Plan of The EAMEX Field Experiment
(East Asian Monsoon Experiment)
I. Summer Rainstorm Experiment
II. Winter Rainfall Experiment
1
Scientific goal:
1) To explore genesis mechanisms, and structure/
dynamics of weather disturbances generating
heavy rainfall in East Asia during the summer
and winter monsoon seasons.
2) To improve forecasts of weather disturbances
in East Asia during both seasons, particularly
heavy rainfall events for reducing
flood damage.
2
I. Summer Rainstorm Experiment
GMS IR
A 1998 SCSMEX case
JMAJMA-sfc
?
3
Climatology
Contribution to rainfall
onset
onset
4
Scientific issues (Pilot Studies)
1) Importance of Rainstorms
2) Rainstorm Genesis Mechanism
a. Environmental flow
b. Genesis mechanism
c. Diurnal variation
d. Structure & downscale development
e. Dynamics
f. Hydrological cycle
g. Dissipation process
3) Rainstorm Forecastability by NCEP GFS
4) Intraseasonal Variation
5) Interannual Variation
5
1. Importance of rainstorms
Rainstorm impact on Vietnam
13Z 5/27/2006
Hanoi
Hanoi
Disastrous impact on Taiwan
高雄縣寶來(荖農溪 )
The Flood of 2006
6/9/06
6/9/06
嘉義
6/9/06
南投縣仁愛鄉
嘉義
6/9/06
7
Rainstorm impact on southwest Japan
June 1999 rainstorms
June 1999
湯本地区(southwest Japan)
2005 年6月14～18日までの間、沖縄本島地方は観測
史上最高の豪雨に見舞われました。
の異常豪雨による土石流被害
(Southwest Japan)
Rainfall cycle
⋅season-1
Rainy season
PTaiwan
Taiwan rainfall
6/16-7/15
5/15-6/15
7/16-9/15
mmd-1
⋅season-1
Break
Active Revival
Rainstorm TC
(Wang and Chen 2007)
(Chen et al. 2004)
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2) Rainstorm Genesis Mechanism
a. Environmental Flows
L
200mb
H
L
400mb
doubledoublejets
H
H
L
600mb
H
H
L
850mb
H
L
H
L
H
L
10
∂θ/
∂θ/∂y
11
b. Genesis mechanism
CharneyCharney-Stern baroclinic instability
African easterly waves
Jet
m·s-1
15 May ~ 15 June, 2005-06
Jet
6
5
Instability
10-4mbms
-1
5ms-1
12
c. Diurnal variation
Early morning
00Z
00 (07L)
,Terrain
Late evening
12Z
12 (19L)
300mb
925mb
13
d. Structure & downscale development
May, 2006
700mb
MTSAT
& GFS
15
2 types of genesis
X
X
m
Latitude varies with time
following the RS
2005
Northern
Vietnam
Northern
SCS
Northern
Vietnam
Northern
SCS
s-1
GFS initial analysis
16
, IR
from N. Vietnam
Type 1
6/11-15/05
V(600mb), IR
from N. SCS
ζ, ZE
00Z 6/14/05
22°N
12Z 6/14/05
22°N
18Z 6/15/05
23°N
06Z 6/17/05
25°N
Type 2
6/14-17/05
CI:2x10-5s-1
m
e. Rainstorm propagation
The vorticity budget equation:
ζ t = −V ⋅ ∇(ζ + f ) − (ζ + f )∇⋅V
Vorticity tendency
Vorticity advection
Vortex stretching
Case Jun, 2005
20
f. Dissipation
Dissipation process
RS → midlat. cyclone
RS → dissipated
L
L
L
L
L
L
L
L
L
L
L
g. Hydrological cycle
∂W
+ ∇ ⋅Q = E − P ,
∂t
Q = QR + QD
χ Q = ∇ −2 [∇ ⋅ QD ] ≈ −∇ −2 ( P)
ψ Q = ∇ −2 [∇ × QR ]
∆: MJ climate
removed
•
• RS geneses
3) Rainstorm Forecastability by the NCEP GFS
Case 2 (R7; June 11-15, 2005)
Analysis
Forecast
(actual trajectory)
(actual trajectory)
23
, IR
Analysis
Case June 11-15, 2005
Forecast from 00Z 6/12/05
24
GFS forecast performance
(MJ, 2005-2006)
km (x-direction)
For the midmid-tropospheric perturbation: (actual – forecasted)
240
200
Error of position
RMS of dx between real &
forecast trough locations
depicted in v(600mb)
160
120
80
1 standard deviation
40
t=0
ms-1
8
6
48
24
72
96 hr
Error of propagation speed
4
2
0
1 standard deviation
determined by trough
location at 600mb
-2
t=0
48
24
72
Average duration
to reach Taiwan
4) Intraseasonal Variation
96 hr
25
• 30-60 day mode
• 12-24 day mode
Variance of U-wind
total
H
1212-24 day
H
3030-06 day
H
SCS monsoon index
26
Case 1993
bandpass filtered
Total
rainstorm
3030-60 day
1212-24 day
27
5) Interannual Variation
Population of rainstorm
(genesis)
28
Suggested Research Areas
(1) Multiple-scale processes
• Interannual
• MJO
• 12-24 day mode (cold surge)
• Synoptic disturbance
(2) Tropics-midlatitude interaction
• East Asian monsoon life cycle
• Rainstorm genesis/development
• Monsoon onset
(3) Regional hydrological cycle
Contribution of rainstorm to hydrological cycle of
northern Vietnam, Taiwan, and southern Japan
prior to the East Asian monsoon break
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Scientific objectives
1. Late spring/early summer rainstorms
climatology, structure, basic dynamics,
propagating mechanism
2. Hydrological processes
late spring/early summer flooding disasters over
southwestern Taiwan
3. Impact of multiple-scale process on
rainstorm activity
Interannual, MJO, 12-24 day mode, Synoptic disturb.
4. Effect of the midlatitude-tropical interaction
on rainstorm activity
EAM life cycle, Genesis/development, Monsoon onset
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Science plan
Observation/
Initialization
TropicalTropical-midlatitude
interaction
MultipleMultiple-scale
interaction
9Z 5/28/06
Downstream
Amplification
Upstream
Genesis
Regional hydrological
cycle
NWP/Simulation
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Summer Monsoon Rainstorm Experiment
CJC Project
EAMEX
• RS (afternoon / evening)
• RS (night / morning)
MayMay-June, 2008
32
II. Winter Rainfall Experiment
Historic
perspective
L
H
L
L
H
H
33
(Lau and Lau 1984)
(Lau and Chang 1987)
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Winter climatology of East/Southeast Asia
CMAP / ERA-40
1979-2002
A
Midlatitude
East Asia
B
Indochina
Tropical Southeast Asia
C
35
120ºE
PCMAP
135ºE
A
B
C
C
tropical
Southeast
Asia
East Asia
tropical
Southeast
Asia
midlatitude
36
Scientific issues
1. Importance of synoptic disturbances in winter rainfall
2. Genesis mechanisms of winter synoptic disturbances
3. Multiple-scale process
4. Interannual variation
Pilot Studies:
• Importance of Winter Rainfall
• Impact of Cold Surge on Winter Monsoon Rainfall
a. East Asia
b. Midlatitude
c. Indochina
d. Tropical Southeast Asia
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1) Importance of synoptic disturbances in winter rainfall
Impact on Japan Taiwan lowlow-induced winter cyclones
Taiw
an L
ow
Similar events
Snow
accumulation
Impact on Taiwan
• Cold surge
• Taiwan low: rainfall
18Z 1/13/05
2/26/05
3/8/05
11/28/03
3/5/05
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Impact on Vietnam
ColdCold-surge vortices
OctOct-Nov, 2007
Floods kill 46 in Vietnam
November 05, 2007 (Canada.com)
H
Vietnam floods kill 67,
as new storm threatens
November 06, 2007 (Agence France-Presse)
Vietnamese officials say floods have
killed at least 77 people in central
Vietnam since late last month…
L
L
L
Impact on Vietnam ColdCold-surge vortices
H
H
V(925mb)
L
L
L
Heavy rains add to SE Asia floods
(16 October, 2000) (BBC news)
Vietnam: at least 600 dead
UK Sangha Vietnam Flood Appeal
November 1999, torrential downpour rains have
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devastated Central Vietnam. Record floods in 7 coastal
provinces have killed more than 600 people.
V(925mb)
Impact on Malaysia
ColdCold-surge vortices
H
South Malaysia flooding kills six
(December 22, 2006)(BBC news, UK)
(BBC news, UK)
A second wave of flooding in southern
Malaysia forced more than 90,000
people to flee their homes.
Impact on Indonesia
ColdCold-surge vortices
V(925mb)
H
2–12 February, 2007, Jakarta
(Photo credit: Gajah Mada)
L
L
(BBC news, UK)
2) Impact of Cold Surge on Winter Monsoon
Rainfall
Multiple-scale process
Tropics-midlatitude interaction
(different perspective)
Regional hydrological cycle
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a. East Asia
Taiwan low – no front
Example
cases
Taiwan low – Taiwan front
GFS 2005
Taiwan low – redevelopment of South China front
45
Genesis mechanisms of winter synoptic disturbances
Taiwan trough and Taiwan lows
DJF
H
46
Impact on Taiwan
Contribution of rainfall from different types of perturbation
Rainfall rate
Rainy day
47
MultipleMultiple-scale interaction:
P
b. Midlatitude
49
North Pacific ShortShort-Wave Train during the Extreme Phase of ENSO
( Chen 2002; JCLI)
50
Interannual variation – Cold surge
( Chen et al. 2004; JCLI)
51
c. Indochina: late-fall heavy rainfall in Vietnam
H
October
Climatology
L
L
L
H
November
Climatology
L
L
L
52
400mb
925mb
Oct
Oct
1988~2005
Topo > 400m
cold surge
vortex
Nov
Nov
cold surge
vortex to
Vietnam
Genesis of cold
surge vortex to
Vietnam
Dec
Dec
53
P
Ensemble precipitation:
TRMM: 1998~2003
GPCP: 1997, 2004~2005
GPI: 1979, 1989~1996
MSU+GTS: 1980~1988
surface station
P index location
V(925mb), Variances( ∆P)
Oct~Nov 1988~2005
V(925mb), Variances(∆SST)
NINO3.4
WTP
54
Warm
cold surge vortex
Cold
Cold
Case1
20ms-1 55
Propagation mechanism
Example case
56
d. Tropical Southeast Asia
Cold surge
L
H
H
L
L
L
Cold-s
urge v
ortice
s
57
Cold-surge vortex
example case:
58
MultipleMultiple-scale interaction:
(a)P(97/98)
(b)P(99/00)
EQ-5°N
(a) P(DJF)
(b) P(DJF)(EQ-5°N)
(c)∆P(DJF)(EQ-5°N)
97/98
99/00
59
MultipleMultiple-scale interaction:
99/00 (Cold)
mm·d-1
8
6
Rainfall variability in tropical Southeast
Asia is caused by a multiple-scale
interaction among:
• ENSO
• MJO (30-60 day mode)
• Cold surge (12-24 day mode)
• Synoptic disturbance: cold-surge vortices
61
Suggested Research Areas
(1) Multiple-scale processes
• Interannual
• MJO
• 12-24 day mode (cold surge)
• Synoptic disturbance: Taiwan low, cold-surge vortices,
heavy rainfall in Vietnam
(2) Tropics-midlatitude interaction
• Cold surge / 12-24 day mode
• Taiwan low
• South-China front
• Cold-surge vortices
• Heavy rainfall events in Vietnam
(3) Regional hydrological cycle
Contributions from synoptic disturbances of Taiwan low,
cold-surge vortices, and heavy rainfall events in Vietnam
62
Scientific objectives
1. Taiwan lows:
genesis, structure, propagation mechanism
2. AMTEX storm:
development from Taiwan low
transition from Taiwan low to midlatitude cyclone
3. Impact of multiple-scale process on genesis
of Taiwan low
Interannual, MJO, 12-24 day mode, Synoptic disturb.
4. Midlatitude-tropics interaction
Cold surge, Taiwan low, South-China front
Cold-surge vortices, Heavy rainfall events in Vietnam
5. Regional hydrological cycle:
particularly the winter rainfall over northern Taiwan63
Science Plan
Observation/
Initialization
V(925mb), pS
L
L
H
H
Multiple-scale
interaction
VIS
Tropics-midlatitude
interaction
Regional hydrological
cycle
NWP/Simulation
64
Winter Rainfall Experiment
Cold Surge Vortex / Heavy Rainfall Events in Late Fall
OctoberOctoberNovember,
2008
65
Google
Winter Rainfall Experiment
Okinawa
Senkaku
Taiwan
Ishigaki
0
|
▓
0
|
▓
December, 2008 - February, 2008
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3. International Collaborations
A. MAHASRI
• MAHASRI domain
• MAHASRI activity related to EAMEX
B. Facilities available from international collaborations
1) Indonesia
4) Philippine
2) Japan
5) Thailand
3) Malaysia
6) Vietnam
C. Domestic facilities (Taiwan)
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A. MAHASRI (Monsoon Asian Hydro-Atmosphere Scientific
Research and Prediction Initiative)
J. Matsumoto − MAHASRI Chairman / Group leader of Japan
Agency for Marine-Earth Science and Technology
(JAMSTEC)
• Domain
ia
E. As
ll Exp.
Winter Rainfa
E
torm xp.
Summer Rains
68
B. Facilities available from international collaborations
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Participating countries
ChinaChina-Japan
Cooperative
Project on Weather
Disaster Reduction
(Tibetan
Plateau)
Japan
Cold surge
research
Taiwan
Vietnam
EAMEX
Thailand
GaMEGaME-T
Philippine
Malaysia
Indonesia
HARIMAU (with Japan)
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Google
4. Time Table (with international projects)
CJ
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(a) Late SpringSpring-Early Summer Rainstorm Experiment:
May 15-June 30, 2008
(b) Winter Rainfall Experiment:
Central Vietnam Heavy Rainfall:
October-November 2008
Taiwan Low-Cold Surge:
December 2008-Feburary 2009
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Thank you
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