Dust deposition and provenance at the Last Glacial Maximum and present day

Ice and ocean core data suggest an increase in atmospheric dust loading at the Last Glacial Maximum, 21,000 years ago, relative to the present day. We present results from a new dust model; in contrast to previous modelling studies, we correctly simulate the observed provenance data in both Antarctica and Greenland, and obtain reasonable agreement with the dust deposition data. The observed increases are attributable to decreases in vegetation, increased surface wind strength, and increased particle lifetime (due to the drier LGM climate). The Patagonian provenance of Antarctic LGM dust is linked to a decrease in soil moisture and an extension in area of the source region, and a high transport efficiency between the two regions. The results show a high degree of interannual variability, which must be taken into account when interpreting previous modelling results.