Influence of interannual atmospheric forcing on North Pacific biogeochemical variability

在这个研究项目中，华盛顿大学的研究人员将研究过去几十年来北太平洋碳循环对大气物理强迫变化的敏感性。北太平洋碳循环和相关过程的十年尺度变化已通过直接观测得到了很好的记录。然而，关于控制机制的基本问题仍然存在，而且对地表和温跃层变率之间的关系知之甚少。最近的一系列模型和观测表明，由于水文循环变化引起的淡水强迫在地表和温跃层水域碳循环过程示踪剂的年代际变化中起着重要作用，这促使研究人员进行了研究。这个问题现在可以使用新发表的历史海洋盐度趋势来解决。此外，CLIVAR项目产生的有价值的数据允许探索地表水和海洋内部生物地球化学变异变化之间的关系。该研究计划将使用海洋环流/生物地球化学模型进行后投模拟，以研究表面碳循环参数和内部O2和DIC分布对海面盐度和营养物质变化的敏感性。研究人员先前开发了一个模型，用于研究北太平洋盆地的物理-生物地球化学变化。虽然该模式目前没有碳循环，但它确实有营养物质和氧气的生物地球化学循环，能够重现气候上的氧气和营养物质分布，以及20世纪后期观测到的温跃层氧气变化的总体格局。因此，直接将碳循环添加到模型中是建立在已证明的捕捉重要的物理和生物地球化学变化模式的能力之上的。然后，这些敏感性实验的结果将通过模型输出与观测到的北太平洋碳循环变率的详细比较进行评估，该比较基于海洋时间序列站，并结合CLIVAR/CO2重复水文计划的数据。这项工作将利用与太平洋海洋环境实验室的主要实验碳循环科学家建立的合作关系。最后，研究小组将进行一系列归因实验，以分离和表征物理、生物和化学过程对模拟碳变率的贡献。虽然这项研究本身是区域性的，但这项研究应该对全球海洋碳循环和相关现象的研究产生更广泛的影响。对空间特征和不同过程控制海洋碳循环变异性的相对重要性的强调，应该为社区对全球碳循环变异性的理解提供信息。该项目将支持一名年轻的博士后研究员和一名初级研究生。

In this research project, investigators at the University of Washington will study the sensitivity of the North Pacific carbon cycle to changes in physical atmospheric forcing over the past few decades. Decade-scale changes in the North Pacific carbon cycle and related processes have been well documented through direct observations. Basic questions remain, however, about the controlling mechanisms, and little is known about the relationship between surface and thermocline variability. The investigators are motivated by a series of recent indications from both models and observations that fresh water forcing due to changes in the hydrological cycle plays an important role in the decadal variability of tracers of carbon cycle processes in both surface and thermocline waters. This issue can now be addressed using newly published historical ocean salinity trends. In addition, valuable data emerging from the CLIVAR program allows the relationships between changes in biogeochemical variability in surface waters and in the ocean interior to be explored.The research plan will involve hind cast simulations with an ocean circulation/biogeochemical model to examine the sensitivity of surface carbon cycle parameters and interior distributions of O2 and DIC to changes in sea surface salinity as well as nutrients. The investigators have previously developed a model for investigations of physical-biogeochemical variability in the North Pacific basin. While the model currently has no carbon cycle, it does have biogeochemical cycles of nutrients and oxygen that are able to reproduce the climatological O2 and nutrient distributions, as well as the overall pattern of thermocline O2 changes observed during the late 20th century. The straightforward addition of a carbon cycle to the model therefore builds on a demonstrated capacity to capture important modes of physical and biogeochemical variability.The results of these sensitivity experiments will then be assessed through a detailed comparison of model output to observed carbon cycle variability in the North Pacific based on ocean time series stations, together with data from the CLIVAR/CO2 Repeat Hydrography Program. This effort will take advantage of established collaborations with leading experimental carbon cycle scientists at the Pacific Marine Environmental Laboratory. Finally, the research team will conduct a series of attribution experiments to isolate and characterize the contribution of physical, biological and chemical processes to simulated carbon variability.Although the study itself will be regionally specific, the study should have broader impacts for the study of the global ocean carbon cycle and related phenomena. The emphasis on the spatial signatures and relative importance of different processes controlling ocean carbon cycle variability should inform the community-wide understanding of the variability of the global carbon cycle. The project will support a young postdoctoral investigator and a beginning graduate student.