Modeled Global Climate Data from the Hadley Centre HadCM2

The Hadley Centre for Climate Prediction and Research HadCM2 global coupled climate model was used to run simulations of 20th century climate and projections of climate into the 21st century. HadCM2 has a spatial resolution of 2.5 deg. x 3.75 deg. (latitude by longitude) over both land and ocean. The model resolves 19 levels in the atmosphere and 20 levels in the ocean. Four soil layers are represented in the land surface scheme and the hydrology scheme is based on a single moist layer and allows for both surface runoff and soil
drainage. A penetrative convective scheme is used, modified to include an explicit down-draught. The large-scale precipitation and cloud scheme is formulated in terms of an explicit cloud water variable. The surface albedo is a function of snow depth, vegetation type and, over snow and ice only, temperature. A 1-day coupling cycle between the atmospheric and oceanic components is used, the oceanic component being updated using daily average fluxes of heat, water and momentum from the atmosphere. Prescribed adjustments (flux adjustments) are made to the heat and water fluxes to reduce errors in the simulation of present climate. The climate sensitivity of this model is
approximately 2.5 deg C. References to publications with more specifics on the model structure and simulations can be found at the IPCC DDC web site mentioned below.

The experiments conducted with HadCM2 include a 240 year control simulation (1860 - 2099) with no change in external forcing, a series of four historically forced climate change experiments with high (1% per year) and low (0.5% per year) anthropogenic forcing scenarios with and without the effects of sulphate aerosols, and for each of these four climate change experiments a set of four ensembles with identical forcing but different initial model conditions.

Monthly time-step data from the HadCM2 global coupled model simulations are archived and distributed by the Intergovernmental Panel on Climate Change (IPCC) Data Distribution Center (DDC) at [http://cera-www.dkrz.de/IPCC_DDC/]. Data are available in 30-year mean monthly time slices. Mean monthly values are available for 1961-1990 and monthly mean change fields are available for time slices, 2010-2039, 2040-2069, and 2070-2099. Data are available for the following variables: total cloud cover (fractional coverage), 1.5m diurnal temperature range (degC), total precipitation (mm/day), 1.5 m temperature (degC), 1.5m temperature minimum and maximum (degC), vapor pressure (hPa), and 10m wind speed (m/s). The IPCC DDC also provides the land-sea mask and topography data sets used with the model simulations. The data is available for download as zipped ASCII files, once the user has registered through the IPCC
DDC web site. Registration is free and indicates that the user has read and agreed to abide by the IPCC DDC data policy. Documentation and discussion relating to these simulations, the model, and data are available on the IPCC DDC web site. These data are also available on CD-ROM along with similar results from other global climate models.

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 surface solar flux (% of clouds), mean sea level pressure (Pa), total precipitation (mm/day), relative humidity (%), 1.5m air temperature (degC), 1.5m maximum and
minimum air temperature (degC), 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].