The evolution and dynamics of an oceanic quasi-linear convective system occurred on Sept. 10, 2004 over the Taiwan Strait Zhao Kun 1,2 and Ben Jong-Dao

The evolution and dynamics of an oceanic The evolution and dynamics of an oceanic quasi-linear convective system occurred on Sept. quasi-linear convective system occurred on Sept.

10, 2004 over the Taiwan Strait10, 2004 over the Taiwan Strait

The evolution and dynamics of an oceanic The evolution and dynamics of an oceanic quasi-linear convective system occurred on Sept. quasi-linear convective system occurred on Sept.

10, 2004 over the Taiwan Strait10, 2004 over the Taiwan Strait

Zhao KunZhao Kun1,21,2 and and Ben Jong-Dao JouBen Jong-Dao Jou11

11Department of Atmospheric Sciences, National Taiwan University, Taipei, TaiwanDepartment of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan22The key laboratory of Mesoscale Severe Weather, Department of Atmospheric SciencesThe key laboratory of Mesoscale Severe Weather, Department of Atmospheric Sciences

Nanjing University, Nanjing ChinaNanjing University, Nanjing China

Oct.Oct. 331, 2001, 20066 BoulderBoulder

Zhao KunZhao Kun1,21,2 and and Ben Jong-Dao JouBen Jong-Dao Jou11

11Department of Atmospheric Sciences, National Taiwan University, Taipei, TaiwanDepartment of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan22The key laboratory of Mesoscale Severe Weather, Department of Atmospheric SciencesThe key laboratory of Mesoscale Severe Weather, Department of Atmospheric Sciences

Nanjing University, Nanjing ChinaNanjing University, Nanjing China

Oct.Oct. 331, 2001, 20066 BoulderBoulder

OutlineOutline

BackgroundBackground, case description, case description Dual-Doppler synthsis (kinematic structure Dual-Doppler synthsis (kinematic structure

and thermodynamic/dynamic retrieval) and and thermodynamic/dynamic retrieval) and results aresults analysisnalysis

Discussion on origin, longevity, and the Discussion on origin, longevity, and the upscale growth of the mesovortexupscale growth of the mesovortex

ConclusionsConclusions

BackgroundBackground, case description, case description Dual-Doppler synthsis (kinematic structure Dual-Doppler synthsis (kinematic structure

and thermodynamic/dynamic retrieval) and and thermodynamic/dynamic retrieval) and results aresults analysisnalysis

Discussion on origin, longevity, and the Discussion on origin, longevity, and the upscale growth of the mesovortexupscale growth of the mesovortex


QLCS#1

QLCS#2

QLCS#3

QLCS#4

QLCS#5

Develop-Mature -Decay 1.5h

Redevelop 1.5hRedevelop 1.5h

Decay 1.5h

A+B

A

B

Dual-Doppler AnalysisDual-Doppler Analysis1. RCTP and RCWF Radars, baseline 60km2. 1.5 hour period, total of 15 analysis volumns 3. Grid spacing: 1000m X 1000 m X 500m4. Domain: 60 km X 60 km X 16 km 5. Boundary conditions: W=0 at upper and lower

boundaries6. Horizontal field at echo top are lightly smoothed wit

h two pass Leise filter prior to divergence calculation and vertical integration for W

Thermodynamic Retrieval: Roux et al.(1990)

Houze et al. 1989

Distance West of RCWF Radar (km)

Dis

tanc

e N

orth

of

RC

WF

Rad

ar (

km)

10m/s

0750UTC 2KM

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dBZ

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Mature stage of mesovortex: after merge, a balanced feature?


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V#3

V#1

V#2

V#1

V#2

CELL

Mesovortices in QLCS#1Mesovortices in QLCS#1


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0732UTC 2KM

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0727UTC 2KM

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ista

nce

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f R

CW

F R

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(km

)

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Vortex MergeV#1+V#3

Distance West of RCWF Radar (km)D

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nce

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th o

f R

CW

F R

adar

(km

)

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0750UTC 2KM

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0634UTC

10m/s(dBZ) 2KM

A

A'

(a)

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(dBZ) 4KM

(b)10 15 20 25 30 35 40 45 50

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-2-1

0

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0

0

00

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-1

2KMVertical Velocity Vertical Vorticity

(c)

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(d)

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r(km

)

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V#2

V#1

10m/s(dBZ) 2KM

B

B'

(a)

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(dBZ) 4KM

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(c)

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(c)

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V#3

Themodynamic Fields at 0750UTCThemodynamic Fields at 0750UTC

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4km

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L


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-5

(b) Dynamic

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Thermodynamic diagnose

For the vortex at mature stage

Cross sectionCross section

Heigh

t (km)

10m/s

5m/s

0750~0756UTC Reflectivity and Wind Field

(a)

0 5 10 15 20 250

2

4

6

8

10

dBZ

101520253035404550

0750~0756UTC Vertical velocity and Vertical vorticity

(b)

Distance (km)

Heigh

t (km)

0 5 10 15 20 250

2

4

6

8

10

Heigh

t (km)

10m/s

5m/s


(a)

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2

4

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10

dBZ

101520253035404550

1

0


(b)

Distance (km)

Heigh

t (km)

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4

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Heigh

t (km)

10m/s

5m/s


(a)

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8

10

dBZ

101520253035404550


(b)

Distance (km)

Heigh

t (km)

0 5 10 15 20 250

2

4

6

8

10

A A’ B B’ C C’

1

1.5

2

2.5

3

3.5

4

4.5

5

Heig

ht(

km

)

(a) VORTEX#1

m

erg

er w

ith

cy

clo

nic

vo

rte

x#

2

Vertical Vorticiy 10 Sep. 2004 Vertical Velocity

1

1.5

2

2.5

3

3.5

4

4.5

5

Time (UTC)

Heig

ht(

km

)

(b) VORTEX#2

0634

0640

0646

0657

0703

0709

0715

0721

0727

0732

0738

0741

0744

0750

0756

Vertical Vorticiy 10 Sep. 2004 Vertical Velocity

VORTEX#1

VORTEX#3

Time-height profiles of the average vorticity and divergence within the vortex 1 and 3

Vorticity Budget

TILT STR VADV HADV LC

)())(()(z

u

y

w

z

v

x

w

y

v

x

uf

zw

yv

xu

t

He

igh

t(km

)

(a)

-2 -1 0 1 2

1

2

3

4

5

VOR

DIV

W

Vorticity budget 10-7s-2

He

igh

t(km

)

(b)

-15 -12 -9 -6 -3 0 3 6 9 12 15

1

2

3

4

5

HADV

VADV

STRTILT

LC

He

igh

t(km

)

(a)

-2 -1 0 1 2

1

2

3

4

5

VOR

DIV

W

Vorticity budget 10-7s-2

He

igh

t(km

)

(b)

-15 -12 -9 -6 -3 0 3 6 9 12 15

1

2

3

4

5

HADV

VADV

STRTILT

LC

0709UTC 0750UTC

DiscussionDiscussion

(1) Origin of vortex(1) Origin of vortex

14104 s

14104 s 141014 s

0657UTC 0750UTC

Stretching + Tilting (?)

(2) Longevity of Vortex(2) Longevity of VortexVortex Rossby RadiusVortex Rossby Radius (Frank 1983)(Frank 1983)Durran and Klemp (1982) Durran and Klemp (1982)

14

15

1

1055.6

1016.6

22

5.4

)5.2(6

s

sf

kmR

kmH

kmmsVt

2/112/1 )2()( fRVf

NHRd

T

2/1)]([z

gN

2/122

])ln

()/(1(

)/(1[

dz

dq

dz

dq

TC

L

dz

d

CpRTqL

RTLqgNm ws

ps

s

kmRdm

sNm

kmRd

sN

66

101.9

88

1029.1

13

12

TaipeiSounding

Dynamical large

MaKungSounding

kmRdm

sNm

kmRd

sN

29

108.4

73

1022.1

13

12

Dynamical small

Different Environment

(Kuo (Kuo et. al et. al

2004)2004)

0 0.5 1 1.5 2 2.50

0.5

1

1.5

2

2.5

0.8

0.7

0.7

0.7

0.8

0.7

0.7

0.7

/R1

0657UTC

0703UTC

0709UTC

0715UTC

(3) Upscale growth of (3) Upscale growth of

VortexVortex

Merger

A A SchematicSchematic diagram of the circulation and the vertical motion/ diagram of the circulation and the vertical motion/ trajectory atrajectory at mature stage of vortext mature stage of vortex ( (0750UTC)0750UTC)

0

2

4

6

8

10

He

igh

t(km

)

dBZ

10 20 30 40 50

Vm

N

B

10km

A

C

D


TThe formation and evolution of thhe formation and evolution of thee mesovorices in mesovorices in QLCS#1 QLCS#1 dependdependss greatly on the greatly on the preexisting boundarypreexisting boundary, , in addition to in addition to the vertical wind shear and CAPEthe vertical wind shear and CAPE..

Contrary to previously documented MCV in QLCS whicContrary to previously documented MCV in QLCS which often accentuated by Coriolis force, this study provideh often accentuated by Coriolis force, this study provides an evidence that the small scale mesovorices originatins an evidence that the small scale mesovorices originating in the convective region can merge and grow upscale tg in the convective region can merge and grow upscale to result in a vortex of greater horizontal and vertical exteo result in a vortex of greater horizontal and vertical extent through an efficient merger process. nt through an efficient merger process.

The MCV at the mature stage exhibited The MCV at the mature stage exhibited somesome features of features of balanced vortex, which may induce a new updraft and cobalanced vortex, which may induce a new updraft and contribute the following convection.ntribute the following convection.

Documents

The evolution and dynamics of an oceanic quasi-linear convective system occurred on Sept. 10, 2004 over the Taiwan Strait Zhao Kun 1,2 and Ben Jong-Dao