Dynamic Meteorology andClimatology for Southeast Asia
Brief introduction of “Tropical Meteorology” lecture
at a Japanese university master course

Manabu D. Yamanaka
Graduate School of Science and Technology, Kobe University
also Frontier Observational Research System for Global Change

Chapter 1: Basic principles and applications to SE-Asia
Chapter 2: Statics of moist atmosphere in tropics
Chapter 3: Zonal-mean dynamics and meridional circulations
Chapter 4: Equatorial wave dynamics and ENSO
Chapter 5: Cloud convection dynamics and tropical cyclone

Chapter 1
Basic principles and applications to SE-Asia
1.1. Why atmospheric dynamics is necessary?
1.2. General principles governing planetary fluid
1.3. Problems in applications to SE-Asia
1.4. How to learn/educate atmospheric dynamics

1.1. Why atmospheric dynamics is necessary?
z Understanding atmospheric phenomena
by a small number of physical principles
z Understanding atmospheric/hydrospheric/oceanic
phenomena by common physical principles
atmosphere＋hydrosphere＋ocean ⇒ climate
z Numerical weather/climate prediction
z Improving operational efficiency

1.2. General principles governing planetary fluidz Planetary (or geophysical) fluid: Gas/liquid under- sphericity: a＝6370 km (for the earth)latitude φ, longitude λ, altitude z
eastward displacement: dx ＝ a cosφ dλnorthward displacement: dy ＝ a dφ
- rotaion: Ω ＝ 2π/86164s (for the earth)
Coriolis parameter: f ＝ 2Ω sinφRossby parameter: β＝ df/dy ＝2Ω cosφ
- gravitation: g ＝ 9.8 m/s2 (for the earth)z Variables: (6 for dry atmosphere)- wind (or stream) velocity components: (u, v, w)- thermodynamical state variables: (T, p, ρ)[ - humidity (or salinity): q ]Mathematical formulation of basic principles
z Mass conservation (continuity):∂u/∂x ＋∂v/∂y ＋ρ−1∂ρw /∂z ＝ 0z Momentum conservation (Newton’s 2nd law):
du/dt − f v ＋ ρ−1 ∂p/∂x ＝ Fx
dv/dt ＋ f u ＋ ρ−1 ∂p/∂y ＝ Fy
dw/dt＋ ρ−1 ∂p/∂z ＝ g
For atmosphere:z Entropy conservation (1st law of thermodynamis):dΘ/dt ＝ Q/T[potential temperature.:Θ＝T (p00/p) R/Cp ]z Ideal gas equation (Boyle-Charles’ law):ρ−1p ＝ RT
For moist atmosphere:z Continuity for humidity q ⇒ Virtual temperature Tv
Everything must be expressed by a superposition of solutions of above
6 (7) equations!

1.3 Problems in applications to SE-Asiaz Low latitude: small f (but not β)
z High solar azimuth: Q with diurnal periodicity⇒ barotropic (relatively high horizontal homogenuity)
relatively weak seasonal variationz High humidity: Q by latent heating⇒ cloud convection, intraseasonal variationsz Complex geography: sea-land, mountain-valley, ...
⇒ local circulationz Interaction with ocean⇒ interannual variations↓
Seemingly less usefulness of atmospheric dynamics

The Indochina Sumatera sectorIndochina-Sumatera sector

1.4. How to learn/educate atmospheric dynamics
z Training of basic physics/mathematics(Principles are not so many! Learn them with reading papars.)z Textbooks of mainly mid-latitude atmospheric dynamics, e.g.,- J.R.Holton, “An Introduction to Dynamic Meteorology”, 3rd Ed., Academic Press, 1992.
- A.E.Gill, “Atmosphere-Ocean Dynamics”, McGraw-Hill?, 1982
- R.S.Lindzen, “Dynamics in Atmospheric Physics”, Cambridge University Press, 1990.
- ・・・

z Texbooks of general meteorology with dynamical aspects:- D.G.Andrews, “An Introduction to Atmospheric Physics”, Cambridge University Press, 2000?
- M.L.Salby, “Fundamentals of Atmospheric Physics”, Academic Press, 1996.
- ・・・

z Textbooks of tropical meteorology/climatology without dynamics
z Environmental/geographical and geochemical knowledges+z Deep theoretical considerationz Strong wishes for numerical predictionz Spirits to establish a new meteorology

Curriculum in Dept. of Earth-Planetary Science, Kobe University
Undergraduate course: 1st/2nd years:z Basic physics, mathematics, …
z General introduction to earth and planetary sciencez Mathematical physics/computers for EPS (including exercises)
Undergraduate course: 3rd/4th years: (Students are requested to have special subjects.)z Geophysical fluid dynamics
z Atmosphere-hydrosphere sciencesz Experiments for atmosphere-hydrosphere sciences (mainly observations)
Master course (2 years after graduation of BSc.):z Introduction to global environmental sciencesz Mid-latitude synoptic-scale meteorologyz Tropical meteorology
PhD course (additional 3 years after taking MSc):z Physical climatology of earth and other planetsz Planetary fluid physics (mainly atmosphere-ocean interaction dynamics)z Special topics on atmosphere/hydrosphere/ocean sciences
Special lectures (4 outside scientists /year)
Seminars and colloquia

Chapter 2
Statics of moist atmosphere in tropics
2.1. Hydrostatic equilibrium
2.2. Radiative-convective equilibrium
2.3. Moisture and conditional instability

2.1. Hydrostatic equilibriumz Horizontally homogeneous:
u〜v〜w〜0, F〜Q〜0− gρ ＋∂p/∂z ＝ 0
with the ideal gas equation ρ＝p/RT⇒ p ＝ p0 exp (−z/H) ,scale hight: H＝RT/gz Pressure coordinate“omega velocity”: ω＝dp/dt ＝ーgρw
z Log-pressure coordinate:∂p/ρ＝gH∂lnp →−g∂z* , g∂z→∂Φ⇒ ∂Φ/∂z*＝RT/H
p in momentum eqs. are also rewritten by Φz* may be conventionally regarded as z

2.2. Radiative-convective equilibriumz Radiative equilibrium
Q ＝∂/∂z [S＋I↑−I↓] ＝0(S〜0 for z ≠0, ozone layer)⇒ ∂/∂p [σT4] 〜S/p1⇒ −∂T/∂z increases downward
z Convective equilibrium (adjustment)∂Θ/∂z ＝ 0
⇒ (dry) adiabatic lapse rate:−∂T/∂z ＝g/Cp ≒10 K/km
z Separation of stratosphere (radiative)
and troposphere (convective)Ztropopause

T2.3. Moisture and conditional instability
Water vapor → IR absorption (warming)
Cloud → Solar rad. reflection (cooling)
zLatent heating∂Θ/∂z ＝ Qlatent/T⇒ ∂Θe /∂z ＝0tropopause

Cloud⇒ moist adiabatic lapse rate:−∂T/∂z ≒5 K/kmLCL

Θ

Θe

Θesat

OLR longterm monthly meanChapter 3
Zonal-mean dynamics and meridional circulations
3.1. Equatorial easterly (trade wind)3.2. Hadley circulation and ITCZ
3.3. Monsoon circulation[ 3.4. Brewer-Dobson circulation andstratospheric ozone transport ]Axi-symmetric dynamicsz Zonally homogeneous:∂u/∂t − f v＝F(angular momentum u− fy conserv. → Equatorial easterly )＋ f u ＋∂φ/∂y ＝ 0− (R/H) T ＋∂φ/∂z ＝ 0∂T/∂t ＋ (R/H) N2 w
＝Q∂v/∂y ＋ρ−1∂ρw /∂z ＝ 0⇒ “Thermal-wind” equilibrium: (without necessity of merid. circ.)
f∂u/∂z ＋(R/H)∂T/∂y ＝ 0(poleward temperature decrease → upward easterly decrease)
Near the equator (f → 0):β∂u/∂z ＋(R/H)∂2T/∂y2 ＝ 0z Slowly time-dependent: ∂/∂t 〜 0⇒ v〜−F / f, w〜 (H/R)N−2 Q 〜 Q/Γ
- Friction on easterly induces an equatorward flow.
- Heating induces an upward flow.
→ Meridional circulation

Zonal-mean temperature and zonal windUpper troposphere: Poleward temperature increase → upward easterly increase
Lower troposphere: Poleward temperature decrease →upward easterly decreaseMeridional Circulations
zGoverning equation:[∂2 / ∂y2 ＋ （ f/N ）2 ・ ∂2 / ∂z2 ] ・ ψ＝G
v＝−∂ψ/∂z , w＝∂ψ/∂yzSymmetric forcing: G 〜−sinlysinmz⇒Hadley circulation: ψ〜sinlysinmz（v〜−sinlycosmz, w〜coslysinmz）
zAntisymmetric forcing: G 〜coslysinmz⇒ Monsoon circulation: ψ〜−coslysinmz（v〜coslycosmz, w〜sinlysinmz）(For details, Holton, Chapter 10)

Monsoon and Hadley circulations

ITCZ

Winter Hadley cellbecomes large
and beyond the equator

SummerEquator

WinterSeasonal-vertical variations
Zonal Wind

Meridional Wind(affected by Monsoon)(Hadley +Monsoon)

ＥＷ
Ｗ

Ｎ
Ｅ

ＮＥ

ＮＷ
ＥＥ
Ｗ

ＮＮ
ＮＥ
Ｗ

Ｅ
Ｅ

Ｎ

Stratospheric response to tropospheric convection(Holton, 1995)(Sherwood, 2000)

Chapter 4
Equatorial wave dynamics and ENSO
4.1. Equatorial waves
4.2. Matsuno-Gill pattern and Walker circulation
4.3. Atmosphere-ocean interaction and ENSO
[ 4.4. Wave-mean flow interaction and QBO ]4.1. Equatorial waves
z Perturbation equations: ( u → u + u’ , etc.)∂u’/∂t − βy v’ ＋∂φ’/∂x ＝ 0∂v’/∂t ＋βy u’ ＋∂φ’/∂y ＝ 0− (R/H) T’ ＋∂φ’/∂z ＝ 0∂T’/∂t ＋ (R/H) N2 w’＝0∂v’/∂y ＋ ∂v’/∂y ＋ ρ−1∂ρw ‘/∂z ＝ 0z Three∂/∂t ⇒ 3 types of solutions:
Eastward/westward propagating inertio-gravity waves
Westward propagating Rossby waves
z Hermit equation and exact solutions
including singular solutions: (Matsuno, 1966)
Westward propagating mixed Rossby-gravity waves
Eastward propagating Kelvin waves

4.2. Matsuno-Gill pattern and Walker circulation
RossbyL

EquatorKelvin

UpL

H

down

Zonal Sectionof Zonal WindWalker
Circulation

4.3. Atmosphere-ocean interaction and ENSO
La Ninalow phigh pWarm water

Cold water

El Ninohigh plow pWarm waterIndonesia

South America

SOI by BOM

Interannual variation of surface wind over Equatorial PacificInterannual variations of OLR over equatorial PacificIndonesian Rainfall and SOIAll (eleven) Indonesian station average

QBO/ENSO related U,Vvariations over Indonesia

Interannual Variations
zDaily rainfall (Hamada et al., 2002; JMSJ)
zRawinsondes (Okamoto et al., 2002; submitted)
zRainwater isotope (Ichiyanagi et al., 2002;GRL)• ENSO, QBO• Decadal-scale variations

Chapter 5
Cloud convection dynamics and tropical cyclone
5.1. Horizontal convection and local circulation
5.2. Vertical convection and cloud dynamics
5.3. CISK and tropical cyclone
5.4. Cloud organization and intraseasonal variation5.1. Horizontal convection and local circulation
Forced motion under stable stratification with differential heating:Sea-land/mountain-valley breeze; City (“Heat island”) circulation↓warmer T

Sea breeze

LandSea↑cooler TDaytime

Land breezeNight(mm)600

Monthly rainfall at Kototabang GAW station, Indonesia

4002000A S ON D J F M AM J J A S ON D J F M A MJ J A S O N D J F MA

Date 102050030

Date 10001224
Local TimeDate 1021001224
Local Time2050030

Date 1021001224Local Time

2030

Apr. 2002

Nov. 2001(mm/hr)(mm/hr)(mm/hr)1030

Apr. 2002

10050Aug. 2001

May 15–Jun.14, 2001

2202002(mm/hr)0Nov. 2001

100(mm/day)

50

2001

Aug. 2001

100(mm/day)(mm/day)

100

2000

(mm/day)

1999
May15–Jun.14, 2001

2
1001224
Local Time

5.2. Vertical convection and cloud dynamics
z Vertical heat transport:- Radiation: electromagnetic (without any media)- Conduction: molecule motions- Convection: hydrodynamic motionsz Classical hydrodynamics of convection- Rayleigh-Taylor, Benard-Rayleigh, …
- viscosity, gravityz (Conditionally) Unstable stratification- Latent heating ⇒ “Pseudo”-adiabatic process- Equivalent potential temperaturez Coupling with cloud microphysics- Condensation/evaporation, freezing/melting, sublimation- Heterogeneous growing, aerosol nuclei, chemistry, electricity- Warm rain: stochastic coalescence, droplet/drizzle/raindrop- Cold rain: ice crystal/snow/graupel /hail

5.3. CISK and tropical cyclonez Cumulus parameterization schemes:- Manabe: “Convective adjustment”- Kuo: Q 〜−α (T ー Tc)- Ooyama: Q 〜 η(entrainment)・Γ・ w|PBL top- Arakawa-Schubert: Statistics of subgrid cloudsz CISK = Convective instability of the second kind
Vortex generation due to Ekman pumping at PBL top
z Tropical cyclone (Typhoon)- Tangential (gradient) wind: Coriolis ＋ centrifugal ＝ pres.grad.
Coriolis force ⇒ Cyclone only in sub-tropics (φ＞10 deg)
- Radial (Ekman) wind: Coriolis ＋ centrifugal ＝ friction
Centrifugal force ⇒ no intrusion of outside air into “Eye”- Warm-core, “eye-wall” cloud, spiral rainband- Typhoon activity and its interannual variation (ENSO)Typhoon as a “mini-earth”
with different heating distribution

coolingheatingheatingfriction< 1000 km〜10000 km

Tangential wind ⇔ Pressure gradient
Radial wind ⇔ Surface friction, turbulence /dragVertical velocity ⇔ Latent heat by cloud/precipitation

5.4. Cloud organization and intraseasonal variationz Wave-CISK and cloud organization mechanisms- Kelvin-wavelike, eastward-propagating ISV (Hayashi-Sumi)z Cloud hierarchical structure observed by GMS- Eastward-propagating super-cluster and 30-60 day ISV(Madden-Julian, Yasunari, …, Nitta et al.)- Westward-propagating clusters inside ISV(Nakazawa, Takayabu, …)
z Modulation of ISV observed by rawinsondes, profilers, GPS, etc.
Jawa (Hashiguchi et al. 1995; Tsuda et al., 1995; …)
Sumatera (Wu et al, 2002; Mori et al., 2002)- 3D structure of ISV by composite analysis of rawinsonde data
- Quasi-4-day period (Widiyatmi et al., 2000, 2001)
longer than – 2-day period over Pacific (Takayabu, ….)- Interaction with local diurnal circulations
North Jawa (Hashiguchi et al., 1995; Araki et al., 2002)
Sumatera (Murata et al., 2002; Sakurai et al., 2002)

TBB by GMS

Kototabang RawinsondeComposite analysis of rawinsonde data around humidity maximum
zonalwindIntraseasonal 1

Remarks
Local diurnal variations↑↓ Cloud generation/modification
Intraseasonal variations↑↓ Sseasonal march modification
Seasonal and nterannual variations

Conclusionz Meteorological/climatological phenomena in SE-Asia are understoodas a sum of solutions of the basic equations of atmospheric dynamics
such as- Trade wind, Hadley and monsoon circulations,- Matsuno-Gill patterns and intraseasonal variations,- Local circulations and clouds.
z Education courses somewhat different from standard (mid-lat.) one ofatmospheric dynamics must be established.
z Observations also must be continued and extended in order to obtainevidence of each component much more, as well as new theoreticalconcept from accumulated observational evidence.