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Article
Nonstationary Internal Tides Observed Using Dual-Satellite Altimetry
Journal of Physical Oceanography
  • Edward D. Zaron, Portland State University
Document Type
Article
Publication Date
9-1-2015
Subjects
  • North Atlantic Ocean,
  • Tidal currents,
  • Oceanography,
  • Surface waves (Water),
  • Ocean models,
  • Data assimilation
Abstract

Dual-satellite crossover data from the Jason-2 and Cryosat-2 altimeter missions are used in a novel approach to quantify stationary and nonstationary tides from time-lagged mean square sea surface height (SSH) differences, computed for lags from 1 to 1440 h (60 days). The approach is made feasible by removing independent estimates of the stationary tide and mesoscale SSH variance, which greatly reduces the sampling error of the SSH statistics. For the semidiurnal tidal band, the stationary tidal variance is approximately 0.73 cm(2), and the nonstationary variance is about 0.33 cm(2), or 30% of the total. The temporal correlation of the nonstationary tide is examined by complex demodulation and found to be oscillatory with first 0 crossing at 400 h (17 days). Because a significant fraction of the time-variable mesoscale signal is resolved at time scales of roughly 150 h by the present constellation of satellite altimeters, the results suggest that it may be feasible to predict the nonstationary tide from modulations of the resolved mesoscale, thus enhancing the efficacy of tidal corrections for planned wide-swath altimeters such as the Surface Water and Ocean Topography (SWOT) mission.

Description

Denotes Open Access content.

DOI
10.1175/JPO-D-15-0020.1
Persistent Identifier
http://archives.pdx.edu/ds/psu/16060
Citation Information
E. D. Zaron, 2015: Nonstationary Internal Tides Observed Using Dual-Satellite Altimetry. J. Phys. Oceanogr., 45, 2239–2246.