The Development of an Atmospheric Aerosol/Chemistry‐Climate Model, BCC_AGCM_CUACE2.0, and Simulated Effective Radiative Forcing of Nitrate Aerosols

Abstract

Abstract This study developed a next‐generation atmospheric aerosol/chemistry‐climate model, the BCC_AGCM_CUACE2.0. Then, the performance of the model for nitrate was evaluated, and the nitrate direct radiative forcing (DRF) and effective radiative forcing (ERF) due to aerosol‐radiation interactions were simulated for the present day (2010), near‐term future (2030), and middle‐term future (2050) under the Representative Concentration Pathway 4.5, 6.0, and 8.5 scenarios relative to the preindustrial era (1850). The model reproduced the distributions and seasonal changes in nitrate loading well, and simulated surface concentrations matched observations in Europe, North America, and China. Current global mean annual loading of nitrates was predicted to increase by 1.50 mg m−2 relative to 1850, with the largest increases occurring in East Asia (9.44 mg m−2), Europe (4.36 mg m−2), and South Asia (3.09 mg m−2). The current global mean annual ERF of nitrates was −0.28 W m−2 relative to 1850. Due to global reductions in pollutant emissions, the nitrate ERF values were predicted to decrease to −0.17, −0.20, and −0.24 W m−2 in 2030 and −0.07, −0.18, and −0.19 W m−2 in 2050 for Representative Concentration Pathway 4.5, 6.0, and 8.5 relative to 1850, respectively. Although global mean nitrate values showed a declining trend, future nitrate loading remained high in East Asia and South Asia.