Advanced Technologies in Earth Sciences
Editors:
L. Stroink, Germany
V. Mosbrugger, Germany
G. Wefer, Germany
For further volumes:
http://www.springer.com/series/8384

Frank Flechtner · Thomas Gruber ·
Andreas Güntner · Mioara Mandea ·
Markus Rothacher · Tilo Schöne · Jens Wickert
Editors
System Earth via
Geodetic-Geophysical Space
Techniques
123
Editors
Dr. Frank Flechtner
Helmholtz Centre Potsdam
GFZ German Research
Centre for Geosciences
Telegrafenberg
14473 Potsdam
Germany
frank.fl[email protected]
Prof. Dr. Mioara Mandea
Université Paris Diderot -
Institut de Physique du
Globe de Paris
Géophysique spatiale et

Telegrafenberg
14473 Potsdam
Germany
[email protected]
Dr. Tilo Schöne
Helmholtz Centre Potsdam
GFZ German Research
Centre for Geosciences
Telegrafenberg
14473 Potsdam
Germany
[email protected]
ISSN 2190-1635 e-ISSN 2190-1643
ISBN 978-3-642-10227-1 e-ISBN 978-3-642-10228-8
DOI 10.1007/978-3-642-10228-8
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address the processing of static and time variable gravity field models from CHAMP,
GRACE and GOCE data including methods for validation (“Improved GRACE
Level-1 and Level-2 Products and their Validation by Ocean Bottom Pressure”,
“More accurate and faster available CHAMP and GRACE Gravity Fields for
v
vi Preface
the User Community” and “Gravity and steady-state Ocean Circulation Explorer
GOCE”). The papers related to CHAMP and GRACE provide deeper insight into
the sensors, the processing methods and the applied algorithms. Results of orbit and
gravity field determination including validation are presented as well. As GOCE was
not yet in orbit during the project period, the rationale of GOCE gravity gradient pro-
cessing to static geoid solutions and their validation are described in several papers.
Two out of the eight coordinated projects are related to applications of GRACE
results, altimeter, GPS and other data for geophysical analyses (“Time-Variable
Gravity and Surface Mass Processes: Validation, Processing and First Application
of New Satellite Gravity Data”; “Sea Level Variations – Prospects from the Past to
the Present”). The papers in these chapters focus on the use of geodetic observa-
tions for assessing variations in the global water cycle and the analysis of sea level
variations derived from satellite altimetry and observations taken at GPS and tides
gauge stations. The remaining three chapters address contributions to the Global
Geodetic-Geodynamic Observing System (GGOS), the atmospheric sounding by
the geodetic based GPS radio occultation technique with CHAMP and GRACE and
the observation of the Earth’s magnetic field with CHAMP (“Integration of Space
Geodetic Techniques as the Basis for a Global Geodetic-Geophysical Observing
System – GGOS-D”, “Near-Real-Time Provision and Usage of Global Atmospheric
Data from GRACE and CHAMP” and “The Earth’s Magnetic Field: At the CHAMP
Satellite Epoch”). The articles in the GGOS section address the consistent pro-
cessing of space-geodetic data, combination techniques and solutions for a global
terrestrial reference frame. Results of atmospheric sounding using GPS radio occul-
tation with CHAMP and GRACE are summarized in the subsequent chapter. Special

Rolf König, and Christoph Förste
Orbit Predictions for CHAMP and GRACE 59
Krzysztof Snopek, Daniel König, and Rolf König
Rapid Science Orbits for CHAMP and GRACE Radio
Occultation Data Analysis 67
Grzegorz Michalak and Rolf König
Parallelization and High Performance Computation
for Accelerated CHAMP and GRACE Data Analysis 79
Karl Hans Neumayer
Part II GRACE
Improved GRACE Level-1 and Level-2 Products
and Their Validation by Ocean Bottom Pressure 95
Frank Flechtner
The GRACE Gravity Sensor System 105
Björn Frommknecht and Anja Schlicht
vii
viii Contents
Numerical Simulations of Short-Term
Non-tidal Ocean Mass Anomalies 119
Henryk Dobslaw and Maik Thomas
Improved Non-tidal Atmospheric and Oceanic De-aliasing
for GRACE and SLR Satellites 131
Frank Flechtner, Maik Thomas, and Henryk Dobslaw
Global Gravity Fields from Simulated Level-1 GRACE Data 143
Ulrich Meyer, Björn Frommknecht, and Frank Flechtner
ITG-GRACE: Global Static and Temporal Gravity Field Models
from GRACE Data 159
Torsten Mayer-Gürr, Annette Eicker, Enrico Kurtenbach,
and Karl-Heinz Ilk
Validation of GRACE Gravity Fields by In-Situ Data of Ocean

Pressure Variations Against In Situ Bottom Pressure Measurements . . 297
Detlef Stammer, Armin Köhl, Vanya Romanova,
and Frank Siegismund
Part IV SEAVAR
Sea Level Variations – Prospects from the Past to the Present
(SEAVAR) 313
Tilo Schöne and Jens Schröter
Radar Altimetry Derived Sea Level Anomalies – The Benefit of
New Orbits and Harmonization 317
Tilo Schöne, Saskia Esselborn, Sergei Rudenko,
and Jean-Claude Raimondo
Combining GEOSAT and TOPEX/Poseidon Data by Means
of Data Assimilation 325
Manfred Wenzel and Jens Schröter
Reanalysis of GPS Data at Tide Gauges and the Combination
for the IGS TIGA Pilot Project 335
Sergei Rudenko, Daniela Thaller, Gerd Gendt,
Michael Dähnn, and Tilo Schöne
Sea Level Rise in North Atlantic Derived from Gap Filled Tide
Gauge Stations of the PSMSL Data Set 341
Heiko Reinhardt, Dimitry Sidorenko, Manfred Wenzel,
and Jens Schröter
Using ARGO, GRACE and Altimetry Data to Assess the Quasi
Stationary North Atlantic Circulation 351
Falk Richter, Dimitry Sidorenko, Sergey Danilov, and Jens Schröter
A 15-Year Reconstruction of Sea Level Anomalies Using Radar
Altimetry and GPS-Corrected Tide Gauge Data 359
Nana Schön, Saskia Esselborn, and Tilo Schöne
Part V TIVAGAM
Continental Water Storage Variations from GRACE

and Torsten Schmidt
Near-Real Time Satellite Orbit Determination for GPS Radio
Occultation with CHAMP and GRACE 443
Grzegorz Michalak and Rolf König
The Operational Processing System for GPS Radio Occultation
Data from CHAMP and GRACE 455
Torsten Schmidt, Jens Wickert, and Grzegorz Michalak
Assimilation of CHAMP and GRACE-A Radio Occultation
Data in the GME Global Meteorological Model of the German
Weather Service 461
Detlef Pingel, Andreas Rhodin, Werner Wergen,
Mariella Tomassini, Michael Gorbunov, and Jens Wickert
Contents xi
Part VII MAGFIELD
The Earth’s Magnetic Field at the CHAMP Satellite Epoch 475
Mioara Mandea, Matthias Holschneider, Vincent Lesur,
and Hermann Lühr
Part VIII GGOS-D
Integration of Space Geodetic Techniques as the Basis for a
Global Geodetic-Geophysical Observing System (GGOS-D):
An Overview 529
Markus Rothacher, Hermann Drewes, Axel Nothnagel,
and Bernd Richter
GGOS-D Data Management – From Data
to Knowledge 539
Wolfgang Schwegmann and Bernd Richter
GGOS-D Consistent, High-Accuracy Technique-Specific Solutions 545
Peter Steigenberger, Thomas Artz, Sarah Böckmann, Rainer Kelm,
Rolf König, Barbara Meisel, Horst Müller, Axel Nothnagel,
Sergei Rudenko, Volker Tesmer, and Daniela Thaller

Bremerhaven, Germany, [email protected]
Carmen Böning Alfred Wegener Institute for Polar and Marine Research,
D-27570 Bremerhaven, Germany, [email protected]
Roland Braun Department of 1 ‘Geodesy and Remote Sensing’, Helmholtz
Centre Potsdam, GFZ German Research Centre for Geosciences, 14473 Potsdam,
Germany, [email protected]
Phillip Brieden Institut für Erdmessung, Leibniz Universität Hannover, 30167
Hannover, Germany, [email protected]
xiii
xiv Contributors
Jan Martin Brockmann Institute of Geodesy and Geoinformation, University of
Bonn, Bonn, Germany, [email protected]
Jianqing Cai Institute of Geodesy, University of Stuttgart, 70174 Stuttgart,
Germany, [email protected]
Christoph Dahle Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Michael Dähnn Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany; Current affiliation: Norwegian Mapping Authority, N-3507
Hønefoss, Norway, [email protected]
Sergey Danilov Alfred-Wegener-Institute for Polar- and Marine Research,
D-27570 Bremerhaven, Germany, [email protected]
Heiner Denker Institut für Erdmessung (IfE), Leibniz Universität Hannover,
D-30167 Hannover, Germany, [email protected]
Reinhard Dietrich Institut für Planetare Geodäsie, Technische Universität
Dresden, 01219 Dresden, Germany, [email protected]
Henryk Dobslaw Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]

Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Lutz Gericke Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Centre for GeoInformation Technology, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Michael Gerstl Deutsches Geodätisches Forschungsinstitut, D-80539 München,
Germany, gerstl@dgfi.badw.de
Michael Gorbunov Obukhov Institute for Atmospheric Physics, Moscow, Russia,
[email protected]; [email protected]
Thomas Gruber Institute of Astronomical and Physical Geodesy, Technische
Universiät München, Munich, Germany, [email protected]
Andreas Güntner Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 5: Earth Surface Processes, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Sean B. Healy European Centre for Medium-Range Forecasts, ECMWF,
Reading, UK, [email protected]
Stefan Heise Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Rico Hengst Department 1 ‘Geodesy and Remote Sensing’, Helmholtz Centre
Potsdam, GFZ German Research Centre for Geosciences, 14473 Potsdam,
Germany, [email protected]
Matthias Holschneider Institut für Mathematik, Universität Potsdam, 14469
Potsdam, Germany, [email protected]
Martin Horwath Institut für Planetare Geodäsie, Technische Universität Dresden,
01219 Dresden, Germany, [email protected]
xvi Contributors
Michael Hosse Institut für Astronomische und Physikalische Geodäsie (IAPG),
Technische Universität München, D-80333 München, Germany,
[email protected]

Vincent Lesur Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 2: Physics of the Earth, Telegrafenberg, 14473 Potsdam,
Germany, [email protected]
Contributors xvii
Hermann Lühr Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 2: Physics of the Earth, Telegrafenberg, 14473 Potsdam,
Germany, [email protected]
Andreas Macrander Alfred Wegener Institute for Polar and Marine Research,
D-27570 Bremerhaven, Germany, [email protected]
Mioara Mandea Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 2: Physics of the Earth, Telegrafenberg, 14473 Potsdam,
Germany; Now at Universitee Paris Diderot, Institut de Physique du Globe de
Paris, France, [email protected]
Torsten Mayer-Gürr Institute of Geodesy and Geoinformation, University of
Bonn, 53115 Bonn, Germany, [email protected]
Barbara Meisel Deutsches Geodätisches Forschungsinstitut, D-80539 München,
Germany, meisel@dgfi.badw.de
Vivien Mende Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Centre for GeoInformation Technology, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Ulrich Meyer Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum
(GFZ), D-82234 Weβling, Germany; Astronomical Institute, University of Bern,
3012 Bern, Switzerland, [email protected]
Grzegorz Michalak Helmholtz Centre Potsdam, GFZ German Research Centre
for Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg,
14473 Potsdam, Germany, [email protected]
Jürgen Müller Institut für Erdmessung, Leibniz Universität Hannover, 30167
Hannover, Germany, [email protected]
Jan Müller Bundesamt für Kartographie und Geodäsie (BKG), D-60598
Frankfurt am Main, Germany, [email protected]

Bernd Richter Bundesamt für Kartographie und Geodäsie, 60598 Frankfurt am
Main, Germany, [email protected]
Bernd Ritschel Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Centre for GeoInformation Technology, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Vanya Romanova Institut für Meereskunde, KlimaCampus, Universität Hamburg,
Hamburg, Germany, [email protected]
Markus Rothacher ETH Zürich, Photogrammetrie, HPV G 52, Schafmattstr. 34,
8093 Zürich [email protected]
Sergei Rudenko Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Axel Rülke Institut für Planetare Geodäsie, Technische Universität Dresden,
01219 Dresden, Germany, [email protected]
Reiner Rummel Institute of Astronomical and Physical Geodesy, Technische
Universiät München, Munich, Germany, [email protected]
Anja Schlicht Institute for Astronomical and Physical Geodesy, 80333 München,
Germany, [email protected]
Contributors xix
Torsten Schmidt Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Nana Schön Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Tilo Schöne Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Jens Schröter Alfred Wegener Institute for Polar and Marine Research, D-27570
Bremerhaven, Germany, [email protected]

Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Ralph Timmermann Alfred Wegener Institute for Polar and Marine Research,
Bremerhaven, Germany, [email protected]
Mariella Tomassini Deutscher Wetterdienst, Offenbach, Germany,
[email protected]
Christian Voigt Institut für Erdmessung (IfE), Leibniz Universität Hannover,
D-30167 Hannover, Germany, [email protected]
Manfred Wenzel Alfred Wegener Institute for Polar and Marine Research, 27570
Bremerhaven, Germany, [email protected]
Werner Wergen Deutscher Wetterdienst, Offenbach, Germany,
[email protected]
Martin Wermuth Institute for Astronomical and Physical Geodesy, TU Munich,
now at Deutsches Zentrum für Luft und Raumfahrt (DLR), Oberpfaffenhofen,
Germany, [email protected]
Susanna Werth Helmholtz Centre Potsdam GFZ German Research Centre for
Geosciences, 14473 Potsdam, Germany, [email protected]
Jens Wickert Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Herbert Wilmes Bundesamt für Kartographie und Geodäsie (BKG), D-60598
Frankfurt am Main, Germany, [email protected]
Insa Wolf Institut für Erdmessung, Leibniz Universität Hannover, 30167
Hannover, Germany, [email protected]
Kerstin Wolf Geomathematics Group, Department of Mathematics, TU
Kaiserslautern, 67653 Kaiserslautern, Germany, [email protected]
Johann Wünsch Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473
Potsdam, Germany, [email protected]
Part I

F. Flechtner (B)
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences,
Department 1: Geodesy and Remote Sensing, Telegrafenberg, 14473 Potsdam, Germany
e-mail: frank.fl[email protected]
3
F. Flechtner et al. (eds.), System Earth via Geodetic-Geophysical Space Techniques,
Advanced Technologies in Earth Sciences, DOI 10.1007/978-3-642-10228-8_1,
C

Springer-Verlag Berlin Heidelberg 2010
4 F. Flechtner
Fig. 1 CHAMP key instrumentation. Not shown is the LRR and the reflectometry antenna on the
nadir side and the GPS limb sounding antenna array on the back side. The S-band antenna is used
for communication purposes only
of GPS signals from ocean surfaces for GPS-altimetry. Unfortunately this experi-
ment could never been performed due non provided software. A synchronization
pulse delivered every second is used for precise onboard timing purposes, and the
autonomously generated navigation information is used by both the CHAMP AOCS
(Attitude and Orbit Control System) and the star sensors (see below) to update their
orbital position.
The STAR accelerometer sensor was provided by the Centre National d’Etudes
Spatiales (CNES) and manufactured by the Office National d’Etudes et de
Recherches Aerospatials (ONERA). It serves for measuring the non-gravitational
accelerations such as air drag, Earth albedo and solar radiation acting on the
CHAMP satellite. The STAR accelerometer uses the basic principle of an electro-
static micro-accelerometer: a proof-mass is floating freely inside a cage supported
by an electrostatic suspension. The cavity walls are equipped with electrodes thus
controlling the motion (both translation and rotation) of the test body by elec-
trostatic forces and thus supports the recovery of the orbit from GPS data and
by this the gravity field estimation. By applying a closed loop-control inside t he

the Earth magnetic field and is regarded as the prime instrument for the mag-
netic field investigations of the CHAMP mission. The interpretation of the vector
readings requires the knowledge of the sensor attitude at the time of measure-
ment. For that reason the FGM is mounted rigidly together with star cameras (cf.
Advanced Stellar Compass) on an optical bench. For redundancy reasons a sec-
ond FGM is accommodated on the optical bench, 60 cm inward from the primary
sensor.
The Overhauser Magnetometer (OVM) was developed and manufactured under
contract by LETI (Laboratoire d’Electronique de Technologie et d’Instrumentation)
at Grenoble. It serves as the magnetic field standard for the CHAMP mission. The
purpose of this scalar magnetometer is to provide an absolute in-flight calibration
capability for the FGM vector magnetic field measurements. A dedicated program
ensuring the magnetic cleanliness of the spacecraft allows for an absolute accuracy
of the readings of <0.5 nT.
The Digital Ion Drift Meter (DIDM) is provided by the AFRL (Air Force
Research Laboratory, Hanscom). The DIDM is an improved version of an analogue
ion drift-meter type flown successfully on many upper atmospheric satellites. The
purpose of this instrument is to make in-situ measurements of the ion distribution
and its moments within the ionosphere. A number of key parameters can be deter-
mined from the readings, such as the ion density and temperature, the drift velocity
and the electric field by applying the (v × B)-relation. Together with the magnetic
field measurements these quantities can be used to estimate the ionospheric current
distribution. Knowing these currents will help significantly to separate internal from
external magnetic field contributions. All components and functions of DIDM are
performing nominally except of two problems: the intermediate loss after launch of
one of the two nearly redundant sensors, and an uneven gain evolution of the micro-
channel-plate used for ion detection that has required development of an in-space
calibration procedure (Cooke et al., 2003). In combination with the DIDM a Planar
Langmuir Probe (PLP) is operated. This device provides auxiliary data needed to