Transcript The ATHAM Model: Code Structure and Usage Michael Herzog, GFDL Princeton, USA

The ATHAM Model:
Code Structure and Usage
Michael Herzog,
GFDL Princeton, USA
Gunnar Luderer,
MPI Mainz, Germany
Joerg Trentmann,
University of Mainz, Germany
Christiane Textor,
LSCE Paris, France
ATHAM Workshop, Cambridge, UK, June 19-22, 2006
Features of New ATHAM Code

revised code structure
– namelist control to avoid recompile
– directory structure to separate code from i/o
– more user-friendly (makefiles, libraries,
defined interfaces for adding new modules or
variables)

MPI support for parallel computing
– larger problem size (3d, more processes)
(in cylindric coordinates serial only)
Getting Started (unix-like system)

expand archive file atham_[dd.mm.yyyy]_tar.gz
– subdirectories source/ and input/

create directories exec/, output/, save/

specify compiler/flags in source/Makefile.COMPILE

compile code, create executable: make [atham, rebuild]

modify input files in input/

run executable exec/atham (or with make run)

visualize and analyze output files in output/
Input Files

vertical profiles:
– INPUT_profile: T(z), RH(z), u(z), v(z)
– INPUT_kinetic: viscosity, free path length of air

namelist files:
– INPUT_atham_setup: type, domain, timing
– INPUT_volcano:
processes, tracer, forcing
– INPUT_procsconfig,
INPUT_fireforcing,
INPUT_twomicrophys, INPUT_zgrid,
INPUT_coignimbrit,
INPUT_dynamic_setup
INPUT_atham_setup

type or configuration:
e.g. if volcano_setup read INPUT_volcano

coordinate system:

boundary condition: cyclic or no slip

output format:

domain size, number of grid points

number of processors for MPI version

location of zoom, spatial resolution at zoom
cylindric or cartesian
netcdf or binary
INPUT_volcano

active process modules (bulk cloud microphysic)

number of tracer
(ntrac, ntgas, ntpas)

tracer properties
(cp, cv, density, radius)

tracer names for output files
Executing and Output

executable exec/atham
– reads from input/ (except restart from output/)
– writes to output/ (old output files overwritten)

output from Parallel (MPI) version:
– separate restart and output files
for each processor, e.g. ATDAT_<px>_<py>
– output files can be recombined with exec/rebuild
– no(!) rebuild for ATDAT
– single output file if netcdf

output can be viewed with grads (qview) or ferret
Code Structure

subdirectories in source/:
– Basic/: data module, phys constants
– Atham/: dynamical core
– ProcessModules/: processes, forcing
=> add new process using process_data, .e.g. radiation
– Configurations/: problem description
=> add new problem, e.g. coignimbrit eruption
Adding a Process
Example: Radiation for volcano_setup

add radiation.F90 in source/ProcessModules/

use data from module process_data.F90 (and atham_module.F90)

register radiation module
in module processes.F90 and Makefile.COMPILE

add temperature forcing to tetflx

add radiation calls in source/Configurations/volcano.F90
– radiation_init in routine volcano_init
– radiation_preset in routine volcano_preset
– radiation_flux in routine volcano_flux
– diagnostics
in volcano_diagnostic
and volcano_final_diagnostic
Treating a New Problem
Example: Co-ignimbrite Eruption

add coignimbrit.F90 in source/Configurations/ containing:
– coignimbrit_init (coignimbrit_pointer)
– coginimbrit_preset
– coignimbrit_flux (incl. coignimbrit_forcing)
– coignimbrit_fallvel
– coignimbrit_diagnostic, coignimbrit_final_diagnostic

register coignimbrit module in module configurations.F90 and
Makefile.COMMON
use data from atham_module
add flag coignimbrit_setup in source/Basic/atham_module.F90
add coignimbrit calls in source/Atham/atham_setup.F90,
atham_forcing.F90, atham_fallvelocity.F90, atham_output.F90
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Questions, Comments?