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GCM Data File Format

Nomenclature

The files have been given an eight letter prefix and three letter suffix to make them compatible with all computers and media, thus the filename structure is:

AACCD122.xxx

AA = Experiment: EE = ECHAM4; HH = HadCM2; GG = GFDL-R15; AA=CSIROMK2; CC = CCCMA; NN=NCAR-DOE and JJ=CCSR/NIES
CC = Forcing Details: GG = Greenhouse Gas; GS = Greenhouse Gas and Aerosols
D= Scenario Details: A = 1% per annum (IS92a); D = 0.5% per annum (IS92d)
1 = Ensemble Member 1,2,3 or 4. X = Ensemble Mean
22 = Timeslice: 61 = 1961-1990; 20 = 2010-2039 (i.e. the 2020's); 50 = 2040-2069 (i.e. the 2050's);80 = 2070-2099 (i.e. the 2080's);
xxx= Variable Code CLD = Cloud
DTR = Diurnal Temperature Range
PRE = Precipitation
RAD = Radiation
TMP = Mean Temperature
TMX = Maximum Temperature
TMN = Minimum Temperature
VAP = Vapour Pressure
WND = Wind
zip = Zipped file

Examples, therefore are:

EEGGA120.TMP represents Mean temperature change for the period 2010-2039 under IS92a Greenhouse Gas forcing scenario using ECHAM4.

HHGSD461.PRE represents Precipitation from ensemble member 4 for the period 1961-1990 under the IS92d greenhouse gas and sulphate forcing scenario using HadCM2.

GCM Grid Details - For the download files from the Green Pages

ECHAM4 
Spectral Model
T42 Resolution
Grid 128*64
Approximates to 2.8125 x 2.8125 degrees
Starting Grid Cell Centred on: 0.00ºE 87.8638ºN
Grid Details
HadCM2 
Grid Box Model
Grid 96*73
3.75 x 2.5 degrees
Staring Grid Cell Centred on 0.00ºE 90.0ºN
Grid Details
GFDL-R15 
Spectral Model
R-15 Resolution
Grid 48*40
Approximates to 7.5 x 4.5 degrees
Starting Grid Cell Centred on 0.00ºE 86.598ºN
Grid Details
CGCM1 
Spectral Model
T32 Resolution
Grid 96 *48
Approximates to 3.75 x 3.75 degrees
Starting Grid Cell Centred on: 0.00ºE 87.1591ºN
Grid Details
 
CSIRO-Mk2b
Spectral Model
R21 Resolution
Grid 64*56
Approximates to 5.625 x 3.214 degrees
Starting Grid Cell Centred on: 0.00ºE 87.5613ºN
Grid Details
NCAR-DOE
Spectral Model
R-15 Resolution
Grid 48*40
Approximates to 7.5 x 4.5 degrees
Starting Grid Cell Centred on 0.00ºE 86.598ºN
Grid Details
CCSR/NIES
Spectral Model
T21 Resolution
Grid 64x32
Approximates to 5.625x 5.625 degrees
Starting Grid Cell Centred on: 0.00ºE 85.761ºN
Grid Details 
   

Data Format

The format of the Scenario Download files is as follows. There is a six line header for each month, the codes for the header fields in italics (e.g. Model Name) are given below. The following is an example of the structure of the scenario data files.

 

IPCC-Data-Distribution-Centre-ModelName-Results---Date

Grid-is-xxx-*-yyy----Month-is-Jan

Mean-Change-values-for-year-year-with-respect-to-1961-1990

ForcingDetails---ExperimentCode

Variable-Name-(Units)

DataItems-----Format is 10f8.2---Missing-Value-is-9999.99

 12.34  12.34  12.34  12.34  12.34  12.34  12.34  12.34  12.34  12.34
 45.67  45.67  45.67  45.67  45.67  45.67  45.67  45.67  45.67  45.67
 .                  
 .                  
 .                  
 .                  

IPCC-Data-Distribution-Centre-ModelName-Results---Date

Grid-is-xxx-*-yyy----Month-is-Feb

Mean-Change-values-for-year-year-with-respect-to-1961-1990

ForcingDetails---ExperimentCode

Variable-Name-(Units)

Data Items-----Format is 10f8.2---Missing-Value-is-9999.99

 .                  
 .                  
 .                  
 .                  

IPCC-Data-Distribution-Centre-ModelName-Results---Date

Grid-is-xxx-*-yyy----Month-is-Dec

Mean-Change-values-for-year-year-with-respect-to-1961-1990

ForcingDetails---ExperimentCode

Variable-Name-(Units)

Data Items-----Format is 10f8.2---Missing-Value-is-9999.99

Codes for header Fields

Model Name ECHAM4  
  HadCM2  
  GFDL-R15  
  CCCMA  
  CSIRO-Mk2b  
  NCAR-DOE  
  SELECTION-->CCSR/NIES /SELECTION-->  

Grid - Number of x Co-ordinates and Number of y Co-ordinates (e.g. 96 x 73)

Month - Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec

Year- Year - time slice data are for, e.g., 2010-2039

NOTE: For the period 1961-1990 the data are the actual values, for the 2010-2039, 2040-2069 and 2070-2099 the data are the changes with respect to the 1961-1990 period.

Forcing Details - GG = Greenhouse Gas: GS = Greenhouse Gas and Sulphate Aerosols; A = 1% per annum (IS92a); D= 0.5% per annum (IS92d); 1, 2, 3 or 4 represents the ensemble member or X = Ensemble mean.

Experiment Code -Refers to the first six characters of the file name (i.e., AACCD1)

Data Items - The product of xxx*yyy (e.g. 7008)

 

Content last modified: 02 April 2014