GEM: Validating Self-Consistent Inner Magnetospheric Models: Assessing Effects of Uncertainties in Plasma Sheet and Electric Field Boundary Conditions on Simulating Storms

GEM：验证自洽内磁层模型：评估等离子体片和电场边界条件的不确定性对模拟风暴的影响

• 批准号: 1203195
• 负责人: Margaret Chen
• 金额: $ 34万
• 依托单位: Aerospace Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203195&HistoricalAwards=false
• 关键词: GEM; Validating; Self; Consistent; Inner

This project will examine the uncertainties in the magnetospheric cross polar cap potential (CPCP) and in the plasma sheet population and how these uncertainties affect the intensity and spatial distribution of the magnetospheric ring current during magnetic storms. It will examine how much of the disagreements between models and observations of the ring can be attributed to the uncertainty in the boundary conditions rather than other causes such as missing physical processes in the models. Previous simulation studies have shown that changes in the magnetospheric convection electric field and the plasma sheet distribution, which is the major source to the ring current, strongly influence the ring current. For this reason, success in modeling common ring current observables, such as the Dst index, ground magnetic perturbations and magnetic field at geosynchronous orbit, and plasma parameters is dependent on knowing the CPCP and the plasma sheet densities and temperatures. Because of limited spatial and temporal resolution of in-situ measurements of such quantities, averages from statistical re-analysis or empirical models are often used to specify the boundary conditions for inner magnetospheric models. However, there are large uncertainties associated with these boundary condition specifications. This project will quantify how sensitive simulated storms are to the uncertainties in the CPCP and in the ion and electron plasma sheet density and temperature boundary conditions of self-consistent inner magnetospheric models. The approach is to investigate the statistical variations of plasma sheet parameters measured by the NASA THEMIS spacecraft and the CPCP from DMSP (Defense Meteorological Satellite Program) measurements relative to reference models commonly used to provide simulation boundary conditions. For these data sets, a statistical model of the residual errors of reference models for CPCP and central plasma sheet parameters will be developed. The multivariate error covariance statistics will be computed and Monte Carlo scenarios of the plasma and electric field boundary conditions will be generated. In some cases, the Monte Carlo scenarios will be constrained by available in-situ data. For the different boundary conditions scenarios, the magnetically and electrically self-consistent Rice Convection Model-Equilibrium (RCM-E) will be used to simulate Dst, ground magnetic perturbations and magnetic field and plasma parameters at geosynchronous orbit. By comparing the metrics for the different boundary condition scenarios, the project will determine whether the RCM-E is physically sufficient given the uncertainties in the boundary conditions, or whether it needs additional physical processes.This project will help determine whether researchers need to continue to focus on adding more realistic physics to models of the ring current or if they should shift their focus toward improving the specification of the boundary conditions the control the models. Ultimately it will pave the way to generating ensemble space weather nowcasts and forecasts of the inner magnetosphere's plasma and fields. The project is headed by a woman scientist and also involves research ties between industry (Aerospace Corp.) and universities.

该项目将研究磁层跨极冠电位和等离子体片种群的不确定性，以及这些不确定性如何影响磁暴期间磁层环电流的强度和空间分布。它将研究模型和环的观测之间的分歧有多少可以归因于边界条件的不确定性，而不是其他原因，如模型中缺少物理过程。以往的模拟研究表明，磁层对流电场和等离子体片分布的变化，这是环电流的主要来源，强烈影响环电流。由于这个原因，成功地模拟常见的环电流观测值，如Dst指数，地面磁扰动和地球同步轨道的磁场，等离子体参数是依赖于知道的CPCP和等离子体片的密度和温度。由于这些量的现场测量的空间和时间分辨率有限，统计再分析或经验模型的平均值往往被用来确定内磁层模型的边界条件。然而，有很大的不确定性与这些边界条件规范。该项目将量化模拟风暴对CPCP以及自洽内磁层模型的离子和电子等离子体片密度和温度边界条件的不确定性的敏感程度。该方法是研究NASA THEMIS航天器和DMSP（国防气象卫星计划）测量的CPCP测量的等离子体片参数相对于通常用于提供模拟边界条件的参考模型的统计变化。对于这些数据集，CPCP和中央等离子体片参数的参考模型的残差的统计模型将开发。将计算多变量误差协方差统计，并生成等离子体和电场边界条件的蒙特卡罗场景。在某些情况下，蒙特卡罗情景将受到现有现场数据的限制。对于不同的边界条件情景，将使用磁和电自洽的赖斯对流模型-平衡（RCM-E）来模拟地球同步轨道上的Dst、地面磁扰动以及磁场和等离子体参数。通过比较不同边界条件情景的指标，本项目将确定RCM-E在考虑到边界条件的不确定性的情况下是否充分，或者它是否需要额外的物理过程。这个项目将有助于确定研究人员是否需要继续专注于在环电流模型中添加更真实的物理过程，或者他们是否应该将重点转移到改进环电流的规范上。边界条件控制模型。最终，它将为生成集合空间天气临近预报和内磁层等离子体和磁场预报铺平道路。 该项目由一名女科学家领导，还涉及工业界之间的研究联系（航空航天公司）。和大学。