Planetary Mantle Dynamics

行星地幔动力学

• 批准号: RGPIN-2014-05913
• 负责人: Lowman, Julian
• 金额: $ 2.19万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=658006
• 关键词: Planetary; Mantle; Dynamics

Heat loss from the terrestrial planets in our solar system is governed by convection in their outer silicate shells. In the case of the Earth, this convection is manifested as plate tectonics and the continental drift that results. The research encompassed in this proposal will focus on the thermal evolution of planetary interiors and the feedback between surface and interior dynamics. The methodology will focus on utilizing computer models of two- and three-dimensional convecting fluids contained within either self-gravitating spherical shells or plane-layer systems. Motivation for a substantial amount of the proposed activity derives from the observation that the Earth is the only planet in the solar system featuring plate tectonics and our desire to understand why this is so. Specific topics of interest will include examining the influence of system geometry (i.e., mantle thickness) and particularly planetary core size on the thermal character of mantle convection. In addition, we shall investigate the influence of a mobile surface on mantle convection as well as the physical requirements for plate motion. The nature of the thermal evolution of rocky planets and icy moons will be explored by investigating the influence of fluid parameters (e.g., thermal viscosity dependence) on convection characteristics. Moreover, the role in planetary thermal evolution that may be played by continents and deep chemically distinct anomalies will drive a portion of the proposed work. Extension of the models and applications to exosolar planets will also be examined.**The research is facilitated by utilizing sophisticated computational models run on distributed memory parallel computing platforms (i.e., utilizing many processors). Presently, a small planetary interiors group of four graduate students works under my guidance at the University of Toronto-Scarborough (UTSC) and benefits from access to the SciNet General Purpose Computing (GPC) Cluster. Over the past five years the research group has migrated all of the computer codes used for our research to SciNet's GPC. Consequently, all tools required for the research proposed here are already available, tested and ready to use. In addition, we are now utilizing codes developed at UTSC as well as new computer codes, obtained from collaborative ventures that are well suited to capitalize on SciNet's capabilities. This will enable the research projects described here to probe physical behaviour in regimes, and on time-scales, not previously accessible. For example, the codes and high performance computing facilities now available will allow researchers at UTSC to model planetary convection in systems featuring both the convective vigour and the surface area of an Earth-like planet over periods simulating billions of years of evolution.**The underlying theme of all of these studies is investigation of the time-dependence of planetary heat loss and surface motion. The research involved will train highly qualified personnel (HQP) in the use of high performance computing for investigating problems in geophysical fluid dynamics. To undertake these projects , support for a group of six researchers is sought. Over the next five years, the general makeup of this group will include the Principal Investigator, a post-doctoral research assistant and four graduate students, engaged in both MSc and PhD studies. These HQP will be engaged in international collaborative research stemming from use of the computing tools required for the research. Funding would support the completion of six PhD and four MSc degrees and the HQP will complete their research projects having obtained experience that will include training as geodynamicists and exposure to the methods by which scientific results are disseminated.

在我们的太阳系中，类地行星的热量损失是由它们的硅酸盐外壳中的对流控制的。在地球的情况下，这种对流表现为板块构造和大陆漂移的结果。这项建议所包含的研究将侧重于行星内部的热演化以及表面和内部动力学之间的反馈。该方法将侧重于利用计算机模型的二维和三维对流流体包含在自引力球壳或平面层系统。大量拟议活动的动机来自于地球是太阳系中唯一具有板块构造的行星这一观察结果，以及我们想了解为什么会这样的愿望。感兴趣的具体主题将包括检查系统几何形状的影响（即，地幔厚度），特别是行星核大小对地幔对流热特征的影响。此外，我们还将研究一个移动的表面对地幔对流的影响以及板块运动的物理要求。岩石行星和冰卫星的热演化的性质将通过研究流体参数的影响来探索（例如，热粘度依赖性）对流特性。此外，大陆和深层化学性质不同的异常可能在行星热演化中发挥的作用将推动部分拟议工作。还将审查模型的扩展和对太阳系外行星的应用。通过利用在分布式存储器并行计算平台上运行的复杂计算模型（即，利用许多处理器）。目前，一个由四名研究生组成的小型行星内部小组在我的指导下在多伦多-斯卡伯勒大学（UTSC）工作，并受益于SciNet通用计算（GPC）集群。在过去的五年里，研究小组已经将我们研究中使用的所有计算机代码迁移到了SciNet的GPC上。因此，这里提出的研究所需的所有工具都已经有了，经过测试，可以使用。此外，我们现在正在利用UTSC开发的代码以及新的计算机代码，这些代码是从非常适合利用SciNet能力的合作企业获得的。这将使这里描述的研究项目能够在以前无法访问的制度和时间尺度上探测物理行为。例如，现在可用的代码和高性能计算设施将使UTSC的研究人员能够模拟系统中的行星对流，这些系统在模拟数十亿年进化的时期内具有对流活力和类地行星的表面积。所有这些研究的基本主题是调查行星热损失和表面运动的时间依赖性。所涉研究将培训使用高性能计算调查地球物理流体动力学问题的高素质人员。为了开展这些项目，寻求对一个由六名研究人员组成的小组的支助。在接下来的五年里，这个小组的一般组成将包括主要研究员，博士后研究助理和四名研究生，从事硕士和博士研究。这些HQP将参与国际合作研究，研究所需的计算工具的使用。资金将支持完成六个博士学位和四个硕士学位，HQP将完成他们的研究项目，获得经验，包括培训地球动力学家和接触传播科学成果的方法。