This dataset contains climate model output from Deutches
    Klimarechenzentrum (DKRZ) in Germany.  The model output consists
    of monthly mean grids for several variables from three runs of
    the ECHAM4 model.  The three runs are a control (constant
    atmospheric forcing) run, a greenhouse gas run which
    assumes a compounded 1% per year increase in CO2, and
    an aerosol run which combines CO2 and
    sulphate aerosol concentrations.  The model is run at T42
    resolution, resulting in a 128 by 64 latitude/longitude gaussian
    output grid (approximately 2.8-degree by 2.8-degree
    resolution).  The grids are in GRIB format (Edition 1).
    DSS has computed decadal means for each decade-month from the
    monthly mean grids.  The decade means are computed from years 0
    through 9 of each decade.  We also computed smoothed decadal
    means by computing 30-year running means of the decadal mean
    grids.  Because of the large variability in the decadal means of
    variables such as precipitation, we recommend using the 30-year
    (smoothed decadal) means and applying them to the year at the
    middle of the 30-year period (i.e. - the 30-year mean for
    2070-2099 should be applied at year 2085).