High Resolution Towed Body Surveys of Submesoscale Variability Generated by Mean and Tidal Flows through the Lombok Strait
Abstract
The long-term goal of this project is to understand mixing processes and intensity within a complex archipelago and how well they can be inferred from satellites and numerical models. During our 2008 measurements, we concentrated on three aspects of flow and mixing through the Philippine archipelago: flow separation around Apo Reef, flows forced by gap winds and winds around headlands, and water mass changes in the triple junction ("mixing bowl") between Mindoro and Panay Islands. We operated two depth-cycling towed bodies, Triaxus and SWIMS3, to examine the spatial and temporal variability of flow, water structure, and overturns for the three regimes studied. Turbulent dissipation rates and diapycnal diffusivities were then inferred by combining observed overturning scales with the stratification. All data have been reduced and plotted. Scientific analysis has been limited because the 2008 and 2009 cruises used all our funds, and we are waiting for analysis funding. To consider one of our focus regions, the region south of Mindoro and west of Panay is a large "mixing bowl" blending water from the South China Sea with that coming from the Pacific by two routes through the archipelago, one around the north end of Panay from San Bernadino Strait and the other coming south of Panay from Suriago Strait. Ship tracks along or across sills bounding the mixing bowl were made with SWIMS3. Other, longer and shallower sections were made with Triaxus across shoals bounding the deep region. Only one run was made across the southern entrance. Comparing average TS relations at the three entrances to the mixing bowl suggests significant mixing for water shallower than 250 m. Water less dense than 24.5 coming from the Pacific appears to be mixed to produce the water over the eastern sill, linking the mixing bowl with the South China Sea. The mixing rates presented here will be used to constrain diapycnal diffusivities in numerical models of flow through the archipelago.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2009
- Accession Number
- ADA527199
Entities
People
- Craig Lee
- Michael C. Gregg
Organizations
- University of Washington