UNB News
News and stories from one of Canada’s top universities

UNB geodesy group ends half-century long scientific debate

Author: UNB Newsroom

Posted on Nov 1, 2022

Category: UNB Fredericton

A geodesy and geomatics engineering team at the University of New Brunswick (UNB) ended a half-century scientific debate at an international conference in Italy this past summer.

For years, the International Association of Geodesy has struggled to agree on whether to use geoid or quasi-geoid to represent the mean sea level on land where the separation between the two surfaces is as large as four meters.

"In geodesy, we consider an idealized mean sea level to have a height equal to zero - that is what we call the geoid,” said Dr. Marcelo Santos, geodesy and geomatics engineering professor at UNB.

Representatives from the UNB geodesy group have been a driving force behind convincing the world to abandon the use of a quasi-geoid and adopt the geoid to establish a functional height system grounded in physics.

“The use of a quasi-geoid causes real problems from a physical and mathematical point of view because the quasi-geoid is not a physical surface; it has folds and is quite rough,” added Santos.

A geoid is a physical horizontal sea level surface reference that can extend through oceanic areas and land masses. Think of it as an imaginary line that details the shape of the ocean surface if other influences such as winds and tides, were absent. It helps us understand the earth's internal structure and allows scientists to measure surface elevation and the depth of earthquakes or other deep items more accurately beneath the earth’s surface.

“Details matter. What seems like a small change makes a big impact when a climatologist is trying to measure the temperature of the atmosphere, or an engineer is measuring the height of structures,” said Santos. “It’s innately important to have accurate measurements. Otherwise, we may not know the full extent of a phenomena, such as global warming.”

Dr. Santos has been a faculty member of the department of geodesy and geomatics engineering at UNB since 2000.

In the department of geodesy and geomatics engineering, Santos holds the flag of geodesy and he is a member of many organizations, including the International Association of Geodesy, the Canadian Institute of Geomatics, and the Association of Professional Engineers and Geoscientists of New Brunswick.

“I am extremely proud of UNB’s geodesy and geomatics team, and I am thankful for the scientists worldwide who have supported us, particularly our Czech and Italian colleagues,” said Santos. “This is an exciting moment in history for the science community at UNB and in Canada.”

Media contact: Kathleen McLaughlin