Downscaling Last Glacial Maximum climate over southern Africa

Abstract We conducted the first dynamic downscaling of Last Glacial Maximum (LGM) climate over southern Africa using a regional climate model. Eight coupled global climate model (CGCM) projections of LGM climate were downscaled to 8 km resolution, and compared to a downscaling of present-day climate. It is projected that temperatures were significantly lower during the LGM compared to the present-day, with annual average temperatures 4–6 °C lower along the eastern escarpment, south-north aligned Cape Fold Mountains and western escarpment. Southern Africa is projected to have been generally wetter during the LGM, with a significant extension in the northward reach of frontal rainfall. The largest rainfall increases are projected for the south-north aligned Cape Fold Mountains and the western escarpment of South Africa, but with rainfall decreases projected for the Cape south coast region. Rainfall seasonality is projected to have been significantly different from that of the present-day, with an all-year rainfall region plausibly extending as far north and east as the present-day Free State and Gauteng provinces of South Africa. Evaluations of the downscalings against key published proxy records for the LGM from southern Africa suggest good agreement and few deviations.