PMIP 2 Preliminary Variables' Study

WARNING! The official variables' list is available in the Design/Variables section!

Problems

• Define a list of standard variables/diagnostics that the models should generate and specify what variables are mandatory, recommanded or optional.
• Define standard units (and scaling factors) and sign conventions.
• Define standard variables' names. Try to define names in such a way that related variables have names that will be grouped together when sorted alphabetically (follow the AMIP naming convention?).
• Define standard file names and number/types of variables stored in the files.
• Define the number/types of levels for 3D variables
  
  AMIP: 17 WMO standard pressure levels compatible with reanalysis products: 1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50,30, 20, 10 hPa.
  
  AMIP/GRIPS: for those groups participating in GRIPS, the following levels are also encouraged: 15, 7, 5, 3, 2, 1.5, 1, 0.5 hPa.
   
• Define the length of the runs.
• Define the frequency of the means (yearly/seasonaly/monthly/daily/6-hourly)
  
  AMIP 6-hourly: 0, 6, 12, 18Z
   
• Define what meta-variables should be supplied along with the standard variables: land/sea mask, regions' masks.
• Make sure everybody agrees to use netCDF file format, and define what conventions should be used (GDT/COARDS? CF? subset of GDT/CF?)
• Try to find the best conventions to make the future use of CVS/DODS/agregation with CDML/etc... possible
• Determine the size required to store 1 time step of a 2D variable for each model, so that total storage space can be estimated.
• Decide if diagnostics that can be computed/derived from existing diagnostics in the database should be included in the base or not. If they are included, should they be supplied by the models' contact persons or computed by the person responsible for the database?
• Decide if variables' variances should be supplied.

AMIP

Official AMIP home page

Data format

The data files are in netCDF format with the COARDS convention, or GRIB format, and were created with the LATS library.

Variables

AMIP II Standard Model Output

WGNE Standard Diagnostics of Mean Climate

Variables' naming conventions

Acronyms

WGNE: JSC/CAS Working Group on Numerical Experimentation

CAS: Commission for Atmospheric Sciences

CMIP

Official CMIP home page

Variables

The fields required by CMIP1 and CMIP2 are listed in the Diagnostic Subproject page.  

GLASS

Official GLASS home page

Variables

The variables follow the ALMA data exchange convention.

ALMA Standard Model Output.

Acronyms

GLASS: Global Land Atmosphere System Study

ALMA: Assistance for Land Surface Modeling Activities

IPCC

Official IPCC home page

Official IPCC Data Distribution Centre home page

Data format

The files are in FM 92 GRIB and zip format. The file formats/nomenclature are described in:

• DDC GCM Data File format
.
• SRS Scenario Runs: is there a list of required variables (and the associated units)? A list can be obtained by following the links in the Survey of available SRES Scenarion Runs page
.
• Scenario Download files' format
.
• Observed Climate Download files' format
.

Acronyms

DDC: Data Distribution Centre

Documents

An Introduction to Simple Climate Models used in the IPCC Second Assessment Report: IPCC Technical Paper II

Guidelines On The Use Of Scenario Data For Climate Impact And Adaptation Assessment: pdf Guidance Document

Variables

The variables mentioned on the DDC web site are listed in the PMIP 2 and IPCC variables page. The GCM data requested by the IPCC DDC is also detailed in ipcc_variables.doc.  

OCMIP

Official OCMIP home page

Data format

The data files are in netCDF format and follow the COARDS convention (check also this link), with the GDT extension.

Variables

The requested variables depend on the simulation and are described in the HOWTO pages. The following table gives shortcuts to the HOWTO documents.

PMIP

Official PMIP home page.

Data format

The data files are in netCDF format and loosely follow the COARDS convention (check also this link). You can get more details in the PMIP File Formats page.

Variables

The different types of variables required in the PMIP projects are described here.