Sunday 21st Oct, 2018

Data from buoys show warmer waters

Photo: A detail of LPC's buoy map; credit: LPC
Photo: A detail of LPC's buoy map; credit: LPC

A FLEET of 14 monitoring buoys deployed around Lyttelton Harbour on New Zealand’s South Island have collected data showing water temperatures in December 2017 were about five degrees warmer than the same time last year.

Dr Leonie Andersen from Vision Environment installed the buoys in September 2016 to provide baseline data on the harbours natural fluctuations before channel deepening dredging operations begin this year.

Dr Andersen said the inshore sites were always warmer and fluctuated more than the sites offshore, which are exposed to oceanic currents.

“The water temperatures within the harbour itself strongly respond to air temperatures and it was a pretty hot December,” she said.

“We can see the water temperature cycling during the day – heating during the day and cooling at night. Sometimes it can vary up to five degrees in 24 hours.”

Dr Andersen said the monitoring system was commissioned so Lyttelton Port Corporation could manage its dredging in real time.

“But, what we’re learning about the harbour is amazing for science,” she said.

“Prior to this, the harbour had only a few data points, but we’ve been gathering so much information on currents, water chemistry and sedimentation.”

The buoys send data via 3G networks every 30 minutes, which is publically available on the LPC website.

LPC environment manager Kim Kelleher hopes that giving the public access to the data will stimulate interest in the local marine environment.

“We’re learning a lot about how the harbour functions and what the natural variations look like,” she said.

“Data is able to be viewed by the public in real time on a custom built viewing platform at the same time as LPC, without a delay. It’s really interesting when there’s some sort of event going on, such as a big southerly or a pumping swell.”

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