmospheric
Fig．5−5between
eruption
levels
at
various
LANDSAT
the
MSS
images
crater
or
well
of
at
bands
clouds
is
concentrations
the
several
at
the
those
of
thick
features
high
sea
onthe
in
of
of
at
of
No．4band
the
of
the
sea
values
extent
which
level
surface
those
of
clouds，but
decreasing
pattems，especially
the
Sakurajima
spreading
radiation
and
in
portions
atmospheric
the
whole，the
was
ofthe
Fig．5−7．The
those
a
Fig．5−6）．
surfaces
portions
No．4band
atmospheric
surface，but
also
compared
in
areas．As
radiation−1evel
patterns
particles
cloud
dependency
level
known
center
of
the
Sakurajima
atmospheric
that
the
like
might
surface，and
of
shown
dependency
different
the
points
low
city
cloud（see
with
Fig．5−61high
with
of
central
bands
and
rather
the
nearly
in
Fig．
towards
No．
and
atmospheric
with
radiation
Fig．5−7）．
both
been
the
showed
or
eruption
are
coincides
extent
possibility
the
that
radiation
parallel
of
than
forest
atmospheric
in
the
of
LANDSAT
cloudswere
radiation
eruption
of
as
as
pattems
higher
pattem
clouds．The
to
radiation
surface．The
atmospheric
due
which
sea
shows
has
are
range
crater
near
of
brightness
l4，1979．Both
the
surfaces，and
concentrations．It
not
about30（see
mixture
level
radiation
presence
levels
Fig．5−4，where
general，but
area
surface
spreading
on
indicate
a
sea
over
the
over
in
radiation
forest
leve1，which
tips
levels
of
area．The
of
taken
the
values
November
eruption
radiation
clouds，despite
in
No．7band．Thispattemisinparallelwiththepattemsof
pattems
eruption
and
the
scattering
the
low
and
surface，but
of
shown
to1281evels．The
patterns
October9，and
the
as
1987
No．7ban（1．
surface，city
taken
Res．Inst．No．22
be
clouds．On
eruption
the
in
cloud
atmospheric
the
form
therefore，reflects
patterns
diffemce
of
that
the
density
droplets
and
their
be
or
of
the
radiation
might
eruption
Simple
is
cloud．So
of
explained
thickness
of
coated
the
of
sea
ice
as
atmospheric
and
ice，water
surface
an
water
ejected
water
their
a
or
with
by
size・distributions．When
一75一
of
materials
characteristics
levels
showed
consideration，these
composed
droplets
clouds
or
ice
or
of
thickness
large
cloud
or
quantity
is
of
ejected
the
materials
eruption
are
bome
clouds
contribution
of
will
the
quantity
of
atmospheric
of
bome
observed
results
water
cases
droplets
For
the
are
several
on
problems
of
be
to
observe
spread
disperse
within
explosions
to
purposes，a
The
its
detection
fine
are
the
of
GMS
limit
of
of
optical
concentrations
of
ejected
do
that
is
not
the
almost
estimate
or
decrease
the
a
large
concentration
similar
total
substituting
clouds
contain
to
that
volume
the
concerning
of
of
or
the
ejected
experimental
or
concentrations
or
volcanic
GMS
the
eruptions
image−monitoring
author
s
opinion
as
of
volcanic
emptions，
follows：
extent
for
at
the
still
inspections
best
altitude
the
and
of
is
is
behavior
ejected
also
time
of
to
necessary
after
of
eruption
high
to
the
the
fundamentally
of
of
an
weather
several
monitoring
monitoring
size，ground
eruption
of
cloud
occurrence
dimensions
detection
small
sequence
small，immediately
interval
the
an
clouds
with
complete
altitudes
detect
of
for
quickly
eruption
occurrence
volcanic
clouds
clouds
volcanic
emption，For
these
demanded．
image
mder
eruption
Careful
of
time．Besides，it
the
eruptions．However，for
Distinguishing
assumed
the
ejections，
them．
in
accurate
volcanic
（3）
which
using
generally，emption
short
they
about10km
horizontal
cloud
effective
the
image・taking
resolution
sufficiently
a
determine
experimentally
in
when
shorter
（2〉Gromd
clouds
cloud
to
to
of
be
eruption
due
ash・clouds
intervals
important
altitudes
might
be
strong
increase
atmospheric
within
solved
eruptions，but
low
of
cases
may
the
possible
eruption
more
in
eruption
an
monitoring
volcanic
at
be
kinds
monitoring
and
compose
bome
to
with
ordinary
will
as
tone．This
inside，it
sate皿ite
establishment
dark
of
spreading
droplets
clouds
coating
which
various
of
（1）Image−taking
is
a
on
ConsiJeration
It
or
a
materials
within
size・distributions
there
of
eruption
cloud．Therefore，it
materials
5．5
inside
many
ejected
size・distribution
1987
manifest
ice
materials．However，in
Tech．Rep．Meteorol．Res．Inst．No．22
of
resolution
eruption
cloud
in
GMS
conditions，but
it
is
km．The
detection
limit
eruption
clouds
of
large
volcanic
of
at
eruptions
least
l
km
in
of
IR
image
reached
usually20−30km
of
more
GMS
image
generated
detail
image
is
by
and
is
big
of
needed，
clouds
GMS
images
by
observers
一76一
will
make
the
detection
of
volcanic
Tech．Rep．Meteorol．Res．Inst．No．22
emption
that
clouds
of
the
vapours
or
that
difficult
to
IR
and
under
far
atmospheric
Cloud．However，since
droplets
mixtures
of
possible，as
have
well
VIS
eruptions
of
detector
such
as
of
eruption
apply
data
clouds
to
Physical
and
do
not
the
have
are
such
strongly
monitor
mass
as
of
the
of
of
TM
clouds
are
coated
to
impossible
of
clouds
to
compared
mostly
with
those
atmospheric
peculiar
atmospheric
based
detect
on
or
of
their
clouds，it
only
eruption
with
composed
water，ice
two
clouds
have
to
eruption
clouds
TOMS（Total
emption
not
only
Ozone
clouds
sensors
is
kinds
spreading
having
to
in
the
Mapping
as
effective
daytime
but
for
also
at
Spectrometer）bome
highly
distinguish
diffrent
concentrated
eruption
on
SO2clouds
clouds．
method
eruption
be
detectors
andusingmicrowave−sensorswillbe
effective
eruption
the
the
purpose
in
the
field
have
to
be
quickly
conducted
into
for
clouds
clouds
for
analyses
dynamics
development
characteristics
distribution
of
data
and
the
an
on
on
to
the
of
of
of
accurately
materials
of
cloud
a
of
of
of
observations
of
volcanic
spreading
volcanic
also，processing
variations
eruption
and
of
hazard−reduction，
processed．And
time
convenient
eruption
and
physical
eruption
eruption
of
clouds
easy−operation
spreading
or
volcanic
system
for
of
cloud−surface
an
the
and
clouds
emption
thermal
optical
in
clouds．The
estimate
the
and
inside
extent，and
the
eruption
一77一
energy
features
and
to
it
is
very
important
or
or
extent
estimate
optical
of
the
mture
emissivity
of
to
releases，H：owever，we
surfaces
atmosphere，including
physical
altitude
cloud
characteristics
the
thickness，transparent
altitude
bome
of
surface
actual
dispersing
variations
the
eruption
distribution
needed
ejected
the
volcanic
emissivities
time
or
image・monitoring
optical
rising，spreading
cloud
GMS
altitude
of
of
purposes，the
enough
distribution
is
required．
Temperature
estimate
clouds
problems，additional
detect
investigate
these
is
could
one
data
image
analyses
MSS
image・processing
image
eruptions．For
i㎡しage
also
movement
the
many
which
operating
or
eruption
similar
from
almost
above・mentioned
images
we
eruption
clouds．
detecting
（Krueger，1983）is
When
is
and
satellite
（5〉
clouds
s
Nimbus
of
eruption
LANDSAT
time．The
many
separate
data．Besides，it
of
ejecta−particles
apparently
the
night
（4）Easy
including
like
distinguishing
feature
features
image
solve
wavelengths
water
the
optical
atmospheric
To
of
as
1987
an
thermal
on
the
actual
of
eruption
the
surface
eruption
energy
of
cloud，to
release
cloud．Observations，measurements
or
and
Tech．Rep．Meteoro1．Res．Inst．No．221987
theoretial
to
get
studies
the
physical
（6）Theoretical
and
the
of
sequences
and
of
conducted
eruption
or
in
the
eruption
rising，spreading
satellite
image
are
important
and
（7）
well
data．The
effective
and
such
as
and
time
for
an
fmdamental
observation
of
and
every
available
method
spreadingemption
cloud
stratosphere
data
on
paper，and
of
EI
be
spreading
sequences
regional
spreading
the
Chich6n
could
the
images（Matson，1984）．Investigations
for
clouds
results
thermal
ofvolcanic
further
and
to
experimental
of
image
this
eruption
estimation
for
technique
volcanological
for
the
them．To
begining
variations
studies
will
of
volcano
be
supported
dynamics
energy
conceming
of
release
eruptions．Their
the
ejected
by
these
eruption
clouds
as
one
of
the
results
will
provide
eruption
mechanism
and
tool
volcanological
make
and
of
the
of
satellite
（8）Establishment
the
aircraft
ejecta・fall
decay
times
are
image
field
of
volcanic
in
their
useful
provide
of
volcanic
a
eruption
and
strongly
are
data．Visual
orbital
important
image
for
the
and
fmdamental
observation
ofejected
from
data
on
further
the
the
data
materials，
information
observations
satellite
demanded
gromd
eruption，mass
clouds
for
effective
effective，precise
communication
hazard
for
the
ground，
sequences
development
of
of
data
ejecta−mass
possible
system
reduction
flight，various
areas，estimation
can
a
more
ground−truth
also
is
analyses．
quick
be
of
observations
a
will
or
eruptions
work，and
technique
so−called
of
regions
volcanic
top−altitude
clouds
investigation
for
the
end
emption
volcanic
eruptions
surveillance
aerial
measurements
wide
of
atmosphere
in
satellite
strength
volcanic
or
over
dynamics
the
eruptions
dispersing
and
data
in
shown
big
using
and
intensity
radar
for
the
example，many
were
accurate
the
In
applying
clouds．
on
clouds
the
traced
investigations，forming
of
by
theoretical
Satellite−monitoring
materials
by
sciences．
Precise
study
eruption
images．For
cloud
of
atmosphere
be
of
intensively
investigations
atmosphere
dynamics
methods
of
emption
satellite
could
evaluation
properties
spread
stratosphere
very
more
mechanism
widely
using
the
conducted
experimental
clouds
of
be
optical
eruption
Detection
well
should
through
work
and
including
information
and
monitoring
analyses
一78一
of
security
are
of
eruption
of
transport，especially
demanded．For
movement
cloud
of
image
forecasts
eruption
data
of
clouds
taken
by
Tech．Rep．Meteoro1．Res．Inst．No．22
GMS．For
and
these
quick
systems
purposes，accurate
image・data
for
the
processing
issuance
occurrence
of
intemational
data−exchange
（9）
For
volcanic
prediction
Monitoring
of
volcanic
monitoring
gromd
ground
thermal
by
but
volcano
are
show
only
sea−water
difficult
by
owing
observations
DCP
by
GMS
active
images
of
IFOV
of
of
volcanic
gentle
system
its
for
of
early
be
commmication
image
data
on
establishment
the
of
an
promoted．
of
monitoring
directly
volcanoes
of
contribute
to
of
deformations
useful
measurements
orbital
GMS
are
images
may
volcanoes．The
means
for
be
images
be
GMS
gromd
should
satellite
radio・telemetered
used
as
volcanic
accompanied
flows
by
active
on
have
the
higher
be
effective
seismological
growth
of
monitor
these
activities
activities
image
activities．
一79一
should
lava
ejections
or
satellite
those
conducted
of
the
as
a
events，
ofvolcanic
gases
activity
not
lava
or
purpose
monitoring
observatories．
volcano
the
prediction
for
should
data
the
which
fully−equipped
IFOV．These
orbital
not
compositions
activities
of
should
of
temperatures，chemical
activities．To
limit
sometimes
no
can
of
of
such
fume
have
pourings
submarine
and
or
that
results
demanded．The
events
kinds
those
sites
non−explosive
also
to
of
those
than
active
sites
analyzed
overrespectivevolcanoes
besides，quick
observation，detection
sites
platform（DCP）for
Observation
useful
at
on
volcanic
and
eruption
clouds
deformations，ground
There
for
aromd
needed，and
strongly
observations．Analyses
activities
etc．from
（10）
volcanic
state
aerial
data・collecting
ground
system
data
are
based
are
erup亡ions，but
resolutions
thermal
wamings
eruption
eruption
volcanic
or
of
systems
emptions．Seismological
of
predicting
of
radio−sounding
1987
be
analyses．Of
of
domes，and
by
monitored
GMS
by
course，the
eruption
clouds，
discolorations
images
is
gromd
or
GMS
can
of
very
aerial
be
a

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