海洋碳循环中颗粒有机碳全球分布的数值模拟

发布时间：2018-04-29 05:08

本文选题：海洋碳循环 + 颗粒有机碳　；参考：《成都信息工程学院》2015年硕士论文

【摘要】：海洋中颗粒有机碳(POC)的垂直输送与降解在海洋碳循环中是很重要的环节,它能迅速将上层海洋吸收的碳转移到深海,对海洋吸收和调节大气CO2起到了重大作用。本文研究主要包括两个方面的内容:一方面是对LICOM海洋环流模式中GM90次网格参数化进行改进,并用被动示踪物CFC-11检验模拟结果;另一方面是使用与LICOM模式耦合的简单生物地球化学模式IAP-OBM,增加IAP-OBM模式对颗粒有机碳的预报,完善该模式的有机碳库种类和碳循环过程,并研究分析中尺度涡旋参数化方案和颗粒有机碳对碳循环过程的影响。主要包括以下结论:1)对LICOM模式中尺度涡旋参数化方案(GM90方案)中涡度扩散系数rA对物理场及CFC-11分布的影响进行了研究。做了两个试验,模拟结果表明,采用在非绝热层以下rA随海洋浮力频率N2垂直变化的参数化方案(浮力试验)对模式物理场的模拟能力有一定程度的提升,如南极绕极流的输送强度比常系数方案增大了约20%~30%,与观测事实更接近;浮力试验对控制试验中过强的南极中层水有一定的削弱作用,使得模式对南大洋高纬次表层位密度的模拟有一定的改善。通过对CFC-11分布、存储以及输送的研究发现,次网格参数取值的不同对南大洋CFC-11模拟情况有较大影响。浮力试验加大了南北高纬CFC-11海表的吸收通量,对南极大陆周边海域向南大洋主储藏区的CFC-11输送能力有一定的增强,使得南大洋对CFC-11储藏量增大,大部分海区与观测资料更接近。通过CFC-11断面分析,浮力试验对南大洋上层海洋位密度模拟的改善使得CFC-11垂直结构与观测更接近。2)使用简单生物地球化学IAP-OBM模式,增加模式颗粒有机碳为预报变量,并设计了三个试验,研究了中尺度涡旋参数化采用浮力方案为背景的物理场下对碳循环的影响,以及在相同物理场下增加颗粒有机碳为预报变量后的不同碳循环过程的模拟差异。模拟结果表明,三个试验均能很好地模拟出海表的磷酸盐、总碱度以及总溶解无机碳的分布特征。采用浮力方案为背景物理场的试验对南大洋深海和赤道附近800-1000m左右的模拟有一定影响,但整体对模式生化变量的模拟差异并不明显。新的碳循环方案对南大洋海表磷酸盐的模拟有一定程度的增加,与观测更贴近。在垂直结构上,新的碳循环方案对磷酸盐、总碱度的模拟有较为明显的改善,但对深海总溶解无机碳的模拟有所偏弱。
[Abstract]:The vertical transport and degradation of particulate organic carbon (POC) in the ocean is an important part of the marine carbon cycle. It can transfer the carbon absorbed by the upper ocean quickly to the deep sea, which plays an important role in the absorption and regulation of atmospheric CO2 by the ocean. This paper mainly includes two aspects: on the one hand, we improve the GM90 subgrid parameterization in the LICOM ocean circulation model, and test the simulation results with the passive tracer CFC-11; On the other hand, a simple biogeochemical model (IAP-OBM) coupled with LICOM model is used to increase the prediction of particulate organic carbon by IAP-OBM model, and to improve the organic carbon pool types and carbon cycle process of the model. The effects of mesoscale vortex parameterization scheme and particulate organic carbon on the carbon cycle are studied. The main conclusions are as follows: (1) the effects of vorticity diffusion coefficient (RA) on physical field and CFC-11 distribution in LICOM model are studied in the mesoscale vortex parameterization scheme (GM90 scheme). Two experiments have been done. The simulation results show that the parameterized scheme (buoyancy test) with the vertical variation of ocean buoyancy frequency N2 below the non-adiabatic layer can improve the simulation ability of the model physical field to a certain extent. For example, the transport intensity of the Antarctic circumpolar current is increased by about 20% compared with the constant coefficient scheme, which is closer to the observed fact, and the buoyancy test has a certain weakening effect on the control of the excessive middle Antarctic water in the experiment. The model improves the simulation of the subsurface potential density of the Southern Ocean in high latitudes. Through the study of CFC-11 distribution, storage and transportation, it is found that the different values of subgrid parameters have great influence on the simulation of Southern Ocean CFC-11. The buoyancy test increases the absorption flux of the surface of the CFC-11 sea surface at high latitudes in the north and the south, and enhances the transport capacity of CFC-11 from the circumjacent waters of the Antarctic continent to the main storage area of the Southern Ocean to a certain extent, which makes the storage of CFC-11 in the Southern Ocean increase, and most of the sea areas are closer to the observational data. Based on the CFC-11 section analysis, the improvement of buoyancy test to the simulation of the oceanic potential density in the Southern Ocean makes the vertical structure of CFC-11 closer to the observation. 2) A simple biogeochemical IAP-OBM model is used, and the model particle organic carbon is added as the prediction variable. Three experiments were designed to study the effect of mesoscale vortex parameterization under the background of buoyancy scheme on the carbon cycle. At the same physical field, the simulation differences of different carbon cycle processes with the addition of particulate organic carbon as predictive variables are also discussed. The simulation results show that the three experiments can well simulate the distribution characteristics of phosphate, total alkalinity and total dissolved inorganic carbon on the sea surface. The experiments using the buoyancy scheme as the background physical field have certain influence on the simulation of the deep sea and near the equator about 800-1000m, but there is no obvious difference in the simulation of the model biochemical variables as a whole. The new carbon cycle scheme increases the simulation of surface phosphate in the Southern Ocean Sea to a certain extent and is closer to the observation. In vertical structure, the simulation of total basicity of phosphate and total alkalinity is improved obviously by the new carbon cycle scheme, but the simulation of total dissolved inorganic carbon in deep sea is weak.
【学位授予单位】：成都信息工程学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P734

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