海洋生物气溶胶增加可能导致晚新生代全球变冷的模型计算  

Model Assessment of the Possible Contribution of Increasing Marine Biogenic Aerosol in Late Cenozoic Cooling

作　　者：李高军[1,2] 陈骏[1] 季峻峰[1] 盛雪芬[1] 李涛 

机构地区：[1]南京大学地球科学系,表生地球化学研究所,南京210093 [2]Department of Earth Sciences,University of Cambridge,Downing Street,Cambridge CB2 3EQ,UK [3]蚌埠气象局,蚌埠233000

出　　处：《高校地质学报》2009年第2期171-183,共13页Geological Journal of China Universities

基　　金：南京大学研究生科研创新基金和优秀博士论文培育基金项目;科技部973项目(2004CB720204);国家自然科学基金项目(40625012,40331001,40473009)联合资助

摘　　要：整合海洋碳、锶、锇同位素记录的地球化学元素循环模型表明,晚新生代大陆化学风化通量随着全球物理侵蚀的增强而升高,促使更多的营养元素磷输入到海洋中,引起海洋生物生产力的爆发,而浮游生物产生大量的二甲基硫最终导致海洋上空的大气气溶胶浓度急剧上升。气溶胶浓度增加一方面会增加云的覆盖率和反射率,据初步估计,该效应导致距今7Ma内地表接收的太阳能减少了16.5Wm-2,相当于全球平衡温度降低13℃;另一方面会抑止云层的降水效能,有利于水汽向高纬地区传输并形成降雪,最终促进两极冰盖生长,从而驱动新生代晚期全球性的气候变冷。Geochemical model coupled with marine isotopic records of carbon, strontium and osmium indicates a late Cenozoic increase in chemical weathering associated with enhanced physical erosion. Marine bio-productivity is largely promoted by the fertilized oceans in response to the increasing riverine phosphorus input. The increasing biogenic aerosol caused by marine bio- booming result in elevated cloud albedo and cloud cover, which would act as a significant negative radiative forcing of about 16.5 W m^-2 over the past -7 Ma that is equivalent to about 13 ℃ global cooling in equilibrium temperature. The increasing atmospheric aerosol also reduces the precipitation efficiency of cloud, which would enable penetration of ocean vapour into high latitudes and ultimately facilitate the accumulation of polar ice sheets.

关 键 词：地球化学模型 风化 生物生产力 气溶胶 新生代变冷 

分 类 号：P532[天文地球—古生物学与地层学] P595[天文地球—地质学]