Thu, Oct 03, 2019 - Page 2 News List

Team makes Kuroshio ocean current discovery

NEW ERA:The NTU team was able to learn more about the ocean with fewer personnel, by using US-made Seagilders that even the military is unable to purchase

By Lin Chia-nan  /  Staff reporter

A team of researchers, including National Taiwan University Institute of Oceanography director Jan Sen, second right, pose with a Seaglider, a US-made uncrewed underwater vehicle, at the Ministry of Science and Technology in Taipei yesterday.

Photo: Chien Hui-ju, Taipei Times

A team of oceanographers from National Taiwan University (NTU) yesterday unveiled the first observations of the Kuroshio Current’s interleaving structures made using a Seaglider, a US-made uncrewed underwater vehicle that they hope will usher in a new era for oceanography studies in Taiwan.

While layered hydrographic structures are often observed in waters with less velocity, such as in the Arctic Ocean and currents near the equator, the team is the first to document such structures in the Kuroshio east of Taiwan, NTU Institute of Oceanography director Jan Sen (詹森) told a news conference at the Ministry of Science and Technology in Taipei.

As part of its long-term observations of the Kuroshio since 2012, the team operated a Seaglider to complete 434 dives down to a depth of 1,000m from December 2016 to March 2017 and obtained high-resolution hydrographic data, Jan said.

They found that two dissimilar water masses within the 500m to 800m part of the Kuroshio do not blend quickly; rather, their contact gives rise to interleaving layers with varying salinity levels and temperatures, revolutionizing their concepts about the Kuroshio, the hydrological layers of which are not as smooth as they had presumed, he said.

The layered underwater structures would not affect rescue efforts, maritime construction or the operation of submarines, as the missions mostly occur 100m to 200m underwater, he said.

The team detailed their findings in a paper published in the journal Scientific Reports on Aug. 6.

It was the first time that Taiwanese oceanographers have made their own Seaglider observations, Jan said.

Thanks to the ministry’s funding, the institute purchased the nation’s two Seagliders for NT$6.5 million (US$209,252) each, he said, adding that he needed “export licenses” from the US Department of Commerce to import the vehicles due to the sensitive nature of the procurements.

Able to work in water for up to nine months, the energy-efficient Seagilders enabled the team to learn more about the ocean and improved global climate change projections using fewer personnel, he said, adding that team members had to constantly monitor the vehicles online.

Coupled with the institute’s buoys for monitoring typhoons and the nation’s ocean research vessels, the gliders would bring Taiwanese oceanography to a new level with increasing demand for driverless vehicles, Jan said.

Even the nation’s military cannot purchase such gliders, so it is significant that the institute has cultivated a team for operating the vehicles and managing related data, said Chiang Kuo-ping (蔣國平), convener of oceanography program under the ministry’s Department of Natural Sciences and Sustainable Development.

Chiang said that a similar vehicle once caused tension between China and the US when a Chinese naval vessel in 2016 intercepted a glider owned by a US survey ship in international waters near the Philippines, which was resolved after the Chinese government returned the glider to the US.

Data collected by the gliders are protected and regulated by the government, especially those collected within territorial waters, Jan added.

The team is also part of the global OceanGliders Boundary Ocean Observing Network set up by the Joint Technical Commission for Oceanography and Marine Meteorology, an intergovernmental body under UNESCO and the World Meteorological Organization.

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