Generation of rainfall scenarios using daily patterns of change from GCMs

摘要

This paper proposes a modification of the perturbation approach to downscaling GCM rainfall. The proposed approach uses a daily pattern of change in ranked rainfalls from the GCM, and then scales the ranked point daily rainfall by this pattern of change. This new approach can produce sequences of "climate change impacted" point daily rainfall that are very different in magnitude to sequences that are produced by simpler perturbation methods, especially in terms of rainfall that will produce runoff. We argue that the proposed method is superior to simpler methods, because the method can produce sequences of "climate change impacted" point rainfall that are consistent with the changes in extreme daily rainfalls and changes in the frequency of wet days that occur in the GCM.