Upper Ocean Meso-Submesoscale Eddy Variability in the Northwestern Pacific from Repeat ADCP Measurements and 1/48-deg MITgcm Simulation
Abstract
With the use of Ka-band radar interferometry, the Surface Water and Ocean Topography (SWOT) satellite will improve the measured sea surface height (SSH) resolution down to the spectral wavelength of 15km, allowing us to investigate for the first time the upper oceancirculation variability at the submesoscale range on the global scale. By analyzing repeat shipboardAcoustic Doppler Current Profiler (ADCP) measurements along 137°E, as well as the 1/48-deg MITgcm simulation output, in the northwest Pacific, we demonstrate that the observed/modeled upper ocean velocities are comprised of balanced geostrophic motions and unbalanced ageostrophic wave motions. The length scale, Lc, that separates the dominance between these two types of motions is found to depend sensitively on the energy level of local mesoscale eddy variability. In the eddy-abundant western boundary current region of Kuroshio, Lc can be shorter than 15km, whereas Lc exceeds 200km along the path of relatively stable North Equatorial Current. Judicious separation between the balanced and unbalanced surface ocean signals will both be a challenge and opportunity for the SWOT mission.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H21L..04Q
- Keywords:
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- 1855 Remote sensing;
- HYDROLOGYDE: 1856 River channels;
- HYDROLOGYDE: 4520 Eddies and mesoscale processes;
- OCEANOGRAPHY: PHYSICALDE: 4594 Instruments and techniques;
- OCEANOGRAPHY: PHYSICAL