South’s clean air ideal for cloud study
‘‘Cloud formation over the Southern Ocean is one of the biggest gaps in our knowledge of climate modelling.’’
Guy Coulson
A team of scientists has gathered in the deep south to try to close a knowledge gap about how clouds form over the Southern Ocean.
Researchers and scientists from Germany, Niwa and the universities of Auckland and Canterbury are spending three weeks at a site overlooking Te Waewae Bay, about 50km west of Invercargill, to do a series of experiments.
Niwa principal scientist and project manager Guy Coulson said the consortium was studying aerosols – tiny airborne particles, some of which are generated from the ocean – that take part in cloud formation.
‘‘Cloud formation over the Southern Ocean is one of the biggest gaps in our knowledge of climate modelling,’’ he said.
‘‘There’s a difference between what the satellite measurements are showing us and what the modelling is telling us.’’
In a bid to close the knowledge gap, the scientists are using a variety of instruments to measure the aerosol particles coming off the sea and track them all the way to the clouds.
A laser beam is used to bounce off the aerosol particles in the air, measuring how far away and how big they are, and tethered balloons with instruments attached are also measuring the aerosols.
‘‘From that we can get a picture of how the aerosols generated by the sea end up at cloud level to form some of the clouds.’’
The findings will be handed to modellers to determine the amount of aerosols being generated and how much of them make up the clouds.
‘‘It will give us more accurate information on what causes clouds to form [over the Southern Ocean] and what conditions cause different amounts of cloud cover.’’
The amount of cloud cover influences the amount of radiation from the Sun onto Earth.
‘‘That’s how it affects the climate modelling and the greenhouse effects,’’ Coulson said.
The area, near Monkey Island between Riverton and Tuatapere, was chosen because its air was clean and it was as close to the Southern Ocean as the scientists could be without getting wet feet.
Most of the funding for the work was coming from German institutes, which had researchers on the ground with the Kiwis.
‘‘There’s an increasing interest globally in the Southern Ocean, from a climate point of view, because it’s the least well understood. That’s why we have got people from Germany coming from halfway around the world,’’ Coulson said.
Great South strategic projects manager Stephen Canny said the regional development agency was an advocate for building knowledge relating to climate change and he applauded the research.
The effect of increases in atmospheric moisture was critically important as water vapour was Earth’s most abundant greenhouse gas, Canny said.
‘‘It’s responsible for about half of Earth’s greenhouse effect. Understanding wider impacts, as well as rainfall intensity, is critically important for understanding . . . local impacts on our industries, farming and communities.’’