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Geodetic and Oceanographic Aspects of Absolute versus Relative Sea-Level Change

Caccamise, Dana John, II
http://orcid.org/0000-0002-4874-9761
http://rave.ohiolink.edu/etdc/view?acc_num=osu1543357751520828

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Earth Sciences.
Tide gauges record relative sea level (RSL), i.e. the vertical position of the sea surface relative to the adjacent land mass or relative to the seafloor under the gauge. A tide gauge cannot distinguish between a rise in sea level or subsidence of the land or seawall or pier that supports the gauge. Absolute sea level (ASL) refers to the level or height of the sea surface stated in some standard geodetic reference frame, e.g. ITRF2008. Since satellite altimeters make a geometrical measurement of sea level, this constitutes a determination of ASL. Satellite altimeters suffer from instrumental drift and thus need to be calibrated using tide gauges. This requires us to estimate the rate of RSL change at each tide gauge and convert this into an estimate of the rate of ASL change. This is done using a GPS station located at or near the tide gauge, since it can measure the vertical velocity of the lithosphere – often referred to as vertical land motion, VLM – which allows us to exploit the relationship ASL = RSL + VLM. This goal has motivated geodesists to build dozens of continuous GPS (or CGPS) stations near tide gauges – an agenda sometimes referred to as the CGPS@TG agenda. Unfortunately, a significant fraction of all long-lived tide gauges – especially those in the Pacific - have also recorded non-steady land motion caused by earthquakes. Rather than simply delete such datasets from the agenda, this thesis explores a new analytical method, based on the concept of a geodetic station trajectory model, that allows us to compute RSL and ASL rates even at tide gauges affected by regional earthquakes. We illustrate this method using two tide gauges (PAGO and UPOL) and three GPS stations (ASPA, SAMO and FALE) located in the Samoan islands of the Southwest Pacific. In addition to managing the impact of large regional earthquakes, we also seek new approaches to reducing noise in RSL rate estimates by suppressing the higher frequency sea level changes associated with ocean dynamics. We do this by augmenting our trajectory models using an ocean climate index or using numerical models of the sea surface state.
Michael Bevis (Committee Chair)
C.K. Shum (Committee Member)
Loren Babcock (Committee Member)
Michael Barton (Committee Member)
108 p.
Earth; Geological; Geophysical; Geophysics; Geotechnology; Ocean Engineering; Oceanography
GPS TG; GPS at Tide Gauge; tide gauge; Sea Level; sea; level; altimetry; satellite altimeters; calibrate; calibration; VLM; Samoa; ASL; RSL; Reference Frame; PAGO PAGO; ASPA; PAGO; UPOL; Apia; Upolu; Subsidence; Vertical land motion; FALE; SAMO; GNSS;

Recommended Citations

Citations

  • Caccamise, II, D. J. (2019). Geodetic and Oceanographic Aspects of Absolute versus Relative Sea-Level Change [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543357751520828

    APA Style (7th edition)

  • Caccamise, II, Dana. Geodetic and Oceanographic Aspects of Absolute versus Relative Sea-Level Change. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1543357751520828.

    MLA Style (8th edition)

  • Caccamise, II, Dana. "Geodetic and Oceanographic Aspects of Absolute versus Relative Sea-Level Change." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543357751520828

    Chicago Manual of Style (17th edition)

osu1543357751520828
304
© 2019, some rights reserved.Creative Commons License Geodetic and Oceanographic Aspects of Absolute versus Relative Sea-Level Change by Dana John Caccamise II is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.