Retrieval of sea level and surface loading variations from geodetic observations and model simulations : an integrated approach

• Main Author: Rietbroek, Roelof
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Rheinische Friedrich-Wilhelms-Universität Bonn, Landwirtschaftliche Fakultät, IGG - Institut für Geodäsie und Geoinformation 2015
• Subjects: Kombination; Inversion; GRACE; Altmetrie; Gravimetrie; GPS; Deformation; Massentransporte; Ozeanmodell; Cryosphäre; Grönland; Antarktis; Meeresspiegel; sterisch; SNREI; GIA; Geozentrum; OBP; Bodendruck; Joint inversion; gravimetry; altimetry; surface loading; sea level; ocean bottom pressure; geocenter; cryosphere; steric; ice sheet; ocean model; mass transport; ddc:526.1; Antarktis*; Ice Sheet
• Online Access: https://hdl.handle.net/20.500.11811/1631

The mass distribution in the system Earth changes dynamically over time. Time-variable mass transport mainly arises from the interplay between the terrestrial hydrological water cycle, the ocean and atmosphere, and the Earth’s cryosphere. To understand the dynamics of the system Earth and its climate, it is of paramount importance to establish and maintain an accurate observational basis of these surface processes, against which models and theories can be tested. A variety of observational techniques are used today. The time-variable gravity is measured from space by the Gravity Recovery and Climate Experiment (GRACE), Earth deformation processes are monitored by a permanent global network of GPS stations, and sea surface changes are detected by a family of satellite altimeters. The underlying motivation of this work is that the combination of the different observation types allows the mitigation of some of the technique-specific limitations. In the framework of this dissertation, several types of geodetic observations have been combined in a least-squares sense to estimate present-day changes of surface mass storage in the Earth system, using dynamically consistent surface loading theory. Two types of inversion schemes have been designed and implemented. In the first scheme, time variable gravity from GRACE, deformations of a permanent GPS station network, and simulated ocean bottom pressure changes from an ocean model, are used to estimate weekly surface loading changes covering the entire globe. In the second inversion scheme, (inter-)annual changes of the Earth’s cryosphere, ocean and terrestrial water cycle, are parameterized by a predefined set of standing waves, whose time variations are estimated by combining GRACE gravimetry with satellite altimetry from Jason-1 and Jason-2. Ein kombinierter Ansatz zur Bestimmung von Meeresspiegelschwankungen und Auflastsveränderungen aus geodätischen Beobachtungen und Modellsimulationen Die Verteilung der Massen im System Erde verändert sich dynamisch über die Zeit. ...