Scenario Files


We include climate scenarios from eight climate change experiments in the database. Seven of these experiments are from atmospheric general circulation model (GCM) 1xCO2 and 2xCO2 equilibrium runs. These GCMs were implemented with a simple "mixed-layer" ocean representation that includes heat storage and vertical exchange of heat and moisture with the atmosphere but omits or specifies rather than calculates horizontal ocean heat transport. The eighth scenario is from a limited-area nested regional climate model (RegCM) experiment for the U.S. which was supported by the MECCA project. The CCC and GFDL R30 runs are among the high resolution GCM experiments reported in IPCC (1990).

Changes in monthly mean temperature and relative humidity were represented as differences and those for monthly precipitation, solar radiation, vapor pressure and horizontal wind speed as change ratios. GCM grid point change values were derived from archives at the National Center for Atmospheric Research (NCAR; Jenne 1992) and spatially interpolated to the 0.5 VEMAP degree grid. 60-km RegCM grid values were reprojected to the 0.5 degree grid. This provided smoothed monthly change fields that were applied to the VEMAP base climate to generate altered-climate inputs. We determined differences for relative humidity based on the VEMAP base climate and climate changes for temperature, vapor pressure, and surface pressure. Vapor pressure (and relative humidity) were not available for the CCC run.

o User's Guide

Each subdirectory from this level contains files from runs of various climate models.

The files within each directory are named according to the protocol VV_GGG.MMM where VVV is the variable name, GGG the climate model name and MMM the month.

The scaling factor is the factor by which the data were multiplied before they were put into the files. To get the values back into the units described in the file header, you need to divide the values in the files by the scaling factor.

For example, temperature is given in units of degrees C and has a scaling factor of 10. This means that a value in the file of 56 is actually 5.6 C.


A description of how to use the SVF format files is presented here. Included in this description are methods for transforming information between the formats of lat/lon, gridpoint, and file position. The file is also available in downloadable format:



o P
Precipitation [change ratio: 2xCO2/1xCO2]
Scaling factor: 1000
o RH
Relative humidity [change difference: 2xCO2 - 1xCO2][%]
Scaling factor: 10
o SR
Total incident solar radiation [change ratio: 2xCO2/1xCO2]
Scaling factor: 1000
o T
Surface air temperature [change difference: 2xCO2 - 1xCO2][C]
Scaling factor: 10
o VP
Surface vapor pressure [change ratio: 2xCO2/1xCO2] Not available for CCC.
Scaling factor: 1000
o W
Surface wind speed [change ratio: 2xCO2/1xCO2]
Scaling factor: 1000


Canadian Climate Centre. High resolution GCM experiment. (Boer, McFarlane, and Lazare 1992)
Goddard Fluid Dynamic Lab R15 4.5 x 7.5 degree grid runs with Q-flux corrections. (Manabe and Wetherald 1990, Wetherald and Manabe 1990)
o GFDL R15
R15 4.5 x 7.5 degree grid runs without Q-flux corrections. (Manabe and Wetherald 1987)
o GFDL R30
R30 2.22 x 3.75 degree grid run. High resolution GCM experiment. (Manabe and Wetherald 1990, Wetherald and Manabe 1990)
Goddard Institute for Space Studies. (Hansen et al. 1984)
o MM4
Nested climate model based on Pennsylvania State University/NCAR Mesoscale model MM4. Driven by 1xCO2 and 2xCO2 GCM runs. (RegCM, Giorgi et al. 1994)
Oregon State University. (Schlesinger and Zhao 1989)
("UKLO" low resolution run, Wilson and Mitchell 1987)
UK Meteorological Office model.


Month name abbreviated to three letters e.g. jan, feb, mar, or could also be 'ann' for annual change fields.


The files are grouped by model. Click on the model you are interested in for a complete listing:


o ccc
o gfdl_qflux.
o gfdl_r15
o gfdl_r30
o giss
o mm4
o osu
o ukmo

The files are also available in tared and compressed format, grouped by variable and model. These are exactly the same files as those listed above, just in a different format.

o All Scenario Files

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