Radiative Forcing And Climatological Effect Of Dust Aerosol Simulated By BCC_Agcm2.0.1_CAM

A new coupling model system BCC_AGCM2.0.1_CAM, which is consisted by the second generation of general circulation model of National Climate Center BCC_AGCM2.0.1and Canadian aerosol model CAM, is assessed preliminarily, and the radiative forcing and climate effect of soil dust is simulated by the coupling model system in this paper. The simulation of five typical aerosols (sulfate, black carbon, organic carbon, soil dust and sea salt) is generally reasonable, comparing with the medium level of AeroCom and AERONET observational data, and is improved in terms of sulfate, soil dust and sea salt comparing with the monthly mean aerosol data of BCC_AGCM2.0.1. What’s more, the improvement of the aerosol scheme is reflected in the simulation of the global mean and distribution of climate variables in comparison with the observational and reanalyzed data as ERBE, NCEP, and so on. The simulated adjusted radiative forcing ("AF" for short) of soil dust is-0.51W/m2(short-wave AF-0.56W/m2, and long-wave AF+0.05W/m2) on the top of the atmosphere, and-2.34W/m2(short-wave AF-2.58W/m2and long-wave AF+0.15W/m2) on the surface. Surface albedo can affect the amount, even the sign of short-wave AF on the top of the atmosphere. And the existence of cloud can decrease the short-wave and long-wave AF of soil dust on the top of the atmosphere and the surface, however, soil dust changes the RF of clouds little. Because of its effects on irradiation, soil dust can decrease the temperature of surface and troposphere, and increase the temperature of stratosphere. And it can also reduce (enhance) the precipitation in the tropical and subtropical areas of the Northern (Southern) Hemisphere through strengthening (weakening) the Hadley circulation. Soil dust may reduce the total proportion of global arid and semi-arid area, and weaken extent of the aridity in the Northwest China, middle Asia, the center of Sahara desert and the West America, and at the same time, it may strengthen the aridity of India, the east part of Africa, Central America, and so on. What’s more, soil dust can reduce the surface wind velocity in arid and semi-arid area, and thus reduce the emission of dust aerosol itself.