A5024101174- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Geomagnetism and Paleomagnetism Studies
- Inertial Sensor and Navigation
- Solar and Space Plasma Dynamics
- 3D Surveying and Cultural Heritage
- Optical measurement and interference techniques
- Ionosphere and magnetosphere dynamics
- Advanced Measurement and Metrology Techniques
- Geophysical and Geoelectrical Methods
- Planetary Science and Exploration
- Atmospheric and Environmental Gas Dynamics
- Geological formations and processes
- Statistical and numerical algorithms
- Hydrology and Watershed Management Studies
- Distributed and Parallel Computing Systems
- Remote Sensing and LiDAR Applications
- Satellite Image Processing and Photogrammetry
- Geographic Information Systems Studies
- Climate change and permafrost
- Landslides and related hazards
- Cryospheric studies and observations
- Image and Object Detection Techniques
- Hydrology and Drought Analysis
- Earthquake Detection and Analysis
Jet Propulsion Laboratory
2021-2024
York University
2017-2021
Queen's University
2017
Aristotle University of Thessaloniki
2015
Abstract We integrate Global Positioning System displacements, Gravity Recovery and Climate Experiment gravity data, reservoir water volumes, snowpack to estimate change in subsurface California. find 29% of precipitation infiltrates mountain soil fractured bedrock each autumn winter is lost the spring summer by evapotranspiration lateral flow either within watersheds or into California's Central Valley. The Valley groundwater at 2.2 ± 0.7 km 3 /yr from 2006 2021, with 68% loss occurring...
JPL has developed a terrestrial reference frame (TRF) based on combining space geodetic techniques at the observation level. The current version includes observations from Global Positioning System (GPS), Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI); it been shown to be competitive with international standard (ITRF2020) in terms of fundamental parameters (origin scale) their temporal evolution, both linear seasonal. In this work, we build processing...
The vision of the International Association Geodesy’s Global Geodetic Observing System (GGOS) is “Advancing our understanding dynamic Earth system by quantifying planet’s changes in space and time.” This mission, as well work toward goals objectives GGOS Strategic Plan, partly supported targeted engagement with external stakeholders, managed a component Coordinating Office. External Relations includes portfolio that focuses on advocacy, visibility,...
The RL07 series of GRACE gravity field products generated at JPL is a reprocessing updated Level 1 data for the entire mission duration. Some aspects 2 processing have been from RL06 series, in an effort to improve solution quality and uncertainty quantification.Level improvements include co-estimation use full observation covariance matrices both GPS inter-satellite ranging KBR observations, background (GOCO06s) other models. updates ensure consistency continuity with GRACE-FO record, which...
Abstract. Quantification of uncertainty in surface mass change signals derived from Global Positioning System (GPS) measurements poses challenges, especially when dealing with large datasets continental or global coverage. We present a new GPS station displacement dataset that reflects load and their uncertainties. assess the structure quantify vertical land 3045 stations distributed across US. Monthly means daily positions are available for 15 years. list required corrections to isolate...
Abstract The intersatellite range measurements between the Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO) satellite pair enable mapping time variations in Earth's gravity field. Laser Ranging Interferometer (LRI) Microwave Instrument (MWI) provide independent measurements. We compare fields derived from two instruments. LRI captures time‐variable field signals up to 21 mHz (165 km half‐wavelength) globally, while MWI reaches frequencies 15 (230 km). Time‐variable mass free...
Abstract The Gravity Recovery and Climate Experiment (GRACE) gravitational models suffer from a dominant systematic error, usually referred to as “longitudinal stripes.” These stripes contaminate useful geophysical signals limit the spectrum of geoscience applications that can be benefited GRACE GRACE‐Follow On. Analyses spatiotemporal structure latitudinal stripe profiles show consistent spectral characteristics throughout three years monthly solutions. Using an elegant combination sampling...
Abstract We describe the development and assessment of a new terrestrial reference frame (TRF) based on combination geodetic techniques at observation level over period 2010–2022. Included in solution are observations from Global Positioning System (GPS), Satellite Laser Ranging (SLR) Very Long Baseline Interferometry (VLBI). A key feature our strategy is use space ties low‐Earth orbit to connect SLR GPS. Though resulting TRF only 12.6 years data, it competitive with international (ITRF2020)...
Abstract A new paradigm views the recently launched Gravity Recovery and Climate Experiment (GRACE) follow‐on mission as a gradiometer system, outside mission's design concept, promising potentially major implications in geosciences. We develop an innovative straightforward “GRACE mode,” to process future GRACE measurements derive three‐dimensional gravitational gradients. Using positions, accelerations, attitude from identical predecessor GRACE, we generate common differential...
We describe the development and assessment of a new terrestrial reference frame (TRF) based on combining GPS, SLR VLBI at observation level over period 2010–2022. Included in solution, addition to station coordinates precise orbit solutions for all participating satellites, are Earth orientation parameters (EOP) low-degree zonal coefficients (J2 J3) geopotential. The overall solution concept grew from earlier efforts realize TRF using GPS data alone, capitalizing receivers ground...
We are strengthening the application of GPS's capability to estimate change in total water using measurements elastic displacements Earth's surface; breaking down into its components such as snow, soil moisture, and groundwater; integrating GRACE gravity data infer groundwater basins. In California's Sierra Nevada, GPS each day tracks dumping dissipation storm water.  Water Year 2023, increased abruptly during two sequences snow-dominated atmospheric rivers.  Subsurface...
The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), launched in May 2018, provides invaluable information about mass change the Earth system, continuing legacy of GRACE. Fundamental requirements for successful recovery are precise orbit determination inter-satellite ranging, relative clock alignment ultra-stable oscillators (USOs), attitude determination, accelerometry. NASA/Caltech Jet Propulsion Laboratory is official Level-1 data processing analysis center weekly Level-1A/B...
This talk will provide a status update on Level-2 data processing at JPL.  Included be an overview of products currently delivered to the community, focusing newly released RL06.3 GRACE-FO fields.  Assessments quality and error levels, along with detailed discussions solution strategy included.  A look towards RL07 reprocessing GRACE additionally provided.  The plans incorporate estimation full noise covariance model satellite observations in gravity...
The GRACE Follow-On (GRACE-FO) mission’s Laser Ranging Interferometer (LRI) technology demonstration has produced ranging data functionally equivalent to the dual-band microwave (KBR) for most months between June 2018 and 2023. Despite LRI having much better measurement precision than KBR, in presence of temporal aliasing errors quality unconstrained spherical harmonic gravity solutions using been at best mostly comparable KBR data. We present recent efforts JPL make improved view...
The RL07 series of GRACE gravity field products generated at JPL is a reprocessing updated Level 1 data for the entire mission duration. Some aspects 2 processing have been from RL06 series, in an effort to improve solution quality and uncertainty quantification.Level improvements include co-estimation use full observation covariance matrices both GPS inter-satellite ranging KBR observations, background (GOCO06s) other models. updates ensure consistency continuity with GRACE-FO record, which...
Abstract. Quantification of uncertainty in surface mass change signals derived from GPS measurements poses challenges, especially when dealing with large datasets continental or global coverage. This study recommends a method for preparing and processing use future joint solution GRACE(-FO)-like observations. We assess the structure quantify vertical land displacement 3045 stations distributed across US. Monthly means daily positions are available 15 years. list required corrections to...
Geopotential models derived from Gravity Recovery and Climate Experiment (GRACE) mission measurements are significantly obscured by the presence of a systematic artifact, known as longitudinal stripes. Based on our previous work (Peidou Pagiatakis, 2020) we provide an in-depth analysis latitudinal sampling characteristics GRACE reveal intriguing mechanism that creates sub-Nyquist artifacts (stripes). Because poorly understood, simple simulation example to elucidate artifact generation....
<p>Low Earth Orbit (LEO) satellites are subject to numerous disturbances related the Earth’s upper ionosphere. Perturbations induced by activity of electromagnetic field (EM) at ionospheric layers have not been fully understood yet. This study focuses on shown GRACE-FO accelerometer measurements when EM was disturbed an intense geomagnetic storm occurred August 2018. A thorough analysis GRACE-C as well magnetic and electric from Swarm constellation is conducted,...
<p>This talk will provide a status update on Level-2 data processing at JPL.  Included be an overview of products currently delivered to the community, including gravity fields with updated accelerometer transplant product.  Assessments quality and error levels, along detailed discussions solution strategy included.  A comparison LRI KBR provided..  look towards RL07 reprocessing GRACE GRACE-FO additionally...