Environmental reconstruction and climate modelling of the Late Quaternary in the winter rainfall region of the Western Cape, South Africa

The southwestern Cape is an environmentally heterogeneous and floristically biodiverse region of South Africa. The area experiences mainly winter rainfall and is an important southern hemisphere example of a Mediterranean-type climate. Proxy palaeoenviron- mental data are crucial to understanding the climatic changes that have occurred during the Late Quaternary in this region, especially with a view to palaeoclimatic modelling. Evaluation of palaeo- climatic simulations provides opportunities for climate model validation under conditions different from those used in the simula- tion of current climate, and is an important means of improving levels of confidence in such models. By relating palaeoclimatic reconstructions for the southwestern Cape to a regional climate model, therefore, one can assess the accuracy of the model, as well as identifying additional sites necessary for improving the evalua- tion. The primary global circulation model we have used is from the NOAA/Geophysical Fluid Dynamics Laboratory at Princeton University. Model results thus far show significant differences for the Last Glacial Maximum (LGM) between the southern and western coastal regions of the southwestern Cape, although both fall within the winter rainfall region. The western coastal regions seem to have experienced a cool and moist LGM, compared to the colder and drier southern regions. In addition, this model is used to suggest synoptic scale climatic features, possibly responsible for the changes observed in the palaeoecological record.