Mesoscale Ionospheric Electrodynamics as a Driver of Rapid Geomagnetic Variability

ROSES ID: NNH19ZDA001N      Selection Year: 2019      

Program Element: Focused Science Topic

Principal Investigator: Kareem Sorathia

Affiliation(s): Johns Hopkins University

Project Member(s):
Kuvshinov, Alexey Co-I EIDGENOSSISCHE TECHNISCHE HOCHSCHULE ETH
Vines, Sarah K Co-I Johns Hopkins University
Michael, Adam T Co-I Johns Hopkins University
Blake, Sean Co-I Catholic University of America
Merkin, Viacheslav G. Co-I Johns Hopkins University
Pulkkinen, Antti A Co-I NASA Goddard Space Flight Center
Ohtani, Shin-ichi Co-I Johns Hopkins University

Summary:

Science Goals and Objectives.
Ongoing work has identified the critical role of complex and localized geomagnetic disturbances (GMDs), and their interaction with the Earth's 3D conductivity distribution, in driving geoelectric fields (GEFs). These localized and rapid GMDs are not only a key space weather target but also a manifestation of fundamental magnetospheric processes and their auroral ionospheric counterparts at mesoscales. The overarching goal of the proposed project is to "Understand the physical processes responsible for the generation of localized and rapid GIC variability by characterizing magnetospheric drivers and ground effects of mesoscale ionospheric electrodynamics."

Predicting GICs is a grand challenge of geospace modeling, ground effects are the end result of a causal chain of processes ultimately driven by the interaction of solar disturbances with the magnetosphere. To accomplish our goal we will utilize a combination of cutting-edge first-principles models and a collection of heterogeneous data sets spanning geospace: in the magnetosphere, ionosphere, and on the ground. We will address the following science questions:

SQ#1: What is the role of magnetotail bursty bulk flows in driving localized (<500 km), rapid surface geomagnetic disturbances? How does it depend on the level of geomagnetic activity?

SQ#2: What is the relationship between the intensity and spatiotemporal scale of geomagnetic surface disturbances? Do spatially localized disturbances consistently (statistically) produce larger surface magnetic field temporal variations (dB/dt)?

SQ#3: How do rapid ground geomagnetic disturbances interact with global and mesoscale structure in the Earth's ground conductivity to create hazardous geoelectric field magnitudes?

Methodology.
Our investigation will proceed along three major thrusts:
Multi-scale and multi-domain modeling: We will deploy a physics-based model pipeline combining a global magnetosphere model with an electromagnetic induction model incorporating global or regional realistic 3D conductivities. Each of the models has a demonstrated capability of resolving GIC-critical scales, hundreds of km on the ground.

Cross-domain and cross-scale validation: We will isolate and quantify model errors at each stage between the solar wind and ground by using "bracketing" data sets: THEMIS and GEOTAIL (magnetotail), AMPERE (ionosphere), and SuperMAG, augmented by POLAR and IMAGE (ground). We will formulate our validation strategy to focus on the ability of the models to reproduce statistical relationships seen in data at all pertinent scales.

Community access and stakeholder engagement: The modeling we propose to undertake is timely as it will respond directly to the need for improved characterization of extreme GEFs to inform ongoing work to update GMD standards. We will work with stakeholders to transition new research-based understanding to inform evolving standards.

Relevance and contributions to Focused Science Topic (FST).
This work contributes to all three primary goals of FST#3: high-resolution modeling will connect solar wind driving to ground GMDs at GIC-critical scales (FST Goal #1); using surface GMDs as an input to 3D conductivity models will predict GEFs and their characteristic scales (FST Goal #2); and finally, by combining the previous two efforts, we will identify the critical ground-scales for situational awareness and hazard mitigation and informing spacing and location of ground-based observatories (FST Goal #3). Beyond direct contribution to the FST primary goals, this work will also complement the broader FST team effort by providing high-resolution model predictions of GMDs and GEFs.

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