Some
Characteristic Features of Cloud Lines
Seenin GMS
Imageries
HidekiItoh*and TakashiTsuchiya*
Abstract
Cloud lines consisting of cumulonimbi
(Cb lines) are frequently observed in GMS
ries, especially in regions south o￡the main
in the northwestern
Pacific Ocean
baroclinic zone.
Such
image-
Cb lines are studied
with respect to the morphological and analytical
aspects｡
It is revealed that the frequency of the occurrence of Cb lines is maximum
and minimum
autumn
in winter.
Spatial distribution of the occurrence
than in any other season.
All the Cb lines in
are classifiedinto seven categories.
analysed herein.
According
Two
GMS
of them
imageries
in summer
is broader in
for three years
different types of Cb lines are sｅ!ected and
to the ｡results of the analysis. it is clearly pointed out that
ａ stable layer exists between
800 and 900 mb
and a potentially unstable layer is observed
under the stable layer on the eastern side of Cb lines. Such the unstable layer extends vertically up to 600 mb
the development
in just front of the cloud lines. This
tral condition is observed at lower
and middle levels of the troposphere.
1. Introduction
Cloud
lines
the routine works
lines consisting
frequently
observed
especially
in regions
zone. Once such
some
12-18
kilometres.
imageries
and
shown
several
hundred
mature
the
from
Cb lines in
and
imageries
extend
of
(MSC)
are
which
GMS
Cb lines are also detectable by radar observation
net works
for
October
in
less than
more
combined
the study
1979
this study
taken
6
-
area
at three hours
and Ｔ. "Ｗ.Harrold,1970).
ment
those researches｡
is set up
intervals
The
of such
main
mechanisms
； Ｋ. Ａ.
Fine
struc･-
of the develop-
cloud lines have been revealed
by
purpose in this paper is placed on re-
re・
vealing gross features of Cb lines by classifying all
for
the Cb lines observed for the three years, analysing
1981
composed
and Ｔ. Akiyama,1974
tures of Cb lines and
more than
to September
are
Browning
are defined
hours,
studies have been achieved on
with conventional data (e, g. R. Tatehira,
1971 ； Ｋ. Ninomiya
150 kilometres
than
and many
this kind of subject by rader observation data
reveal
limited
are
for meteorologi-
they last
for several
this paper
other conventional meteorological data
are easily obtainable at MSC
cal analyses｡
morphologi
a
and
at Meteorological Satellite Centre
baroclinic
to
to the
life time
and
period
used
and
within
kilometres,
three
the GMS
the main
respect
aspects
stage
The
the data
coverage,
The authers tried
width
spectively.
years
hours
with
in Fig. 1.
in
of
hereafter)
Cb
features of those cloud lines seen
analytical
as that length,
the
south
characteristic
in GMS
and
within
(called
Cb lines appearing,
for about
hundred
cal
of cumulonimbi
or cloud lines for simplicity
usually
provides preferable condition to
of convective clouds. In the rear of Cb lines, dry and stable and/or ｎｅｕ･
the seasonalヽchange of the spatial distribution of
of
the occurrence of Cb lines and achieving some
in
studies for typical examples
of tolerance.
*Meteorological SatelliteCenter.
―
33 ―
case
within ａ certain degree
METEOROLOGICAL
SATELLITE
CENTER
Fig. 1
2.
Classification
Cb
lines
in
GMS
patterns.
Fig.
which
commonly
are
(Fig.
1).
given
below.
(a)
associated
A
cloud
cloud
area
with
the
2
with
cyclonic
band
stretches
(marked
a cyclonic
seems
a
in
or
area
(c)
be
tion.
will
of
of cloud
which
utive low
pressure
systems
just
from
wave
the
the
low
the
cloud
of
line
spite
of
pressure
band
two
frontal
steady
Cb
cold
line
suggesting
aloft which
a boundary
is often observed
causes
considerable development
low pressure system
at surface (SFC)
in
just
cloud
ahead
band
of
the
often
sometimes
for a few
width becomes
thousand
upon
south.
After
occasion just ahead
this kind of cloud bands.
(d)
kilometres
band.
This
its
that, a Cb
of and
This suggests
along
that this
boundaries
between
and the polar air mass.
Cb lines in the warm
sector of low pressure
systems.
zone.
A Cb line appears in front of a cloud band which
cloud
type
and
narrower gradually as the cloud band
towards east and
line forms
along
accompanies
of a
the east
of Japan in winter season. The cloud band stretches
the subtropical air mass
consec-
of strong
cold vortex
stretches to southwest
from
a cloud area
associated with a low pressure system.
frontal
most
in northeast
flanks to a well denned
type of Cb lines occurs along
bands.
A
and is observed
within the target area than any
cold air advection
moves
(line).
westerly
cold
The
often
system
sometimes
in the
cold
model.
is connecting
ahead
of a
cloud
in
along
this case, the
representation
of
the
associated
forms
1982
Cb lines along the front of cold air advec-
to souahwest
In
lines stretches
cloud band
lines
of cloud bands
Cb line
stationary
accompanying
Cb
2
2 (a))
band.
frontal
whole
(b)
A
part
movement
type
Fig.
edge
Fig.
cloud
Norwegian
slowly
This
C
5. MARCH
other types.
them
target
southwestward
to be the
becomes
is
the
for
disturbance.
of the
southwestern
which
in
frequently by GMS
various
of
disturbances.
by
tip of
eastward
in
patterns
the front
No.
area in this paper.
A cloud band
lines along
front in the
appear
observed
NOTE
parallel to the cloud band
typical
explanations
front edge
cloud line
Target
lines
imageries
shows
Some
Cb
of Cb
TECHNICAL
a
is
of cloud lines is rather apart from
within a warm
34 ―
sector when
which
This
is
type
the cloud band
it appears firstand the
気象衛星センター 技術報告 第５号 1982年３月
Fig. 2 Various
patterns of Cb lines as seen in GMS
−35−
imageries.
See text for details.
METEOROLOGICAL
band
approaches
（ｅ）Cb
to the Cb
lines in
pressure
SATELLITE
line
gradually.
the periphery
lines
band
appear
which
along
in cloudless
and
in
warmer
above
south
(g)
lines
the
outer
developed
reaches
Areal
extent
season
to season. Fig.
In
winter,
and
locations
of upper
and
cold lows.
pattern
appears
forms
regions of
and
west
Cb
winter
lines
and
region
of ａ tropical
cyclone,
ａ well
Cb line appears sometimes and often
This
observed
to northeast
in
the north
type of cloud
of the
more
sometimes
consists
with
of ａ part
the
of ａ cloud
area
which
cyclone and indicates lower
level
circulation
In
this classification, there
of the cyclone.
exist some
and
rence
of Cb
−180°E)
difficulties
few
types
among
of occurrence
of Cb
case. This
suggests
occur
under
lines
and
close synoptic
the developing
a disturbance is
when
the
case
of (b).
each
disturbance
Cb
lines,
other.
extension
and
up to one
a well
defined
metres
the case
under
pressure
such
systems
extending
In
appears.
thousand
existing
however,
of (a),
early develop０ｎ the other
defined in
for several
the
hundred
kilometre.
stretching
for ａ few
conditions
broadly
Cb
both
east-west
cloud lines
20°Ｎ. Cloud
of cloud lines
Further
widely
autumn is
range
10
Various types
observed
in this
(110
lines
is from
season
as in
110
with
northwest
the occur-
mentioned in
region
by Fig.
The
bigger
season. The
to 40°Ｎ.
fre-
appear in
spreaded
lines is indicated
directions in autumn.
occurrence in
most
region
than
in
3（d）
of the
any
to 180°Ｅ and
of cloud lines are
other
from
also
summer｡
Such variation of the occurrence of Cb lines
would
be
closely
the synoptic
related
situation
to the
seasonal
change of
in this region investigated.
of the cloud lines in both
and long
of (c)
of
in
disturbances
the case
is not clearly
contrary,
break
of
Scales
the
distinct and in the
kilometres
in
2 in some
of
of（a）ａｎｄ（b）ａｒｅusuUy
appear
Fig.
situations.
the cloud line
The
in
stage
types
to be different
hand,
(c)
that Cb lines in those types
accompanying those
stage
and
in both
to
Fig.
of the occur-
suggesting
section.
direc-
in this season.
in this season,
rence of various
in
cloud
concaving
and
form
the
are observed
No
below
the previous
(a), (b),
lines
southeast,
north
than
of
convex shape towards south,
in assigning ａ proper type to ａ given Cb line
types
spring
east3 (a).
directions （20-50°Ｎ）ｃｏｍ-
spring.
the southern region
１０−
and
in Fig.
the areal extent
north-south
in
observed
in north-south
cloud
that Cb lines
to that
vari-
direction (105-170°Ｅ:〉
lines is broadened
and
only
in
appear
and
are
occurrence
is observed
southeast
seasonal
area｡
as seen
frequently
A
lines varies
north-south
out in east-west
in summer
pared
cyclone centre. Southernmost of the cloud line
is associated
northwest
both
3 (b)). The
3 (c) indicates
lines is
quadrant
of Cb
in limited range of
respectively,
less extention
quently
to ａ cloud area which is associated with
are
125-155°Ｅ in
appear
such
the target
cloud lines
of them
lines is spread
tropical
in
several
(Fig.
of Cb
3 shows
season
directions,
A
of the low.
outer
30°N
in
Ocean.
ａ Cb line
the tropical cyclone.
cases
which
of the occurrence
of the occurrence
for each
appear
simultaneously.
variation
tion (15-35０N).
In an
ing
pressure system
lines
ation
cyclones.
seem
１９８２
causes the cold air advection.
with ａ certain angle
periphery
in
baroclinic
of the Pacific
to south
to southwest
a
in the westerly
a blocking
part
travels
Cb
with
the periphery
seasons,
the northwestern
ｃｕt･offlow
the
Ｎ０．5. MARCH
stage of the low
3. Seasonal
of ａ
usually crosses the
cloud lines
lines in
the
just south
portion
Cb lines
mentioned
or three
（f）Cb
In
high
areas in periphery
associated
type of
band
two
is
the southernmost
zone. This
cloud
NOTE
developing
of subtropical
of subtropical
・
high pressure system
zone
TEICHNCAL
systems.
Cloud
cloud
CENTER
０ｎ the
Cb lines
thousand
as fully developed
and
to the
strong
cold
subtropical
kilolow
air outregions.
3. Case
Two
case
analyse
tions
study
studies
structures
around
among
an
observation
and
lines and synoptic situa-
the cloud lines.
ed
island
were carried out in order to
of Cb
all the cloud
network
the Korean
lines
Those
which
cases
in the Ryukyus,
peninsula.
are select-
passed
Fig.
through
the Kyushu
4 shows
the
In this case, no Cb lines are observed in any early observation network employed for meteorological
-36-
&&ffi￡-fcV*-
Sflftftc %5*%
1982^3 H
I
i
!
i
!
/
s
00
o
&.
cf
6
ID
u
CO
<u
<u
<D
o
ii
cd
60
u
tS
<u
_C
'?
ffi
en
<D
I
UJ
ll
I
o
O
LU
Q
D
oa
OC
LU
hZ
CC
LU
2
CO
o
CD
CS
Ih
CO
<u
a,
a
CS
o
c
_o
C8
l-l
cS
>
o
en
C3
<L>
CO
≪
cn
fa
z
O
―
37 ―
METEOROLOGICAL
SATELLITE
CENTER
TECHNICAL
shown
NOTE
in Fig.
No.
6.
Those
that ａ remarkable
this region
and
vertically.
At
system
continuous
to
rain
SSW。
low
This
quence
at various levels exceptfor the surface
(SFC). A
centre
observed
time sequence at SFC.
（500
analyses of time-space cross sections at various
of 65
in Fig.
(300
Wet
are achieved along the thick
portion
of the analysis
lines and the broken lines in Fig. 4, respectively.
eastern
tip of the Cb line
by station numbers
are orthorized by WMO
communi-
tive convective
areas
are
Ａ
Case
l : 28-29
cloud
area
to ａ low
pressure
indicated
by
system.
about
formation
of the
100 km
ward
by
wide.
about
Cb
line
Fig.
began
5 (d))
The
cloud
and
Ｚ and
weakening
line
passed
Time-space
potential
temperature
(^≪*) at 47936
Warm
and
below
800 mb
in Fig. 7.
800 mb
may
1500
through
of the
km
long
southeastnear
sta-
at 290300 Ｚ ，
Ｚ ，respectively.
after 291200 Ｚ as seen
convective
of the
clouds
equiva-
lent
as seen
moved
equiva-
saturated
line
after the initial
extension
earlier｡
of wind,
(^≪) and
The
in
are
cloud line
and
the
partly
thickness of
at both
Ａ stable layer
potentially
rapidly
the
between
shows
areas
to
the
line
below
advected
air
suppresses
clouds within this
unstable
layer
Ｚ immediately
cloud line. This
develop
at 281200 Ｚ，
900 mb
Thermal structure at
and
at 291200
cross sections at various levels are vicinity of the Cb line.
−38-
and
convective
that ａ wet
of the
Cb
layers
at 290000 Ｚ than
800
unstable layer.
to 600 mb
passage
erable
of
by
levels
winds
of the
unstable
caused
47945.
the potetially unstable layers
stations
development
47945
be
southerly
passage
Potentially
and
into lower
strong
stations before the
increases
the
mainly
rather
when
between
change
temperature
with
ac-
cloud line
data
47945
potential
denoted
seen
the
lent
Fig. 5 (a),
is
where
was
air intrudes
where
this level. Other
291800 Ｚ as mentioned
wet
the north-
level
ａ station
the time
a
in northern
around
of appropriate
through
7 indicates
at both
and47945
291500
in the southwesternmost
at 291800Ｚ.
Fig.
at
stage is for about
The
in
line
as shown
18 hours
5 （d）ａｎｄ（ｅ）. Active
still seen
clouds
development
47918,47936
Ｚ， 290900
development
the cloud
gradually
50 knots
tions of 47909,
290900
and
cloud line.
cloud line in mature
and
Initial
(c). Remarkable
291200 Ｚ (Fig.
291200 Ｚ and
cumuliform
shown)
by Ａ and Ｂ developed
and
1980
by Ｃ in Fig. ５ corresponds
immature
at 281800 Ｚ (not
(b)
March
marked
passed
to the
troposphere,
into
areas
of the lack
is
6 （ｃ）ａｎｄ（d）.
at 500 mb
intrude
even in
and
of the trough
and
east
air
In the middle
mb)
Fig.
domain
clouds
dry
the line has
3.１
by
areas locate just ahead
exists because
cation code.
Wet
system.
upper levels and SFC
All the stations are mentioned
6 (b).
circulation
is outlined
with
knots to the
pressure
and the upper
zone｡
circulation
cyclonic
levels and thermal structures. The cross sections at
in 5-digit which
by a distinct
the
mb)
stretching
characteristic
of the low
distinct trough
and
in ａ westerly
cyclonic
wind
at 850 mb
within
southeast
trough
typical
is passing
southerly
of the
broken line represents stations for
system
changes
- westerly
to strong intensity
ａ cold
is ａ well-defined
depression
direction
northerly
moderate
along
pressure
290600 Ｚ with
point
Wind
to
to the west
ａ cold front accompanied
pressure
maximum
inclined
of the low
dew
indicates the
when
There
Ａ thick line denotes the location for time se-
with
6 indicate
has passed
at about
weather.
to shower
features
Fig. 4 Stations used in meteorological analyses.
47817
easterly -southerly
is altered
line
the centre
temperature,
and
Fig.
disturbance
trough
through
of wind,
（ｎｏt shown)
from
the
１９８２
figures in
cyclonic
SFC,
passed
changes
5. MARCH
convective
provide
clouds
extends
before
the prefin
the
気象衛星センター 技術報告 第５号 1982年３月
Fig. 5 Evolution
of ａ Cb line A-B
and ａ SFC
chart for the Case 1， 29 th Mar.1980.
一
denotes ａ cloud area associated with a low pressure system.
39−
Mark
Ｃ
METEOROLOGICAL
SATELLITE
CENTER
TECHNICAL
NOTE
No. 5. MARCH
1982
47105 ―
47122-
47138 ―
Vc
A
47138―
/
47800―
―35M
―35N
47817-
47807―
47827―
47827-
47837―
18--4""^
J''4/-I
21 -J
47909―
wVJ
w
■
47945―
―30
30 N
/; ＼ V＼ v
''V-i
y
-
Ml
47909―
･ ,^^
47945―
I
I
I
'
I
oSioz
12002
(a)
05&Z
sfc
1200Z
28-31
O§8o2
MAR
1
1228OOZ
1
I
oaooz
1200Z
1980
0000
(b) 850MB
29
OOOOZ
1200Z
Z
28-31
MAR
28
120OZ
1980
-18
47122―
47122―
47138―
47138―
＼
"
^
//
%_-
I
―35N
―35W
47807―
.
＼*
.
/
/ft.
&-―C―5700
47807―
＼―
＼8^>%-'
^-
47827―
47827-
V―
V^-%JS1-L
47909―
47909―
＼
＼
＼
47945 ―
N.
S/-
30
0880Z
1200Z
― 30Ni
47945―
I
ooooz
I
1200Z
(C)
I
OOO O Z
500MB
I
1200Z
28-31
I
OOOOZ
MAR
1200
'
31
000OZ
Z
(d)
Fig. 6
Time
sequence at SFC,
850, 500 and 300 mb.
Thick
areas represent height contours (isobars at SFC), isotherms
less than 3 degrees (rainfall areas at SFC"). Hacthed
47936
'
'
OOOOZ
1200Z
300
MB
28-31
MAR
lines, thin broken
1980
lines and
and wet areas, dew
stipple
point depression
areas denote a Cb line concerned.
47945
330K 340 K
340K
340K
301200Z
3000002
291200Z
(a) 28-30
MAR
1980
Fig. 7
'
1200Z
1980
Time
change
I
34OK
301200Z
340K
290O00Z
of vertical wind
(b)
28-30
MAR
294K0Z
1980
29§ffiZ
profile,equivalent potential temperature ((?c) and
equivalent potential temperature (#e*)
deuiation of 6e from
3&3&Z
at 47909
and
340 K at each obsevation time.
40 ―
47945.
Check
Striped
areas represent
stripes denote approximate
I 'I
340K
281200
Z
saturated
negative
time
of
気象衛星センター 技術報告 第５号 1982年３月
After the passage of the Cb line,the warm
wet
air in the lowest
air appears
at 47936
after 300000 Ｚ .
below
800 mb
southwest
those
with
end
are
very
dry
of the Cb
unstable
at 47945
just
logical
are
no
seen
low
poten-
ｍｕch（ｎｏt shown)
at
almost
condition
as
seen
the nearest
convec-
in Fig.5(e),
not change
station,47918
Ｚ｡
The
cloud line in this case is one
lines in the category
of the type
cloud line
front
formed
in
air mass.
line
causes
tors
mentioned
of typical
the passage
of some
Changes
in Fig.
of cloud
8.Ａ
in the northern
of the Cb
of cirriform
area
clouds
(called
suggests the existence
commonly
movement
and
of
Ｂ in Fig.
A
line
8 (a)
towards
small
and Ｆ
southeastward
and
by
47936
one
developed
tensity
at about
with
at 241800
Ｚ.
This
the cloud
the
and
Clear
near
by
47909
region
8 (d)
(Fig.
and
about
50 knots
former
one
2000
reached
km
cloud
long
line
portions
the maximum
intensity.
and
passed
with
of the Cb
The
cloud
period
Ａ
line
wet
area
and
thermal
played
７００
mb
change
two
study,
easterly
marked
tions.
the middle
and
ical high
in
the low
rapidly
Wet
41
―
is advected
with
from
the
in the warm
in the
9.
the
thermal
The
change
front
of winds
concentration
locate
levels
This
in the
of the
is attrbi-
because
closely
the
each
other
suggests
pressure
stable
ridge
of vertical
wind
during
seen
the
system
winds
at 231200 Ｚ below
has
turned
dis-
above
this
８５０mb
at both
the predominant
system
profile
are
period of
northwesterly
that
(d).
miiddle
47945
southerly
the
and
the
and
mb）
where
9 (c)
below
Although
winds
（500
the area
Figs.
at 47909
scarcely
pressure
but
above
as seen in
change to southerly to
the
thermal
system
forms
change
change
in Fig. 10.
wide
―
the
structure
through
Cb line decayed
mb)
spreads
troposphere. Time
was
to the centre
in Fig. 9（b）bｕt it is too diffi-
that
exists,
100 km
which
detected
This
is ａ warm ridge at the middle
cloud band
line
band
of wind
are
region
in Figs. 8 and
the cloud band
47909
Ｚ and
concentration
line appears
to thethermal
latter
in-
cloud
line in
change
air mass
to coincide
out
upper (300
moved
to maximum
at about 241200
merged
southwestern
through
241200 Ｚ . The
the
and
pressure
Cb
ｃｏｎ･
this case｡
and
by arrows
The
the Cb
system.
the cold
as seen
and
There
to form
the
only
Cb line
in
that
concentration
utable
along
southeast
ob-
of the
weather
to northerly
of the low
cult to point
Ａ
then,
lines
during
passed
240900 Ｚ and
and
is seen
are
of the cloud
to ａ cloud band
thermal
pressure
seemes
thermal
cloud line lasted
cloud
indicates
of winds
the
arrows
low
rainy
owing
direction
in south and
whilst
temperature
hand,
region
8 (e)). Ａ
of the band.
sector
Showers and thunder-
in the rear
other
just behind
major
by iso-
at 241600 Ｚ after the passage
in north-south
the
is indicated
of the
appeared
０ｎ the
concentration
cloud
Ｚ and
is denoted
Those
At 241800 Ｚ ，a frontal
Ｇ in Fig.
line.
descend
sky
exists
west
8 （ａ）
The
Cb line began
which
stations,47909 and 47945,
250000 Ｚ .
Fig.
which
by
240300
This
another
rapidly
about
the southeastern part of the
storms
to the south
first in the sea south
about
7 (c).
of this study. The
and
system
developed
the first one
in Fig.
In
scale disturbance
bars along
pattern
shown
a bulge
following
indicated
southwest.
for about 15 hours
just behind
in
to the bulge.
pressure
Cb
the Kyushu island at
stretched
Ｅ
Ci bulge)
to east-northeast
of ａ low
8 (f).
are
by Ｃ with
of ａ cyclonic disturbance
in the southwest
area Ｃ progressed
in Fig.
in this case
region
a
running
1980
of the analysis
of the low.
of
marked
ａ major
a cold front
rear
that
fac-
part
direction from southerly
features
cloud
with
low,
which
earier.
2 : 24 25 Oct.
meteoro･
At SFC,
rainy weather continues in front of and in
at 850 mb
3.２ Case
of certain
levels.
accompanied
tinues in the southern
with
meteorological
system
cloud line.
Cb
The
trough
sequences
at various
and
served.
at
Fig. 2 (a).
of ａ sharp
Therefore,
the changes
in
merger｡
time
elements
pressure
line
300000
shows
passing
exist. Near
does
after the
9
suggested by the concentration of isotherms is
neutral
line, vigorous
condition
hours
Fig.
and
stable layers,
still observed
potentially
a cold
6
cold
layers
after 291200 Ｚ
and
the
layers are observed at 47945 after
or stable layers
where
and
at 291200 Ｚ and
at 47936
300000 Ｚ . Above
tive clouds
is altered
Remarkable stable
tially unstable
the
layer
sta-
subtrop-
gradually
in this region｡
condition
is seen further east to
to
METEOROLOGICAL
SATELLITE
CENTER
Fig. 8 Same
as Fig. 5 but for 24 th ｏｃt.1980.
−42−
TECHNICAL
NOTE
Ｎ０．
5. MARCH
１９８２
MilfSM^^-
&ffi&%
^5^-
47105―
47122―
47138 ―
47138―
47800―
47817
1982^ 3 n
4
―35N
47807―
―
47827 ―
47827―
47837-
-30N
47909―
47909―
47945I
2<5
OOOOZ
1200Z
(a)
23-26
SFC
24
OOOOZ
1200Z
OCT
23
1200
Z
(b) 850MB
1980
23-26
OCT
1980
^s^^yy^
47122-
■
-y^.
^-5700
Z^-^J"'-^35N
*^^q^>%yW-'
4780747827―
%￡^^-V^―^^
―35N
47807
_12
-^93&0
＼k5"#^--Vfc^^>-'^'
― 30N
5820
^^^-
47909―
%^-
X^fit^"%^^"*^"
＼^--^__
-30N
^"" <^
47945 ―
1
26
OOOOZ
(C)
1
I
1200Z
500MB
I
OOOOZ
23-26
I
1200Z
OCT
Fig. 9
'
I
O§OOZ
1200
1200Z
(d)
1980
Same
300MB
'
OOTOZ
23-26
'
'
120OZ
OCT
OOOOZ
23
1200
Z
1980
as Fig. 6 but for 24 th Oct. 1980.
47909
330K
'
OOOOZ
Z
47945
340K
251200Z
(a)
Fig. 10
Time
equivalent
23-25
OCT
change
340K
340K
340K
251200Z
250000Z
241200Z
(b) 23-25
OCT
1980
1980
of vertical wind
potential temperature
deviation of (0e) from
profile,equivalent potential temperature (#e) and saturated
(#e*)
at 47909
340 K.
―
43
―
and
47945.
Stipple areas
denote
positive
METEOROLOGICAL
the
cloud line
at 47909
Atmospheric
more
wet
condition
unstable
which
air intrusion
800 mb.
in
gradually
through
above
north
near
becomes
and
seasonal
the cloud
by
the lowest
below
the
line
the
neutral
and
troposphere
500 mb
becomes
of the Cb
the
Fig.
10(ａ)).
Cb
air is altered
to cold
ther
dition
band associated with the thermal
stable
those
are
observed
above
the
of
layer
the Cb
below
line, there is ａ
900 mb
as indicated
changes
before 241200
Ｚ in
gradually
mb
Changes
of
with
of wind
southwesterly
the
cloud
forms
neutral
side
of the
unstable
stable
layer
line
at
conexists
47945
at
about
Ｚ and
levels
250000
and
Ｚ ， respec-
Cb
line in
this case was
disturbance in
the
line is cateか)liｓed into
warm
type
associated
sector.
(d)ｉｎ
witl} a
The
cloud
Concluding
are
the Cb limes
can be categolised into seven
types with respect to the morphological point of
The
frequency and the spatial range
occurrence of the Cb lines vary
The
frequency is maximum
mum in winter.
often in autumn
in
unstable
with warmer
600 mb.
the cold
behind the
some
distance
Cb
from
is potentially
Such
air side
layer
and
between
800
problems
the
the
neutral
of the Cb
the relationship
paper
and
atmospheric
at the lowest
exists
above
the
layers
unstable
been
left
behind,
e. g. to
and fine structures of Cb lines,
between types categolised in this
various
studies
In the warm
lines,
900 mb｡
have
causes
lines.
Cb
unstable
usually
Many
at
causes
should
and
more
be
considered
and
so
forth.
achieved on this subject
precisely.
season
of the
to season.
in summer and mini-
spatial range
of the occurrence is broadest in both north-south
and east・west directions in autumn.
There
are no
observations of the Cb lines in the tropical regions
south of 20°Ｎ in summer
and in
the formation and maintenance
(ｉｎJapanese).
of radar rain.band
Journal of Meteorological Reserch,
23, 341-355.
Ninomiya,
K. and Ｔ. Akiyama,1974
ture of mesoscale
echo
: Band
struc-
clusters associated with
low-level jet stream. J. M. S. Japan, 52, 300-313.
Cloud lines are observed more
than in spring. The
References
Tatehira, R。1971 ； Synoptic conditions necesary for
studied. The results are as follows :
view.
system
in the vicinity of cloud
remarks
Cloud lines which consist of cumulonimbi
All
especially in
pressure
even if unstable layers exist in the
levels
successively
4.
of the
to about
but ａ stable layer
Further
Fig. 2.
clearly
layers
reveal
tively｡
are not
are closely related
altered to dry and deep
stable layers
condition
47909
the cloud
and convective activities are suppressed by
air with
before
above
potentially
up
cases
concentration,
cloud lines,
flanks
wea-
In some
lines
those
aloft｡
has
directions,
close to
systems
condition
layer is
and/or
very
of the
east
Atmospheric
unstable
lowest
cloud line through
241200
and
air at lower
in the low-
approximately
occurrences
and
again
layers
pressure
lines is wet
750 mb at
directions are observed from
of the
SFC.
locate
just mentioned
Low
south
below
observed
to westerly
passage
47945 at
the east
no
ａ stable layer
est troposphere
after the
where
Cold air is
251200 Ｚ and
into
the air is in potentially
to the
the
line
of wind
in temperature.
where
side
600
changes
the descend
stable
the passage
250000 Ｚ .
weak
lines cause
the Cb
those relationship
ｙｅt｡
exists
layers
winds
Such
Unfortunately,
revealed
and
the region studied in
a stable layer
unstable
below
during
The
paper.
been
in
800 mb.
10 (b). Warm and wet air is advected by
Cb line.
situations
below
Deep
categories
be closely related to
where
by thermal structure at 47945
southerly
would
layer
eastern
potentially
and
not
defined.
０ｎ
change
Such
causes of Cb lines and large scale changes of
this
line
layer｡
Fig.
the
１９８２
of 30°Ｎ in winter.
meteorological
below
also
the passage
warm
warm
No. 5. MARCH
levels
an unstable
and/or
NOTE
regions
station of 47909 at 241200 Ｚ (see
air in the lowest
TECHNICAL
10 (a).
before
the passage,
CENTER
at 231200 Ｚ in Fig.
is indicated
Temperature
warmer
After
SATELLITE
the temperate
−44−
Browning,
mortion
K. A.
and T.
W.
Harrold,1970
and precipitation growth
Q. J. R. M. S., 96, 369-389.
: Air
at a cold front.
気象衛星センター 技術報告 第５号 1982年３月
気象衛星画像に見られる雲列の特徴
伊藤秀喜・土屋 喬
気象衛星センター解析課
気象衛星画像上には，積乱雲で構成される雲列が見られる。これらの雲列は短かいもので数百km，長いもので数
千kmに及び，数時間から十数時間持続する。 ここでは，これらの雲列の特徴を把握するために，３年間に北西太
平洋域に出現した雲列について調査した。
雲列の出現度数や出現域は季節によって異なる。出現度数は冬に最も少なく，夏に最も多い。出現域は秋に最も広
い。冬には日本の南海上の30°Ｎ以南にしか現われず，夏は20°Ｎ以北でのみ発生する。春は冬よりも頻度を増し，
出現域も広がる。これらの雲列は衛星画像上で７つの型に分類することができる。
東シナ海で発生し南西諸島の観測綱を通過した雲列の中から，異なる型に属する二例を選択して事例解析を行なっ
た。
雲列の進行前面（東側）では，下層で南よりの風が卓越し暖湿気塊の移流によって対流不安定層が形成されてい
た。しかし800−900
mb
には対流を抑圧する安定層があった。雲列のごく近傍ではこの安定層は消滅し.
り下層では湿潤不安定となっていた。一方雲列の西側では700−800
形成され，その上層では湿潤中立または乾燥した状態となっていた。
―
45 ―
600 mb
ml）より下層の気温ｶｔFがり，顕著な安定層が
よ

here - AJ Park

The load history shown in the Fig. 1 is repeatedly applied to

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