A5019304001- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Inertial Sensor and Navigation
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Spacecraft and Cryogenic Technologies
- Planetary Science and Exploration
- Methane Hydrates and Related Phenomena
- Computational Physics and Python Applications
- Reservoir Engineering and Simulation Methods
- Geophysical and Geoelectrical Methods
- Astro and Planetary Science
- Spacecraft Design and Technology
- Space Satellite Systems and Control
- Astronomical Observations and Instrumentation
- Oceanographic and Atmospheric Processes
- Distributed and Parallel Computing Systems
- Meteorological Phenomena and Simulations
- Statistical and numerical algorithms
- Geological Modeling and Analysis
- Flood Risk Assessment and Management
- Climate variability and models
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
The University of Texas at Austin
2016-2025
National Center of Space Research and Technology
2015-2019
Jet Propulsion Laboratory
2004
The GRACE mission is designed to track changes in the Earth's gravity field for a period of five years. Launched March 2002, two satellites have collected nearly years data. A span data available during Commissioning Phase was used obtain initial models. models developed with this are more than an order magnitude better at long and mid wavelengths previous error estimates indicate 2‐cm accuracy uniformly over land ocean regions, consequence highly accurate, global homogenous nature These...
Monthly gravity field estimates made by the twin Gravity Recovery and Climate Experiment (GRACE) satellites have a geoid height accuracy of 2 to 3 millimeters at spatial resolution as small 400 kilometers. The annual cycle in variations, up 10 some regions, peaked predominantly spring fall seasons. Geoid variations observed over South America that can be largely attributed surface water groundwater changes show clear separation between large Amazon watershed smaller watersheds north. Such...
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, models surface mass balance glacial isostatic adjustment to estimate the Earth's polar ice sheets. find that there is good agreement between different methods--especially in Greenland West Antarctica--and combining leads greater certainty. Between 1992 2011, sheets Greenland, East Antarctica, Antarctic Peninsula changed by -142 ± 49, +14 43, -65 26, -20...
Abstract The determination of the gravity model for Gravity Recovery and Climate Experiment (GRACE) is susceptible to modeling errors, measurement noise, observability issues. ill‐posed GRACE estimation problem causes unconstrained RL05 solutions have north‐south stripes. We discuss development global equal area mascon improve information study Earth surface processes. These regularized are developed with a 1° resolution using Tikhonov regularization in geodesic grid domain. derived from...
Abstract Since June, 2018, the Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO) is extending 15‐year monthly mass change record of GRACE mission, which ended in June 2017. The GRACE‐FO instrument flight system performance has improved over GRACE. Better attitude solutions enhanced pointing result reduced fuel consumption gravity range rate post‐fit residuals. One accelerometer requires additional calibrations due to unexpected measurement noise. fields from 2018 through December...
Abstract The scarcity of groundwater storage change data at the global scale hinders our ability to monitor resources effectively. In this study, we assimilate a state‐of‐the‐art terrestrial water product derived from Gravity Recovery and Climate Experiment (GRACE) satellite observations into NASA's Catchment land surface model (CLSM) scale, with goal generating time series that are useful for drought monitoring other applications. Evaluation using in situ nearly 4,000 wells shows GRACE...
The Gravity Recovery and Climate Experiment Follow-On mission was conceived to continue the successful legacy of recently decommissioned and, at same time, serve as a platform demonstrate first-ever in-space intersatellite laser ranging interferometer technology pathfinder for future gravity mapping missions. Launched in May 2018, observatory builds on design original satellites, but incorporates number improvements based lessons learned, features significantly increased complexity due...
Precise measurements of the Earth's time‐varying gravitational field from NASA/Deutsches Zentrum für Luft‐ und Raumfahrt Gravity Recovery and Climate Experiment (GRACE) mission allow unprecedented tracking transport mass across underneath surface Earth give insight into secular, seasonal, subseasonal variations in global water supply. Several groups produce these estimates, while various gravity fields are similar, differences processing strategies tuning parameters result solutions with...
The GRACE Gravity Model 01 (GGM01), computed from 111 days of K‐band ranging (KBR) data, is differenced a global mean sea surface (MSS) decade satellite altimetry to determine dynamic ocean topography (DOT). As test the GGM01 gravity model, large‐scale zonal and meridional geostrophic currents are compared with those derived hydrographic surface. Reduction in residual RMS between two by 30–60% (and increased correlation) indicates that geoid represents dramatic improvement over older models,...
The Ganges, Brahmaputra, and Meghna rivers converge in Bangladesh with an annual discharge second to the Amazon. Most of flow occurs during summer monsoon causing widespread flooding. impounded water represents a large surface load whose effects can be observed Gravity Recovery Climate Experiment (GRACE) GPS data. is at center largest seasonal anomaly GRACE gravity field, reflecting storage Southeast Asia. Eighteen continuous stations record vertical motions up 6 cm that inversely correlate...
Abstract Gravity Recovery and Climate Experiment (GRACE) provides monthly solutions for the Earth's gravity field in form of spherical harmonic coefficients. These can be used to infer changes mass at surface. The pole tide (the response Earth oceans polar motion) causes signals dominated by harmonics degree 2, order 1. If is not removed from GRACE data, it affects coefficients those ( C 21 , S ) introduces errors when using determine surface variations. partially processing centers before...
Abstract We carry out a comprehensive error assessment of Gravity Recovery and Climate Experiment (GRACE) GRACE Follow‐On (GFO) Release‐6 (RL06) solutions from the Center for Space Research (CSR) at University Texas Austin, NASA Jet Propulsion Laboratory (JPL), Geoforschungszentrum (GFZ). The study covers period April 2002 to August 2020 uses two different methods, one based upon open ocean residuals (OOR) other Three‐Cornered Hat (TCH) calculation. General results methods are similar. With...
Abstract We evaluate the impact of Gravity Recovery and Climate Experiment data assimilation (GRACE-DA) on seasonal hydrological forecast initialization over United States, focusing groundwater storage. GRACE-based terrestrial water storage (TWS) estimates are assimilated into a land surface model for 2003–16 period. Three-month hindcast (i.e., past events) simulations initialized using states from reference (no assimilation) GRACE-DA runs. Differences between two initial condition (IHC)...
Using orbital simulations of the Gravity Recovery and Climate Experiment (GRACE) spacecraft, we examined effects on gravity recovery due to short period, non‐tidal temporal mass variability in atmosphere, ocean, continental hydrology. We found that magnitude aliasing error was strongly correlated with power high‐frequency models. Degree relative measurement increased by a factor ∼20 atmospheric (corresponding geoid anomalies approximately 1 mm at 500 km wavelengths), ∼10 ocean model, ∼3...
Abstract We analyze global mean ocean mass (GMOM) change over the 12‐year period (January 2005 to December 2016) using three different Gravity Recovery and Climate Experiment (GRACE) RL05 monthly time‐variable gravity solutions compare GRACE results with independent observations from satellite altimeter Argo floats (i.e., Altimeter‐Argo). The new both Altimeter‐Argo show substantially larger GMOM rates than previous estimates, attributed increased ice losses land in recent years. Altimeter...
Abstract The Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO), launched May 22, 2018 collecting science data since June 2018, is extending the 15‐year record of Earth mass change established by its predecessor GRACE mission (2002–2017). GRACE‐FO satellites carry onboard a novel technology demonstration instrument for intersatellite ranging, Laser Ranging Interferometer (LRI), in addition to microwave interferometer (MWI) carried on GRACE. LRI has out‐performed in‐orbit...