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GEOS-Chem: Goddard Earth Observing System -Chemistry model

General information

Model name and version

short nameGEOS-Chem
full nameGoddard Earth Observing System -Chemistry model
revisionv7
dateSep 2006
last change

Responsible for this information

nameRokjin Park
institute
address29 Oxford Street, Cambridge, MA 02138
zip
city
countryUSA
phone
fax
e-mailrpark(belongs-to)fas.harvard.edu

Additional information on the model

Contact person for model code

same as person above
nameRokjin Park
institute
divisions29 Oxford Street, Cambridge, MA 02138
street
zip
city
countryUSA
phone
emailrpark(belongs-to)fas.harvard.edu
fax

Model developer and model user

developer and userHarvard Atmospheric Modeling Group

Level of Knowledge needed to operate model

basic
intermediate
advanced
remarks

Model use at your institution

operational
for research
other use

Model code available?

is available?yes
more details

Minimum computer resources required

type
time needed for run
storage

Further information

documentation
model referencesBey et al., Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23,073-23,096, 2001. Park et al. (2004), Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: implications for policy, J. Geophys. Res., 109, D15204, 10.1029/2003JD004473.
webpagehttp://www.as.harvard.edu/chemistry/trop/geos/index.html
additional information

Model properties

Model type

2D
3D
meteorology
chemistry & transport

Model scale

microscale
mesoscale
macroscale
short term
long term

Meteorological variables

Input data
u
v
w
ζ
pv
T
θ
θl
p
Gph
ρ
qv
qt
qlc
qf
qsc
qlr
qsh
qsg
qss
N
E
ε
K
zi
other variables i
other variables ii
other variables iii

Chemical substances

PrognosticDiagnosticDry depositionWet depositionInput data
SO2
NO
NO2
NOX
NH3
HNO3
O3
CH4
DMS
H2O2
VOC
C6H6
HCHO
CO
CO2
POP
PM 10
PM 2.5
PPM10
PM 0.1
PM 1
NH4
SO4
dust
sea salt
BC
POM
SOA
NO3
Other gasesHg, HgII, HgP
1st radioactivity
2nd radioactivity
3rd radioactivity
Cd
Pb
other heavymetals
pesticides
1st radioactivity
2nd radioactivity
3rd radioactivity
remarks

Approximations

Boussinesq
anelastic
hydrostatic
flat earth
remarks

Parametrizations

Chemistry & transport

photolysis rateFast-J (Wild et al., 2000)
dry depositionA standard resistance-in-series model dependent for gas [Wesely, 1989] and the size-dependent scheme of Zhang et al. [2001] for aerosols. and size resolved aerosols
wet depositionA scheme of Liu et al. [2001]
remarks

Chemical reactions

Gas & wet phase chemistry

chemical transformations calculated
chemical transformations neglected
other
gas phase chemistry (give details)Bey et al. (2001)
wet phase chemistry (give details)
more information

Aerosol chemistry

passive aerosol
dry aerosol
wet aerosol
sectional approach
modal approach
other
nucleation
coagulation
condensation
aerosol mixing
aerosol ageing
primary aerosol formation
aerosol-gas phase interactions
optical properties
give detailssee Park et al. (2004)

Initialization & boundary treatment

Initialization

chemistry & transport
meteorology

Input data (name sources for data, e.g. website)

orography
land use
obstacles
vegetation
meteorologyGEOS–1, GEOS–STRAT, GEOS–3, GEOS-4, and GEOS-5
concentrations
emissionsGEIA, EDGAR, BRAVO, EMEP, Streets et al. (2003, 2006)
remarks

Data assimilation

Chemistry & transport
nudging technique
adjoint model
3D-VAR
4D-VAR
OI
details

Boundary conditions

Chemistry & transport
surface
top
lateral inflow
lateral outflow

Nesting

Chemistry & transport
one way
two way
other
variables nested
nesting online
nesting offline
data exchange by array
data exchange by file
time step for data exchange3hrs
explain methodFirst conduct a global simulation to archive boundary conditions for nested domains and they are used for nested model simulations.
variables nestedall chemical species
other

Solution technique

Coordinate system and projection

Horizontal

cartesian
Lambert conformal
latitude / longitude
rotated lat. / long.

Vertical

z coordinate
surface fitted grid
pressurecoordinate
sigma coordinate
remarksDepending on GEOS meteorology, e.g., sigma coordinate for GEOS-1, GEOS-STRAT, GEOS-3 and later hybrid sigma-pressure coordinate for GESO-4, GEOS-5 Current data are produced using GEOS-4 met data so the vertical coordinate is hybrid sigma-pressure coordinate.

Numeric

Chemistry & transport

Grid

Arakawa A
Arakawa B
Arakawa C
Arakawa D
Arakawa E
uniform grid
nonuniform grid
Euler
Lagrange
Gauss

Time integration

explicit
split-explicit
semi-implicit
time step same as meteorology
other

Spatial discretisation

scalar quantities
additional information
other
chemistry solverSMVGEAR II

Model resolution

Chemistry & transport

HorizontalVertical
max
min

Domain size

Chemistry & transport

HorizontalVertical
max
min

Model Validation and Application

Validation & evaluation

Used validation & evaluation methods

analytic solutions
evaluated reference dataset
model intercomparison
additional validation & evaluation efforts
remarks

Application examples

application examples

Participation in specific model evaluation exercises

AQMEII
List experiments (AQMEII)
Cost728
List experiments (COST728)
HTAP
List experiments (HTAP)
MEGAPOLI
List experiments (MEGAPOLI)