人类黑碳气溶胶与东亚夏季气候年代际变化（英文）

【作者】 李双林； Rashed Mahmood； 万江华；

【机构】 中国科学院大气物理研究所； 中国科学院气候变化研究中心；

【摘要】 Two inter-decadal shifts in East China summer rainfall during the last three decades of the 20 th century have been identified. One shift occurred in the late 1970 s and featured more rainfall in the Yangtze River valley and prolonged drought in North China, along with the substantial weakening of East Asian summer monsoon(EASM). The other shift occurred in the early 1990 s and featured increased rainfall in South China, in accompany with the further weakening of EASM. In this study, the authors used Geophysical Fluid Dynamics Laboratory’s(GFDL’s) atmospheric general circulation model known as Atmosphere and Land Model(AM2.1), which has been shown to capture East Asian climate variability well, to investigate the influence of anthropogenic black carbon(BC) aerosols by conducting sensitive experiments with or without historical BC. The results suggest that the model with the prescribed BC over East Asia reproduces the first shift well, including intensified rainfall in the Yangtze River and weakened monsoonal circulation. However, the model captures only a fraction of the observed variations for the second shift event. Further experiments with prescribed remote upstream BC are conducted, and the results suggest that the decreased BC over Europe around the early 1990 s may have contributed to the second shift of EASM. Thus, the role of BC in modulating the two shift events is different. The local BC’s impact is relatively less important for the early 1990 s event, while the interdecadal decrease of European BC around the early 1990 s may have played an important role.更多还原

【Abstract】 Two inter-decadal shifts in East China summer rainfall during the last three decades of the 20 th century have been identified. One shift occurred in the late 1970 s and featured more rainfall in the Yangtze River valley and prolonged drought in North China, along with the substantial weakening of East Asian summer monsoon(EASM). The other shift occurred in the early 1990 s and featured increased rainfall in South China, in accompany with the further weakening of EASM. In this study, the authors used Geophysical Fluid Dynamics Laboratory’s(GFDL’s) atmospheric general circulation model known as Atmosphere and Land Model(AM2.1), which has been shown to capture East Asian climate variability well, to investigate the influence of anthropogenic black carbon(BC) aerosols by conducting sensitive experiments with or without historical BC. The results suggest that the model with the prescribed BC over East Asia reproduces the first shift well, including intensified rainfall in the Yangtze River and weakened monsoonal circulation. However, the model captures only a fraction of the observed variations for the second shift event. Further experiments with prescribed remote upstream BC are conducted, and the results suggest that the decreased BC over Europe around the early 1990 s may have contributed to the second shift of EASM. Thus, the role of BC in modulating the two shift events is different. The local BC’s impact is relatively less important for the early 1990 s event, while the interdecadal decrease of European BC around the early 1990 s may have played an important role.更多还原