scholarly journals The Role of Non-tidal Atmospheric Loading in the Task of Gravity Field Estimation by Inter-Satellite Measurements

2021 ◽  
Author(s):  
I. O. Skakun ◽  
V. V. Mitrikas ◽  
V. V. Ianishevskii
Keyword(s):  
Gravitational Field ◽  
Gravity Field ◽  
Satellite Measurements ◽  
Atmospheric Loading ◽  
Field Estimation ◽  
Tidal Variations ◽  
Grace Mission ◽  
Monthly Variations ◽  
Water Height

AbstractThe paper reviews models of tidal and non-tidal variations of the Earth's gravitational field. Proposing an algorithm for the estimation of the Stokes coefficients based on inter-satellite measurements of low-orbit spacecrafts. By processing measurements of the GRACE mission, we obtained experimental estimates of gravity field monthly variations. The analysis of these values was carried out by calculating the change in the equivalent water height for a given area.

scholarly journals Mitigation of ionospheric signatures in Swarm GPS gravity field estimation using weighting strategies

2018 ◽  
Author(s):  
Lucas Schreiter ◽  
Daniel Arnold ◽  
Veerle Sterken ◽  
Adrian Jäggi
Keyword(s):  
Gravity Field ◽  
Systematic Errors ◽  
Low Earth Orbit ◽  
Mitigation Strategies ◽  
Dual Frequency ◽  
Satellite Mission ◽  
Gravity Fields ◽  
Data Gaps ◽  
Field Estimation ◽  
Grace Mission

Abstract. Even though ESA's three-satellite mission Swarm is primarily a magnetic field mission, it became more and more important as gravity field mission. Located in a low earth orbit with altitudes of 460 km for Swarm A and Swarm C and 530 km for Swarm B, after the commissioning phase, and equipped with geodetic-type dual frequency GPS receivers, it is suitable for gravity field computation. Of course the Swarm GPS-only gravity fields are not as good as the gravity fields derived from the ultra precise GRACE K-Band measurements, but due to the end of the GRACE mission in October 2017, data gaps in the previous months, and the gap between GRACE and the recently launched GRACE Follow-On mission, Swarm gravity fields became important to maintain a continuous time series and bridge the gap. By validating the Swarm gravity fields to the GRACE gravity fields, systematic errors have been observed, especially around the geomagnetic equator. These errors are already visible in the kinematic positioning from where they propagate into the gravity field solutions. We investigate these systematic errors by analyzing the geometry-free linear combination of the GPS carrier phase observations. Based on this we present different weighting schemes and investigate their impact on the gravity field solutions in order to assess the success of different mitigation strategies.

Comparative analysis and interpretation of grace and grace-fo data

2020 ◽  
Vol 4 ◽  
pp. 101-106
Author(s):  
Konstantin Simonov ◽  
◽  
Alexander Matsulev
Keyword(s):  
Comparative Analysis ◽  
World Ocean ◽  
Satellite System ◽  
Data Archive ◽  
Space Systems ◽  
Satellite Measurements ◽  
Digital Maps ◽  
The World ◽  
Grace Mission ◽  
Anomalous State

The study is devoted to the analysis of the features of the change in the Equivalent Water Height (EWH) parameter over the geoid based on satellite measurements of space systems. The study used the GRACE and GRACE-FO satellite data archive. The assessment was carried out on Earth as a whole, including land areas and the World Ocean. Interpretation of the anomalous state of the geoenvironment is performed using digital maps of the spatial distribution of the EWH parameter based on the histogram approach and correlation analysis. Also, a comparative analysis of the studied data from the GRACE mission and data from the new GRACE-FO satellite system launched into orbit in the summer of 2018 was carried out.

A simulated gravity field estimation for the main belt comet 133P/Elst-Pizarro

2021 ◽  
Vol 366 (6) ◽  
Author(s):  
Wutong Gao ◽  
Jianguo Yan ◽  
Weitong Jin ◽  
Chen Yang ◽  
Linzhi Meng ◽  
...  
Keyword(s):  
Gravity Field ◽  
Main Belt ◽  
Field Estimation

scholarly journals Earth’s Time-Variable Gravity from GRACE Follow-On K-Band Range-Rates and Pseudo-Observed Orbits

2021 ◽  
Vol 13 (9) ◽  
pp. 1766
Author(s):  
Igor Koch ◽  
Mathias Duwe ◽  
Jakob Flury ◽  
Akbar Shabanloui
Keyword(s):  
Gravity Field ◽  
Time Variable ◽  
Time Variable Gravity ◽  
Gravity Field Recovery ◽  
Variable Gravity ◽  
Earth’S System ◽  
Grace Mission ◽  
Insight Into ◽  
K Band

During its science phase from 2002–2017, the low-low satellite-to-satellite tracking mission Gravity Field Recovery And Climate Experiment (GRACE) provided an insight into Earth’s time-variable gravity (TVG). The unprecedented quality of gravity field solutions from GRACE sensor data improved the understanding of mass changes in Earth’s system considerably. Monthly gravity field solutions as the main products of the GRACE mission, published by several analysis centers (ACs) from Europe, USA and China, became indispensable products for quantifying terrestrial water storage, ice sheet mass balance and sea level change. The successor mission GRACE Follow-On (GRACE-FO) was launched in May 2018 and proceeds observing Earth’s TVG. The Institute of Geodesy (IfE) at Leibniz University Hannover (LUH) is one of the most recent ACs. The purpose of this article is to give a detailed insight into the gravity field recovery processing strategy applied at LUH; to compare the obtained gravity field results to the gravity field solutions of other established ACs; and to compare the GRACE-FO performance to that of the preceding GRACE mission in terms of post-fit residuals. We use the in-house-developed MATLAB-based GRACE-SIGMA software to compute unconstrained solutions based on the generalized orbit determination of 3 h arcs. K-band range-rates (KBRR) and kinematic orbits are used as (pseudo)-observations. A comparison of the obtained solutions to the results of the GRACE-FO Science Data System (SDS) and Combination Service for Time-variable Gravity Fields (COST-G) ACs, reveals a competitive quality of our solutions. While the spectral and spatial noise levels slightly differ, the signal content of the solutions is similar among all ACs. The carried out comparison of GRACE and GRACE-FO KBRR post-fit residuals highlights an improvement of the GRACE-FO K-band ranging system performance. The overall amplitude of GRACE-FO post-fit residuals is about three times smaller, compared to GRACE. GRACE-FO post-fit residuals show less systematics, compared to GRACE. Nevertheless, the power spectral density of GRACE-FO and GRACE post-fit residuals is dominated by similar spikes located at multiples of the orbital and daily frequencies. To our knowledge, the detailed origin of these spikes and their influence on the gravity field recovery quality were not addressed in any study so far and therefore deserve further attention in the future. Presented results are based on 29 monthly gravity field solutions from June 2018 until December 2020. The regularly updated LUH-GRACE-FO-2020 time series of monthly gravity field solutions can be found on the website of the International Centre for Global Earth Models (ICGEM) and in LUH’s research data repository. These operationally published products complement the time series of the already established ACs and allow for a continuous and independent assessment of mass changes in Earth’s system.

Quantifying sources and sinks of trace gases using space-borne measurements: current and future science

2008 ◽  
Vol 366 (1885) ◽  
pp. 4509-4528 ◽  
Author(s):  
Paul I Palmer
Keyword(s):  
Trace Gases ◽  
Lower Troposphere ◽  
Biological Interactions ◽  
Satellite Measurements ◽  
Sources And Sinks ◽  
The Past ◽  
Fundamental Understanding ◽  
Earth’S Climate ◽  
New Generation

We have been observing the Earth's upper atmosphere from space for several decades, but only over the past decade has the necessary technology begun to match our desire to observe surface air pollutants and climate-relevant trace gases in the lower troposphere, where we live and breathe. A new generation of Earth-observing satellites, capable of probing the lower troposphere, are already orbiting hundreds of kilometres above the Earth's surface with several more ready for launch or in the planning stages. Consequently, this is one of the most exciting times for the Earth system scientists who study the countless current-day physical, chemical and biological interactions between the Earth's land, ocean and atmosphere. First, I briefly review the theory behind measuring the atmosphere from space, and how these data can be used to infer surface sources and sinks of trace gases. I then present some of the science highlights associated with these data and how they can be used to improve fundamental understanding of the Earth's climate system. I conclude the paper by discussing the future role of satellite measurements of tropospheric trace gases in mitigating surface air pollution and carbon trading.

scholarly journals On the role of the GRACE mission in the joint assimilation of altimetric and TAO data in a tropical Pacific Ocean model

2006 ◽  
Vol 33 (14) ◽  
Author(s):  
F. Castruccio ◽  
J. Verron ◽  
L. Gourdeau ◽  
J. M. Brankart ◽  
P. Brasseur
Keyword(s):  
Pacific Ocean ◽  
Ocean Model ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
Grace Mission

scholarly journals Role of geo-potential models in gravity field determination

2009 ◽  
pp. 34-37
Author(s):  
Niraj Manandhar ◽  
Rene Forsberg
Keyword(s):  
Gravity Field ◽  
Geopotential Model ◽  
Potential Models ◽  
Geopotential Models ◽  
Gravity Field Determination ◽  
Major Emphasis

This paper sets out to describe the developments of geopotential models and its role in gravity field determination. The paper also focuses in different geopotential models those are available and in use from 1980 onwards till at present with major emphasis placed on WGS84 EGM96 geopotential model.

SPACE–TIME ENERGY–MOMENTUM, THE OBSERVER AND UNCERTAINTY IN GENERAL RELATIVITY

2010 ◽  
Vol 19 (14) ◽  
pp. 2353-2359 ◽  
Author(s):  
F. I. COOPERSTOCK ◽  
M. J. DUPRE
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Uncertainty Principle ◽  
Ricci Tensor ◽  
Space Time ◽  
Energy Integral ◽  
New Approach ◽  
Extended Space ◽  
Energy And Momentum

In this essay, we introduce a new approach to energy–momentum in general relativity. Space–time, as opposed to space, is recognized as the necessary arena for its examination, leading us to define new extended space–time energy and momentum constructs. From local and global considerations, we conclude that the Ricci tensor is the required element for a localized expression of energy–momentum to include the gravitational field. We present and rationalize a fully invariant extended expression for space–time energy, guided by Tolman's well-known energy integral for an arbitrary bounded stationary system. This raises fundamental issues which we discuss. The role of the observer emerges naturally and we are led to an extension of the uncertainty principle to general relativity, of particular relevance to ultra-strong gravity.

Impact of low-degree gravity field estimation in the SLR data processing of spherical satellites at AIUB

2021 ◽  
Author(s):  
Linda Geisser ◽  
Ulrich Meyer ◽  
Daniel Arnold ◽  
Adrian Jäggi ◽  
Daniela Thaller
Keyword(s):  
Gravity Field ◽  
Lower Altitude ◽  
Earth’S Gravity Field ◽  
Low Degree ◽  
Station Coordinates ◽  
Earth Rotation Parameters ◽  
Field Estimation ◽  
University Of Bern ◽  
The University ◽  
The Impact

<p>The Astronomical Institute of the University of Bern (AIUB) collaborates with the Federal Agency for Cartography and Geodesy (BKG) in Germany to develop new procedures to generate products for the International Laser Ranging Service (ILRS). In this framework the SLR processing of the standard ILRS weekly solutions of spherical geodetic satellites at AIUB, where the orbits are determined in 7-day arcs together with station coordinates and other geodetic parameters, is extended from LAGEOS-1/2 and the Etalon-1/2 satellites to also include the LARES satellite orbiting the Earth at much lower altitude. Since a lower orbit experiences a more variable enviroment, e.g. it is more sensitive to time-variable Earth's gravity field, the orbit parametrization has to be adapted and also the low degree spherical harmonic coefficients of Earth's gravity field have to be co-estimated. The impact of the gravity field estimation is studied by validating the quality of other geodetic parameters such as geocenter coordinates, Earth Rotation Parameters (ERPs) and station coordinates. The analysis of the influence of LARES on the SLR solution shows that a good datum definition is important.</p>

ROLE OF MULTIPLE SCATTERING IN OZONE PROFILE RETRIEVAL FROM SATELLITE MEASUREMENTS IN THE ULTRAVIOLET

1980 ◽  
pp. 219-231 ◽  
Author(s):  
S.L. Taylor ◽  
P.K. Bhartia ◽  
V.G. Kaveeshwar ◽  
K.F. Klenk ◽  
Albert J. Fleig ◽  
...  
Keyword(s):  
Multiple Scattering ◽  
Satellite Measurements ◽  
Ozone Profile
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