Spherical Slepian function modelling of the magnetic field to probe the outer core
Lead Research Organisation:
University of Edinburgh
Department Name: Sch of Geosciences
Abstract
This project will develop techniques to better model and understand the regional magnetic field and core surface flows and internal dynamics using spherical Slepian functions
People |
ORCID iD |
| Kathy Whaler (Primary Supervisor) | |
| Hannah Rogers (Student) |
Publications
Rogers H
(2019)
Investigation of regional variation in core flow models using spherical Slepian functions
in Earth, Planets and Space
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| NE/R009228/1 | 01/09/2017 | 31/08/2023 | |||
| 1960295 | Studentship | NE/R009228/1 | 01/10/2017 | 28/02/2022 | Hannah Rogers |
| Description | My PhD was based on using a mathematical methodology (spherical Slepian functions) to look at regional dynamics occurring at the top of the outer core. We take measurements of magnetic field change from satellites and complete an inversion process to investigate the motion of the liquid iron at the top of the outer core. Traditionally this is done using spherical harmonics, which can be compared to breaking the signal down into a number of waves on a sphere. Spherical harmonics have many benefits but are not suitable for regional studies, such as the investigation of the impact of low seismic wave speed anomalies at the base of the mantle. The main findings of the PhD can be split into two categories. Firstly, we have completed methodology development and can explain the behaviour of spherical Slepian functions to a greater degree now. Also, we have integrated spherical Slepian functions into the inversion process in order to invert directly into a region as opposed to separating a global model after the inversion. The second main finding was the investigation of the impact of the two Large Low Velocity Provinces at the base of the mantle. These features are thought to be hotter than the surrounding mantle but little is known about their internal structure or formation and the impact of these features on the core. We found that the proportional energy of the LLVPs is different from the proportional surface area, and there seems to be a correlation between periods of known magnetic field acceleration change and the timing of turning points in the power of the separated secular variation power. We conclude that spherical Slepian functions may not be the best methodology to study regional dynamics at the Earth's outer core surface but further work needs to be done to investigate the impact of LLVPs. |
| Exploitation Route | We have found out new information about the behaviour of spherical Slepian functions which can be applied to any topic using spherical harmonics. The work on LLVPs can be used to understand the core-mantle interactions to a greater extent |
| Sectors | Environment,Other |
| Description | I have worked on outreach and education and passionately feel that one of the best things to do is to bring current research to the general public and to education settings |
| First Year Of Impact | 2019 |
| Sector | Education |
| Impact Types | Cultural |
| Description | Fieldwork Equipment Guides |
| Geographic Reach | Local/Municipal/Regional |
| Policy Influence Type | Influenced training of practitioners or researchers |
| Impact | The teaching for undergraduate students will be more consistent and ensuring that the equipment has working instructions that ensure future use |
| Description | IUGG19 - Travel Grant - REGISTRATION FEE and ADDITIONAL SUPPORT |
| Amount | $1,000 (CAD) |
| Organisation | International Union of Geodesy and Geophysics |
| Sector | Charity/Non Profit |
| Country | Germany |
| Start | 07/2019 |
| End | 07/2019 |
| Description | SEDI 2022 Travel Grant |
| Amount | $650 (USD) |
| Organisation | Study of the Earth's Deep Interior |
| Sector | Academic/University |
| Start | 06/2022 |
| End | 06/2022 |
| Description | Travel Grant for "Observing and simulating Earth's core and the magnetic field" RAS Meeting |
| Amount | £150 (GBP) |
| Organisation | Royal Astronomical Society |
| Sector | Academic/University |
| Country | United Kingdom |
| Start | 11/2019 |
| End | 11/2019 |
| Title | Spherical Slepian functions incorporated into inversion techniques for magnetic data |
| Description | New methodology for inverting magnetic secular variation (measured using satellite geomagnetic virtual observatories) for regional core surface flow by using spherical Slepian functions |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | Investigation of regional dynamics and regional mantle influence on core surface flow. Used to investigate the regional influence of Large Low Velocity Provinces (LLVPs) at the base of the mantle and found a consistency between the timings of jerks and peaks within the SV power spectrum. Paper in prep before May |
| Description | BGS CASE Partnership |
| Organisation | British Geological Survey |
| Department | Geomagnetism Group |
| Country | United Kingdom |
| Sector | Public |
| PI Contribution | As a PhD student I have been investigating topics of interest highlighted by the original grant. This has mostly involved investigations into spherical Slepian functions using MATLAB coding. |
| Collaborator Contribution | Ciaran Beggan, from the BGS Geomagnetism team, is a supervisor on my project and has provided guidance during my PhD. As well as this, the geomagnetism team have provided opportunities for me to visit magnetic observatories, assist with the SWIGS project fieldwork, invited me to seminars and been a friendly and helpful source of guidance and information. BGS has also provided some introductory training at their Nottingham headquarters and invited me to attend further workshops. |
| Impact | Rogers, H.F., Beggan, C.D. & Whaler, K.A. (2019). https://doi.org/10.1186/s40623-019-0997-7 |
| Start Year | 2017 |
| Description | Orbital Micro Systems NPIF Placement |
| Organisation | Orbital Micro Systems |
| Country | United States |
| Sector | Private |
| PI Contribution | I had a compulsory national productivity investment fund (NPIF) 6 month internship to complete as part of the PhD studentship funding. Within this time, I did a number of tasks to assist Orbital Micro Systems (OMS) with their activities. These included: • looking at the data output from passive microwave radiometers in an attempt to design a product for the insurance industry focused around assessing crop damage from hail • the submission of two proposals to the European Space Agency (ESA) • developing a python software pipeline from the SEDAS API source to download 1C satellite data from ESA sources • watching live as the first OMS cubesat was launched from the International Space Station • write presentations for the Government of Kerala when OMS aimed to set up a Centre of Excellence in India • Completed website updates and improved general design • Worked on social media outreach • Attended Scottish Space sector events and meetings as a representative of OMS, improving my knowledge of the industry and providing input across multiple projects • Assisted the development of the University of Edinburgh Space Policy to be adopted in 2020 • Promoted the involvement of further geophysicists to engage with the Space sector by speaking about my experiences at the SEG virtual student conference • Attended the UK Space Conference 2019 in Cardiff, Wales. I attended talks from industry and academics, was responsible for talking to data suppliers in a sales role, represented the company and formed contacts with other members of the space sector • Helped organise an event for the US Consulate of Scotland for the launch of the ICED platform |
| Collaborator Contribution | I had guidance to complete given tasks, freedom to work on tasks, facilities to complete given tasks, paid for conference travel and entry, introduced me to various members of the Scottish Space Community. |
| Impact | Two grant applications to the European Space Agency Updated Website and social media Promotion of Orbital Micro Systems at National events Python software pipeline from the SEDAS API source |
| Start Year | 2019 |
| Description | 'Skype a Scientist' Participant |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | Was a participant of the 'Skype a Scientist' initiative to talk to the general public and schools about the science I was undertaking. I undertook 2 calls: 1) with a family with a female child who wanted to understand how maths and physics can be used in science, and 2) with a school to talk about the Earth and how we can relate maths/physics to the Earth |
| Year(s) Of Engagement Activity | 2020,2021 |
| Description | Co-Chair of IAGA Social Media Working Group |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Formed and managed the working group and social media platforms to increase awareness of IAGA. I have assisted organisation of IAGA Social Media Group Business Meetings, gave multiple talks on our work, and co-convened a session at IAGA-IASPEI 2021. Assisted in blog writing, creating content, and multiple outreach films including the raising of funding for such projects. |
| Year(s) Of Engagement Activity | 2019,2020,2021,2022,2023 |
| URL | https://iaga-aiga.org/index.php?id=education-outreach |
| Description | Edinburgh University Women in STEM mentor |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Undergraduate students |
| Results and Impact | Worked with an undergraduate female STEM student to develop her skills, build confidence and apply for opportunities to develop her STEM career |
| Year(s) Of Engagement Activity | 2020,2021 |
| Description | Invited ETH Zurich Seminar Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Gave an online seminar talk entitled "Investigating regional flow and secular variation on the core-mantle boundary: adapting spherical Slepian functions for virtual observatory satellite data inversion" to the Earth and Planetary Magnetism Group at ETH Zurich |
| Year(s) Of Engagement Activity | 2021 |
| Description | Invited Princeton Global Geophysics Seminar Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Attended Princeton to give a invited seminar talk entitled "Investigating regional heterogeneity at the core-mantle boundary and its impact on outer core flow by applying spherical Slepian functions" to the Global Geophysics Research Group |
| Year(s) Of Engagement Activity | 2022 |
| Description | Invited Scripps Institution of Oceanography Magnetism Group Seminar Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited seminar talk at Scripps Institute of Oceanography entitled "Investigating regional heterogeneity at the core-mantle boundary and its impact on outer core flow" |
| Year(s) Of Engagement Activity | 2022 |