koreacam-eulag february 2008 implementation of a non-hydrostatic, adaptive-grid dynamics core in the...

KoreaKorea CAM-EULAGCAM-EULAG February 2008February 2008

Implementation of a Implementation of a Non-Hydrostatic, Adaptive-Grid Non-Hydrostatic, Adaptive-Grid

Dynamics Core Dynamics Core in the in the

NCAR Community Atmospheric ModelNCAR Community Atmospheric ModelWilliam J. Gutowski, Jr.William J. Gutowski, Jr.11,,Babatunde J. AbiodunBabatunde J. Abiodun1,2,31,2,3

andandJoseph M. PrusaJoseph M. Prusa1,41,4

11Iowa State University, Ames, Iowa, USAIowa State University, Ames, Iowa, USA22Federal Univ. Technology, Akure, NigeriaFederal Univ. Technology, Akure, Nigeria

33University of Cape Town, South AfricaUniversity of Cape Town, South Africa44Teraflux Corp., Boca Raton, Florida, USATeraflux Corp., Boca Raton, Florida, USA

EULAG MeetingEULAG Meeting CAM-EULAGCAM-EULAG October 2008October 2008

OutlineOutline

• MotivationMotivation

• Model development (CAM-EULAG)Model development (CAM-EULAG)

• CAM-EULAG vs. Existing Dynamics CoresCAM-EULAG vs. Existing Dynamics Cores

• ApplicationsApplications


MotivationMotivation


Motivation: Scale IssuesMotivation: Scale Issues

Regional features Regional features in global climate in global climate simulation often simulation often need accurate need accurate simulation simulation encompassing a encompassing a range of scales.range of scales.


Grid AdaptationGrid Adaptation

(2) Dynamic GA: (2) Dynamic GA: for features of interestfor features of interest• storm tracks storm tracks • hurricaneshurricanes• squall lines squall lines • convectionconvection• tornadoestornadoes• … …

One approach is to use grid adaptation (GA) in global modelsOne approach is to use grid adaptation (GA) in global models

(1)(1) Static GA:Static GA: for areas of interestfor areas of interestalternative to nested grid regional modelsalternative to nested grid regional modelsadvantages: advantages: • consistent dynamics over high & low resolution areasconsistent dynamics over high & low resolution areas• small scale & large scale features fully coupledsmall scale & large scale features fully coupled


Model Development: Model Development: CAM-EULAGCAM-EULAG


Coupled Model: CAM-EULAG

Combines the numerical and mathematical rigor of Combines the numerical and mathematical rigor of the advanced the advanced dynamicsdynamics core core EULAGEULAG (Smolarkiewicz et al.) …(Smolarkiewicz et al.) …

… … with the climate-system physics of the U.S. with the climate-system physics of the U.S. National Center for Atmospheric Research (NCAR)National Center for Atmospheric Research (NCAR) Community Atmospheric Model, v3 (Community Atmospheric Model, v3 (CAM3CAM3))


The physics package includes radiation, The physics package includes radiation, boundary-layer, convection and cloud-physics boundary-layer, convection and cloud-physics routines. routines.

Standard model has three hydrostatic dynamic Standard model has three hydrostatic dynamic cores: cores: Finite Volume Finite Volume (FV), (FV), Eulerian Spectral Eulerian Spectral (ES) and Lagrangian Spectral (LS)(ES) and Lagrangian Spectral (LS)

For details see Collins et al. (2004).For details see Collins et al. (2004).

CAM3CAM3


CAM-EULAG: CouplingCAM-EULAG: Coupling

• Thermodynamic pressure and temperatureThermodynamic pressure and temperature

• CAM vertical pressure velocityCAM vertical pressure velocity

• CAM tendencies: process-split couplingCAM tendencies: process-split coupling

• Parallel codingParallel coding

)(5.0)~( 11 nnn PDtMPDATA ψψψψ +Δ+= ++ )PD(t5.0~ nnn

ψψ +Δ+ψ=ψ

κθ= )p/p(T rphyphy)0z(/'Wt/'2p

Rpp bbb

)1/(1

r

edbrphy =ρρ−Δπρ+⎟⎟

⎠

⎞⎜⎜⎝

⎛ θρ=

κ−

i

phyi*

phy

x

pv

td

dp

∂∂

==ω


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 CAMCompare results with current dynamic cores in CAM

• 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


Comparison of Dynamics CoresComparison of Dynamics Cores


Comparison of dynamic coresComparison of dynamic cores

• Cores: Cores: EULAG, FV and ESP EULAG, FV and ESP • Experiment: Experiment: Aqua-planetAqua-planet• Forcing: Forcing: Idealized, zIdealized, zonally symmetric SSTonally symmetric SST• Horizontal resolutions : Horizontal resolutions : 2˚x2.5˚ [EULAG and FV] 2˚x2.5˚ [EULAG and FV]

and T42 [ESP]and T42 [ESP] • Vertical grid: Vertical grid: 26 levels26 levels• Time step: Time step: 600s (EULAG), 900s (FV and ESP)600s (EULAG), 900s (FV and ESP)• 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


• Westerly Jet cores: Westerly Jet cores:

EULAG (55 m/s)EULAG (55 m/s)

FV (65 m/s)FV (65 m/s)

ESP (60 m/s)ESP (60 m/s)

• Easterly peaks:Easterly peaks:

EULAG (10 m/s)EULAG (10 m/s)

FV (10 m/s)FV (10 m/s)

ESP (10 m/s)ESP (10 m/s)

Zonally Averaged Zonally Averaged Zonal WindZonal Wind


• Maximum updrafts: Maximum updrafts:

EULAG (4.0 cm/s)EULAG (4.0 cm/s)

FV (2.2 cm/s)FV (2.2 cm/s)

ESP (1.8 cm/s)ESP (1.8 cm/s)

• Updraft locations:Updraft locations:

~ ~ ++ 3˚ off equator 3˚ off equator

Zonally Averaged Zonally Averaged Vertical WindVertical Wind


PrecipitationPrecipitation


Tropical Precipitation vs. Time/LongitudeTropical Precipitation vs. Time/Longitude

> 7 mm/d> 7 mm/d > 9 mm/d > 9 mm/d

Tropical Tropical PrecipitationPrecipitation

(averaged (averaged over 10˚ S - over 10˚ S - 10˚ N)10˚ N)

DA

YS

80

Longitude

PeriodsPeriods

EUL ~ 30 dEUL ~ 30 d

FV > 45 dFV > 45 d

ESP ~ 22 dESP ~ 22 d

40


(D. Williamson, (D. Williamson, NCAR, 2007)NCAR, 2007)

Power Spectra: Kinetic Energy


ApplicationsApplications


Simulation Simulation with with

Static GA: Static GA: GridsGrids

90 (lat) x 144 90 (lat) x 144 (lon)(lon)

1.1. Uniform (2˚)Uniform (2˚)

2.2. Meridional Meridional Double Nest Double Nest (DBL)(DBL)

3.3. Zonal Stretch Zonal Stretch + Meridional + Meridional Double Nest Double Nest (DBS)(DBS)


Simulation with Simulation with Static GA:Static GA:

Zonal Flow & Zonal Flow & PrecipitationPrecipitation

Versus UniformVersus Uniform

1.1. Jets about 1˚ closer to equatorJets about 1˚ closer to equator

2.2. DBL jet stronger by about 5 DBL jet stronger by about 5 m/sm/s

3.3. Layer of equatorial westerly Layer of equatorial westerly flowflow

4.4. Precipitation slightly weakerPrecipitation slightly weakerNo abrupt changes in structureNo abrupt changes in structure


Precipitation vs. Latitude: Precipitation vs. Latitude: Uniform GridsUniform Grids

Double Maximum

Different Magnitude

Broader Hadley Cell

Resolutions:Resolutions:• LU = 4˚ meridional (2˚ zonal)LU = 4˚ meridional (2˚ zonal)• HU = 2˚ meridional (2˚ zonal)HU = 2˚ meridional (2˚ zonal)


Precipitation Precipitation vs. Latitudevs. Latitude

Extratropical changes in Extratropical changes in resolutionresolution

Expand width of Expand width of tropical high tropical high

resolution regionresolution region

Tropical changes in Tropical changes in resolutionresolution


Precip. Power Spectra: Symmetric WavesPrecip. Power Spectra: Symmetric Waves


Precip. Power Spectra: Anti-symmetric WavesPrecip. Power Spectra: Anti-symmetric Waves


Resolution of Resolution of Tropical Tropical WavesWaves

(Power vs. Latitude)(Power vs. Latitude)


Additional SimulationsAdditional Simulations


Dynamic GA: Tracking a Tropical VortexDynamic GA: Tracking a Tropical Vortex


High Resolution Grid over West AfricaHigh Resolution Grid over West Africa


SummarySummaryCAM3 coupled to a non-hydrostatic CAM3 coupled to a non-hydrostatic

dynamic core with capability for both dynamic core with capability for both static and dynamic grid adaptation static and dynamic grid adaptation (EULAG)(EULAG)

CAM-EULAG aqua-planet simulation CAM-EULAG aqua-planet simulation agrees well with standard CAM3agrees well with standard CAM3

ICTZ features linked to resolving tropical ICTZ features linked to resolving tropical and extratropical wavesand extratropical waves


Thank you!Thank you!

Abiodun, B.J., J.M. Prusa and W.J. Gutowski, 2008: Implementation of a Non-hydrostatic, Adaptive-Grid Dynamics Core in CAM3. Part I: Comparison of Dynamics Cores in Aqua-Planet Simulations. Clim. Dynamics [DOI 10.1007/s00382-008-0381-y].

Abiodun, B.J., W.J. Gutowski and J.M. Prusa, 2008: Implementation of a Non-hydrostatic, Adaptive-Grid Dynamics Core in CAM3. Part II: Dynamical Influences on ITCZ Behavior and Tropical Precipitation. Clim. Dynamics [DOI 10.1007/s00382-008-0382-x].

koreacam-eulag february 2008 implementation of a non-hydrostatic, adaptive-grid dynamics core in the...

Documents

eulag meeting cameulag

cameulag slide

coupled slide

motivation slide

hydrostatic dynamic

current dynamic cores

usa slide

coupled model