Frank Flechtner
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View article: COST-G: Status and new developments
COST-G: Status and new developments Open
The Combination Service for Time-variable Gravity fields (COST-G) of the IAG looks back at an eventful and very successful year. The operational combination of the monthly GRACE-FO gravity fields now comprises eight analysis centers, provi…
View article: Stochastic modeling of non-tidal atmospheric and oceanic dealiasing models for GFZ GRACE/GRACE-FO Level-2 processing
Stochastic modeling of non-tidal atmospheric and oceanic dealiasing models for GFZ GRACE/GRACE-FO Level-2 processing Open
The central hypothesis of the Research Unit (RU) New Refined Observations of Climate Change from Spaceborne Gravity Missions (NEROGRAV), funded for the second three-year phase by the German Research Foundation DFG, reads: only by concurren…
View article: GFZ daily GRACE/GRACE-FO Kalman filter solutions
GFZ daily GRACE/GRACE-FO Kalman filter solutions Open
The satellite missions GRACE (Gravity Recovery And Climate Experiment) and GRACE-Follow-on (GRACE-FO) measure gravity field variations with homogeneous global coverage. Standard GRACE/GRACE-FO solutions are usually provided by different an…
View article: Current status of the planned GFZ RL07 GRACE/GRACE-FO Level-2 time series
Current status of the planned GFZ RL07 GRACE/GRACE-FO Level-2 time series Open
As part of the Science Data System, the GFZ Helmholtz Centre for Geosciences is one of the official GRACE/GRACE-FO Level-2 processing centers which routinely provide monthly gravity field models. These models are used by a wide range of ge…
View article: Towards 30-years of mass change observations: GRACE Follow-On extended mission phase, and GRACE-Continuity developments 
Towards 30-years of mass change observations: GRACE Follow-On extended mission phase, and GRACE-Continuity developments  Open
The GRACE Follow-On (GRACE-FO) satellite mission, a partnership between NASA (US) and GFZ (Germany), successfully completed its nominal five-year prime mission phase in May 2023, and is currently in its extended mission phase. GRACE-FO con…
View article: Optimized gravity field retrieval for the MAGIC mission concept using background model uncertainty information
Optimized gravity field retrieval for the MAGIC mission concept using background model uncertainty information Open
Errors in ocean tide and non-tidal atmospheric and oceanic models are among the largest error sources in gravity field recovery from space. We co-estimate corrections to these background models subject to uncertainty constraints during the…
View article: GravIS: mass anomaly products from satellite gravimetry
GravIS: mass anomaly products from satellite gravimetry Open
Accurately quantifying global mass changes at the Earth's surface is essential for understanding climate system dynamics and their evolution. Satellite gravimetry, as realized with the Gravity Recovery and Climate Experiment (GRACE) and GR…
View article: GRACE-FO: science results, mission status and outlook
GRACE-FO: science results, mission status and outlook Open
Since 2018, the GRACE Follow-On satellite mission, a partnership between NASA (US) and GFZ (Germany), is continuing the unique essential climate data record of mass change across the Earth system initiated in 2002 by the GRACE mission (200…
View article: Using stochastic information on geophysical processes for daily GRACE Kalman filter solutions
Using stochastic information on geophysical processes for daily GRACE Kalman filter solutions Open
The Research Unit (RU) New Refined Observations of Climate Change from Spaceborne Gravity Missions (NEROGRAV) aims at improving the understanding and providing new information about sensor data, background models and the processing strateg…
View article: Gravity field recovery using co-estimation of background model errors to improve de-aliasing capabilities of the MAGIC double-pair constellation
Gravity field recovery using co-estimation of background model errors to improve de-aliasing capabilities of the MAGIC double-pair constellation Open
GFZ has performed various full-scale simulations within the ESA NGGM/MAGIC Science Support Study, including instrument noise and background model error assumptions. The focus was set on developing and applying extended parameterization tec…
View article: Comparison of monthly GRACE-FO gravity fields from KBR and different LRI Level-1B data sets
Comparison of monthly GRACE-FO gravity fields from KBR and different LRI Level-1B data sets Open
The main observations to recover monthly gravity fields from the GRACE-FO mission are provided by two different and independent instruments, which are the K-band ranging (KBR) instrument and the Laser Ranging Interferometer (LRI). From gen…
View article: Global gravity and mass change observations beyond GRACE-FO: updates on the upcoming GRACE-Continuity mission
Global gravity and mass change observations beyond GRACE-FO: updates on the upcoming GRACE-Continuity mission Open
We will present an update on the development of the next pair of satellites, GRACE-Continuity (GRACE-C), to track Earth system mass change.  The satellites are being developed in partnership between the United States and Germany, cont…
View article: High-resolution Greenland ice sheet mass anomalies from data fusion using graph neural networks
High-resolution Greenland ice sheet mass anomalies from data fusion using graph neural networks Open
The Greenland Ice Sheet (GrIS) plays an important role in the climate system. Since the twenty-first century, GrIS has been melting rapidly due to oceanic and atmospheric warming, leading to a global mean sea level rise of more than 1 mill…
View article: Stochastic modelling of non-tidal atmospheric and oceanic dealiasing models for GFZ GRACE/GRACE-FO Level-2 processing
Stochastic modelling of non-tidal atmospheric and oceanic dealiasing models for GFZ GRACE/GRACE-FO Level-2 processing Open
The central hypothesis of the Research Unit (RU) New Refined Observations of Climate Change from Spaceborne Gravity Missions (NEROGRAV), funded for the second three years phase by the German Research Foundation DFG, reads: only by concurre…
View article: GravIS: mass anomaly products from satellite gravimetry
GravIS: mass anomaly products from satellite gravimetry Open
Accurately quantifying global mass changes at the Earth’s surface is essential for understanding climate system dynamics and their evolution. Satellite gravimetry, as realized with the Gravity Recovery and Climate Experiment (GRACE) and GR…
View article: Non‐Tidal Ocean Loading Signals of the North and Baltic Sea From Terrestrial Gravimetry, GNSS, and High‐Resolution Modeling
Non‐Tidal Ocean Loading Signals of the North and Baltic Sea From Terrestrial Gravimetry, GNSS, and High‐Resolution Modeling Open
Non‐tidal ocean loading (NTOL) signals are known to be a significant source of geophysically induced noise in gravimetric and geodetic observations also far‐away from the coast and especially during extreme events such as storm surges. Ope…
View article: Non-tidal ocean loading signals of the North and Baltic Sea from terrestrial gravimetry, GNSS, and high-resolution modeling
Non-tidal ocean loading signals of the North and Baltic Sea from terrestrial gravimetry, GNSS, and high-resolution modeling Open
Non-tidal ocean loading signals are known to be a significant source of geophysically induced noise in gravimetric and geodetic observations also far-away from the coast and especially during extreme events such as storm surges. Operationa…
View article: A New Knowledge Portal on Mass Transport Satellite Missions: www.globalwaterstorage.info
A New Knowledge Portal on Mass Transport Satellite Missions: www.globalwaterstorage.info Open
Dedicated satellite gravity missions orbiting the Earth at very low altitudes have greatly improved our knowledge about mass transport processes. That includes the terrestrial water cycle, ice sheet and glacier dynamics, ocean mass variabi…
View article: G3P v1.12: Advancements of a Global Groundwater Storage Anomaly Dataset from Satellite Gravimetry
G3P v1.12: Advancements of a Global Groundwater Storage Anomaly Dataset from Satellite Gravimetry Open
The Global Gravity-based Groundwater Product (G3P) has evolved with a new version (V1.12), bringing substantial enhancements to our satellite-based groundwater storage anomaly dataset—a prototype for a future product within the EU Co…
View article: Advanced processing strategies for a future GFZ GRACE/GRACE-FO Level-2 data release
Advanced processing strategies for a future GFZ GRACE/GRACE-FO Level-2 data release Open
Being part of the GRACE/GRACE-FO Science Data System, the GFZ German Research Centre for Geosciences is one of the official Level-2 processing centers routinely providing monthly gravity field models. These models are used by a wide variet…
View article: Gravity field recovery using co-estimation of background model errors to improve de-aliasing capabilities of the MAGIC double-pair constellation
Gravity field recovery using co-estimation of background model errors to improve de-aliasing capabilities of the MAGIC double-pair constellation Open
GFZ has performed various full-scale simulations within the ESA NGGM/MAGIC Science Support Study, including instrument noise and background model error assumptions. The focus was set on developing and applying extended parameterization tec…
View article: GravIS Portal: User-friendly Ocean Bottom Pressure data from GRACE and GRACE-FO
GravIS Portal: User-friendly Ocean Bottom Pressure data from GRACE and GRACE-FO Open
The German Research Centre for Geosciences (GFZ), together with the Alfred-Wegener-Institute (AWI) and the Technische Universität Dresden, maintains the ‘Gravity Information Service’ portal (GravIS, gravis.gfz-potsdam.de).…
View article: 20 years of the ICGEM Service and the new developments  
20 years of the ICGEM Service and the new developments   Open
ICGEM is one of the five services coordinated by the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG). The service has been actively responding to the needs of the scientific community for the la…
View article: The COST-G GRACE RL02
The COST-G GRACE RL02 Open
In 2019 the Combination Service for Time-variable Gravity fields (COST-G) started its operation with the first release of combined monthly GRACE gravity field models. Meanwhile almost five years have passed, while new experience was gained…
View article: Will the MAGIC mission improve the observability of extreme hydrological events?
Will the MAGIC mission improve the observability of extreme hydrological events? Open
NASA and DLR will launch in 2028 GRACE-C (Gravity Recovery and Climate Experiment – Continuation). This mission will again be launched into a polar orbit at 500 km initial altitude and extend the observation of the time-variable Eart…
View article: GRACE-FO: science results, project status and further plans 
GRACE-FO: science results, project status and further plans  Open
The GRACE Follow-On satellite mission, a partnership between NASA (US) and GFZ (Germany), successfully completed its nominal five-year prime mission phase in May 2023, and has already entered its extended mission phase. GRACE-FO continues …
View article: EPOS-OC, a Universal Software Tool for Satellite Geodesy at GFZ
EPOS-OC, a Universal Software Tool for Satellite Geodesy at GFZ Open
The adjustment of parameters from different observations describing the state and change of system Earth has been conducted at the Helmholtz Centre Potsdam—GFZ German Research Centre for Geosciences via satellite observations for many deca…
View article: Satellite Gravity Field Recovery Using Variance‐Covariance Information From Ocean Tide Models
Satellite Gravity Field Recovery Using Variance‐Covariance Information From Ocean Tide Models Open
Monthly gravity field recovery using data from the GRACE and GRACE Follow‐On missions includes errors limiting the spatial and temporal resolution of the estimated gravity fields. The major error contributions, besides the noise of the acc…
View article: A superconducting gravimeter on the island of Heligoland for the high-accuracy determination of regional ocean tide loading signals of the North Sea
A superconducting gravimeter on the island of Heligoland for the high-accuracy determination of regional ocean tide loading signals of the North Sea Open
SUMMARY The superconducting gravimeter GWR iGrav 047 has been installed on the small offshore island of Heligoland in the North Sea approximately at sea level with the overall aim of high-accuracy determination of regional tidal and non-ti…