Implementation of Grid Adaptation Implementation of Grid Adaptation

in CAM: in CAM: Comparison of Dynamic CoresComparison of Dynamic Cores

Babatunde J. AbiodunBabatunde J. Abiodun1,21,2

William J. GutowskiWilliam J. Gutowski11, , andand

Joseph M. PrusaJoseph M. Prusa1,31,3

11Iowa State University, Ames, IAIowa State University, Ames, IA22Federal Univ.Technology, Akure, NigeriaFederal Univ.Technology, Akure, Nigeria

33Teraflux Corp., Boca Raton, FLTeraflux Corp., Boca Raton, FL

MotivationMotivation►Accurate Representation of regional features Accurate Representation of regional features

in global climatein global climateStatic GA:Static GA: for areas of interestfor areas of interest

• alternative to nested grid regional modelsalternative to nested grid regional models• advantages: advantages:

consistent dynamics over high and low resolution areasconsistent dynamics over high and low resolution areassmall scale and large scale features fully coupledsmall scale and large scale features fully coupled

Dynamic GA: Dynamic GA: for features of interestfor features of interest• storm tracks, hurricanes, squall lines, storm tracks, hurricanes, squall lines, frontal precipitation, Asian monsoon,frontal precipitation, Asian monsoon, tornadoes, convectiontornadoes, convection

EULAG EULAG (Smolarkiewicz, NCAR)(Smolarkiewicz, NCAR)

• is a non-hydrostatic dycore is a non-hydrostatic dycore • allows static and dynamic GAallows static and dynamic GA

OverviewOverview

► Features of EULAG dynamic coreFeatures of EULAG dynamic core► CAM-EULAGCAM-EULAG► Baseline Simulation TestsBaseline Simulation Tests► SummarySummary

Features of Features of EULAG: Basic Moist EULAG: Basic Moist EquationsEquations

wherewhere

0x

)u*(j

js

d dt

usk e

x k S

d

dt

t

u *k x k and j,k = 1,2,3and j,k = 1,2,3

Jacobian weighted density

* G

G jk

(Continuity)(Continuity)

(Momentum)(Momentum)

(Potential Temperature)(Potential Temperature)

Normalized elements of Jacobi matrix

Density normalized pressure perturbation

e

Potential temp. perturbation

Environmental potential temp.

Allows strict adherence of numerics to fundamental conservation Allows strict adherence of numerics to fundamental conservation lawslaws

j

3

j

b

d

k

k

j S'

gx

'

td

udG~

j

dqvd t

Pv (Moisture)(Moisture)

Features of EULAG Dynamic coreFeatures of EULAG Dynamic core Grid Adaptivity (GA) via continuous transformation of Grid Adaptivity (GA) via continuous transformation of coordinatecoordinate

- A signature characteristic of EULAG- A signature characteristic of EULAG Nonhydrostatic, Deep Moist Anelastic ApproximationNonhydrostatic, Deep Moist Anelastic Approximation

- Simplifies the design of accurate and efficient numerical solvers.- Simplifies the design of accurate and efficient numerical solvers. Non-oscillatory Forward in Time (NFT) advection solverNon-oscillatory Forward in Time (NFT) advection solver

- Smolarkiewicz and Margolin (1998), - Smolarkiewicz and Margolin (1998), Smolarkiewicz et al. (1999)Smolarkiewicz et al. (1999) - Multidimensional, Positive Definite Advection Transport- Multidimensional, Positive Definite Advection Transport Algorithm (MPDATA)Algorithm (MPDATA) - Positive definite solver- no spurious sign changes- Positive definite solver- no spurious sign changes - Monotonicity option prevent dispersive ripples- Monotonicity option prevent dispersive ripples - Can do nested grids with sudden changes in metric

coefficients Eulerian and semi-Lagrangian advection solver Eulerian and semi-Lagrangian advection solver

These charateristics make EULAG a good dynamic These charateristics make EULAG a good dynamic core for GA simulations in CAMcore for GA simulations in CAM

Held-Suarez (1994) flow [static grid]Held-Suarez (1994) flow [static grid]]] ((Prusa and Gutowski, 2006Prusa and Gutowski, 2006))

- flat terrain - flat terrain - idealized Andes - idealized Andes

Regional inertio-gravity waves [dynamic Regional inertio-gravity waves [dynamic grid]grid]

(Prusa & Smolarkiewicz, 2003)(Prusa & Smolarkiewicz, 2003)

Potential flow between flapping Potential flow between flapping membranes membranes

[dynamic grid][dynamic grid] (Wedi & Smolarkiewicz, 2004)(Wedi & Smolarkiewicz, 2004)

Stratified flow over a winding valley [static Stratified flow over a winding valley [static grid]grid]]]

(Smolarkiewicz & Prusa, 2004(Smolarkiewicz & Prusa, 2004))

EULAG: Previous Dynamic core TestingEULAG: Previous Dynamic core Testing

CAM-EULAG: CouplingCAM-EULAG: Coupling►Thermodynamic Pressure and TemperatureThermodynamic Pressure and Temperature

►CAM vertical pressure velocityCAM vertical pressure velocity

►CAM TendenciesCAM Tendencies - process-split coupling- process-split coupling

- EULAG requires tedencies from CAM physics- EULAG requires tedencies from CAM physics - EULAG (MPDATA) advects all prognostic fields- EULAG (MPDATA) advects all prognostic fields

►Parallel versionParallel version

)PD(t5.0)~(MPDATA nn1n

)PD(t5.0~ nnn

)p/p(T rphyphy)0z(/'Wt/'2

p

Rpp bbb

)1/(1

r

edbrphy

i

phyi*

phy

x

pv

td

dp

CAM-EULAG: Baseline Simulation TestsCAM-EULAG: Baseline Simulation Tests

► Aqua-planet (Neale & Hoskins, 2001)Aqua-planet (Neale & Hoskins, 2001)- Ensure dynamic core and physics suites are well coupled.Ensure dynamic core and physics suites are well coupled.

- Compare results with current dynamic cores in CAM (FV and ESP)Compare results with current dynamic cores in CAM (FV and ESP)

- Further test static and Dynamic GAFurther test static and Dynamic GA

► AMIP II: Full surface-atmospheric physicsAMIP II: Full surface-atmospheric physics- Fine tune CAM physics for EULAG dynamic coreFine tune CAM physics for EULAG dynamic core

- Compare results with observation and other modelsCompare results with observation and other models

► SGMIP II: Full surface-atmospheric physics with GA SGMIP II: Full surface-atmospheric physics with GA - Fine tune CAM physics for high-resolution simulations- Fine tune CAM physics for high-resolution simulations

- Compare results with observations and other GA models- Compare results with observations and other GA models

Aqua-planet: Comparison of 3 dynamic Aqua-planet: Comparison of 3 dynamic corescores

► Candidates: Candidates: EULAG, FV and ESP [in CAM]EULAG, FV and ESP [in CAM]► Aims: Aims: To compare similarities and differences. To compare similarities and differences. ► Horizontal resolutions : Horizontal resolutions : 2x2.5 [EULAG and FV] and 2x2.5 [EULAG and FV] and

T42 [ESP] T42 [ESP] ► Vertical grid point: Vertical grid point: 26 level26 level► Time step: Time step: 600s (EULAG), 900s (FV and ESP)600s (EULAG), 900s (FV and ESP)► Forcing: Forcing: Idealised zIdealised zonally symmetric SSTonally symmetric SST

► Initialization: Initialization: Eulag started from rest, FV and Eulag started from rest, FV and ESP from their standard initial conditionsESP from their standard initial conditions

Zonally averaged zonal wind

• Westerly Jet cores:

EULAG (55 m/s)

FV (65 m/s)

ESP (60 m/s)

•Easterly peaks:

EULAG (10 m/s)

FV (10 m/s)

ESP (10 m/s)

Zonally averaged potential Temperatue

•There is a good agrement between EULAG and FV

•ESP simulates coldest boundary layer in the tropics

Zonally averaged specific humidity

Hovemoller plot of convective precipitation,averaged over 10oS-10oN

Aqua-planet: Simulation with static GAAqua-planet: Simulation with static GA

Resolution (o)

Aquaplanet: Video of simualtion with Static GAAquaplanet: Video of simualtion with Static GA

Aquaplanet: Simulation with Static GAAquaplanet: Simulation with Static GA

ERA40 - Feb 79ERA40 - Feb 79

AMIP: CAM-EULAG - Feb 79AMIP: CAM-EULAG - Feb 79

NCEP - Feb 79NCEP - Feb 79

SGMIP: CAM-EULAG GridSGMIP: CAM-EULAG Grid

SummarySummary►A non-hydrostatic dynamic core that has A non-hydrostatic dynamic core that has

capability for both static and dynamic grid capability for both static and dynamic grid adaptation (EULAG) is coupled with CAM.adaptation (EULAG) is coupled with CAM.

►CAM-EULAG aqua-planet simulation agree well CAM-EULAG aqua-planet simulation agree well those from standard CAMthose from standard CAM

►AMIP and SGMIP simulations using CAM-EULAG AMIP and SGMIP simulations using CAM-EULAG are in progress!!!are in progress!!!

Thank you!!!Thank you!!!