Program for Climate Model Diagnosis and Intercomparison
Lawrence Livermore National Laboratory
E-mail: covey1@llnl.gov
3 November 2003
Introduction
The following list of standard output for the CMIP "20th Century Climate in Coupled Models" pilot project (20C3M; see ann_20c3m.html) assumes that output is produced in network Common Data Form (netCDF; see http://www.unidata.ucar.edu/packages/netcdf) and that the NetCDF Climate and Forecast (CF) Metadata Conventions (see http://www.cgd.ucar.edu/cms/eaton/cf-metadata) are followed. Use of netCDF and adherence to the CF convention are required for future contributions to CMIP and will be followed in future releases of CMIP data.
The NetCDF software library is maintained by the Unidata Program Center in Boulder, Colorado, under sponsorship of the University Corporation for Atmosphere Research; the Climate Data Analysis Tools (CDAT) software infrastructure (see http://esg.llnl.gov/cdat) also supports netCDF. NetCDF is now the most common format for exchange of ocean-atmosphere model output. The new CF conventions for netCDF data generalize and extend the Cooperative Ocean / Atmosphere Research Data Service (COARDS) conventions developed in the 1990s.
Output fields
| CF Standard name | PCMDI name | Units | |
|---|---|---|---|
| 1 | air_pressure_at_sea_level | psl | Pa |
| 2 | precipitation_flux | pr | kg m-2 s-1 |
| 3 | air_temperaturea | tas | K |
| 4 | sea_surface_elevation | m | |
| 5 | sea_surface_temperature | K | |
| 6 | sea_ice_area_fraction | sic | (dimensionless fraction) |
| 7 | sea_ice_thickness | sit | m |
| 8 | moisture_content_of_soil_layerb | mrsos | kg m-2 |
| 9 | soil_moisture_contentc | mrso | kg m-2 |
aAlso known as "surface air temperature." Distinguish from 3-D air temperature by specifying a size-one dimension of height with coordinate value 2 m.
bIn the upper 0.1 m only.
cTotal for all soil layers.
| CF Standard name | PCMDI name | Units | |
|---|---|---|---|
| 1 | cloud_area_fraction_in_atmosphere_layer | cl | (dimensionless fraction) |
| 2 | air_temperatured | ta | K |
| 3 | sea_water_temperature | to | K |
| 4 | sea_water_salinity | so | ppt (parts per thousand) |
dOn AMIP standard pressure levels (= NCEP reanalysis levels): 1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10 hPa.
| CF Standard name | PCMDI name | Units | |
|---|---|---|---|
| 1 | air_pressure_at_sea_level | psl | Pa |
| 2 | precipitation_flux | pr | kg m-2 s-1 |
| 3 | air_temperaturea, e | tasmin | K |
| 4 | air_temperaturea, f | tasmax | K |
aAlso known as "surface air temperature." Distinguish from 3-D air temperature by specifying a size-one dimension of height with coordinate value 2 m.
eDaily minimum value. Designate by a cell_methods attribute specifying "time: minimum within days," where "time" is the name of the time dimension.
fDaily maximum value. Designate by a cell_methods attribute specifying "time: maximum within days," where "time" is the name of the time dimension.