摘要
针对政府间气候变化专业委员会历次报告中“表层-深层”海水间碳通量的差异,利用改进的“上升-扩散”（upwelling-diffusion,UD）模式模拟海洋碳循环状态.除了改进模式结构外,还建立了直接计算海洋溶解无机碳（dissolved inorganic carbon,DIC）δ13C分布的控制方程.区别于目前广泛采用的深度参数的方法,直接利用沉积物捕获器的观测计算分解流量,减少了参数的引用.为更加符合海洋生物地球化学循环,采用地球化学海洋断面研究计划GEOSECS（Geochemical Ocean Sections Study）的海洋磷酸盐分布来标定两个深海动力参数：垂直扩散系数3 000 m2/a和上涌速率3.5 m/a,从而得到温跃层平均深度为860 m,这些参数都在直接观测和其他模式标定的结果之间.通过复原稳定状态下DIC分布并与GEOSECS的观测进行对比,得出自产业革命到20世纪70年代中期的海洋吸收大气CO2约为78 GtC（Gigatonnes Carbon,1 Gt=1×1015 g）,与其他的模式估计及观测计算结果相吻合.模式模拟的“混合层-深层”海水间的碳通量为46 GtC/a,远小于IPCC第四次报告（101 GtC/a）而与第三次报告（42 GtC/a）的估算相一致,但仍小于δ13C质量守恒法确定的范围（60～ 80 GtC/a）.
Due to the unresolved conflict in the current IPCC assessment reports about carbon fluxes be- tween the surface and deep ocean, an upwelling-diffusion （UD） global carbon cycle model was devel- oped to investigate the oceanic carbon cycle.Except model structure, the control formulations for 813C of oceanic dissolved inorganic carbon（DIC） were also established.Different from present UD models ,the global sediment trap observations were directly used to calculate the in situ regeneration flux without in- corporating the well-used depth parameters.The two dynamic parameters, namely, the vertical eddy dif- fusivity（k） of 3 000 m2/a and the upwelling velocity（w） of 3.5 m/a, were calibrated to match the GEOSECS phosphate distribution and to get a thermocline depth scale at 860 m.These parameters were all between direct observations and model calibrations.By comparing the DIC profiles from model esti- mate in steady state with those from GEOSECS ,we got an oceanic uptake of 78 GtC（ Gigatonnes Car-bon, 1 Gt= 1 × 1015 g）from the Industrial Revolution until mid-1970s.This result was considerably sup- ported by other models and data-based estimates.Model estimated the flux from deep ocean to the mixed layer to be 46 GtC/a, which is consistent with that from the IPCC＇ s third assessment report （42 GtC/ a） but far less that from the fourth one （ 101 GtC/a） ,but still less than the range of 813C budget tech- nique （ 60-80 GtC/a）.
出处
《大气科学学报》
CSCD
北大核心
2014年第6期772-779,共8页
Transactions of Atmospheric Sciences
基金
中国气象局气候变化专项(CCSF2007-44)
江苏高校优势学科建设工程资助项目(PAPD)
