LGM DUST DISTRIBUTION AND RADIATIVE FORCING: SENSITIVITY TO VEGETATION RECONSTRUCTION

Understanding observed changes in dust deposition from the LGM to the present will improve the accuracy of predictions of future dust emissions. The plausible range of LGM vegetation distributions leads to significant uncertainty in the predicted LGM dust distribution. We investigate these uncertainties using multiple vegetation datasets in the Dust Entrainment and Deposition (DEAD) module running in the NCAR General Circulation Model. The uncertainty in dust deposition and distribution attributable to uncertainty in vegetative constraints is greatest in and downwind of Asia. We compare our model results to observations (e.g., DIRTMAP) to gain insight into the quality of the vegetation reconstructions. The range of uncertainties in dust radiative forcing and feedbacks attributable to LGM vegetation reconstruction will also be assessed.