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Author (up) Nelson, A.D.; Arbic, B.K.; Zaron, E.D.; Savage, A.C.; Richman, J.G.; Buijsman, M.C.; Shriver, J.F.
Title Toward Realistic Nonstationarity of Semidiurnal Baroclinic Tides in a Hydrodynamic Model Type $loc['typeJournal Article']
Year 2019 Publication Journal of Geophysical Research: Oceans Abbreviated Journal J. Geophys. Res. Oceans
Volume 124 Issue 9 Pages 6632-6641
Keywords
Abstract Semidiurnal baroclinic tide sea surface height (SSH) variance and semidiurnal nonstationary variance fraction (SNVF) are compared between a hydrodynamic model and altimetry for the low- to middle-latitude global ocean. Tidal frequencies are aliased by similar to 10-day altimeter sampling, which makes it impossible to unambiguously identify nonstationary tidal signals from the observations. In order to better understand altimeter sampling artifacts, the model was analyzed using its native hourly outputs and by subsampling it in the same manner as altimeters. Different estimates of the semidiurnal nonstationary and total SSH variance are obtained with the model depending on whether they are identified in the frequency domain or wave number domain and depending on the temporal sampling of the model output. Five sources of ambiguity in the interpretation of the altimetry are identified and briefly discussed. When the model and altimetry are analyzed in the same manner, they display qualitatively similar spatial patterns of semidiurnal baroclinic tides. The SNVF typically correlates above 80% at all latitudes between the different analysis methods and above 60% between the model and altimetry. The choice of analysis methodology was found to have a profound effect on estimates of the semidiurnal baroclinic SSH variance with the wave number domain methodology underestimating the semidiurnal nonstationary and total SSH variances by 68% and 66%, respectively. These results produce a SNVF estimate from altimetry that is biased low by a factor of 0.92. This bias is primarily a consequence of the ambiguity in the separation of tidal and mesoscale signals in the wave number domain.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-9275 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @ Serial 1086
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Author (up) Savage, A.C.; Arbic, B.K.; Alford, M.H.; Ansong, J.K.; Farrar, J.T.; Menemenlis, D.; O'Rourke, A.K.; Richman, J.G.; Shriver, J.F.; Voet, G.; Wallcraft, A.J.; Zamudio, L.
Title Spectral decomposition of internal gravity wave sea surface height in global models Type $loc['typeJournal Article']
Year 2017 Publication Journal of Geophysical Research: Oceans Abbreviated Journal J. Geophys. Res. Oceans
Volume 122 Issue 10 Pages 7803-7821
Keywords
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-9275 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 372
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Author (up) Savage, A.C.; Arbic, B.K.; Alford, M.H.; Ansong, J.K.; Farrar, J.T.; Menemenlis, D.; O'Rourke, A.K.; Richman, J.G.; Shriver, J.F.; Voet, G.; Wallcraft, A.J.; Zamudio, L.
Title Spectral decomposition of internal gravity wave sea surface height in global models: INTERNAL GRAVITY WAVE SEA SURFACE HEIGHT Type $loc['typeJournal Article']
Year 2017 Publication Journal of Geophysical Research: Oceans Abbreviated Journal J. Geophys. Res. Oceans
Volume 122 Issue 10 Pages 7803-7821
Keywords high-frequency motions; atmospheric pressure; dynamic height
Abstract Two global ocean models ranging in horizontal resolution from 1/128 to 1/488 are used to study the space and time scales of sea surface height (SSH) signals associated with internal gravity waves (IGWs). Frequency-horizontal wavenumber SSH spectral densities are computed over seven regions of the world ocean from two simulations of the HYbrid Coordinate Ocean Model (HYCOM) and three simulations of the Massachusetts Institute of Technology general circulation model (MITgcm). High wavenumber, high-frequency SSH variance follows the predicted IGW linear dispersion curves. The realism of high-frequency motions (>0:87 cpd) in the models is tested through comparison of the frequency spectral density of dynamic height variance computed from the highest-resolution runs of each model (1/258 HYCOM and 1/488 MITgcm) with dynamic height variance frequency spectral density computed from nine in situ profiling instruments. These high-frequency motions are of particular interest because of their contributions to the small-scale SSH variability that will be observed on a global scale in the upcoming Surface Water and Ocean Topography (SWOT) satellite altimetry mission. The variance at supertidal frequencies can be comparable to the tidal and low-frequency variance for high wavenumbers (length scales smaller than 50 km), especially in the higher-resolution simulations. In the highest-resolution simulations, the high-frequency variance can be greater than the low-frequency variance at these scales.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-9275 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ rl18 @ Serial 993
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Author (up) Savage, A.C.; Arbic, B.K.; Richman, J.G.; Shriver, J.F.; Alford, M.H.; Buijsman, M.C.; Thomas Farrar, J.; Sharma, H.; Voet, G.; Wallcraft, A.J.; Zamudio, L.
Title Frequency content of sea surface height variability from internal gravity waves to mesoscale eddies Type $loc['typeJournal Article']
Year 2017 Publication Journal of Geophysical Research: Oceans Abbreviated Journal J. Geophys. Res. Oceans
Volume 122 Issue 3 Pages 2519-2538
Keywords internal gravity waves; internal tides; spectral density
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-9275 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ mfield @ Serial 14
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