scholarly journals Mass distribution and mass transport in the Earth system

2012 ◽  
Vol 59-60 ◽  
pp. 1-8 ◽  
Author(s):  
Jürgen Kusche ◽  
Volker Klemann ◽  
Wolfgang Bosch
Keyword(s):  
Mass Transport ◽  
Mass Distribution ◽  
Earth System ◽  
The Earth

Future Gravity Mission Concepts for Sustained Observation of Mass Transport in the Earth System

2021 ◽  
Author(s):  
Roland Pail
Keyword(s):  
Mass Transport ◽  
Closed Loop ◽  
Cold Atom ◽  
Radial Component ◽  
Transport Processes ◽  
Single Pair ◽  
Earth System ◽  
Next Generation ◽  
The Earth ◽  
Gravity Mission

<p>Next Generation Gravity Missions are expected to enhance our knowledge of mass transport processes in the Earth system, establishing their products applicable to new scientific fields and serving societal needs. Compared to the current situation (GRACE Follow-On), a significant step forward to increase spatial and temporal resolution can only be achieved by new mission concepts, complemented by improved instrumentation and tailored processing strategies.</p><p>In extensive numerical closed-loop mission simulations studies, different mission concepts have been studied in detail, with emphasis on orbit design and resulting spatial-temporal ground track pattern, enhances processing and parameterization strategies, and improved post-processing/filtering strategies. Promising candidates for a next-generation gravity mission are double-pair and multi-pair constellations of GRACE/GRACE-FO-type satellites, as they are currently jointly studied by ESA and NASA. An alternative concept is high-precision ranging between high- and low-flying satellites. Since such a constellation observes mainly the radial component of gravity-induced orbit perturbations, the error structure is close to isotropic, which significantly reduces artefacts of along-track ranging formations. This high-low concept was proposed as ESA Earth Explorer 10 mission MOBILE and is currently further studies under the name MARVEL by the French space agency. Additionally, we evaluate the potential of a hybridization of electro-static and cold-atom accelerometers in order to improve the accelerometer performance in the low-frequency range.</p><p>In this contribution, based on full-fledged numerical closed-loop simulations with realistic error assumptions regarding their key payload, different mission constellations (in-line single-pair, Bender double-pair, multi-pairs, precise high-low tracking) are assessed and compared. Their overall performance, dealiasing potential, and recovery performance of short-periodic gravity signals are analyzed, in view of their capabilities to retrieve gravity field information with short latencies to be used for societally relevant service applications, such as water management, groundwater monitoring, and forecasting of droughts and floods.</p>

Recovering climate-related mass transport signals by current and next-generation gravity missions

2020 ◽  
Author(s):  
Roland Pail ◽  
Henryk Dobslaw ◽  
Annette Eicker ◽  
Laura Jensen
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Mass Transport ◽  
Gravity Field ◽  
Transport Processes ◽  
Measuring System ◽  
Climate Projections ◽  
Earth System ◽  
Next Generation ◽  
The Earth

<p>Gravity field missions are a unique geodetic measuring system to directly observe mass transport processes in the Earth system. Past and current gravity missions such as CHAMP, GRACE, GOCE and GRACE-Follow On have improved our understanding of large-scale mass changes, such as the global water cycle, melting of continental ice sheets and mountain glaciers, changes in ocean mass that are closely related to the mass-related component of sea level rise, which are subtle indicators of climate change, on global to regional scale. Therefore, mass transport observations are also very valuable for long-term climate applications. Next Generation Gravity Missions (NGGMs) expected to be launched in the midterm future have set high anticipations for an enhanced monitoring of mass transport in the Earth system with significantly improved spatial and temporal resolution and accuracy. This contribution will present results from numerical satellite mission performance simulations designed to evaluate the usefulness of gravity field missions operating over several decades for climate-related applications. The study is based on modelled of mass transport time series obtained from future climate projections until the year 2100 following the representative emission pathway RCP8.5 Numerical closed-loop simulations will assess the recoverability of mass variability signals by means of different NGGM concepts, e.g. GRACE-type in-line single-pair missions, Bender double-pair mission being composed of a polar and an inclined satellite pair, or high-precision high-low tracking missions following the MOBILE concept, assuming realistic noise levels for the key payload. In the evaluation and interpretation of the results, special emphasis shall be given to the identification of (natural or anthropogenic) climate change signals in dependence of the length of the measurement time series, and the quantification of robustness of derived trends and systematic changes.</p>

scholarly journals Simulation of the time-variable gravity field by means of coupled geophysical models

2011 ◽  
Vol 4 (1) ◽  
pp. 27-70 ◽  
Author(s):  
Th. Gruber ◽  
J. L. Bamber ◽  
M. F. P. Bierkens ◽  
H. Dobslaw ◽  
M. Murböck ◽  
...  
Keyword(s):  
Time Series ◽  
Gravity Field ◽  
Mass Distribution ◽  
Time Variable ◽  
Data Sets ◽  
Earth System ◽  
Time Variable Gravity ◽  
The Earth ◽  
Gravity Fields ◽  
Variable Gravity

Abstract. Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on "Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites". The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested via a Website.

The GGOS Bureau of Products and Standards

2021 ◽  
Author(s):  
Detlef Angermann ◽  
Thomas Gruber ◽  
Michael Gerstl ◽  
Robert Heinkelmann ◽  
Urs Hugentobler ◽  
...  
Keyword(s):  
Data Sharing ◽  
Mass Distribution ◽  
Working Group ◽  
System Modeling ◽  
Earth System ◽  
Earth System Modeling ◽  
The Earth ◽  
External Stakeholders ◽  
Definition Of

<p>This presentation gives a summary of the role and the activities of the Bureau of Products and Standards (BPS) to support IAG’s Global Geodetic Observing System (GGOS) in its goal to provide observations and consistent geodetic products needed to monitor, map and understand changes in the Earth’s shape, rotation and mass distribution. In its present structure, the two Committees “Earth System Modeling” and “Essential Geodetic Variables” as well as the Working Group “Towards a consistent set of parameters for the definition of a new GRS” are associated with the BPS. A key objective of the BPS is to keep track and to foster homogenization of adopted geodetic standards and conventions across all IAG components as a fundamental basis for the generation of consistent geometric and gravimetric products. Towards this aim, an updated 2<sup>nd</sup> version of the BPS inventory of standards and conventions used for the generation of IAG products has been published in the Geodesist’s Handbook 2020. In the framework of the renewing of the GGOS website, the BPS supports the GGOS Coordinating Office in particular regarding the representation of geodetic products. Furthermore, the BPS contributes to the rewriting of the IERS Conventions as Chapter Expert for Chapter 1 “General definitions and numerical standards” and interacts with external stakeholders regarding standards and conventions, such as ISO, IAU, BIPM, CODATA and the UN GGIM Subcommittee on Geodesy, including its Working Group “Data Sharing and Development of Geodetic Standards”.</p>

scholarly journals Simulation of the time-variable gravity field by means of coupled geophysical models

2011 ◽  
Vol 3 (1) ◽  
pp. 19-35 ◽  
Author(s):  
Th. Gruber ◽  
J. L. Bamber ◽  
M. F. P. Bierkens ◽  
H. Dobslaw ◽  
M. Murböck ◽  
...  
Keyword(s):  
Time Series ◽  
Gravity Field ◽  
Mass Distribution ◽  
Time Variable ◽  
Data Sets ◽  
Earth System ◽  
Time Variable Gravity ◽  
The Earth ◽  
Gravity Fields ◽  
Variable Gravity

Abstract. Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on ''Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites''. The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested.

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