Mapping ‘ocean weather’ with ocean robots. A Cafe Scientifique with Joanne O’Callaghan

Date/Time
Date(s) - Thu 28 September
18:00 - 19:30

Location
Wholly Bagels, Knights Road, Lower Hutt


We live in a data-rich world where access to instant information is the rule, not the exception. This paradigm cannot yet be applied to the marine environment around NZ, despite it being the ‘backyard’ for 75% of the population. ‘Shelf seas’ are regions of the ocean where water depths are less than 200 m. Around NZ, this can span open coastlines through to shallower harbours, and is where most marine economic and societal activity takes place. Ocean flows in shelf seas are a balance between processes such as river flows, tides, wind mixing and surface heating at the main boundaries. The way these processes interact varies in space and time, causing ocean flows and stratification. These pathways moving through the ocean are therefore complex, three dimensional and are considered ‘ocean weather’. Ocean stratification – layers of temperature and salinity below the surface – is one of the big unknowns in understanding how the shelf seas ‘work’, yet it is critical for knowing how and where sediment, nutrients or biological material are (re)distributed by ocean flows. Using underwater gliders (autonomous vehicles that map ocean stratification below the surface of the ocean), we are starting to unravel the complexities of shelf sea processes. Ocean gliders are essential elements towards a real-time ocean observation network for NZ.

Joe O’Callaghan is an oceanographer at NIWA, and has worked on a broad range of projects, e.g. fish farms in the Marlborough Sounds, tailrace flows from the Manapouri hydro-electric power station in Doubtful Sound, and continental shelf dynamics on the West Coast of the South Island. She has led numerous observational campaigns around NZ, on small coastal vessels through to NIWA’s RV Tangaroa. She primarily adopts an observational approach to better understand regions of the ocean where people work and play. The latest observational tool Joe is working with are underwater gliders, which are emerging at the forefront of ocean science for NZ.