Interannual variability of the simulated hydrology in a climatic model-implications for drought

A 10-year simulation of the atmosphere has been performed with a two-level global general circulation model. The model takes account of realistic topography and the hydrological cycle, and computes its own cloud cover, snowfall and sea ice distributions. The seasonally varying sea surface temperatures are specified from climatology. The results presented in this paper are restricted to hydrological aspects of the integration, particularly the soil moisture variations. The model exhibits considerable temporal and regional variability in its simulation of the hydrological cycle, generally reproducing quite fair agreement with observations. Some geographical regions were found to have very noticeable interannual variability, with the occurrence of annual or multi-annual drought a feature at a number of locations. The implications of such naturally occurring drought are discussed.