Modeling the Impact of Icebergs on the Southern Ocean Freshwater Budget and Circulation

摘要-0350912从南极冰盖释放出来的冰山被风和洋流吹散，最终融化，并占南大洋淡水输入量的30%。由于缺乏对长期冰山崩解通量、海洋分布和溶解的全面观测估计，对南大洋冰山的调查仅限于间接估计以及冰山过程的理论和计算模型。这项研究将开发一个复杂的陆冰-冰山-海冰-海洋模型，根据冰川学和海洋学观测结果对其进行验证，并与气候变化和变率情景一起运行。陆冰、海冰和海洋成分的现成模型将与冰山运输的新公式相结合。一个计算效率高的欧拉方法的基础上计算的时间依赖分布函数的冰山大小将被用来代替更常见的拉格朗日冰山模型，需要更多的计算开销。这样的分布函数传达了关于在空间和时间中的给定点处发现预定大小的冰山的概率的信息，而不需要独立地跟踪它们中的每一个。一个1公里分辨率的“冰山解析”模型也将用于再现2000年至今罗斯海巨型冰山B-15的演变。对实验结果的分析将有助于改进现有的冰山动量平衡参数化，并在必要时制定新的参数化，更广泛的影响将包括改进用于现代和古气候研究的冰山参数化。在与NCAR海洋学科的密切合作下，冰山模型将被纳入共同体气候系统模型。一名暑期本科生将接受培训，了解海洋和气候动力学方面的当前问题。一名高中生将在本项目范围内接受指导，参加英特尔科学人才搜索竞赛。

ABSTRACTOCE-0350912Icebergs released from the Antarctic Ice Sheet are dispersed by the winds and ocean currents, ultimately melting and accounting for up to 30 percent of the freshwater input to the Southern Ocean. In the absence of comprehensive observational estimates of long-term iceberg calving fluxes, oceanic distribution and dissolution, the investigation of icebergs in the Southern Ocean is limited to indirect estimates, and theoretical and computational models of iceberg processes. This study, will develop a model of the complex land ice-iceberg-sea ice-ocean, validate it against glaciological and oceanographic observations, and run with it climatic change and variability scenarios. Off-the-shelf models of the land ice, sea ice, and ocean components will be combined with a novel formulation for iceberg transport. A computationally efficient Eulerian approach based on the calculation of a time-dependent distribution function for iceberg size will be used instead of the more common Lagrangian iceberg models which require far more computational overhead. Such a distribution function conveys information on the probability of finding icebergs of a predetermined size at a given point in space and time, without the need of tracking each of them independently. A 1-km-resolution, "iceberg-resolving" model will also be used to reproduce the evolution of the giant iceberg B-15 across the Ross Sea from 2000 till today. Analysis of the experimental results will help to improve existing parameterizations of the iceberg momentum balance and the development of new ones if necessary.Broader impacts will include improved iceberg parameterization for present-day and paleoclimate studies. With close collaboration with the Oceanography Section of NCAR, the iceberg model will be incorporated into the Community Climate System Model. A summer undergraduate student will be trained and introduced to current problems in ocean and climate dynamics. A high school student will be mentored within the scope of this project to participate in the Intel Science Talent Search competition.