Published In
Journal of Physical Oceanography
Document Type
Article
Publication Date
4-2018
Subjects
Ice shelves, Tidal currents -- Mapping, Oceanography, Surface waves (Water), Ocean models, Data assimilation
Abstract
A new empirical model of ocean tides has been developed for the Weddell Sea, south of 668S, between 908W and 08, using six years of radar altimeter data from the CryoSat-2 satellite mission. Because of its long groundtrack repeat period (368 days) and its diverse measurement modes, low-rate mode (LRM) over the ocean and synthetic aperture radar interferometric mode (SARin) over ice surfaces and parts of the ocean, the CryoSat2 data pose a number of challenges for tidal analysis. The space and time sampling properties of the exact repeat, near-repeat, and crossover ground tracks have been analyzed to discover which tides may be estimated using a combination of conventional harmonic analysis and local spatial regression. Using this information, the M2, S2, K2, N2, K1, O1, P1, and Q1 tides have been mapped for both the ocean and floating ice shelves in this domain. Validation against independent in situ data, along with comparison with existing tide models, finds that the CryoSat-2-derived tides are consistent with previous estimates and that they are more accurate than other models at the M2 and S2 frequencies. The high inclination of the CryoSat-2 orbit causes the orbit plane to precess relatively slowly, which leads to significantly less accurate estimates of the K2 tide. This purely empirical model ought to provide improved tidal corrections for studies of low-frequency variability and secular trends in ice shelf thickness, and it suggests that further increases in quantitative accuracy could be achieved by assimilation of CryoSat-2 data into dynamical tide models.
DOI
https://doi.org/10.1175/JPO-D-17-0247.1
Persistent Identifier
http://archives.pdx.edu/ds/psu/25366
Citation Details
Zaron, Edward, "Ocean and Ice Shelf Tides from CryoSat-2 Altimetry" (2018). Civil and Environmental Engineering Faculty Publications and Presentations. 436.
http://archives.pdx.edu/ds/psu/25366
Description
Supplemental information related to this paper is available at the Journals Online website: https://doi.org/10.1175/JPO-D-17-0247.s1.
Copyright Notice:
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