Overview of the TaIwan Multi-scale Community Ocean Model (TIMCOM)

Wee-Beng Tay1, Yu-heng Tseng1, Nelson Chien2, Yu-chiao Liang1, Mu-hua Chien1

1Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan,

2National Taiwan University, Taipei, Taiwan,

OutlinesOutlinesIntroductionIntroduction

ObjectivesObjectives

Model FormulationsModel Formulations

FeaturesFeatures

Code Flow ChartCode Flow Chart

Test CasesTest Cases

ReferencesReferences

IntroductionIntroductionTIMCOM - TaIwan Multi-scale Community Ocean Model TIMCOM - TaIwan Multi-scale Community Ocean Model

Flexible community ocean model for simulating a variety of Flexible community ocean model for simulating a variety of idealized and real ocean flows over a wide range of scales idealized and real ocean flows over a wide range of scales and boundary conditions. and boundary conditions.

Written in Fortran 90 with a flexible user interface, allowing customization with ease.

Evolved from DieCAST (Dietrich Center for Air Sea Technology) ocean model (Dietrich et al., 1997). Complete family tree of TIMCOM is shown below:

ObjectivesObjectivesProvide a flexible, simple and user friendly community ocean modeling system for simulating a wide variety of real and idealized ocean flows over a wide range of scales and boundary conditions.

Multiple-grid capability resolves the key and fine features if needed (Dietrich et al., 2008).

Model suitable for resolving the multi-scale ocean dynamics.

Public version released by June 30 on the internet at http://efdl.as.ntu.edu.tw/research/timcom.

Model FormulationsModel FormulationsGoverning equations of the hydrostatic TIMCOM model based on the 3D primitive equations for an incompressible, stratified fluid. (Quasi non-hydrostatic version also available.)

Conservation of potential temperature and salinity:

Horizontal momentum equations:

,h T

T TLT D T K

t z z

,h S

S SLS D S K

t z z

0

tan 1,

cos m u

u u p uLu f v D u A

t R R z z

0

tan 1,m v

v u p vLv f u D v A

t R R z z

Model FormulationsModel FormulationsConservation of mass, Hydrostatic equation and Equation of state:

The convection, horizontal diffusion operators L,Dm(h) are defined as:

1 ( cos )0,

cos

u v w

R z

( ) ,p

gz

( , , ),S T p

,cos

u vL w

R R z

2 2( )

( ) 2 2 2 2

1tan ,

cosm h

m h

AD

R

FeaturesFeaturesSupporting hydrostatic/quasi non-hydrostatic approximation

Fully fourth-order-accurate approximations in the solution procedure and a new EVP parallel solver

Lagrangian tracers releases capacity

Grid coupling, multiple gridded one- and two-way grid coupling are supported (Dietrich et al., 2004; Dietrich et al., 2008)

Several turbulence parameterization options (PP, KPP and PWP)

FeaturesFeaturesDifferent time-advanced schemes options (Filtered, unfiltered Leap-frog, modified Leap-frog (Williams, 2009), Adam-Bashforth and Runge-Kutta third-order)

Immersed boundary methods for topology (mid. 2010)

NetCDF output to allow machine independent access and sharing of data.

NCL graphics output for portability and robustness

Ensemble simulation capability

Code Flow ChartCode Flow ChartPreprocessor

MetgenMetgen

- KbviewKbview

- YzgridYzgrid

-Z coordinates dataZ coordinates data

- Topography parametersTopography parameters

IndataIndata

- ZkbZkb

- InitialInitial

- BoundariesBoundaries

- DepthDepth

- InvuInvu

-AnnualevitusAnnualevitus

- WindsWinds

- FixedlevFixedlev

- Depth, land/water classification- Depth, land/water classification

- Old temperature, salinity dataOld temperature, salinity data

- Sponge layer climatologySponge layer climatology

- Depth infoDepth info

- Model and input levelModel and input level

- Old temperature, salinity dataOld temperature, salinity data

-Levitus climatology/ Hellerman windsLevitus climatology/ Hellerman winds

- Modelfied Levitus climatologyModelfied Levitus climatology

PrepPrep

- Rundata Rundata

- Kbview_prepKbview_prep

- EVPEVP

-WindmixWindmix

-IbmarrayIbmarray

- Vertical diffusion coefficients Vertical diffusion coefficients

- Z level infoZ level info

- EVP pressure solver coefficientEVP pressure solver coefficient

- VBK, VHK dataVBK, VHK data

- Immersed boundary dataImmersed boundary data

Code Flow ChartCode Flow ChartMain processing - Source Code StructureSource Code Structure

There are 7 kinds of template source code typeThere are 7 kinds of template source code type

P - General procedure for main and inputP - General procedure for main and input

O - General modules and useful solvers , tools O - General modules and useful solvers , tools

M - TIMCOM principal template source codeM - TIMCOM principal template source code

I - Include file for M type codeI - Include file for M type code

S - Ocean dynamic simulation template source code S - Ocean dynamic simulation template source code

T - Multi-zone coupling template source codeT - Multi-zone coupling template source code

G - Non-directory, file generated by configuratorG - Non-directory, file generated by configurator

Code Flow ChartCode Flow ChartMain processing - ConfiguratorConfigurator

Target code generator, generate case source code from Target code generator, generate case source code from template source code.template source code.

Configure fileConfigure file ：： read in by configurator, defines domain read in by configurator, defines domain name by typing DOMAIN <DOMAIN> key word.name by typing DOMAIN <DOMAIN> key word.

Supports one domain and multi domain Supports one domain and multi domain

UsageUsage ：： ./configure <configure file>./configure <configure file>

ExampleExample ：： ./configure configure.txt./configure configure.txt

An example for configure.txtAn example for configure.txt DOMAIN NPBDOMAIN NPB DOMAIN TAIDOMAIN TAI

Code Flow ChartCode Flow ChartMain processing - Multi-Domain diagramMulti-Domain diagram

ZONE A

ZONE BZONE C

MASTER SLAVE SLAVEDOMAIN TYPE for TIMCOM

SZONE2DZONE

DZONESZONE

DZONESZONE

DZONESZONE

DZONESZONE

DZONE2SZONE

Code Flow ChartCode Flow ChartMain processing - Main ProcedureMain Procedure

MAIN ( P typeMAIN ( P type ：： main.f90 )main.f90 ) TIMCOM_GETARGSTIMCOM_GETARGS TIMCOM_OPENLOGTIMCOM_OPENLOG INITINIT TIME EVOLUATION LOOPTIME EVOLUATION LOOP

TIMCOM ( G type )TIMCOM ( G type )

STOPSIG CHECKSTOPSIG CHECK

STOPSIG READSTOPSIG READ END OF TIME EVOLUATION LOOPEND OF TIME EVOLUATION LOOP TIMCOM_CLOSELOGTIMCOM_CLOSELOG TIMCOM_STOPSIG_SIGNALTIMCOM_STOPSIG_SIGNAL

Time Evolution Loop

Code Flow ChartCode Flow ChartRunning Controller - STOPSIGRunning Controller - STOPSIG

Controlling running stepControlling running step FileFile ：： stoprunstoprun LocationLocation ：： working directoryworking directory ValueValue：：

00 ：： finish the job without any conditionfinish the job without any condition

11 ：： checkpoint job and stop itcheckpoint job and stop it

2 or above2 or above ：： re-assign maximum evolution re-assign maximum evolution timesteptimestep

Coding in O type template source codeCoding in O type template source code ：： general.f90general.f90

Code Flow ChartCode Flow ChartRunning Controller - RestartRunning Controller - Restart

Restarting a runRestarting a run ensure all restart file has been preparedensure all restart file has been prepared

restart directoryrestart directory ：： <work directory>/TEMP_<DOMAIN>/<work directory>/TEMP_<DOMAIN>/ restart case with “./timcom 1”restart case with “./timcom 1”

Return SignalReturn Signal

Job return signal when job leave user spaceJob return signal when job leave user space 00 ：： job successful completejob successful complete 11 ：： job has been checkpoint and stopjob has been checkpoint and stop 22 ：： job failurejob failure Coding in O type template source codeCoding in O type template source code ：： general.f90general.f90

Test CasesTest CasesTwo dimensional flow over an island

Two dimensional, hydrostatic TIMCOM ocean model, simulating the idealized oceanic flow around small islands patterned after Barbados, W. I. (Dietrich et al., 1996). The velocity fields are illustrated in the figure below at day 5 and 111 at (80x80).

Test CasesTest CasesInvestigating the generation processes of internal solitary waves (ISWs) in LS using a 2-D numerical model with idealized topography (Tao et al., 2008).

A strong tide is imposed, giving a steeper initial depression and a group of ISWS being generated.

Test CasesTest CasesThe idealized bottom density current problem for The Dynamics of Overflow Mixing and Entrainment (DOME) (Tseng and Dietrich (2006), patterned after the Denmark Strait).

Snapshots of bottom boundary tracer concentration (c) on 4 different model days from the 2.5-km resolution run (R3L).

Test CasesTest CasesDual-grid North Pacific Ocean (DUPOM) to simulate the regional circulation in Asian Marginal Seas.

Left figure shows the coupled model domains while the right shows the western Pacific domain with a higher horizontal resolution of 1/8°×1/8°.

Test CasesTest CasesDual-grid North Pacific Ocean (DUPOM) to simulate the regional circulation in Asian Marginal Seas.

The cycle of the Kuroshio path in the region south of Japan between LM and NLM paths repeats with a period of more than a year in this model. Strong broclinic dynamics are observed from the transition.

Test CasesTest CasesThe global 2°x2° resolution ocean model with 31 vertical levels.

Higher resolution is used for climate study. Sample instantaneous temperature contour and surface velocity vector are shown below.

Test CasesTest CasesThe global 2°x2° resolution ocean model with 31 vertical levels.

Tracer capability of TIMCOM is also demonstrated below.

Thank you very much!