![]() Results for the period 2010–2019 are from NASA’s comprehensive CM6 geomagnetic field model. The team produced two animations of the geomagnetic intensity variation from 2010 to 2025, one on the Earth’s mean surface, and the other on the core-mantle boundary (CMB) that is nearly 3,000 kilometers below the surface. ![]() The magnetic observations used in GEMS are the geomagnetic gauss coefficients provided by independent global geomagnetic field models derived from observations over the past four centuries. Time variations of the state variables are governed by the magnetohydrodynamic and thermal equations, and are solved with proper initial and boundary conditions. The core dynamics model utilizes a hybrid finite difference/pseudo-spectral scheme in space, with the state variables including the magnetic field, the fluid velocity field, and the temperature anomaly. The systems works by generating an analysis at a given “analysis time” by EnKF_SYS, which will then be used as the initial state for MoSST_SYS to make forecasts until the next analysis time. This system includes a numerical core dynamics model, MoSST_SYS, for simulating the geodynamo in the Earth’s core an ensemble Kalman-filter system, EnKF_SYS, for assimilating geomagnetic observations with model forecasts and a shell-based driver, GDAS_SYS, to manage the entire assimilation process. The main tool used in the GDAS project is the Geomagnetic Ensemble Modeling System (GEMS). In addition to fundamental scientific research, the team’s assimilation results contribute to the International Geomagnetic Reference Field (IGRF), which is widely used for broad scientific research and applications. The GDAS project goals are to: 1) understand the responses of the geodynamo model to the assimilation of geomagnetic observations 2) estimate the dynamic state in the Earth’s core via assimilated geodynamo solutions 3) investigate interactions between the fluid core and the solid Earth and 4) make forecasts of geomagnetic secular variation (SV) on sub-decadal timescales. "NASA high-performance computing resources are vital for the success of our project." Weijia Kuang, NASA Goddard Project Details It is also a geomagnetic hazard to low-Earth orbit space missions, and is therefore, important to monitor and understand for fundamental science research and societal applications. ![]() The SAA provides unique opportunities for probing the nature of the Earth’s deep interior. One of our recent geomagnetic predictions is the continuous westward expansion of the South Atlantic Anomaly (SAA), an area at the Earth’s surface where the geomagnetic field intensity is exceptionally low and stretches from southern Africa, across the southern Atlantic and South America, to the eastern Pacific. A collaborative team of researchers from the Geodesy and Geophysics Lab at NASA’s Goddard Space Flight Center and the University of Maryland, Baltimore County have been working on the geomagnetic data assimilation (GDAS) project, in which space-borne and ground-based magnetic measurements are assimilated with core dynamics models via an ensemble Kalman-filter (EnKF) algorithm, with the goal to better estimate the dynamic core state and predict geomagnetic variations.
0 Comments
Leave a Reply. |