Acquisition of a Computational Facility for Numerical Dynamo Theory

9724568 Bloxham这笔赠款是通过重大研究仪器(MRI)计划提供的，提供178,885美元，作为在哈佛大学购买新的计算设施的部分费用，用于使用最近开发的3-D动态自洽地球发电机代码对地球发电机进行建模。具体地说，他们将购买一台新的Silicon Graphics Origin 2000服务器，配备16个CPU、45 GB磁盘存储和2 GB扩展内存。目前的Kuang和Bloxham(哈佛)的三维地球发电机模型和Glatzmaier(LANL)和Roberts(UCLA)的模型是目前世界上仅有的两个目前开发的和实用的地球发电机模型，其结果最近被刊登在国际和多学科期刊《自然》和《科学》的封面上。Kuang-Bloxham模型模拟了在靠近核-地幔边界的内核上方产生的磁场，而Glatzmaier-Roberts模型预测了在内核上方产生的磁场。这两个模型都显示了几次衰变后的偶极反转，Glatzmaier-Roberts模型得到了地球古地磁反转记录的支持。Glatzmaier-Roberts模型是最早开发的，已经运行了足够长的时间来模拟大约10万年和20万年的其他地磁反转。这些模型的不同之处在于每种模型的边界条件的设置和初始参数的选择，以及每种模型表示的地球物理基础可以并正在论证。由于这项研究的计算资源有限，两个小组都被迫对模型进行简化，以产生可以在合理的时间内运行的代码(Kuang-Bloxham模型目前需要在他们的Cary计算机上花费一个月的专门时间来模拟地球发电机的一次衰变时间)。考虑到这些限制，初始参数的不切实际的值被使用(即Ekman数、Prandtl数、Rayleigh数；见Merrill的修订版)。然而，很明显，需要增加并行处理和内存，以便在合理的时间长度内运行该代码，以在地质上重要的时间段内对地球的地球发电机进行建模，并且重要的是支持使用这两个相互竞争的模型的持续开发和后续模拟。***

9724568 Bloxham This grant, made through the Major Research Instrumentation (MRI) Program, provides $178,885 as partial support of the costs of acquiring a new computational facility at Harvard University for modeling the Earth's dynamo using their recently developed 3-d, dynamically self-consistent geodynamo code. Specifically, they will acquire a new Silicon Graphics Origin 2000 server with sixteen CPU's, 45 Gb of disk storage and 2 Gb of expanded memory. The current Kuang and Bloxham (Harvard) 3-d geodynamo model and the Glatzmaier (LANL) and Roberts (UCLA) model, whose results have recently been featured on the covers of the international and multi-disciplinary journals Nature and Science, are the only two currently developed and functional models of the geodynamo in the world. The Kuang-Bloxham model simulates a magnetic field that is generated well above the inner core close to the core-mantle boundary, while the Glatzmaier-Roberts model predicts a field generated just above the inner core. Both models show dipole reversals after a few decay times and the Glatzmaier- Roberts model, which was developed first and has been run long enough to simulate other geomagnetic reversals at ca. 100,000 ybp and 200,000 ybp, is supported by the Earth's paleomagnetic reversal records. The difference between these models lies in the setup of boundary conditions and choice of initial parameters for each of the models and the geophysical basis for each model representation can be and is, argued. Given limited computational resources for this research, both groups are forced to make simplifications to the models that result in codes that can be run in a reasonable amount of time (the Kuang-Bloxham model currently requires one month of dedicated time on their CARY computer for simulation of the Earth's dynamo for only one decay time). Given these limitations, unrealistic values of initial parameters are used (i.e. Ekman number, Prandtl number, Rayleigh number; see rev iew by Merrill). However, it is clear that increased parallel processing and memory are required to run this code within reasonable lengths of time to model the Earth's geodynamo over geologically significant time periods and it is important to support continued development and subsequent simulations using both of these competing models. ***