**Model Information of Potential Use to the IPCC Lead Authors and the
AR4.**

**ECHAM5_MPI-OM**

31 January 2005

# Model identity:

A.  Institution, sponsoring agency, country: Max Planck Institute for
    Meteorology, Germany

B.  Model name (and names of component atmospheric, ocean, sea ice, etc.
    models): ECHAM5/MPI-OM

C.  Vintage (i.e., year that model version was first used in a published
    application): 2005

D.  General published references and web pages: Jungclaus et al. (2005)

E.  References that document changes over the last \~5 years (i.e.,
    since the IPCC TAR) in the coupled model or its components. We are
    specifically looking for references that document changes in some
    aspect(s) of model performance. N/A

F.  IPCC model version\'s global climate sensitivity (KW^-1^m^2^) to
    increase in CO~2~ and how it was determined (slab ocean expt.,
    transient expt\--Gregory method, ±2K Cess expt., etc.): Climate
    sensitivity parameter is 0.835 (estimated from slab ocean
    experiments: control and CO2 doubling: ∆T=3.35K; adjusted forcing at
    the tropopause: 4.01 Wm^-2^)

G.  Contacts (name and email addresses), as appropriate, for:

    1.  coupled model: Erich Roeckner (roeckner@dkrz.de)

    2.  atmosphere: Erich Roeckner

    3.  ocean: Johann Jungclaus (jungclaus@dkrz.de)

    4.  sea ice: Uwe Mikolajewicz (mikolajewicz@dkrz.de)

    5.  land surface: Erich Roeckner

    6.  vegetation: Stefan Hagemann (hagemann@dkrz.de)

    7.  other?

# Besides atmosphere, ocean, sea ice, and prescription of land/vegetated surface, what can be included (interactively) and was it active in the model version that produced output stored in the PCMDI database?

A.  atmospheric chemistry? Yes (not active)

B.  interactive biogeochemistry? Yes (not active)

C.  what aerosols and are indirect effects modeled? In the IPCC runs
    done so far, sulfate aerosol is prescribed (direct and first
    indirect effect). An experiment with interactive aerosols is in
    progress (A1B) including the first and second indirect effects as
    well as the semi-direct effect.

D.  dynamic vegetation? No

E.  ice-sheets? No

# List the community based projects (e.g., AMIP, C4MIP, PMIP, PILPS, etc.) that your modeling group has participated in and indicate if your model results from each project should carry over to the current (IPCC) version of your model in the PCMDI database.

AMIP (yes)

# Component model characteristics (of current IPCC model version):

A.  Atmosphere (ECHAM5; Roeckner et al., 2003)

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1.  resolution: T63 L31 (TAR = T42 L19)

2.  numerical scheme/grid (advective and time-stepping schemes; model
    top; vertical coordinate and number of layers above 200 hPa and
    below 850 hPa): Spectral, semi-implicit/leap-frog, flux form
    semi-Lagrangian scheme (Lin and Rood, 1996) for water components;
    top level at 10 hPa, 9 layers above 200 hPa, 5 layers below 850 hPa)

3.  list of prognostic variables: Vorticity, divergence, temperature,
    log surface pressure, water vapor, cloud liquid water, cloud ice.
    Model output variable names are not needed, just a generic
    descriptive name (e.g., temperature, northward and eastward wind
    components, etc.): N/A

4.  name, terse descriptions, and references (journal articles, web
    pages) for all major parameterizations. Include, as appropriate,
    descriptions of:

    a.  clouds: Prognostic equations for the water phases (vapor,
        liquid, ice), bulk cloud microphysics (Lohmann and Roeckner,
        1996), relative humidity based cloud cover parameterization. The
        microphysics scheme includes phase changes between water
        components and precipitation processes (autoconversion,
        accretion, aggregation). Evaporation/sublimation of rain/snow
        and melting of snow are considered as well as sedimentation of
        cloud ice.

    b.  convection: Mass flux scheme for shallow, mid-level and deep
        convection (Tiedtke, 1989) with modifications for deep
        convection according to Nordeng (1994). The scheme is based on
        steady state equations for mass, heat, moisture, cloud water and
        momentum for an ensemble of updrafts and downdrafts including
        turbulent and organized entrainment and detrainment. Cloud water
        detrainment in the upper part of the convective updrafts is used
        as source term in the stratiform cloud water equations. For deep
        convection, an adjustment-type closure is used with convective
        activity expressed in terms of convective available potential
        energy.

    c.  boundary layer: Surface fluxes are computed from bulk
        relationships with transfer coefficients according to
        Monin-Obukhov similarity theory. Transpiration is limi ted by
        stomatal resistance and bare soil evaporation by the
        availability of soil water. Eddy viscosity and diffusivity are
        parameterized in terms of turbulent kinetic energy and length
        scales involving the mixing length and stability functions for
        momentum and heat, respectively (Brinkop and Roeckner, 1995).

    d.  SW, LW radiation: The SW scheme (Fouquart and Bonnel, 1980) uses
        the Eddington approximation for the integration over zenith and
        azimuth angles and the delta-Eddington approximation for the
        reflectivity of a layer. The scheme includes Rayleigh
        scattering, absorption by water vapor, ozone, and well-mixed
        gases. The scheme has four spectral bands, one for visible+UV
        range, and three for the near infrared. (TAR = one for near
        infrared). Single scattering properties of clouds are determined
        on the basis of Mie calculations using idealized size
        distributions for cloud droplets and ice crystals. The LW (RRTM)
        scheme (Mlawer et al., 1997), is based on the correlated-k
        method. Absorption coefficients were derived from the LBLRTM
        line-by-line model (Clough et al., 1989) and include the effect
        of the CKD2.2 water vapor continuum. The RRTM scheme computes
        fluxes in the spectral range 10 cm**^-1^** to 3000 cm**^-1^**.
        The computation is organized in 16 spectral bands and includes
        line absorption by water vapor, ozone and well-mixed gases. For
        cloud droplets, the mass absorption coefficient is a function of
        the respective effective radius with coefficients independent of
        wavenumber as obtained from a polynomial fit to the results of
        Mie calculations. For ice clouds, an inverse dependency of the
        mass absorption coefficient on the ice crystal effective radius
        is assumed and the coefficients vary with wavenumber (Ebert and
        Curry, 1992).

    e.  any special handling of wind and temperature at top of model:
        Gradual increase of the horizontal diffusion coefficients in the
        top 5 layers.

    f.  gravity wave drag: The scheme (Lott and Miller, 1997) takes into
        account two main mechanisms of interaction between subgrid-scale
        orography and the atmospheric flow: momentum transfer from the
        earth to the atmosphere accomplished by orographic gravity
        waves, and the drag exerted by the subgrid-scale mountain when
        the air flow is blocked at low levels.

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B.  Ocean (Marsland et al., 2003)

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1.  resolution: 1.5 deg, conformal mapping grid with grid poles over
    Greenland and Antarctica, 40 vertical levels

2.  numerical scheme/grid, including advection scheme, time-stepping
    scheme, vertical coordinate, free surface or rigid lid, virtual salt
    flux or freshwater flux: C-grid, semi-implicit solver for barotropic
    part, free surface, fresh water flux, z-coordinate with partial
    cells.

3.  list of prognostic variables and tracers: u, v, w, t, s, surface
    elevation

4.  name, terse descriptions, and references (journal articles, web
    pages) for all parameterizations. Include, as appropriate,
    descriptions of:

    a.  eddy parameterization: Gent et al., 1995; Griffies, 1998.

    b.  bottom boundary layer treatment and/or sill overflow treatment:
        Beckmann-Doescher like BBL parameterization with modifications
        (Marsland et al., 2003).

    c.  Tracer advection: Sweby et al., 1984

    d.  Isopycnal diffusion**:** Redi, 1982

    e.  mixed-layer treatment: Vertical eddy viscosity and diffusion:
        Richardson-number dependent scheme of Pacanowski and Philander
        (1981). Additional wind mixing parameterization included. Wind
        stirring near the surface is proportional to the cube of the 10
        m wind speed and decays exponentially with depth.

    f.  sunlight penetration: exponential decay, constant e-folding
        depth.

    g.  tidal mixing: N/A

    h.  river mouth mixing: N/A

    i.  mixing isolated seas with the ocean N/A

    j.  treatment of North Pole \"singularity\": Pole rotation

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C.  sea ice

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1.  horizontal resolution, number of layers, number of thickness
    categories: same horizontal resolution as ocean, one layer (plus
    snow), one ice category.

2.  numerical scheme/grid, including advection scheme, time-stepping
    scheme: C-grid as in ocean, implicit, upwind advection

3.  list of prognostic variables: ice thickness, ice concentration, ice
    velocities (u,v), snow depth

4.  completeness (dynamics?: YES rheology?: Hibler, 1979,
    thermodynamics: Semtner, 1976. Leads?: YES snow treatment on sea
    ice?: one snow layer, conversion of snow to ice)

5.  treatment of salinity in ice: constant sea ice salinity (5psu)

6.  brine rejection treatment: YES

7.  treatment of the North Pole \"singularity\" (filtering, pole
    rotation, artificial island?): as in ocean component: pole rotation

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D.  land / ice sheets (some of the following may be omitted if
    information is clearly included in cited references.

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1.  resolution (tiling?), number of layers for heat and water: The
    resolution is the same as for the atmosphere (no tiling). 5 layers
    for heat, 1 layer for water (bucket).

2.  treatment of frozen soil and permafrost: No special treatment of
    frozen soil, no permafrost.

3.  treatment of surface runoff and river routing scheme: Surface runoff
    and drainage depend on the heterogeneous distribution of field
    capacities within a grid-cell (Dümenil and Todini, 1992). The
    hydrological discharge is computed at a resolution of 0.5° (Hagemann
    and Dümenil Gates, 2001). Overland flow (fed by surface runoff) and
    riverflow are both represented by a cascade of n equal linear
    reservoirs, and baseflow (fed by drainage and grid box inflow) is
    represented by a single linear reservoir.

4.  treatment of snow cover on land: The snow cover is a function of
    snow depth and slope of terrain approximated by the subgrid-scale
    standard deviation of height. The snow cover of the canopy is
    defined as the ratio of snow depth at the canopy and the
    interception capacity which is a function of the leaf area index
    (Roesch et al., 2001)

5.  description of water storage model and drainage. Changes in soil
    water due to rainfall, evapotranspiration, snow melt surface runoff,
    and drainage are calculated for a single bucket with geographically
    varying field capacity. The amount of drainage is governed by the
    ratio of soil water and field capacity.

6.  surface albedo scheme: The albedo of snow and ice depends on surface
    temperature. Over snow covered land, the mean albedo of a grid-cell
    depends on fractional forest area, leaf area index, bare soil
    albedo, snow albedo, fractional snow cover at both ground and canopy
    and slope of terrain (Roesch et al, 2001). Ground albedo is obtained
    from allocation to global ecosystem types blended with satellite
    data over desert regions (Hagemann, 2002).

7.  vegetation treatment (canopy?) Vegetation cover, leaf area index,
    and forest fraction are prescribed for every month (Hagemann, 2002).

8.  list of prognostic variables: Soil temperature, snow at the canopy,
    snow at the surface, liquid water at the canopy, and soil water.

9.  ice sheet characteristics (How are snow cover, ice melting, ice
    accumulation, ice dynamics handled? How are the heat and water
    fluxes handled when the ice sheet is melting?) Ice sheets are
    prescribed. There is neither melting nor accumulation of snow, i.e.
    (snowfall-sublimation) is transferred to the ocean.

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E.  coupling details

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1.  frequency of coupling: daily (atmosphere and ocean/sea ice)

2.  Are heat and water conserved by coupling scheme? yes

3.  list of variables passed between components:

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a.  atmosphere -- ocean: heat, freshwater, momentum, 10m wind speed,
    solar radiation, sea surface temperature, ocean surface current (u,v
    components)

b.  atmosphere -- land: single system (no flux coupler used)

c.  land -- ocean: water flux to ocean (also from ice sheets)

d.  sea ice -- ocean: single system (no flux coupler used)

e.  sea ice -- atmosphere: conductive heat flux, residual heat flux
    (used for melting of sea ice), snowfall-sublimation, momentum, sea
    ice concentration, sea ice thickness, snow depth on ice, ice
    velocity (u,v components)

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4.  Flux adjustment? (heat?, water?, momentum?, annual?, monthly?). No

# Simulation Details (report separately for each IPCC simulation contributed to database at PCMDI):

A.  IPCC \"experiment\" name: PIcntrl

B.  Initialized at year 300 of an experiment with a similar (but not
    identical) model version and present-day greenhouse gas
    concentrations. The model was then run for another 144 years (with
    minor changes) under pre-industrial conditions until it was 'frozen'
    in model year 2122 (note that only model years 2150-2655 are
    available in the database).

C.  Well-mixed greenhouse gases (CO2, CH4, N2O) are constant (year
    1860). Present-day ozone climatology (Fortuin and Kelder, 1998) and
    background aerosol (Tanre et al., 1984) is applied.

D.  IPCC \"experiment\" name: 20C3M

E.  Jan 2190 from PIcntrl (run1), Jan 2015 from PIcntrl (run2), Jan 2040
    from PIcntrl (run3)

F.  There are only anthropogenic forcings, i.e., CO2, CH4, N2O, F11
    (effective), F12, ozone (Kiehl et al., 1999), and sulfate
    (<http://www-loa.univ-lille1.fr/~boucher/sres/>). Anthropogenic
    ozone is defined as the difference between the actual value in the
    respective year and the 'pre-industrial' value (year 1870).

G.  IPCC \"experiment\" name: Commit

H.  Continuation of 20C3M (runs1,2,3)

I.  Concentrations as in 20C3M, but kept constant (year 2000) throughout
    the simulations

J.  IPCC \"experiment\" name: SRESA2

K.  Continuation of 20C3M (runs1,2,3)

L.  CO2, CH4, N2O, F11 (effective), F12, anthropogenic ozone
    (stratosphere only), and anthropogenic sulfate
    (<http://www-loa.univ-lille1.fr/~boucher/sres/>).

M.  IPCC \"experiment\" name: SRESA1B

N.  Continuation of 20C3M (runs1,2,3)

O.  CO2, CH4, N2O, F11 (effective), F12, anthropogenic ozone
    (stratosphere only), and anthropogenic sulfate
    (<http://www-loa.univ-lille1.fr/~boucher/sres/>). Constant
    concentrations after year 2100

P.  IPCC \"experiment\" name: SRESB1

Q.  Continuation of 20C3M (runs1,2,3)

R.  CO2, CH4, N2O, F11 (effective), F12, anthropogenic ozone
    (stratosphere only), and anthropogenic sulfate
    (<http://www-loa.univ-lille1.fr/~boucher/sres/>). Constant
    concentrations after year 2100

S.  IPCC \"experiment\" name: 1%to2x

T.  Jan 2190 from PIcntrl (run1), Jan 2015 from PIcntrl (run2), Jan 2040
    from PIcntrl (run3)

U.  1% increase of CO2 per year until CO2 doubling (model year 1930) and
    stabilization thereafter (until model year 2080)

V.  IPCC \"experiment\" name: 1%to4x

W.  Jan 2030 from 1%to2x (run2)

X.  1% increase of CO2 per year until CO2 quadrupling (model year 2000)
    and stabilization thereafter (until model year 2150)

Y.  IPCC \"experiment\" name: Slabcntl

Z.  Jan 1978 from AMIP (run1) including precalculated Q-flux from AMIP
    (run1)

A.  Well-mixed greenhouse gases (CO2, CH4, N2O, F11, F12) are constant
    (year 1985). Present-day ozone climatology (Fortuin and
    Kelder, 1998) and background aerosol (Tanre et al., 1984) is
    applied.

B.  IPCC \"experiment\" name: 2xCO2

C.  Jan 1978 from AMIP (run1) including precalculated Q-flux from AMIP
    (run1)

D.  Instantaneous CO2 doubling w.r.t. Slabcntl (model years 2001-2100 in
    database)

E.  IPCC \"experiment\" name: AMIP

F.  Jan 1978 (observed) for all 3 runs. Initial perturbations in runs2,3
    are realized by small changes in the horizontal diffusion
    coefficients during the first month.

G.  Well-mixed greenhouse gases (CO2, CH4, N2O, F11, F12) are constant
    (year 1985). Present-day ozone climatology (Fortuin and
    Kelder, 1998) and background aerosol (Tanre et al., 1984) is
    applied.

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