History of Changes Made to IPCC Standard Output

16 October 2007:

1. Corrected notes for entry 44 in table A1a (clivi) to indicate that only the solid-phase water (not the liquid or vapor)should be considered in calculating the atmosphere cloud ice content.

15 September 2005:

1. Added accommodation for the hybrid height coordinate, which appears in the Hadley Centre models. Also included depth coordinate for ocean fields, which had been previously inadvertently omitted.

7 December 2004:

1. Added the following clarification for the global_average_thermosteric_sea_level_change: "In a rigid-lid model this quantity can be calculated by using a reference 3D salinity field to compute density as the 3D temperature field evolves."

2. Added a recommendation that daily mean data be computed for intervals beginning at midnight, i.e., 0 Z (UTC), and ending the following midnight at 0 Z.

22 November 2004:

1. Replace occurrences of zostogm with zostoga and zosgm with zosga.

17 November 2004:

1. Clarified how zos should be computed.

2. Added zostoga and zosga to list of high priority output variables (Table O1c).

3. Added to Table O1d the "qflux" as a high priority field for slab ocean experiments.

4. Added monthly-mean tasmin and tasmax to Table A1f.

5. For mrfso, indicated explicitly in the comment column that it was frozen water only that should be considered.

6. Expanded descriptions of clwvi and clivi.

7. Indicated that ISSCP simulator output should be generated from data sampled no less frequently than every 15 hours.

8. Noted that htovgyre and htovovrt should exlcude 'bolus velocity' contributions from the Gent-McWilliams parameterization; further noted that htovdiff and hfogo should include any 'bolus velocity' contribution.

9. Specified that in calculating wfo, zos, and zobt, only the ocean portion of each grid cell should be considered.

10. Changed 'atmospheric_boundary_layer_thickness' to 'atmosphere_boundary_layer_thickness'.

11. We now request that in identifying forcing agents (table A5) the term that is "most specific", not "most general" should be used (e.g., if the only anthropogenic effect included in the model simulation is an increase in carbon dioxide, use "co2", not "a" or "g").

12. Corrected the cell_methods attribute associated with the time-dimension for daily maximum and minimum surface air temperature.

30 September 2004:

1. Corrected length of first ensemble member requested for the 550 ppm stabilization experiment (SRES B1): changed last year from 2200 to 2300.

2. Added 20 year interval to the daily data requested for each of the 1%/yr CO2 experiments: 20 years centered on time of doubling for doubling experiment. and 20 years centered on time of quadrupling for the quadrupling experiment.

3. Included a table of contents with links to sections of the document.

15 September 2004:

1. Noted that 3-hourly precipitation data should be averaged over the intervals 0-3Z, 3-6Z, ... 21-24Z, whereas the "snapshots" should be sampled at 0, 3, 6, ... 21Z.

2. Noted that stfmmc should exclude 'bolus velocity' contribution from the Gent-McWilliams parameterization.

3. Clarified that all time intervals in the last table of experiments should be interpreted as extending from the beginning of the first year indicated through the end of the last year indicated. For example, years 1961-2000 means 0Z 1-1-2000 through 0Z 1-1-2001.
4. Added a row to the coordinate dimension table for 'time1' which is needed in the 3-hourly table (A3) to define the time axis for "snapshot" (rather than time-mean) data (i.e., all but the precipitation field in this table).

3 September 2004:

Revised web links to be consistent with new PCMDI web site.

25 August 2004:

1. Clarified in the last table that yearly data (i.e., extreme indices) should be submitted for the same years as the monthly data.

2 August 2004:

1. Changed period for which 3-hourly data should be reported in the "pre-industrial control experiment" from "last year" to "last year of reported daily data (i.e., corresponding to year 2000 of the 20C3M expt.)".

2. Modified description of a few fields to make them clearer.

20 July 2004:

1. Changed years requested for the committed climate change experiment from tables A2a,b to be consistent with other experiments (i.e., 2046-2065, not 2031-2050).

19 July 2004:

1. Changed one of the experiment names in the last table of the document: 'climate of the 20th Century (20C3M)' was changed to 'climate of the 20th Century experiment (20C3M)'.

14 July 2004:

1. Added table of experiments and years of requested data.

2. Moved dimension table to near the end of the document.

3. Noted that "flux-correction" fields need to be reported only for a single year, assuming it applies to all experiments.

4. Noted that disk space constraints will likely limit quick access to monthly-mean 3-d ocean output to a single member of each ensemble.

5. Noted that daily data should only be reported for a single member of each ensemble, except for the surface air temperature (mean, max. and min.) and precipitation, which should be reported for all members.

5 July 2004:

1. The requested fields listed under "Highest priority output fields" were not changed, but some of the information given there was modified.
2. The "PCMDI names" are now identified as "output variable names", because these are the variable names that should appear in the netCDF files. These also serve as unique reference names for CMOR. Several names were changed in this version to make them consistent with the existing CMIP data base: ssh ==> zos, sst ==> tos, siu==>usi, siv==>vsi, prme==>wfo, sftbaro==>stfbarot, topot==>thetao, and rhopot==>rhopoto
3. The following units were changed: for ocean meridional overturning stream function, kg3 s-1 ==> m3 s-1. for ocean barotropic stream function, kg3 s-1 ==> m3 s-1. For several variables, percent ==> % (nb. CMOR will accept "percent" as an alias for "%", but the netCDF file will show "%").
4. A few corrections were made to the "standard_names"
5. The "source" column in the tables was replaced by a "notes" column providing explanatory information. These notes should be studied carefully to ensure conformance with IPCC requirements.
6. Dimensionless units are now expressed simply as a numeric factor (e.g., '1' or '1e-3') or as '%', but not as a dimensionless ratio (e.g., 'kg/kg').
7. Tables were constructed and detailed information was provided (for the first time) for the "Lower priority fields" (previously identified as "optional")..
8. The following lower priority fields were eliminated: sea surface salinity (already collected as part of the 3-d salinity field), the vertical and horizontal components of temperature and salinity fluxes as a function of longitude, latitude, model layer, and month (this was the only field requested on model levels and is difficult to treat uniformly; interpolating to depth levels would make it impossible to treat precisely and might not be any better an approximation than multiplying velocity times salinity or temperature, which is possible from fields collected as high priority), temperature on all sea ice model levels (too difficult to uniformly treat sea ice models with different vertical coordinates, and although this field would be useful for energy budget studies, other terms in the budget are not being collected), surface snow thickness (already collected as high priority field), "tendency of sea ice thickness due to thermodynamics" (of little value without all the other terms needed to balance the sea ice equation), and certain land surface fields, including total heat storage, albedo, soil types, vegetation fraction etc (difficult to define uniformly across models).
9. A table with dimension information was added.