ICRCCM III Procedure and Data Files

Step 1: retrieve the data files

  • The following files contain the profiles necessary to run the cases. To download them, simply use the "save as" option from your browser's menu after clicking on the file name.
    • Clear-sky reference and homogeneous cloud cases
      • STANDARD_TROPICAL (you will need to manually input cloud mixing ratios for the homogeneous cloud cases)
    • CRM fields
    • If you need water vapor mixing ratios at levels, you will have to calculate them. We have provided the file STANDARD_TROPICAL_WV_LEV against which you can compare your results for the standard tropical atmosphere.
    • Here is a legend describing the columns in the 1D data files. As well, some potentially useful comments are given below.

      values at levels:
      ----------------
      - level: altitude at model levels (km) (surface = 0 km)
      - press: pressure (mb)
      - temp: temperature (K)
      - ozone: ozone mixing ratio (g/g)

      mean values for layers:
      ----------------------
      - mid-layer: altitude at mid-layer (km)
      - density: density (kg/m**3)
      - cf_(liq): cloud fraction (liquid)
      - cf_(ice): cloud fraction (ice)
      - cf_(both): cloud fraction (both phases)
      - acf_dn_(liq): downward accumulated cloud fraction (liquid)
      - acf_dn_(ice): downward accumulated cloud fraction (ice)
      - acf_dn_(both): downward accumulated cloud fraction (both)
      - acf_up_(liq): upward accumulated cloud fraction (liquid)
      - acf_up_(ice): upward accumulated cloud fraction (ice)
      - acf_up_(both): upward accumulated cloud fraction (both)
      - mr_(liq): mean cloud mixing ratio (g/kg) (liquid)
      - mr_(ice): mean cloud mixing ratio (g/kg) (ice)
      - mr_(both): mean cloud mixing ratio (g/kg) (both)
      - std_mr_(liq): std. deviation cloud mixing ratio (g/kg) (liquid)
      - std_mr_(ice): std. deviation cloud mixing ratio (g/kg) (ice)
      - std_mr_(both): std. deviation cloud mixing ratio (g/kg) (both)
      - log_mr_(liq): mean log[cloud mixing ratio (g/kg)] (liquid)
      - log_mr_(ice): mean log[cloud mixing ratio (g/kg)] (ice)
      - log_mr_(both): mean log[cloud mixing ratio (g/kg)] (both)
      - wv_mr_(clr): mean water vapour mixing ratio (g/kg) (clear portion)
      - wv_mr_(cld): mean water vapour mixing ratio (g/kg) (cloudy portion)
      - wv_mr_(all): mean water vapour mixing ratio (g/kg) (entire layer)

      Comments:
      --------
      1. Cloud mixing ratios (g/kg) are converted to water contents in g/m^3 by multiplying them by values in the 'density' column.

      2. Water contents are in turn converted to water paths by multiplying by the geometric thickness of each layer in metres (i.e., differences between values in the 'level' column multiplied by 1000 (km -> m)).

      3. Cloud mixing ratios are for the cloudy fraction of a layer; they are NOT averages for the entire layer which would include clear sky.

      4. Conversion of the mean logarithm of mixing ratios (i.e., 'log_mr'), where mixing ratio is g/kg, into mean logarithm of water contents, where water content is in g/m^3, is obtained by: log[density] + log_mr. *** All logarithms are in base e (i.e., natural logarithms) ***

      5. If a value of 'log_mr' is zero and corresponding 'mr' is non-zero, this implies that clouds in that layer are homogeneous.

      6. Mean water vapour mixing ratios for entire layers ('wv_mr (all)') are defined simply as: wv_mr(clr)*[1-cf(both)] + wv_mr(cld)*cf(both).

      7. Note that: cf(both) .le. [cf(liquid) + cf(ice)]. This is because cells in the cloud-resolving model can contain BOTH liquid and ice. As such, the same goes for variables relating to cloud mixing ratios.

      8. The accumulated cloud fractions, both downward ('acf_dn') and upward ('acf_up') provide information regarding cloud overlap. Basically, it is the fractional area of a domain with cloud exposed to space as one progressed from either cloudtop to surface or surface to cloudtop. Like 'cf': acf(both) .le. [acf(liquid) + acf(ice)].

      9. Note that the values of 'acf_dn' and 'acf_up' in the lowest and highest layer, respectively, are identical and equal total cloud amount.

      10. REMEMBER, when doing liquid + ice experiments for the GATE fields, use the columns with headers: cf_(both), acf_dn_(both), acf_up_(both), mr_(both), std_mr_(both), and log_mr_(both).

Step 2: run your code!

Step 3: send us your results (Deadline: December 31, 1999)

  • Participants will return:
    • Up- and down-welling fluxes at all levels (W/m^2).
    • TOA albedo (total up flux at TOA / total down flux at TOA)
    • Surface absorptance (total net flux at surface / total down flux at TOA)
    • Atmospheric absorptance (total absorption by atmosphere / total down flux at TOA)

  • (A) Albedo/Absorptance files - If possible, provide values of TOA albedo, surface absorptance, and atmospheric absorptance for the entire solar spectrum and for values integrated up to ~0.7 microns and beyond ~0.7 microns.

    In the first record of the file, indicate the number of groupings (1 if only the full spectrum, 3 if the full spectrum plus the visible/near-IR partition). The next 20 records should have the cos(SZA) followed by the values as illustrated below.

    3
  0.05      .    .    .      .    .    .      .    .    .
  0.10      .    .    .      .    .    .      .    .    .
   .        .    .    .      .    .    .      .    .    .
   .        .    .    .      .    .    .      .    .    .
   .        .    .    .      .    .    .      .    .    .
  0.95      .    .    .      .    .    .      .    .    .
  1.00      .    .    .      .    .    .      .    .    .

cos(SZA)   a1   a2   a3     a1   a2   a3     a1   a2   a3
           |          |     |          |     |          |
           ------------     ------------     ------------
             0.2 - 5.0      ~0.2 to ~0.7     ~0.7 to ~5.0
              microns          microns          microns

  • (B) Level flux files - For all experiments, provide profiles of fluxes at model levels for only cos(SZA) = 0.25, 0.5, and 1.0. We will compute heating rates if and when need be. Within each file, however, include profiles for all three values of cos(SZA) with the first record being fluxes at the TOA and the last record those at the surface. Thus, the files should look like this: 
    
   ~100         .          .         .          .         .          .
     .          .          .         .          .         .          .
     .          .          .         .          .         .          .
     .          .          .         .          .         .          .
     0          .          .         .          .         .          .

  alt (km)  flux_down  flux_up   flux_down  flux_up   flux_down  flux_up
            |                |   |                |   |                |
            ------------------   ------------------   ------------------
             cos(SZA) = 0.25       cos(SZA) = 0.5       cos(SZA) = 1.0

  • Naming your files - If everyone does all the experiments, we will receive ~600 files. Obviously, it will be much easier for us to process them if a file naming convention is adhered to strictly. Therefore, please name your files as (using UPPER CASE letters):

    [experiment]_[information].[surname]_[model number]

    [experiment]:
    ----------
    CLEAR --> Clear-sky reference
    CLOUD_A --> Homogeneous overcast cloud (low cloud)
    CLOUD_B --> Homogeneous overcast cloud (high cloud)
    GATE_A_L --> GATE (clusters of deep convection; liquid only)
    GATE_B_L --> GATE (tropical squall line; liquid only)
    GATE_C_L --> GATE (scattered trade cumulus; liquid only)
    GATE_A_LI --> GATE (clusters of deep convection; liquid only)
    GATE_B_LI --> GATE (tropical squall line; liquid + ice)
    GATE_C_LI --> GATE (scattered trade cumulus; liquid + ice)
    OPEN_CELLS --> cold air outbreak
    ATEX --> ATEX
    BOMEX --> BOMEX

    [information]:
    -----------
    FL --> level fluxes
    AA --> albedos and absorptances

    [surname]:
    -------
    Simply spell out your last name.

    [model number]:
    ------------
    If you have more than one model entered, identify the model with 1, 2, 3... If you have only one model, set [model number] = 1.

    As an example, if G. Stephens has three models entered, the two file names for his second model's results for GATE with clusters of deep convection (i.e., case a), liquid + ice version would be named:

    GATE_A_LI_FL.STEPHENS_2
    GATE_A_LI_AA.STEPHENS_2

    Likewise, files for his clear-sky references for his first model would be named:

    CLEAR_FL.STEPHENS_1
    CLEAR_AA.STEPHENS_1

  • If you perform all the experiments, you will return 24 files. Please send them, all at once, via ftp to:

    ftp ccrp.tor.ec.gc.ca
    user name: anonymous
    password: your e-mail address
    cd /pub/upload/barker

    Once sent, please notify Howard Barker by e-mail at:

    howard.barker2@ec.gc.ca

    In this notification e-mail, could you also supply a short description of your code including (much of this you already provided but it may have changed over the past year):

    - # of spectral bands
    - type of solution (e.g., two-stream, four-stream...)
    - novelties (e.g., overlap method, effective optical thickness...)
    - basis of gaseous absoprtion and cloud optics parametrizations
    - what your code is used for (e.g., GCM, NWP, personal research...)
    - list of publications that document your code

    Remember, the deadline is December 31, 1999!


This page maintained by Philip Partain at the Colorado State University Department of Atmospheric Science