# SFP Announcements of Opportunity
**Source**: http://announcements.surf.caltech.edu/index.cfm?event=ViewAODetail&id=2987&inFrame=&type=
**Parent**: http://announcements.surf.caltech.edu/index.cfm?event=ShowAOPublicList&formType=UROH
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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | | | | --- | --- | --- | | | | | | | | | | | | --- | --- | --- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | | | --- | --- | --- | --- | | | | | --- | | Student-Faculty Programs Office Summer 2026 Announcements of Opportunity | | | | [<< Prev](http://announcements.surf.caltech.edu/index.cfm?event=ViewAODetail&id=2988&inFrame=&type=#ao_nav_links) Record 3 of 12 [Next >>](http://announcements.surf.caltech.edu/index.cfm?event=ViewAODetail&id=2985&inFrame=&type=#ao_nav_links) [Back To List](http://announcements.surf.caltech.edu/index.cfm?event=ShowAOPublicList&inFrame=&type=#ao_list) --- | | | | --- | --- | | Project: | **Voronoi-Based Spatial Weighting for Robust Geocenter Motion Estimation from JTRF** (JPL AO No. 16875) | | Disciplines: | Geophysics, Space Geodesy, Aerospace Engineering | | Mentor: | Claudio Abbondanza, (JPL), [Claudio.Abbondanza@jpl.nasa.gov](mailto:Claudio.Abbondanza@jpl.nasa.gov), Phone: (818) 354-1870 | | Background: | The center-of-mass (CM) of the total Earth system (solid Earth plus fluid envelope) is commonly referred to as geocenter. Geocenter motion describes the motion of the CM relative to the center-of-figure (CF) of the solid Earth surface. This quantity plays a fundamental role in satellite orbit determination, terrestrial reference frame realization, and studies of global mass redistribution. Geocenter motion is primarily driven by degree-1 loading processes and reflects large-scale mass transport in the Earth system. It is therefore critical for understanding sea level rise, atmospheric and ocean circulation, hydrology, glacial isostatic adjustment, and deep Earth processes. | | Description: | ## Project Description The objective of this project is to develop and test a Voronoi-based spatial weighting scheme for improving JTRF-derived geocenter motion estimates. The student will contribute to the following tasks: 1. Station Selection and Quality Control \* Identify high-quality station time series based on: \* Length of observing history \* Repeatability metrics \* Formal uncertainties \* Exclude stations exhibiting significant nonlinear or poorly modeled motion 2. Spherical Voronoi Tessellation \* Compute spherical Voronoi polygons for selected JTRF stations (using e.g. Python’s scipy.spatial.SphericalVoronoi) \* Compute polygon areas on the sphere 3. Spatial Weight Computation \* Derive normalized station weights based on spherical polygon area \* Investigate regularization strategies to: \* Enforce smoothness between neighboring polygons \* Constrain adjacent weights toward equality within a prescribed variance 4. Integration into Geocenter Estimator \* Modify the existing geocenter estimation code to incorporate spatial weights \* Compare weighted and unweighted CM–CF solutions \* Quantify reduction in geometric bias ## Expected Outcomes By the end of the internship, the student will: \* Deliver a reproducible Python-based Voronoi weighting pipeline \* Produce quantitative comparisons between classical and weighted geocenter estimates \* Document the methodology and validation results \* Present findings at an internal JPL seminar \* Potentially contribute to a conference abstract | | References: | ## Key References - Rebischung et al. (2024), \*ITRF2020 seasonal geocenter motion model\*, Journal of Geodesy - Caroli et al. (2009), \*Robust and Efficient Delaunay triangulations of points on or close to a sphere\* - Wu et al. (2019), \*Improved global nonlinear surface mass variation estimates from geodetic displacements and reconciliation with GRACE data\*, JGR Solid Earth | | Student Requirements: | - Coursework in applied mathematics, physics, aerospace engineering, planetary sciences, space geodesy or computer science - Exposure to numerical methods, linear algebra, and- basic estimation theory - Familiarity with spherical geometry concepts - Programming experience in Python, MATLAB, Fortran, or C++ | | Location / Safety: | Project building and/or room locations: . Student will need special safety training: . | | Programs: | This AO can be done under the following programs: | | | | | | --- | --- | --- | --- | | | | Program | Available To | | | | [SURF@JPL](https://sfp.caltech.edu/undergraduate-research/programs/surfjpl) | both Caltech and non-Caltech students | Click on a program name for program info and application requirements. | --- [<< Prev](http://announcements.surf.caltech.edu/index.cfm?event=ViewAODetail&id=2988&inFrame=&type=#ao_nav_links) Record 3 of 12 [Next >>](http://announcements.surf.caltech.edu/index.cfm?event=ViewAODetail&id=2985&inFrame=&type=#ao_nav_links) [Back To List](http://announcements.surf.caltech.edu/index.cfm?event=ShowAOPublicList&inFrame=&type=#ao_list) | --- | | | | --- | --- | | Problems with or questions about submitting an AO? Call [Student-Faculty Programs](mailto:sfp@caltech.edu) of the Student-Faculty Programs Office at (626) 395-2885. | [About This Site](http://announcements.surf.caltech.edu/About-Mighty-Ant-DataWorks.cfm) | | | | | | | | | |