Dr Jen-ping Peng¹, Dr. Nicole Jones¹, Dr. Matt Rayson¹, Dr. Gregory Ivey¹, Dr. Shane Keating², Dr. Callum Shakespeare³

¹UWA, Perth, Australia, ²University of New South Wales, Sydney, Australia, ³Australian National University, Canberra, Australia

Satellites now provide unprecedented spatial resolution of sea surface temperature, revealing small-scale fronts and eddies with strong lateral density gradients. These small-scale physical processes are frequently observed in the surface mixed layer of the ocean and are crucial to dynamics and primary production in the open ocean, coastal seas, and rivers due to their importance for turbulent mixing, vertical transport of tracers, and mixed layer restratification, however, they have been neglected until recent decades, leaving them largely unresolved in the current operational and climate models. To this end, a better understanding of these small-scale processes is critical.

Here, we used a combination of an IMOS ocean glider, an IMOS mooring, a ship-based ADCP, and satellite products to capture the fine-resolution spatial, temporal, and vertical variability of small-scale fronts and eddies on the Northwest Shelf. The observations show that when fronts are forced by down-front winds, frontal Ekman dynamics are triggered, which transport dense over light waters, resulting in frontal instability. These instabilities will cause further turbulence and mixing, which is capable of both transporting nutrient-rich waters from subsurface layers up into the light-rich surface layer, stimulating primary production, and transporting dissolved substances downward (such as carbon and oxygen). This frontal turbulent mixing eventually triggers a vigorous exchange of tracers between the atmosphere, ocean surface, and interior, as revealed by the spatial variability of satellite chlorophyll-a.

Biography:

Dr. Jen-Ping Peng, a sea-going physical oceanographer, is currently working in the research group of Prof. Nicole Jones at the Ocean Graduate School at the University of Western Australia. His general research interests include fronts and eddies, turbulence and mixing, air-sea interactions, and oceanic and coastal freak waves. He performs his research using a variety of techniques, including field measurements, satellite images, theoretical modeling, and machine learning modeling. He just relocated to Perth from Germany in February of this year and is eager to establish a local scientific and industrial network.