Gill (1980) response to heating Qo

Gill (1980) response to heating Qc

Zebiak’s (1986) heating Qc of the Gill model•Forcing is due to the canonnical SST anomaly at the of thewarm phase of ENSO

•Heating

Qc = Qs(z) + Qo(z)

P = H{ E - div (uq)*dp}

!

L P = Qo" dp

Qs(z) =

Qo(z) =

Evaporation Moisture Convergence

Evaporation

Zebiak’s (1986) heating Qc of the Gill model

SST(observed)

Winds(observed)

•Forcing is due to the canonnical SST anomaly at the of thewarm phase of ENSO•Heating Qc = Qs(z) + Qo(z) P = H{ E - div (uq)*dp}

!

L P = Qo" dp

Winds(evap only)

Winds Qc

(evap only)

all Qc

!

"#r u

!

"#r u

(observed)

!

"#r u

Nb: easterlies problem ineastern half of Pacific

Problems w/ Gill/Zebiak (1980) and LN (1987)

Lindzen/Nigam

Reduced Gravity (BHS 1990)

Chiang (2001) response to heating Qs + Qo

Q = Qs(z) + Qo(z) P = H{ E - div (uq)*dp}

!

L P = Qo" dp

Qs(z) PBL

Precipitation (forcing)

SST (forcing)975mb Wind

Zonal WindComponent

Meridonal Wind

Fields are thefirst EOF of thecombined SST,wind vector andprecipitationanomalies inthe tropics

Simulated using total heating Qc and Qs

Observed Simulated Wind/T

a

U

V

Win

d/S

ST

Wind and Ta at 975mb

Simulated using elevated heating Qc only

Observed Simulated Wind/T

a

U

V

Win

d/S

ST

Wind and Ta at 975mb

Simulated using surface heating Qs only

Observed Simulated Wind/T

a

U

V

Win

d/S

ST

Wind and Ta at 975mb

Correlation of Model vs Observed MonthlyAnomalies (1979-99)

Zonal Wind

MeridionalWind

Qc = Qs(z) + Qo(z)

Evaporation Turbulent

Qc = Qs(z) + Qo(z)

P = H{ E - div (uq)*dp}

!

L P = Qo" dp

Qs(z) =

Qo(z) =

Evaporation

Evaporation

Qs(z) PBL

Moisture Convergence

Qs(z) =Turbulent (T,q)

Chiang Qc

P = H{ E - div (uq)*dp}

!

L P = Qo" dpQo(z) =

Qc = Qs(z) + Qo(z)

Gill/Zebiak heating Qc