Influence of the latitudinal temperature gradient on soil dust concentration and deposition in Greenland

To investigate the effects of changes in the latitudinal temperature gradie nt and the global mean temperature on dust concentration in the Northern He misphere, experiments with the GISS GCM are performed. The dust concentrati on over Greenland is calculated from sources in central and eastern Asia, w hich are integrated on-line in the model. The results show that an increase in the latitudinal temperature gradient increases both the Asian dust sour ce strength and the concentration over Greenland. The source increase is th e result of increased surface winds, and to a minor extent, the increase in Greenland dust is also associated with increased northward transport. Cool ing the climate in addition to this increased gradient leads to a decrease in precipitation scavenging, which helps produce a further (slight) increas e in Greenland dust in this experiment. Reducing the latitudinal gradient r educes the surface wind and hence the dust source. with a subsequent reduct ion in Greenland dust concentrations. Warming the climate in addition to th is reduced gradient leads to a further reduction in Greenland dust due to e nhanced precipitation scavenging. These results can be used to evaluate the relationship of Greenland ice core temperature changes to changes in the l atitudinal and global temperatures.