Quick Summary ofAqua Planet Experiment (APE)
Kensuke NAKAJIMA(4), Yoshi-Yuki HAYASHI(1) ,Michael Blackburn(2), David Williamson(3),Yukiko YAMADA(5),Yoshiyuki O. TAKAHASHI(1) ,Masaki ISHIWATARI(5), Wataru OHFUCHI(6)and 14 APE Modeling groups
1) Center for Planetary Science/Kobe University,
2) Reading University, 3) NCAR, 4) kyushu University,5) Hokkaido University, 6) Earth Simulator Center /JAMSTEC

WTK Workshop at CPS 14 March 2013

We have come back to the Earth,the planet we know best.
But understanding the behaviorof the atmosphere (or its models)is still not an easy taskeven in the simplest set-ups.

BackgroundHeld (2005) Bulletin of the American Meteorological Soc.

We have been developinga hierarchy of numerical models.
地球流体電脳倶楽部
GFD Electric brain Club
Still a long way to go…
(Very limited human resources.)Aqua Planet Experimentin the hierarchy of models
Idealizedboundary condition“Full GCMs”
are used.

Realiststic
boundary condition
Blackburn and Hoskins (2013)

The Earliest Aqua Planet ExperimentHayashi and Sumi (1986)

observed features

Rainfeatures in the numerical modelU

OLR (cloud activity)

super cloud cluster

MJO

Schematic diagram for hierarchy of ISV.
(Nakazawa, 1988)

The APE project

273K poleward of 60 deg.

Proposal : Neale and Hoskins (2000a,b)
Numerical Experiments Performed: 2003-2006
Workshops: 2005@Reading UK, 2007@Choshi JP
Results: APE ATLAS (2011), JMSJ Special Issue (2011)
Idealised climates simulated by AGCMs which are being usedand developed for NWP and climate research.
Several idealised distributions of SST, focusing on- the distribution and variability of convection in the tropics- the storm-tracks in mid-latitudes.
A benchmark of current model behavior
Understand the causes of inter-model differences
subgrid-scale parameterization suites,
dynamical cores, resolution

Group-IDResolution,Dynamics, horizontal

Deepconvection

AGUforAPE

T39L48 (3x3)SpectralEmanuel (1991)

CGAM

2.5 x 3.75 L30

Arakawa B grid

Gregory-Rowntree penetrative massflux convection

14 groups from
6 countries + ECMWFCSIRO (standard)

C48 L18 (2x2)

Conformal cubic grid

Mass flux type with downdraft

CSIRO (old)C48 L18 (2x2)

Conformal cubic grid

Mass flux type with downdraft

DWD

ni=64 L31

icosahedral grid

Bulk mass flux (Tiedke, 1989)

T159L60 (2x2)

Spectral

Bulk mass flux (Tiedke, 1989)

ECMWF_07

T159L60 (2x2)

Spectral

Bulk mass flux (Tiedke, 1989)

FRCGC

7km mesh (0.063x)

Icosahedral grid

Cumulus (partial) resolving

GSFC

2 x 2.5 L34

4th order global grid

Relaxed AS (Moorthi &Suarez, 1992)

GFDL?

?

Relaxed AS

K-1 Japan

T42L20 (2.8x2.8)

Spectral

Prognostic AS (Pan &Randall, 1998)

LASG

R42L9 (2.8x2.8)

SpectralSlingo cloud parameterization scheme,
Manable convective parameterization

MIT?

?

Relaxed AS (Moorthi &Suarez, 1992)

MRI

T42L30 (2.8x2.8)

Spectral

Prognostic AS

NCAR

T42 L26 ? (2.8x2.8)

SpectralZhang and McFarlane (1995)

UKMO_n48

N48L38 (2.5x3.75)

Arakawa C grid

Gregory-Rowntree

UKMO_n96

N96L38(1.25x1.625)

Arakawa C grid

Gregory-Rowntree

ECMWF

NOTABLE FEATURES FOUND IN APE
OWING TO IT’S IDEALIZED SET-UP

Normal Modes easy to identify
Example1: “raw” Wavenuber-Frequency Spectrumof Surface Pressure (UKMO, control)

k=1 barotropic Kelvin wave

k=1-4 barotropic Rossby wavesk=5 stationary baroclinic wave

EXAMPLE OF COMPARISON(ZONALLY UNIFORM SST)
DIVERSITY OF TROPICAL CONVECTIVE
ACTIVITY100day

AGUforAPEe

Precipitation at EQ (x,t)
0day
CGAM

CSIRO(standard)

CSIRO(old)

DWD

ECMWF

ECMWF (2007)

FRCGC (15day only)

GFDL

GSFC

K1JAPAN

LASG

MIT

MRI

NCAR

UKMO (n48)

UKMO (n96)AGUforAPEe

Precipitation Spectra
Kelvin wave like signal can be found in most models.
CGAM

CSIRO(standard)

CSIRO(old)

DWD

ECMWF

ECMWF (2007)

FRCGC (15day only)

GFDL

GSFC

K1JAPAN

LASG

MIT

MRI

NCAR

UKMO (n48)UKMO (n96)Spectral filters
defined from Wheeler & Kiladis plots

AGUforAPEe

KW filter : Kelvin wave signals
GW filter : westward gravity wave signals
AD filter : “advective” signals

GW filter
AD filter
KW filter

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

KW filter / composite [ T, (u, omg) ]Westward phse tilt? … Probably.

AGUforAPEeml

ECMWF(05/07) and LASG.
Westward phase tilt is evident (wave-CISK like).
GSFC : Eastward tilt
AGUforAPE: cold upward motion

CSIROmay want to
ECMWFYouknow
ECMWF (2007)
why these difference develop.

But, it is very difficult
tounderstand
LASG
GSFC
NCAR
the results.

EXAMPLE OF COMPARISON( WITH SST ANOMALY)RESPONSE TO SST ANOMALYIS VERY “STRANGE”.

Surface pressure and wind (3keq)
The intensity ofmid latitude Rossby response
diverges considerably.

AGUforAPE

CGAM

CSIRO(std)

CSIRO(old)

DWD

ECMWF

GFDL

GSFC

K1JAPAN

LASG

MIT

MRI

NCAR

UKMO (n96)Significant difference fromclassical Matsuno-Gill pattren
No westward outflow.

Poleward outflow

No eastward outflow.
Trough along the equator.

upper tropospheric response (CGAM)

3KW1 vs “Walker circulation”
In APE,high pressure
develops
to the east ofwarm SST area.

In the real atmosphere,
high pressure develops
to the west ofwarm SST area.

upper tropospheric pressure and wind fields

Why is the response in APE strange?
Zonal mean stateobtained in APE
is not so realistic.

“Westerly jets extends
To very low latitude
Rainfall is concentrated
at the equator.
PV is almost uniform
in the tropics.
 Equatorial Rossby wave is weak.

Anticyclone

CycloneLow level
Kelvindivergenceaffected by response
Rossby response
Anticyclone

CycloneSharp PV gradient at the Jets, where westerly wind dominates.
Anticyclonic vorticity source due to PV advection
by the divergent wind from convection center.
(Cf. Saradeshmukh and Hoskins, 1988)

Retrospect on APE• APE as Idealized experiments• Simple set-up allows clear display of “waves” and their mutualinteraction.
• Interpretation, however, is not necessarily easy.
• It is not easy to choose or justify setup• Apparently subtle difference in set-up can result in large difference.
• Compromize between “reality” and “idealization”• APE as an intercomparison project• Variety among results from different models is VERY DIVERSE.
• Interpretation, again, is not necessarily easy. To help it, we need
• Enough data (variables, space-time coverage/resolution)• Enough description of participating models (source codes?)• Cooperation among modelers, theoreticians, and data-analysts

Concluding remarks• Aqua planet is not easy to understand.
• Aqua Planet setup is one of the most serious test
beds of AGCMs.
• Necessity and possibility of “APE2”?
• More complete data should be collected.
• Advancement since 2005 may improve convergenceof results.
Thank you for your attention!

Background Equatorial hierarchical structure of precipitation
activity It has been argued that there exists three types of structure with different
time and spatial scales; MJO, super cloud cluster and cloud cluster.
 The representations in GCMs differ model by model.

super cloud cluster

MJO

Time-longitude section of transient OLR averaged between the equatorand 5N from May to July in 1980. (Nakazawa, 1988)

Schematic diagram for hierarchyof ISV. (Nakazawa, 1988)

Normal Modes maybe useful for comparison

Normal Modes easy to identify
Example2: “raw” Wavenuber-Frequency Spectrumof Precipitation (UKMO, flat)

K=1 diurnal tideSignal Modulation easy to identify
Example3: Spectrum of Precipitation
Modulation of Tropical Signals by Atmospheric Tide

UKMO control

UKMO qobs

Product of two waves in real space <-> sum in wavenumber space
exp[i(k1x-f1t)] * exp[i(k2x-f2t)] = exp[i{(k1+k2)x-(f1+f2)t}]
Product with diurnal tide<-> shift of (k,f)  (k-1 , f + (1/1day) )Note they are NOT “inertio gravity waves”.

UKMO flat

APE RESULTS• No model is similar to others.
• Because of it’s simple set up,
we can safely identify that the difference iscaused by model implementation of theatmosphere, not from the surface
inhomogeneity.
APE is a good (tough) tool of modelintercomparison.
• However, it is not very easy to understand what
is going on, how they are different, …
Let us try spectral analysis to identify possible
disturbance structures

GW filter / composite [ T, (u, omg) ]AGUforAPEe

Eastward phase tilt? … Probably.
ECMWF05 and LASG:
Eastward phase tilt is evident (wave-CISK like).
GSFC: strong power but …

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

GW filter / composite [mslp,uv925]
More or less n=1 westward inertio gravity wave like.

AGUforAPE

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

GW filter /composite [phi,u,v250]
More or less GW-like.
All are similar.

AGUforAPE

Because c-U is large,
Not affected by U.

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

AD filter / composite [ T, (u,omg) ]AGUforAPEe

No phase tilt?
Vertical structure displays significant variety:
Vertical structure of T suggests complex
structure of heating (downdrafts, ice phase etc.)

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

AD filter / composite [mslp,uv925]
AGUforAPE

Horizontal structure displays
significant variety.

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

AD filter /composite [phi,u,v250]
More or less GW-like.
All are similar.

AGUforAPE

Because c-U is large,
Not affected by U.

CSIRO

ECMWF

ECMWF (2007)

GSFC

LASG

NCAR

Response to SSTA on different basic
SST distribution (precipitation)
3Keq

flat3Keq

Qobs3Keq

H1998

AGCM5.3 (simple model, T42L16)

Yamada et al.

Precipitation (3keq)
AGUforAPE

CGAM

CSIRO(std)

CSIRO(old)

DWD

ECMWF

GFDL

GSFC

K1JAPAN

LASG

MIT

MRI

NCAR

UKMO (n96)Resolution Dependence• AFES1.15-ape (CCSR-NIES AGCM 5.4.02 tuned for theEarth Simulator)– Cumulus parameterization• non: no parameterizaion (only large scale condensation)– SST: zonally uniform, symmetric to the equator• The control profile of APE– Resolution• L48• T39, T79, T159, T319

Dependence on resolution (non)
T39L48

T79L48

T159L48

T159L48

T319L48

Yamada et al.

Dependence on resolution (T159L48_non)

15m/s

wavenumber-frequency power spectrum
calculated as Wheeler and Kiladis (1999)• Eastward moving features– 15m/s
Yamada et al.

Dependence on resolution (T159L48_non)power spectrum
7m/swavenumber-frequency
calculated as Wheeler and Kiladis (1999)• Westward moving features– 15-20m/s– 8-10m/s

Yamada et al.

Characteristic spectrum of IGW frommodulation of in Kelvin “envelope”

Shift of (k,f) due to a single
characteristic inertio gravity
wave component?

Mechanism of the positive rainfall anomaly tothe east in Hosaka et al (1998)
Rossby response to the west

Negative rainfallanomaly

Kelvin response to the east

Secondary rainfall anomaly

Heating over SSTA

We can understand H98 in the framework of“Matsuno-Gill pattern” and Low level Ekman flow

Response to SSTA on different basic
SST distribution(surfacepressure)3Keq
flat3KeqQobs3Keq

AGCM5.3 (simple model, T42L16)

H1998

Yamada et al.

control

Qobs

flat

H1998

Importance of “basic states”
Ubar 250hPa
H1998
Flat
Qobs
control
Beta-Uyy 250hPa
H1998
Flat
Qobs
control

3KW1 vs “Walker circulation”