Visiting Scientist from Japan Collaborating on Shoreline-Change Research

This article is part of the April-May 2018 issue of the Sound Waves newsletter.  

Coastal engineer Masayuki Banno is spending a year-long sabbatical with the USGS Pacific Coastal and Marine Science Center in Santa Cruz, California. He is working with the coastal-change group, led by research geologist Patrick Barnard, using their beach-survey data to test and improve his model for predicting how beaches will respond to sea-level rise and changing storm-wave patterns.

Since 2009, Masayuki has been a research scientist with Japan’s Port and Airport Research Institute (PARI), a government agency similar to the USGS. While working with PARI, he earned a Ph.D. degree in engineering from Kyushu University, awarded in 2016. Masayuki is stationed at the agency’s headquarters in Yokosuka and commutes once a week to its Hazaki Oceanographical Research Station on the Hasaki coast, a 16-kilometer (10-mile) stretch along the Pacific Ocean (see map, below). As a senior researcher in PARI’s Coastal and Estuarine Sediment Dynamics Group, he studies short-term beach response to waves, as well as processes that drive long-term coastal change.

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Among Masayuki’s recent projects is the development of a mathematical model for predicting shoreline change, which he calibrated with data from a long-term study at the Hazaki Oceanographical Research Station. The station includes a pier about 400 meters (1,300 feet) long. In 1986, station personnel began measuring the beach profile along the pier every workday; in April 2011, the interval was changed to once a week. To measure depths to the sand beneath the water, the scientists lower a lead-weight line from the pier (see photo). They use a surveyor’s level and staff to measure sand elevations on the shore. This study continues to produce a rich dataset documenting changes to the beach’s shape and the position of its shoreline.

Masayuki used this dataset as he developed his shoreline-change model, which accounts for the effects of both waves and sea-level rise. Then he used the model to project future shoreline change on the Hasaki coast under various scenarios of sea-level rise and changes in wave patterns expected from global climate change. The model forecasts that, on average, the shoreline will move landward about 30 meters (100 feet) by the year 2095. Additionally, waves will reach higher elevations, and erosion will be more severe than at present.

These findings are specific to the Hasaki coast. Masayuki’s goal at the USGS is to use data from other beaches to generalize the model so it can project shoreline change on various coasts around the globe and help communities plan for climate change. He is working, for example, with measurements that Patrick Barnard’s team has been collecting since 2004 from San Francisco’s Ocean Beach during regular onshore and nearshore mapping surveys.

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Masayuki and Patrick have worked together before; Masayuki was a co-author on a Nature Geoscience paper led by Barnard that drew on data from around the Pacific Ocean—including the long-term study at the Hazaki Oceanographical Research Station—to show that El Niño and La Niña events are the dominant force behind coastal erosion and flooding hazards across the entire Pacific region.

“Masayuki is a talented young researcher who is developing cutting-edge shoreline-change models through collaborations worldwide, including common colleagues in Australia and France,” says Patrick. “Our work together is part of the Coastal Climate Impacts project’s ongoing effort to bring the best and brightest researchers together to ensure we are developing the most robust scientific products possible.”