A comparison of absolute and relative changes in precipitation in multimodel climate projection

This study compares two methods of multimodel averaging for the future projection of precipitation based on the classically defined absolute and relative climate changes. In the relative change scheme, the multimodel average of the percentage changes in precipitation is multiplied by the observed present climate to form the future projection; this method is equivalent to applying unequal weighting to the absolute change scheme which potentially implies a bias correction. The new scheme and the classical equal weight scheme for the absolute change do not produce radically different large-scale patterns of the trend in precipitation. Nevertheless, notable differences emerge in regional scales.