Effects of anthropogenic aerosols on temperature changes in China during the twentieth century based on CMIP5 models

Abstract

Using three models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), we compare the direct and other effects of anthropogenic aerosols on observed and simulated annual, winter, and summer temperature changes. Three regions, namely, arid–semiarid area, humid–semiarid area, and the whole of China, are studied. The temperature changes caused by other effects of anthropogenic aerosol (OE) are calculated from the difference between the anthropogenic aerosol forcing run (AA) and the anthropogenic aerosol direct effect forcing run (DE). When the combined effects are considered, a significant area-averaged cooling rate varies in the range of −0.86 to −0.76 °C per century throughout China. Meanwhile, the isolated direct and other effects lower the temperature nationwide by −0.66 to −0.55 °C per century, and −0.31 to −0.11 °C per century, respectively. From a nonlinear perspective, the aerosol-induced temperature experiences a cooling trend, with AA having the largest cooling trend changes both annually and in the summer, while DE has the greatest reduction in the winter. Additionally, the influence of OE cannot be detected in observed annual changes over the arid–semiarid area and the whole of China, while the others are clearly detectable in all cases. AA (DE, OE) reduces the observational temperature mainly over the humid–semihumid region, where the contribution to the observed warming ranges from −515.2 % (−298.7 %, −198.9 %) to −173.6 % (−130.3 %, −66.4 %).