Diurnal cycle of Southern China Monsoon: characteristics and - - PowerPoint PPT Presentation

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Diurnal cycle of Southern China Monsoon: characteristics and preliminary simulation Outline 1. Briefly on Southern China Monsoon. 2. Diurnal variations revealed by TRMM (1998~2006). 3 . Some results by the trial experiments . 4 .

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Diurnal cycle of Southern China Monsoon: Diurnal cycle of Southern China Monsoon: Diurnal cycle of Southern China Monsoon: Diurnal cycle of Southern China Monsoon:

characteristics and preliminary simulation characteristics and preliminary simulation characteristics and preliminary simulation characteristics and preliminary simulation

Guixing CHEN and Weiming Sha Atmospheric Science Lab, Tohoku University, Sendai

chen@wind.geophys.tohoku.ac.jp; sha@wind.geophys.tohoku.ac.jp

Outline Outline Outline Outline 1. 1. 1. 1. Briefly Briefly Briefly Briefly

n Southern China Monsoon.
n Southern China Monsoon.
n Southern China Monsoon.
n Southern China Monsoon.

2. 2. 2. 2. Diurnal Diurnal Diurnal Diurnal variations revealed variations revealed variations revealed variations revealed by by by by TRMM TRMM TRMM TRMM (1998~2006). (1998~2006). (1998~2006). (1998~2006). 3 3 3 3 . Some results by the trial . Some results by the trial . Some results by the trial . Some results by the trial experiments experiments experiments experiments . . . . 4 4 4 4 . . . . Summary and p Summary and p Summary and p Summary and p

tential works.

tential works. tential works. tential works.

Hakone, 9th Mar 2007

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India India India India

Baiu front Baiu front Baiu front Baiu front Warm Warm Warm Warm Pool Pool Pool Pool

SCS SCS SCS SCS Southern Southern Southern Southern China China China China S S S S

China China China China Sea Sea Sea Sea

presummer presummer presummer presummer summer summer summer summer

tropical monsoon tropical monsoon tropical monsoon tropical monsoon Subtropical monsoon Subtropical monsoon Subtropical monsoon Subtropical monsoon

S S S S easonal easonal easonal easonal r r r r ainfall ainfall ainfall ainfall and and and and t t t t

pography
pography
pography
pography

around around around around s s s s

uthern China
uthern China
uthern China
uthern China

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A h A h A h A h eavy rain case eavy rain case eavy rain case eavy rain case , 1 , 1 , 1 , 1 9 9 9 9 ~2 ~2 ~2 ~2 4 4 4 4 June, June, June, June, 2005 2005 2005 2005

South China Sea

Inland Inland Inland Inland noon~afternoon peak noon~afternoon peak noon~afternoon peak noon~afternoon peak 11:00 Coastal Coastal Coastal Coastal morning morning morning morning peak peak peak peak 05:00 08:00 08:00 11:00 17:00 08:00 14:00 11:00

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D D D D iurnal iurnal iurnal iurnal cycle cycle cycle cycle

rain rain rain rain rate rate rate rate in presummer in presummer in presummer in presummer (TRMM (TRMM (TRMM (TRMM 1998~2006) 1998~2006) 1998~2006) 1998~2006)

noon noon noon noon midnight midnight midnight midnight l a t e n i g h t l a t e n i g h t l a t e n i g h t l a t e n i g h t sunrise sunrise sunrise sunrise morning morning morning morning sunset sunset sunset sunset afternoon afternoon afternoon afternoon e a r l y e a r l y e a r l y e a r l y n i g h t n i g h t n i g h t n i g h t

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Regional variation of diurnal rainfall cycle Regional variation of diurnal rainfall cycle Regional variation of diurnal rainfall cycle Regional variation of diurnal rainfall cycle

c c c c

astal
astal
astal
astal

Total rain Total rain Total rain Total rain

Precentage of convetive Precentage of convetive Precentage of convetive Precentage of convetive rain rain rain rain

c c c c

astal
astal
astal
astal

c c c c

astal
astal
astal
astal

Spring Spring Spring Spring Spring Spring Spring Spring Presummer Presummer Presummer Presummer Presummer Presummer Presummer Presummer S S S S ummer ummer ummer ummer S S S S ummer ummer ummer ummer

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T T T T

p
p
p
p
graphic
graphic
graphic
graphic

impacts impacts impacts impacts

rainfall amplification rainfall amplification rainfall amplification rainfall amplification

(proposed by Xie et al. JC 2006)

Accumulated rain 19~24Jun 2005 Accumulated rain in presummer(1998~2006) JJA rainfall (1997~2004)TRMM-PR Orography in Asia mean flow mean flow mean flow mean flow Green Green Green Green area: area: area: area: Mountain Mountain Mountain Mountain (>500m) (>500m) (>500m) (>500m) Green Green Green Green area: area: area: area: Mountain Mountain Mountain Mountain (>500m) (>500m) (>500m) (>500m)

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Introduction on Introduction on Introduction on Introduction on DS DS DS DS

3 3 3 3

( ( ( ( D D D D

S S S S caling caling caling caling S S S S imulation imulation imulation imulation S S S S ystem ystem ystem ystem ) ) ) )

00 00 00 00 z z z z 19 19 19 19 June2005 June2005 June2005 June2005 DS DS DS DS

3 3 3 3

1 1 1 0km( 0km( 0km( 0km( 10 10 10 10 2 2 2 2 * * * * 10 10 10 10 2) 2) 2) 2) 00 00 00 00 z z z z 24 24 24 24 June2005 June2005 June2005 June2005 00 00 00 00 z z z z 19 19 19 19 June2005 June2005 June2005 June2005 DS DS DS DS

3 3 3 3

30km(

30km( 30km( 30km( 7 7 7 7 2 2 2 2 * * * * 7 7 7 7 2) 2) 2) 2) 00 00 00 00 z z z z 24 24 24 24 June2005 June2005 June2005 June2005 Inintial & boundary: JMA-GSM, NOAA-OISST Convection scheme: Kain-Fritsch Cloud physics: mixed-phase, graupel process simplified Time step: 60 Sec

DS3 (a 'small' JMA): NHM model (dx=15km→4km→1km) Coupled with CFD•LES model (dx~100m) Schemes for two trial experiments:

elevation of domain 1 elevation of domain 2

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Accumulated precipitation

TRMM-3G42 simulated by DS3(30km)

North rainbelt along baroclinic front is good. Rainfall due to mountains are weak. South rainbelt along coast is too weak.

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Inland Coastal Inland Coastal

Evolution of precipitation

TRMM-3G42 simulated by DS3(30km)

11:00 05:00 08:00 08:00 11:00 17:00 08:00 14:00 08:00 08:00 10:00 11:00 13:00 14:00 14:00 17:00 16:00

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Accumulated precipitation

TRMM-3G42 simulated by DS3(10km)

North rainbelt along baroclinic front is weak. Rainfall due to mountains are weak. South rainbelt along coast is good.

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Inland Coastal Inland Coastal

Evolution of precipitation

TRMM-3G42 simulated by DS3(10km)

11:00 05:00 08:00 08:00 11:00 17:00 08:00 14:00 14:00 12:00 11:00 13:00 10:00 09:00 10:00 14:00 17:00

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Summary and potential works

1.Monsoon on southern China has distinct diurnal variations with morning peak in coast & noon~afternoon peak over inland. 2.Along with surface heating, disturbances developed in coast & eastern Tibetan plateau may merge to bring the noon~afternoon peak over inland in presummer season. 3.With topographic effects, these diurnal cycles play an important role on the location and timing of heavy rains. With DS3, high resolution experiments with are on the way: (1) Sensitive Exp. on interactions between baroclinic system, monsoon flow and local land-sea breeze; (2) Sensitive Exp. on topographic impacts (small mountains & complex coast) on disturbance gensis and rainfall amplification; (3) Sensitive Exp. on convection, radiation schemes & surface processes and their impacts on diurnal rainfall cycle.