IGPP is pleased to invite you to join its Spring 2024 Seminar Series presentation featuring Yao Yu. Dr. Yu's talk, "Seafloor Roughness and Deep Ocean Mixing: New Findings from SWOT" will occur at 3pm WEDNESDAY April 10, 2024.
Time: 3:00pm, Pacific Time
Location: MUNK Conference Room
Abstract: When tidal flows interact with rough seafloor features, such as ridges, seamounts, and abyssal hills, tidal energy is converted into internal tides. While deep ocean mixing driven by internal tides was a major career focus of Walter Munk and many others, our understanding has evolved over time. Today, our attention will be focusing on the improvement in seafloor mapping. Knowledge of the seafloor roughness is essential for calculating the energy conversion from barotropic to internal tides, which contributes to ocean mixing, sustains ocean mass and heat transport, and drives the thermohaline circulation.
Currently only 26% of seafloor is mapped by ship soundings at a spatial resolution of O(100m), while the remaining 74% relies on predictions from satellite altimetry data collected over the past 30 years, with a resolution of 12 km in full wavelength. The recent launch of the SWOT (Surface Water and Ocean Topography) wide-swath altimetry mission in December 2022 is a significant advancement. SWOT measures global ocean height 100 times more efficiently than traditional altimetry, and at higher precision. SWOT promises an 8-km resolution seafloor map, which would be a substantial leap in marine gravity accuracy and precision, enabling future discovery of uncharted small seamounts and details of the bathymetry. In parallel, the state-of-the-art high-resolution synthetic bathymetry model — SYNBATH (Sandwell et al., 2022) integrates shipborne depth soundings, predicted bathymetry from satellite altimetry, synthetic realizations of abyssal hills and modelling of small seamounts. SYNBATH allows for the global tidal conversion calculation up to mode 50 (or O(1 km)).
This presentation will cover the following key points:
- the state of seafloor mapping;
- the accuracy and resolution of SWOT at the Foundation Seamounts (in review);
- plans for global gravity and predicted bathymetry from SWOT;
- examples of how seafloor roughness impacts deep ocean mixing using SYNBATH;
- uncertainties in global ocean tidal conversion (in prep).