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Meteorology seminar. 2004.9.3. 1. Daisuke NAITO. 2. Mamami NOMURA. Miyakojima island. 台風. 梅雨. GAME HUBEX ’ 98- ’ 99. X-BAIU ’ 99, ’ 01, ’ 02. 長江下流域 ’ 01-’02. LAPS/CREST ’ 03- ’ 04. TAMEX ’ 87. Baiu season ( early ). SCSMEX ’ 98. Baiu season ( later ). - PowerPoint PPT Presentation
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Meteorology seminar2004.9.3
1. Daisuke NAITO
2. Mamami NOMURA
Miyakojima island
梅雨
台風
SCSMEX ’98
GAME HUBEX ’98-’99
Baiu season ( early )
長江下流域 ’01-’02
X-BAIU’99,’01,’02
Baiu season ( later )
TAMEX ’87LAPS/CREST ’03-’04
Observation at Okinawa ( 13 May – 26 June 1987 )
・MRI Doppler radar ( X-band )
・ ODA radar ( C-band ) *ODA = Okinawa
Development Agency
Radar
Other
・ Sounding ( at NAHA )
AMTEX ’74-’75
Air Mass Transformation Experiment14–28 Feb 1974 and 1975
There are no observation around Miyakojima-island at Baiu/Meiyu season.
・ Boundary layer・ Flux over the ocean
・Medium-Scale Depression (Saito1977)・ Precipitation (Takeda 1979)
Evolution of the Kinematic Structure within a Meso-β-Scale Convective System
in the Growing and Mature Stages
KENJI AKAEDA, TATSUO YOKOYAMA, AKIRA TABATA, MASAHITO ISHIHARA AND
HITOSHI SAKAKIBARA
Monthly Weather Review 1991 Volume 119 2264 - 2676
Introduction
Cloud Cluster
Squall cloud cluster
Nonsquall cloud cluster
One meso-β-scale convective system
One or several meso-β-scale convective system
We are not understand the structure and the time variation of the convective system in a cloud cluster.
Ogura et al.(1985)
Cloud cluster
Propagating mesoscale convective system( in a early stage)
Stationary mesoscale convective system( in a later stage)
Akaeda et al.(1987)The distribution of convective system changed depending on cloud clusters evolutionary stages.
ObjectsThe structure and evolution of a meso-β-scale convective system (Time variation)
are analyzed.
My motivation in this paper
・ Characteristic of the convection around Okinawa
Similar to convection around Miyako or not ?
・ Technique of single Doppler analysis
・MRI Doppler radar ( X-band )・ODA radar
( C-band )・GMS hourly IR images
・ Surface weather map ( 09JST 6 June 1987 )
・ Sounding ( at NAHA ) ( 21JST 5 June 1987and 09JST 6 June 1987 )
PPI reflectivity data ( 5 min interval )
Volume scan and RHI ( 7 min interval? )
Data
09JST 6 June 1987
Synoptic situation
Low θe
TIME
LCL 986hPaLFC 763hPa
CAPE 567m2/s2
before during
before
during
before
during
Lowest levels - southeast
Lower levels - northwest
Mid to upper levels - southwest
Bulk Richardson number = 27
Moderate shear
OKINAWA
The meso-β-scale convective system
Observation area of MRI radar
MRI Doppler radarSTA
GE 1
STA
GE 2
7m/s
STAGE 1 STAGE 2
STAGE 1MRI radar
A-typeStationary cells
B-typeMoving cells
LocationSouthwestern part of the line
Northeastern part of the line
MovementNortheastward at the speed 5.5m/s
Almost stationary
EvolutionSouthwest side of the old cell
Not regular
Nonpropagating stage(line shape)
Outermost contour 45dBZInterval 5dBZ
Reflectivity(dBZ) Doppler velocity(m/s)
斜線部:遠ざかる速度白抜き:近づく速度
減衰
:convergence
:divergence
Rear inflow
STAGE 2Propagating stage(convex shape)
C-typeMoving cells
LocationCentral part of the system
MovementEast-northeastward at the speed 4.5m/s
EvolutionSoutheast side of the old cell
Reflectivity(dBZ) Doppler velocity(m/s)
減衰 Rearinflow
Gust font
Outflow
A3
C1
Conclusion
Discussion
Maximum updraft – near 30m/s (CAPE 567m2/s2 )
So large!!Wmax = (2*CAPE)1/2
= 33.6m/s
The sounding did not represent prestorm environment.
Surface condition( 21JST 5 June ) 23.6℃、 90%
Surface condition( 05JST 6 June ) 25.0℃、 90%
CAPE 567m2/s2
CAPE 1463m2/s2
For my study
Characteristic of the convection around Okinawa・ Very strong reflectivity ( over 50dBZ )
・ Low LCL( the lowest layer is moist )
Technique of single Doppler analysis
・ Very useful for my study I will try soon!
対流雲の発達や内部の詳細な構造の時間変化について調べたものはない。
Akaeda et al 1987
Ogura et al 1985
MRI Doppler radar
通過
Temperature drop(3℃ )
Pressure rise
Gust frontfrom the north
MRI Doppler radar
通過
TIME
減衰
Time variation of echo area
stage1stage2
In stage2 , the strong echo maintained their area and the system was long-lived.
The formation of a squall-line-type circulation is important in maintaining a strong system.