Modeled Global Climate Data from the Hadley Centre HadCM3

The Hadley Centre for Climate Prediction and Research HadCM3 global coupled atmosphere-ocean GCM was used to run simulations of 20th century climate and projections of climate into the 21st century. The atmospheric component of the model has 19 levels with a horizontal resolution of 2.5 degrees of latitude by 3.75 degrees of longitude, which produces a global grid of 96 x 73 grid cells. The oceanic component of the model has 20 levels with a horizontal resolution of 1.25 x 1.25 degrees. At this resolution it is possible to represent important details in oceanic current structures. A more complete model description along with a list of references can be found at the IPCC DDC web site.

The ISA92 and similar scenario experiments conducted with HadCM3 include a 240 year control simulation in which the atmospheric forcing is kept constant; a greenhouse gas integration with historical and IS95a forcing, with specification of CO2 and various minor gases individually; and an all anthropogenic forcing integration in which the greenhouse gas forcing is increased gradually to represent the observed changes in forcing due to all the greenhouse gases plus the direct and first indirect effect of sulphate aerosols, and ozone changes.

SRES scenario experiments were also conducted with HadCM3 and the results are available from IPCC DDC. The IPCC published a Special Report on Emissions Scenarios (SRES) in 2000. This report describes the new set of emissions scenarios used in the Third Assessment Report. The SRES A2 scenario envisions population growth to 15 billion by the year 2100 and rather slow economic and technological development. It projects slightly lower GHG emissions than the IS92a scenario, but also slightly lower aerosol loadings, such that the warming response differs little from that of the earlier scenario. The SRES B2 scenario envisions slower population growth (10.4 billion by 2100) with a more rapidly evolving economy and more emphasis on environmental protection. It therefore produces lower emissions and less future warming. Climate change results based on the A2 and B2 scenarios are discussed in the IPCC Third Assessment Report.

The monthly mean time series from these simulations can be obtained from the DDC Global Climate Model (GCM) Archive hosted at the German Climate Computing Centre (DKRZ), Hamburg. Monthly time series ranging from 1860 to 2099 for each simulation are available for the following variables: total downward shortwave flux, at surface (W/m**2), mean sea level pressure (Pa), total precipitation (mm/day), 1.5m relative humidity (%), 1.5m air temperature (K), and 10m wind
speed (m/s). The web site allows users to download data files from the DDC in two formats, GRIB (machine independent, self-descriptive binary format, WMO standard) and GZIP (compressed ASCII format). Documentation on data format and
information on extracting and reading the data are also available. Additional variables and resolutions are available through the Climate Impacts LINK Project web site at [http://www.cru.uea.ac.uk/link/].