Ocean holds clues to climate change
For many of us, the temperature of the ocean simply determines whether or not we go for a quick dip or opt for lazing on the beach instead.
However, for a group of scientists who have been measuring the temperature of the Tasman Sea for the past two weeks, the temperature of the ocean has much greater significance.
The scientists from Australia and New Zealand have been measuring the temperature, salinity, and dissolved oxygen content of the Tasman Sea at depths of between 0-5000 m, to try and understand how ocean temperature affects our climate.
The crew and scientific staff, including three New Zealanders from the National Institute of Water and Atmospheric Research (NIWA), arrived at Aotea Quay in Wellington Harbour this week on board the Australian marine research vessel Franklin - the first time the vessel has visited our shores for many years. Their voyage from Sydney to Wellington is one of three voyages planned by Australia’s largest scientific and industrial research organisation, CSIRO, to study ocean climate.
"The ocean makes up half of the global climate system," says NIWA scientist Phil Sutton. "It’s important, therefore, that we measure temperature variations in the ocean so we can understand variations in our climate."
Oceans store and transport vast amounts of heat - the top 2.5 m depth of water can store as much heat as the entire atmosphere.
"In New Zealand, the state of the Tasman Sea is especially important because our prevailing westerly winds have to cross the Tasman before reaching us."
The measurements from this voyage will contribute to an ongoing United States, Australia, and New Zealand programme measuring the temperature in the upper ocean in the Tasman Sea. As part of this programme, the temperature between the surface and 800 m between Sydney and Wellington has been measured from container ships about four times each year since 1991.
Franklin left Wellington yesterday bound for Tonga, and then to Fiji, and on to Brisbane, completing a full circuit of the Tasman Sea. The scientists will take similar measurements on route.
