Global patterns of internal wave variability from observations of full-depth rotary shear spectra

Internal waves are ubiquitous throughout the world ocean and are generated by a combina- tion of processes including the tides and winds. The vertical directionality of low-frequency internal waves can be diagnosed by separating shear components into their rotary-with- depth components. Partitioning of energy in upward and downward propagation is helpful for understanding how energy is distributed and potentially lost in the global ocean energy budget. Using observations of horizontal velocity from the GO-SHIP surveys and interpreting North Hemisphere clockwise-with-depth (South Hemisphere counterclockwise- with-depth) signals as downward propagating, there is approximately 10% more downward than upward propagating shear variance at 120-320 m vertical wavelengths in the upper 2000 m. There is more upward and downward shear variance in the bottom 2000 m associated with rough topography.