Global distribution and radiative forcing of soil dust aerosols in the Last Glacial Maximum simulated by the aerosol climate model
1Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan
2Interdisciplinary Graduate School of Engineering Sciences, Kyushu Univ., Fukuoka, Japan
3Center for Climate System Research, University of Tokyo, Chiba, Japan
Abstract. The integrated simulation for the global distribution and radiative forcing of soil dust aerosols in the Last Glacial Maximum (LGM) is done by an aerosol climate model, SPRINTARS, in this study. It is compared with another simulation in the present climate condition. The global total emission flux of soil dust aerosols in the LGM is simulated to be about 2.4 times as large as that in the present climate, and the simulated deposition flux is in general agreement with estimations from ice core and marine sediment samplings though it might be underestimated over the Antarctic. The calculated direct radiative forcing of soil dust aerosols in the LGM is close to zero at the tropopause and −0.4 W m−2 at the surface, which are about twice as large as those in the present climate. SPRINTARS also includes the microphysical parameterizations of the cloud-aerosol interaction both for liquid water and ice crystals, which affect the radiation budget. The positive radiative forcing of the indirect effect due to soil dust aerosols, that is mainly caused by a role of ice nuclei, is simulated to be smaller in the LGM than in the present. It is suggested that atmospheric dust might contribute to the cold climate during the glacial periods both through the direct and indirect effects, relative to the interglacial periods.